This work was supported by the National Institutes of Health (P30GM103486).

<ol>
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B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Alpaca+(Lama+pacos)+as+a+convenient+source+of+recombinant+camelid+heavy+chain+antibodies+(VHHs).">Alpaca (Lama pacos) as a convenient source of recombinant camelid heavy chain antibodies (VHHs).</a> Journal of Immunological Methods. 324 (1-2), 13-25 (2007).</li><li>Pardon, E., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+general+protocol+for+the+generation+of+Nanobodies+for+structural+biology.">A general protocol for the generation of Nanobodies for structural biology.</a> Nature Protocols. 9 (3), 674-693 (2014).</li><li>Hertveldt, K., Belien, T., Volckaert, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=General+M13+phage+display:+M13+phage+display+in+identification+and+characterization+of+protein-protein+interactions.">General M13 phage display: M13 phage display in identification and characterization of protein-protein interactions.</a> Methods in Molecular Biology. 502, 321-339 (2009).</li><li>Kushwaha, R., Schafermeyer, K. R., Downie, A. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+protocol+for+phage+display+and+affinity+selection+using+recombinant+protein+baits.">A protocol for phage display and affinity selection using recombinant protein baits.</a> Journal of Visualized Experiments. (84), e50685 (2014).</li><li>Hamers-Casterman, C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Naturally+occurring+antibodies+devoid+of+light+chains.">Naturally occurring antibodies devoid of light chains.</a> Nature. 363 (6428), 446-448 (1993).</li><li>Muyldermans, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Camelid+immunoglobulins+and+nanobody+technology.">Camelid immunoglobulins and nanobody technology.</a> Veterinary Immunology and Immunopathology. 128 (1-3), 178-183 (2009).</li><li>Muyldermans, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nanobodies:+natural+single-domain+antibodies.">Nanobodies: natural single-domain antibodies.</a> Annu Rev Biochem. 82, 775-797 (2013).</li><li>Muyldermans, S., Cambillau, C., Wyns, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Recognition+of+antigens+by+single-domain+antibody+fragments:+the+superfluous+luxury+of+paired+domains.">Recognition of antigens by single-domain antibody fragments: the superfluous luxury of paired domains.</a> Trends in Biochemical Sciences. 26 (4), 230-235 (2001).</li><li>Wang, Y., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nanobody-derived+nanobiotechnology+tool+kits+for+diverse+biomedical+and+biotechnology+applications.">Nanobody-derived nanobiotechnology tool kits for diverse biomedical and biotechnology applications.</a> International Journal of Nanomedicine. 11, 3287-3303 (2016).</li><li>Van Saun, R. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nutritional+requirements+and+assessing+nutritional+status+in+camelids.">Nutritional requirements and assessing nutritional status in camelids.</a> Veterinary Clinics of North America: Food Animal Practice. 25 (2), 265-279 (2009).</li><li>Jones, M., Boileau, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Camelid+herd+health.">Camelid herd health.</a> Veterinary Clinics of North America: Food Animal Practice. 25 (2), 239-263 (2009).</li><li>Daley, L. P., Gagliardo, L. F., Duffy, M. S., Smith, M. C., Appleton, J. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Application+of+monoclonal+antibodies+in+functional+and+comparative+investigations+of+heavy-chain+immunoglobulins+in+new+world+camelids.">Application of monoclonal antibodies in functional and comparative investigations of heavy-chain immunoglobulins in new world camelids.</a> Clinical and Diagnostic Laboratory Immunology. 12 (3), 380-386 (2005).</li><li>Romao, E., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Identification+of+Useful+Nanobodies+by+Phage+Display+of+Immune+Single+Domain+Libraries+Derived+from+Camelid+Heavy+Chain+Antibodies.">Identification of Useful Nanobodies by Phage Display of Immune Single Domain Libraries Derived from Camelid Heavy Chain Antibodies.</a> Current Pharmaceutical Design. 22 (43), 6500-6518 (2016).</li><li>Henry, K. A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Isolation+of+TGF-beta-neutralizing+single-domain+antibodies+of+predetermined+epitope+specificity+using+next-generation+DNA+sequencing.">Isolation of TGF-beta-neutralizing single-domain antibodies of predetermined epitope specificity using next-generation DNA sequencing.</a> Protein Engineering, Design and Selection. 29 (10), 439-443 (2016).</li><li>Burg, J. S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Structural+biology.+Structural+basis+for+chemokine+recognition+and+activation+of+a+viral+G+protein-coupled+receptor.">Structural biology. Structural basis for chemokine recognition and activation of a viral G protein-coupled receptor.</a> Science. 347 (6226), 1113-1117 (2015).</li><li>Wesolowski, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Single+domain+antibodies:+promising+experimental+and+therapeutic+tools+in+infection+and+immunity.">Single domain antibodies: promising experimental and therapeutic tools in infection and immunity.</a> Medical Microbiology and Immunology. 198 (3), 157-174 (2009).</li><li>Harmsen, M. M., De Haard, H. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Properties,+production,+and+applications+of+camelid+single-domain+antibody+fragments.">Properties, production, and applications of camelid single-domain antibody fragments.</a> Applied Microbiology and Biotechnology. 77 (1), 13-22 (2007).</li><li>McMahon, C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Yeast+surface+display+platform+for+rapid+discovery+of+conformationally+selective+nanobodies.">Yeast surface display platform for rapid discovery of conformationally selective nanobodies.</a> Nature Structural &amp; Molecular Biology. 25 (3), 289-296 (2018).</li></ol>

Drs. Whiteheart and Hersh are at the University of Kentucky and operate a core in the Center for Molecular Medicine that produces single domain antibodies in alpaca as a fee-for-service.

As noted, the high affinity and specificity of single domain antibodies, combined with their facile expression and stability, make them ideal reagents for the applications in biomedical research, as critical biochemical reagents, diagnostic tools, or therapeutic agents18. For commercial applications, there are some issues related to intellectual property that must be considered. Additionally, single domain antibodies can be engineered to contain specific markers or tags that can be used as reporters in cellular assays or in diagnostics. The key to these uses is the ability to produce specific single domain antibodies against the antigens of interest. A method is described here to produce single domain antibodies using alpacas, which produces a robust immune response against a wide variety of protein antigens. Considerations for animal handling and regulatory compliance are described. These are key for the success in this part of the process.
There are other strategies for producing single domain antibodies that do not require the immunization, but instead use semisynthetic libraries with different systems for the selection and iterative optimization of affinities19,20. However, the advantage of using libraries derived from immunized animals is the ability to reliably isolate highly enriched, diverse, and high-affinity single domain antibodies. Additionally, not only are significant sequence variations observed, but a significant majority of specific single domain antibodies isolated had unique insertions and deletions, particularly in CDR3. 
Further, single domain antibodies can be produced via a straightforward process that only requires small injections of the antigen, and after this process, the animals can be returned to the herd. Of note, the animal can be freely used for fiber production, but must be excluded from use as meat (human food chain) due to the use of the test antigens and non-FDA approved adjuvant for single domain antibody production. When the procedure is completed, the animals should be monitored for one week, given a final veterinary exam, and then can be either returned to their home farm or rested for six months prior to another round of single domain antibody production.

Alpacas, and other members of the camelid family, have become a popular source for generating antibodies for biomedical research1,2,3. Camelids have a unique immune system in that they produce both normal antibodies as well as heavy-chain only antibodies which allow the production of much smaller single domain antibodies, while retaining high specificity and high affinity. Thus, camelid antibodies provide a versatile reagent useful for a variety of purposes. A method to immunize alpaca and produce single domain antibodies to a variety of protein antigens is here described. These antibodies can be produced in camelids via a relatively straightforward process that only requires the immunization via small injections of the target protein (antigen) and a blood draw4. Subsequently, library construction, M13 phage display5 and panning versus the recombinant antigen6 is used to isolate and produce single domain antibodies with the desired characteristics. Because the process takes advantage of the power of phage display technology, five or more antigens can be simultaneously utilized per animal, thereby reducing the number of animals used and associated costs.
Typical mammalian antibodies or immunoglobulins are large molecules consisting of two types of chains (2 heavy chains and 2 light chains), which are linked together through disulfide bonds. These antibodies are relatively large, exhibiting molecular weights of ~140-190 kDa for the more abundant IgG species from humans, mice, goats, and rabbits. Due to their multi-subunit structure, high molecular weight, and disulfide bonds, immunoglobulins can be rather challenging to produce in large quantities, making their cost high. In the 1990&#39;s, it was discovered that camelids, which includes camels, llamas and alpacas make, in addition to the typical mammalian type immunoglobulin, a novel form of immunoglobulin that is simpler in structure, possessing only heavy chains7. These unique camelid antibodies possess the same ability to specifically bind foreign substances with high affinity but are only made up of one protein chain8. Furthermore, camelid antibodies can be experimentally truncated to an even smaller unit the VHH fragment, also called a single domain antibody9. Due to their small size, single domain antibodies are useful for a wide range of biomedical research applications and are available from a variety of academic and commercial sources1,10. An exception appears to be Western blotting since single domain antibodies are more often directed against conformation dependent epitopes, which are usually lost under the denaturing conditions used in Western blots.
Since they are made up of a single polypeptide chain, specific single domain antibodies can be selected and easily produced in large quantities as recombinant proteins in bacteria. Single domain antibodies can also be genetically engineered to contain specific markers or tags that can be used as &#34;reporter groups&#34; for diagnosing diseases11. This ease of manipulation coupled with their flexibility of use makes single domain antibodies an important resource for researchers at universities and elsewhere.
As part of a National Institutes of Health supported core, existing methods have been adapted to produce single domain antibodies from alpacas3,4. Alpacas have significant advantages in both ease of handling relative to larger camelid family members as well as accessibility. Alpacas are widely raised for fiber and meat and thus can be obtained regionally from local alpaca farmers, who can be identified through their websites or through state breeder associations. Two breeds of alpacas are available, Suri and Huacaya. Huacaya are more common and were used for this protocol, but the protocol is generally applicable to either breeds and also more widely applicable to other camelids.

<table><tbody><tr><td>GERBU FAMA adjuvant</td><td>Biotechnik, Heidelberg, Germany&amp;nbsp;</td><td>3003,6001</td><td></td></tr><tr><td>Serum collection tube</td><td>Becton Dickinson</td><td>367983</td><td></td></tr><tr><td>Blood collection tube</td><td>Becton Dickinson</td><td>366643</td><td></td></tr><tr><td>Vacutainer blood collection set</td><td>Becton Dickinson</td><td>368652</td><td></td></tr><tr><td>Maxisorp Immuno plates</td><td>Nunc</td><td>439454</td><td></td></tr><tr><td>BSA</td><td>Sigma-Aldrich</td><td>A7906</td><td></td></tr><tr><td>HRP-conjugated goat anti-llama IgG antibody&amp;nbsp;</td><td>Bethyl Labs</td><td>A160-100P</td><td></td></tr><tr><td>TMB reagent chromogenic peroxidase substrate&amp;nbsp;</td><td>KPL</td><td>50-76-03</td><td></td></tr><tr><td>Plate Reader</td><td>Spectramax</td><td>M5</td><td>Any UV/VIS capable reader is acceptable</td></tr><tr><td>Uni-SepMAXI+ lyphocyte separation tube</td><td>Novamed</td><td>U-17</td><td></td></tr><tr><td>RNeasy Mini Kit</td><td>Qiagen</td><td>74104</td><td></td></tr><tr><td>QIAshredder column</td><td>Qiagen</td><td>79654</td><td></td></tr><tr><td>Superscript IV reverse transcriptase&amp;nbsp;&amp;nbsp;</td><td>Invitrogen</td><td>18064014</td><td></td></tr><tr><td>AEBSF solution</td><td>Biosynth</td><td>A-5440</td><td></td></tr><tr><td>TG1 phage display competent cells</td><td>Lucigen</td><td>60502</td><td></td></tr></tbody></table>

immunization of alpacas (lama pacos) with protein antigens and production of antigen-specific single domain antibodies

In this manuscript, a method for the immunization of alpaca and the use of molecular biology methods to produce antigen-specific single domain antibodies is described and demonstrated. Camelids, such as alpacas and llamas, have become a valuable resource for biomedical research since they produce a novel type of heavy chain-only antibody which can be used to produce single domain antibodies. Because the immune system is highly flexible, single domain antibodies can be made to many different protein antigens, and even different conformations of the antigen, with a very high degree of specificity. These features, among others, make single domain antibodies an invaluable tool for biomedical research. A method for the production of single domain antibodies from alpacas is reported. A protocol for immunization, blood collection, and B-cell isolation is described. The B-cells are used for the construction of an immunized library, which is used in the selection of specific single domain antibodies via panning. Putative specific single domain antibodies obtained via panning are confirmed by pull-down, ELISA, or gel-shift assays. The resulting single domain antibodies can then be used either directly or as a part of an engineered reagent. The uses of single domain antibody and single domain antibody-based regents include structural, biochemical, cellular, in vivo, and therapeutic applications. Single domain antibodies can be produced in large quantities as recombinant proteins in prokaryotic expression systems, purified, and used directly or can be engineered to contain specific markers or tags that can be used as reporters in cellular studies or in diagnostics.

The protocol presented here was utilized to generate single domain antibodies against a range of protein antigens. Five antigens were utilized per alpaca. Immune monitoring indicated that the majority of antigens showed robust response beginning at three weeks (Figure 1). Production bleeds and library construction after approximately six weeks gives the best balance for the animals that have multiple antigens injected. Two rounds of panning were performed for each antigen, and isolated colonies screened (Figure 2). Sequencing of positive colonies identified diverse single domain antibody sequences for the different antigens. For examples, three unique clones were isolated to the reference antigen Maltose Binding Protein (MBP) (Figure 3A). As is frequently observed, the single domain antibodies contain significant sequence diversity and highly variable CDR3 length (Figure 3). These features are particularly important in single domain antibody/antigen interactions as seen in the reference single domain antibody/CX3CL1 complex17 (Figure 3B).
The majority of full-length single domain antibody sequences can be expressed and purified at 1-10 mg/L of culture (Figure 4A). Because of the diversity in CDR3 length, different single domain antibodies show slight variation in molecular weight. Confirmation of direct binding and application specific performance is critical. For example, after two rounds of selection against Antigen B, a panel of single domain antibodies were identified (Figure 2). Multiple identical sequences were identified, and the single domain antibody was produced and purified. It was then tested via direct pull down with antigen affinity resin and showed robust dose-dependent binding (Figure 4B). Importantly, the single domain antibody showed no binding to control resin. These data demonstrate a direct binding interaction, and one that is well suited for affinity capture in both pull-down and ELISA-based formats.
<img alt="Figure 1" class="xfigimg" src="/files/ftp_upload/58471/58471fig1.jpg" /> 
Figure 1: Representative immune monitoring of two distinct antigens showing the significant specific immune response to distinct antigens in the same animal. Many antigens show robust response as early as three weeks after commencing immunization, with the majority showing maximal response after six weeks. Six weeks also allows for affinity maturation and is the recommended time for the production bleed and B-cell isolation. <a href="https://jove.unicartagenaproxy.elogim.com/files/ftp_upload/58471/58471fig1large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 2" class="xfigimg" src="/files/ftp_upload/58471/58471fig2.jpg" /> 
Figure 2: PCR-based confirmation of positive clones. Primers span the MCS of the pMES4 vector, and a positive nanobody clone produces an amplicon of ~500 bp (marked with *). <a href="https://jove.unicartagenaproxy.elogim.com/files/ftp_upload/58471/58471fig2large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 3" class="xfigimg" src="/files/ftp_upload/58471/58471fig3.jpg" /> 
Figure 3: Antigen-specific sequences highlight alpaca single domain antibody diversity. (A) Alignment of select single domain antibody sequences isolated to MBP with a reference single domain antibody 4XT1, with framework and complementarity-determining regions (Kabat) highlighted below. (B) Structure of alpaca single domain antibody 4XT1 bound to CX3CL1 (PDB 4XT1), emphasizing the critical role of variable CDR loops in specific antigen binding. <a href="https://jove.unicartagenaproxy.elogim.com/files/ftp_upload/58471/58471fig3large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 4" class="xfigimg" src="/files/ftp_upload/58471/58471fig4.jpg" /> 
Figure 4: Purification and validation of single domain antibodies. (A) SDS-PAGE of IMAC purified single domain antibodies, comparing diverse single domain antibodies. Different molecular weights are primarily due to varying length of the CDR3 loop. Differing levels of expression are also observed, with a minority of single domain antibodies showing poor yields of purified protein. (B) Verification of direct binding using an antigen affinity pull-down. Robust dose-dependent single domain antibody binding is observed with antigen-coupled resin but not with control resin.&#160;<a href="https://jove.unicartagenaproxy.elogim.com/files/ftp_upload/58471/58471fig4large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>

Watch this Scientific Journal Video about Immunization of Alpacas Lama pacos with Protein Antigens and Production of Antigen-specific Single Domain Antibodies at JoVE.com

Immunization of Alpacas Lama pacos with Protein Antigens and Production of Antigen-specific Single Domain Antibodies

A method for the production of single domain antibodies from alpacas, including immunization, blood collection, B-cell isolation, and selection is described.

Immunization of Alpacas (Lama pacos) with Protein Antigens and Production of Antigen-specific Single Domain Antibodies

In this manuscript, a method for the immunization of alpaca and the use of molecular biology methods to produce antigen-specific single domain antibodies ...

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23.4K Views.  University of Kentucky. A method for the production of single domain antibodies from alpacas, including immunization, blood collection, B-cell isolation, and selection is described.

Video: Immunization of Alpacas Lama pacos with Protein Antigens and Production of Antigen-specific Single Domain Antibodies

Intralymphatic Immunotherapy and Vaccination in Mice

Vaccines are typically injected subcutaneously or intramuscularly for stimulation of immune responses. The success of this requires efficient drainage of vaccine to lymph nodes where antigen presenting cells can interact with lymphocytes for generation of the wanted immune responses. The strength and the type of immune responses induced also depend on the density or frequency of interactions as well as the microenvironment, especially the content of cytokines. As only a minute fraction of peripherally injected vaccines reaches the lymph nodes, vaccinations of mice and humans were performed by direct injection of vaccine into inguinal lymph nodes, i.e.&#160;intralymphatic injection. In man, the procedure is guided by ultrasound. In mice, a small (5-10 mm) incision is made in the inguinal region of anesthetized animals, the lymph node is localized and immobilized with forceps, and a volume of 10-20 &#956;l of the vaccine is injected under visual control. The incision is closed with a single stitch using surgical sutures. Mice were vaccinated with plasmid DNA, RNA, peptide, protein, particles, and bacteria as well as adjuvants, and strong improvement of immune responses against all type of vaccines was observed. The intralymphatic method of vaccination is especially appropriate in situations where conventional vaccination produces insufficient immunity or where the amount of available vaccine is limited.

Prophylactic and therapeutic vaccination often fails to stimulate strong immune responses due to week drainage of the vaccine to lymph nodes and consequently poor involvement of immune cells. By direct injection of vaccine to lymph nodes, so-called intralymphatic injection, vaccine efficacy can be strongly improved and vaccine doses can be reduced.

Vaccines are typically injected subcutaneously or intramuscularly for stimulation of immune responses. The success of this requires efficient drainage of ...

Immunology and Infection

Generation of Murine Monoclonal Antibodies by Hybridoma Technology

Monoclonal antibodies are universal binding molecules and are widely used in biomedicine and research. Nevertheless, the generation of these binding molecules is time-consuming and laborious due to the complicated handling and lack of alternatives. The aim of this protocol is to provide one standard method for the generation of monoclonal antibodies using hybridoma technology. This technology combines two steps. Step 1 is an appropriate immunization of the animal and step 2 is the fusion of B lymphocytes with immortal myeloma cells in order to generate hybrids possessing both parental functions, such as the production of antibody molecules and immortality. The generated hybridoma cells were then recloned and diluted to obtain stable monoclonal cell cultures secreting the desired monoclonal antibody in the culture supernatant. The supernatants were tested in enzyme-linked immunosorbent assays (ELISA) for antigen specificity. After the selection of appropriate cell clones, the cells were transferred to mass cultivation in order to produce the desired antibody molecule in large amounts. The purification of the antibodies is routinely performed by affinity chromatography. After purification, the antibody molecule can be characterized and validated for the final test application. The whole process takes 8 to 12 months of development, and there is a high risk that the antibody will not work in the desired test system.

An optimized protocol is presented for the generation of monoclonal antibodies based on the hybridoma technology. Mice were immunized with an immunoconjugate. Spleen cells were fused by PEG and an electric impulse with immortal myeloma cells. Antibody-producing hybridoma cells were selected by HAT and antigen-specific ELISA screening.

Monoclonal antibodies are universal binding molecules and are widely used in biomedicine and research. Nevertheless, the generation of these binding ...

Generation of Monoclonal Antibodies Against Natural Products

The analysis of the bioactive components present in foods and natural products has become a popular area of study in many fields, including traditional Chinese medicine and food safety/toxicology. Many of the classical analysis techniques require expensive equipment and/or expertise. Notably, enzyme-linked immunosorbent assays (ELISAs) have become an emerging method for the analysis of foods and natural products. This method is based on antibody-mediated detection of the target components. However, as many of the bioactive components in natural products are small (&lt;1,000 Da) and do not induce an immune response, creating monoclonal antibodies (mAbs) against them is often difficult. In this protocol, we provide a detailed explanation of the steps required to generate mAbs against target molecules as well as those needed to create the associated indirect competitive (ic)ELISA for the rapid analysis of the compound in multiple samples. The procedure describes the synthesis of the artificial antigen (i.e., the hapten-carrier conjugate), immunization, cell fusion, monoclonal hybridoma preparation, characterization of the mAb, and the ELISA-based application of the mAb. The hapten-carrier conjugate was synthesized by the sodium periodate method and evaluated by MALDI-TOF-MS. After immunization, splenocytes were isolated from the immunized mouse with the highest antibody titer and fused with the hypoxanthine-aminopterin-thymidine (HAT)-sensitive mouse myeloma cell line Sp2/0 -Ag14 using a polyethylene glycol (PEG)-based method. The hybridomas secreting mAbs reactive to the target antigen were screened by icELISA for specificity and cross-reactivity. Furthermore, the limiting dilution method was applied to prepare monoclonal hybridomas. The final mAbs were further characterized by icELISA and then utilized in an ELISA-based application for the rapid and convenient detection of the example hapten (naringin (NAR)) in natural products.

This article provides a detailed protocol for the preparation and evaluation of monoclonal antibodies against natural products for use in various immunoassays. This procedure includes immunization, cell fusion, indirect competitive ELISA for positive clone screening, and monoclonal hybridoma preparation. The specifications for antibody characterization using MALDI-TOF-MS and ELISA analyses are also provided.

The analysis of the bioactive components present in foods and natural products has become a popular area of study in many fields, including traditional ...

Homogeneous Glycoconjugate Produced by Combined Unnatural Amino Acid Incorporation and Click-Chemistry for Vaccine Purposes

Genetic code expansion is a powerful tool to introduce unnatural amino acids (UAAs) into proteins to modify their characteristics, to study or create new protein functions or to have access to protein conjugates. Stop codon suppression, in particular amber codon suppression, has emerged as the most popular method to genetically introduce UAAs at defined positions. This methodology is herein applied to the preparation of a carrier protein containing an UAA harboring a bioorthogonal functional group. This reactive handle can next be used to specifically and efficiently graft a synthetic oligosaccharide hapten to provide a homogeneous glycoconjugate vaccine. The protocol is limited to the synthesis of glycoconjugates in a 1:1 carbohydrate hapten/carrier protein ratio but amenable to numerous pairs of biorthogonal functional groups. Glycococonjugate vaccine homogeneity is an important criterion to ensure complete physico-chemical characterization, thereby, satisfying more and more demanding drug regulatory agency recommendations, a criterion which is unmet by classical conjugation strategies. Moreover, this protocol makes it possible to finely tune the structure of the actual conjugate vaccine, giving rise to tools to address structure-immunogenicity relationships.

Genetic code expansion is applied for the introduction of an unnatural amino acid bearing a biorthogonal functional group on a carrier protein at a defined site. The biorthogonal function is further used for the site-selective coupling of a carbohydrate antigen to provide a homogeneous glycoconjugate vaccine.

Genetic code expansion is a powerful tool to introduce unnatural amino acids (UAAs) into proteins to modify their characteristics, to study or create new ...

Bioengineering

Antigenic Liposomes for Generation of Disease-specific Antibodies

Antibody responses provide critical protective immunity to a wide array of pathogens. There remains a high interest in generating robust antibodies for vaccination as well as understand how pathogenic antibody responses develop in allergies and autoimmune disease. Generating robust antigen-specific antibody responses is not always trivial. In mouse models, it often requires multiple rounds of immunizations with adjuvant that leads to a great deal of variability in the levels of induced antibodies. One example is in mouse models of peanut allergies where more robust and reproducible models that minimize mouse numbers and the use of adjuvant would be beneficial. Presented here is a highly reproducible mouse model of peanut allergy anaphylaxis. This new model relies on two key factors: (1) antigen-specific splenocytes are adoptively transferred from a peanut-sensitized mouse into a na&#239;ve recipient mouse, normalizing the number of antigen-specific memory B- and T-cells across a large number of mice; and (2) recipient mice are subsequently boosted with a strong multivalent immunogen in the form of liposomal nanoparticles displaying the major peanut allergen (Ara h 2). The major advantage of this model is its reproducibility, which ultimately lowers the number of animals used in each study, while minimizing the number of animals receiving multiple injections of adjuvant. The modular assembly of these immunogenic liposomes provides relatively facile adaptability to other allergic or autoimmune models that involve pathogenic antibodies.

Described is the preparation of antigenic liposomal nanoparticles and their use in stimulating B-cell activation in vitro and in vivo. Consistent and robust antibody responses led to the development of a new peanut allergy model. The protocol for generating antigenic liposomes can be extended to different antigens and immunization models.

Antibody responses provide critical protective immunity to a wide array of pathogens. There remains a high interest in generating robust antibodies for ...

Intranasal Immunization and Milk Collection in Studies of Maternal Immunization in New Zealand White Rabbits (Oryctolagus cuniculus)

Due to similarities in placentation and antibody transfer with humans, rabbits are an excellent model of maternal immunization. Additional advantages of this research model are the ease of breeding and sample collection, relatively short gestation period, and large litter sizes. Commonly assessed routes of immunization include subcutaneous, intramuscular, intranasal, and intradermal. Nonterminal sample collection for the chronological detection of the immunologic responses to these immunizations include the collection of blood, from both dams and kits, and milk from the lactating does. In this article, we will demonstrate techniques our lab has utilized in studies of maternal immunization in New Zealand White rabbits (Oryctolagus cuniculus), including intranasal immunization and milk collection.

Intranasal Immunization and Milk Collection in Studies of Maternal Immunization in New Zealand White Rabbits Oryctolagus cuniculus

This article describes and demonstrates the administration of intranasal vaccines and the collection of milk from lactating rabbits (Oryctolagus cuniculus) as a means to assess mucosal immunity in a translationally appropriate model of maternal immunization.

Due to similarities in placentation and antibody transfer with humans, rabbits are an excellent model of maternal immunization. Additional advantages of ...

Production of Monoclonal Antibodies Targeting Aminopeptidase N in the Porcine Intestinal Mucosal Epithelium

Porcine aminopeptidase N (APN), a membrane-bound metallopeptidase abundantly present in small intestinal mucosa, can initiate a mucosal immune response without any interference such as low protein expression, enzyme inactivity, or structural changes. This makes APN an attractive candidate in the development of vaccines that selectively target the mucosal epithelium. Previous studies have shown that APN is a receptor protein for both enterotoxigenic Escherichia coli (E. coli) F4 and transmissible gastroenteritis virus. Thus, APN shows promise in the development of antibody-drug conjugates or novel vaccines based on APN-specific antibodies. In this study, we compared production of APN-specific monoclonal antibodies (mAbs) using traditional hybridoma technology and recombinant antibody expression method. We also established a stably transfected Chinese hamster ovary (CHO) cell line using pIRES2-ZSGreen1-rAbs-APN and an E. coli expression BL21(DE3) strain harboring the pET28a (+)-rAbs-APN vector. The results show that antibodies expressed in pIRES2-ZSGreen1-rAbs-APN-CHO cells and mAbs produced using hybridomas could recognize and bind to the APN protein. This provides the basis for further elucidation of the APN receptor function for the development of therapeutics targeting different APN-specific epitopes.

The recombinant antibody protein expressed in pIRES2-ZSGreen1-rAbs-APN-CHO cells and monoclonal antibodies produced using traditional hybridoma technology can recognize and bind to the porcine aminopeptidase N (APN) protein.

Porcine aminopeptidase N (APN), a membrane-bound metallopeptidase abundantly present in small intestinal mucosa, can initiate a mucosal immune response ...

Production of Adeno-Associated Virus Vectors in Cell Stacks for Preclinical Studies in Large Animal Models

Adeno-associated virus (AAV) vectors are among the most clinically advanced gene therapy vectors, with three AAV gene therapies approved for humans. Clinical advancement of novel applications for AAV involves transitioning from small animal models, such as mice, to larger animal models, including dogs, sheep, and nonhuman primates. One of the limitations of administering AAV to larger animals is the requirement for large quantities of high-titer virus. While suspension cell culture is a scalable method for AAV vector production, few research labs have the equipment (e.g., bioreactors) or know how to produce AAV in this manner. Moreover, AAV titers are often significantly lower when produced in suspension HEK 293 cells as compared to adherent HEK293 cells. Described here is a method for producing large quantities of high-titer AAV using cell stacks. A detailed protocol for titering AAV as well as methods for validating vector purity are also described. Finally, representative results of AAV-mediated transgene expression in a sheep model are presented. This optimized protocol for large-scale production of AAV vectors in adherent cells will enable molecular biology laboratories to advance the testing of their novel AAV therapies in larger animal models.

Here we provide a detailed procedure for large-scale production of research-grade AAV vectors using adherent HEK 293 cells grown in cell stacks and affinity chromatography purification. This protocol consistently yields &#62;1 x 1013 vector genomes/mL, providing vector quantities appropriate for large animal studies.

Adeno-associated virus (AAV) vectors are among the most clinically advanced gene therapy vectors, with three AAV gene therapies approved for humans. ...

Antibody Generation: Producing Monoclonal Antibodies Using Hybridomas

Source: Frances V. Sjaastad1,2, Whitney Swanson2,3, and Thomas S. Griffith1,2,3,4 
1 Microbiology, Immunology, and Cancer Biology Graduate Program, University of Minnesota, Minneapolis, MN 55455 
2 Center for Immunology, University of Minnesota, Minneapolis, MN 55455 
3 Department of Urology, University of Minnesota, Minneapolis, MN 55455 
4 Masonic Cancer Center, University of Minnesota, Minneapolis, MN 55455
Polyclonal antibodies are defined as a collection of antibodies directed against different antigenic determinants of an antigen or several antigens (1). While polyclonal antibodies are powerful tools for identifying biological molecules, there is one important limitation - they are unable to distinguish between antigens that share antigenic determinants. For example, when bovine serum albumin is used to immunize an animal, B cells with different surface Ig will respond to different antigenic determinants on bovine serum albumin. The result is a mixture of antibodies in the antiserum. Because bovine serum albumin shares some epitopes with human serum albumin in evolutionarily conserved regions of the protein, this anti-bovine serum albumin antiserum will also react with human serum albumin. Therefore, this antiserum will not be useful for distinguishing between bovine and human serum albumins.
Several approaches have been taken to overcome the specificity issue of polyclonal antisera. One is by absorbing the unwanted antibodies by passing the antiserum through a chromatography column of immobilized antigens (2). This method is tedious and frequently unable to completely remove the unwanted antibodies. Another approach is to isolate individual antibody-producing B cells and expand them in culture. However, like most normal untransformed cells, B cells do not survive in long-term culture.
To overcome the inability of B cells to survive in culture, one approach is to prepare a myeloma-B cell hybridoma. In 1847, Henry Bence-Jones discovered that patients with multiple myeloma, a lymphoid tumor, produced a large quantity of antibodies (3). B cells in these patients have become malignant and grow uncontrollably. Since the malignant B cells are derived from a single clone, they are identical and produce only a single type of antibody (i.e., a monoclonal antibody, or mAb). However, most of these myeloma cells produce antibodies of unknown specificities. In 1975, by fusing a myeloma cell to a B cell, Cesar Milstein and Georges Kohler succeeded in producing a hybridoma that can be cultured indefinitely in vitro and produces an unlimited number of monoclonal antibodies of known antigenic specificity (4). The rationale behind their approach is to combine the immortal properties of the myeloma cell and the antibody producing properties of the B cell. Their technique revolutionized antibody production and provides a powerful means for identification and purification of biological molecules using monoclonal antibodies.
Generally, preparing a monoclonal antibody requires several months. The general procedure includes the following steps:
<ol>
	<li>Immunization and screening of antibody titer</li>
	<li>Fusion of antibody-producing B cells and myeloma cells</li>
	<li>Selective growth of the hybridoma</li>
	<li>Screening the hybridomas for producing the desired monoclonal antibody</li>
	<li>Cloning by limiting dilution - a process whereby cells are diluted to a concentration to statistically allow for less than 1 cell to be added to the wells of a 96-well plate. Some wells will end up with 0 cells and some will have 1 cell. The wells with seeded with 1 cell will eventually grow into a monoclonal population of cells.</li>
	<li>Growth of the hybridoma and preparation of monoclonal antibody</li>
</ol>
This protocol focuses on the last step - growth of the hybridoma and preparation of the monoclonal antibody. The antibody is purified from the culture supernatant by ammonium sulfate precipitation (often referred to as salting out) - a commonly used method of removing proteins from a solution. Proteins in solution form hydrogen bonds, along with other hydrophilic interactions, with water through their exposed polar and ionic groups. When concentrations of small, highly charged ions (such as ammonium or sulfate) are added, these groups compete with the proteins for binding to water. This removes the water molecules from the protein and decreases its solubility, resulting in precipitation of the protein.

Producing Monoclonal Antibodies Using Hybridomas

Source: Frances V. Sjaastad1,2, Whitney Swanson2,3, and Thomas S. Griffith1,2,3,4
1 Microbiology, Immunology, and Cancer Biology Graduate Program, ...

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A Hybridoma Technology for Producing Monoclonal Antibodies against a Metallopeptidase

Source: Xia, P., et al. <a href="https://appjove.unicartagenaproxy.elogim.com/v/62437">Production of Monoclonal Antibodies Targeting Aminopeptidase N in the Porcine Intestinal Mucosal Epithelium.</a> J. Vis. Exp. (2021).
This video demonstrates an assay to produce monoclonal antibodies against porcine aminopeptidase N (APN), a membrane-bound metallopeptidase, using a traditional hybridoma technology. Upon immunizing a mouse with APN, the spleen cells are harvested and fused with immortal myeloma cells to produce hybridomas. The hybridomas are then selected and proliferated using the HAT (hypoxanthine-aminopterin-thymidine) medium to produce monoclonal antibodies specific to different APN epitopes.