Development of this protocol was supported by an operating grant from CIHR (MOP97807) to SED.

No conflicts of interest to disclose.

这里我们介绍与L的EGD株雄性或雌性C57BL / 6J小鼠25 单核细胞增生如何进行基本的实验性感染的协议。该协议被建立用于研究体内 31上的IFN-γ的生产的新的小分子IS001的由先天性和适应性淋巴细胞的影响的目的。通过监测细菌清除和生存感染后，被见解将获得的这些变化中的IFN-γ如何影响主机的控制感染的能力。 议定书中考虑的关键因素<p c...

IFN-γ是一种细胞因子是介导针对细胞内病原体的免疫力和用于控制肿瘤5生长至关重要。该细胞因子在细菌耐药性的重要性在于，与IFN-γ信号传导途径的突变是高度易感分枝杆菌和沙门氏菌6人类观察是显而易见的。同样地，小鼠的缺陷型中任一的IFN-γ或电阻的IFN-γ受体表现出缺陷分枝杆菌7-9和其他细胞内病原体包括单增李斯特菌 10,11， 硕大利什曼原虫 12， 鼠伤寒沙门氏菌 13，以及某些病毒11。除了杀灭病原体，IFN-γ在防止肿瘤14宿主防御了至关重要的作用。虽然较高的生产IFN-γ的是在感染或癌症的情况下是有利的，延长生产这种细胞因子的已链接吨Ø系统性自身免疫15-17的发展和类型的加速I型糖尿病中的非肥胖型糖尿病小鼠模型18。 IFN-γ的主要来源包括NK细胞，NKT细胞，γδT细胞，T辅助1（Th1细胞）细胞和细胞毒性T淋巴细胞（CTL）的5,19,20。 IFN-γ的提高都通过先天和适应性免疫:（1）上调主要组织相容性复合体（MHC）I类和II表达，（2）提高的共刺激分子的抗原呈递细胞上的表达，（3）增强的巨噬细胞吞噬作用和促炎细胞因子和杀微生物因素（ 例如 ，一氧化氮和活性氧），（4）促进幼稚CD4 + T细胞分化成Th1细胞的效应细胞，（5）促进抗体类别转换到免疫球蛋白（ Ig）的图2a和IgG3（在小鼠），（6）诱导产生趋化因子的招募免疫细胞为i的位点nfection，和（7）增强NK细胞和CTL应答5,19。定在宿主响应于病原体和肿瘤的IFN-γ的关键重要性，重组IFN-γ已经过测试作为各种感染和恶性肿瘤（在19中综述）的处理。但是，因为IFN-γ或Th1细胞促进细胞因子白细胞介素-12（IL-12）的全身给药与副作用相关联，并且与剂量相关毒性19,21，存在开发替代策略，以增加IFN-γ的生产的兴趣免疫细胞。的新的生物制剂和小分子的发展需要在体内筛选工具来测试这种试剂是否免疫应答期间增加的IFN-γ的生产，这是否转换成有意义的生物效应，如在动物存活增加。 用革兰氏阳性菌李斯特菌的小鼠实验性感染一直器乐模型破译IFN-γ在宿主免疫对细胞内病原体1,22的作用。与病原体静脉内或腹膜内（IP）的小鼠的感染导致细菌的脾脏和肝脏，在那里他们成为驻地巨噬细胞和肝细胞中的脾3和天后4之间存在的峰细菌负载内化的快速传播感染1,3,22。 NK细胞的IFN-γ生产是巨噬细胞活化和抗病原菌3初期电阻重要;然而在高感染剂量，产生IFN-γ也可能是有害的病原体间隙23。 NKT细胞也可在脾脏和肝脏的IFN-γ的病原体2,24早期控制期间的源极和该生产已被证明是放大由其它细胞类型，包括NK细胞2 IFN-γ的生产。另一方面，后作用自适应T淋巴细胞，CD8 + T细胞在杂色丘拉尔，是调解病原体的清除和提供抗再感染1,4,22保护非常重要。 这种感染模型一直研究人员有许多原因（1综述）具有吸引力。首先，感染病原体是高度可再现的和诱导强Th1和细胞免疫应答。其次，亚致死感染期间，细菌负荷集中在其中可以容易地测量在肝和脾。第三，病原体可以安全地在生物安全等级2（BSL2）条件下处理。第四，有机物和免疫反应，它产生已经被广泛表征。最后，各种突变体和转基因品系已开发了可用于使用。 这里描述的是用于与L的EGD株C57BL / 6J小鼠的接种基本协议菌等 25和用于测量γ -干扰素重新由NK，NKT和自适应淋巴细胞感染后sponses。还描述了如何测量脾细菌负荷和肝脏亚致死感染后，用改性的LD 50剂量的病原体的感染后进行存活研究。最后，有代表性数据示的这个协议如何用于从李斯特菌感染筛选的新的治疗药物上的IFN-γ反应和小鼠存活率的影响。

<table border="0" cellpadding="0" cellspacing="0" width="923">
	<colgroup>
		<col />
		<col />
		<col />
		<col />
	</colgroup>
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:353px;">Brain Heart Infusion Broth, Modified</td>
			<td style="width:191px;">BD</td>
			<td style="width:107px;">299070</td>
			<td style="width:273px;">any brand should be appropriate</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Agar</td>
			<td>BD</td>
			<td style="width:107px;">214010</td>
			<td>any brand should be appropriate</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:353px;">Triton X-100</td>
			<td style="width:191px;">Sigma-Aldrich</td>
			<td style="width:107px;">X100</td>
			<td>any brand should be appropriate</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:353px;">1xPBS</td>
			<td style="width:191px;">Sigma</td>
			<td style="width:107px;">D8537</td>
			<td>any brand should be appropriate</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:353px;">TissueLyser II</td>
			<td style="width:191px;">Qiagen</td>
			<td style="width:107px;">85300</td>
			<td>any brand should be appropriate</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:353px;">Ammonium Chloride (NH3Cl)</td>
			<td style="width:191px;"></td>
			<td style="width:107px;"></td>
			<td>any brand should be appropriate</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:353px;">KHCO3</td>
			<td style="width:191px;"></td>
			<td style="width:107px;"></td>
			<td>any brand should be appropriate</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:353px;">Na2EDTA</td>
			<td style="width:191px;"></td>
			<td style="width:107px;"></td>
			<td>any brand should be appropriate</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:353px;">RPMI 1640</td>
			<td style="width:191px;">Gibco</td>
			<td style="width:107px;">22400089</td>
			<td>any brand should be appropriate</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:353px;">Fetal Bovine Serum&#160;</td>
			<td style="width:191px;">Gibco</td>
			<td style="width:107px;">12483</td>
			<td>Before use, heat-inactivate at 56 &#176;C for 30 min</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:353px;">L-glutamine</td>
			<td style="width:191px;">Gibco</td>
			<td style="width:107px;">25030</td>
			<td>any brand should be appropriate</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:353px;">Non-essential amino acids</td>
			<td style="width:191px;">Gibco</td>
			<td style="width:107px;">11140</td>
			<td>any brand should be appropriate</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:353px;">Penicillin/Streptomycin</td>
			<td style="width:191px;">Gibco</td>
			<td style="width:107px;">15140</td>
			<td>any brand should be appropriate</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:353px;">GolgiStop Protein Transport Inhibitor (containing Monensin)</td>
			<td style="width:191px;">BD</td>
			<td style="width:107px;">554724</td>
			<td>Use 4 &#956;l in 6 ml cell culture</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:353px;">16% Paraformaledehye</td>
			<td style="width:191px;">Electron Microscopy Sciences</td>
			<td style="width:107px;">15710</td>
			<td>Dilute to 4% PFA in ddH20 or 1xPBS</td>
		</tr>
		<tr height="25">
			<td height="25" style="height:25px;width:353px;">10 x Perm/Wash buffer</td>
			<td style="width:191px;">BD</td>
			<td style="width:107px;">554723</td>
			<td>Dilute 10x in ddH20</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:353px;">Fc block, Anti-Mouse CD16/CD32 Purified</td>
			<td style="width:191px;">eBioscience</td>
			<td style="width:107px;">14-0161</td>
			<td>Dilute 1:50</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:353px;">Fixable Viability Dye eFluor 506</td>
			<td style="width:191px;">eBioscience</td>
			<td style="width:107px;">65-0866</td>
			<td>Dilute 1:1000 (we have also used viability dyes from Molecular Probes)</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:353px;">anti-Mouse CD4-PE-Cy5 (GK1.5)</td>
			<td style="width:191px;">eBioscience</td>
			<td style="width:107px;">15-0041</td>
			<td>Manufacturer recommends a certain test size; however this should be titrated before use.</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:353px;">anti-Mouse CD8-FITC (53-6.7)</td>
			<td style="width:191px;">eBioscience</td>
			<td style="width:107px;">11-0081</td>
			<td>Manufacturer recommends a certain test size; however this should be titrated before use.</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:353px;">PBS57/mCD1d tetramer-APC</td>
			<td style="width:191px;">NIH Tetramer Core Facility</td>
			<td style="width:107px;">N/A</td>
			<td>Obtained as a gift from the facility</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">anti-Mouse TCR&#946;-PE-Cy7 (H56-597)</td>
			<td style="width:191px;">eBioscience</td>
			<td style="width:107px;">25-5961</td>
			<td>Manufacturer recommends a certain test size; however this should be titrated before use.</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">anti-Mouse NKp46-APC-eFluor780 (29A1.4)</td>
			<td style="width:191px;">eBioscience</td>
			<td style="width:107px;">47-3351</td>
			<td>Manufacturer recommends a certain test size; however this should be titrated before use.</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:353px;">anti-Mouse CD45 PE-Cyanine7 (30-F11)</td>
			<td style="width:191px;">eBioscience</td>
			<td style="width:107px;">25-0451</td>
			<td>Manufacturer recommends a certain test size; however this should be titrated before use.</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:353px;">anti-Mouse IFN gamma-PE (XMG1.2)</td>
			<td style="width:191px;">eBioscience</td>
			<td style="width:107px;">12-7311</td>
			<td>Manufacturer recommends a certain test size; however this should be titrated before use.</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:353px;">OneComp eBeads</td>
			<td style="width:191px;">eBioscience</td>
			<td style="width:107px;">01-1111</td>
			<td>Manufacturer recommends a certain test size; however this should be titrated before use.</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:353px;">Mouse IFN gamma ELISA kit</td>
			<td style="width:191px;">eBioscience</td>
			<td>88-7314</td>
			<td>Used for measuring the interferon gamma in the culture supernatant</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:353px;">50 mL vented tubes for culture</td>
			<td style="width:191px;"></td>
			<td style="width:107px;"></td>
			<td>Used for culturing the bacteria, any brand should be appropriate</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:353px;">1.5 ml microcentrifuge tubes</td>
			<td style="width:191px;"></td>
			<td style="width:107px;"></td>
			<td>any brand should be appropriate</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:353px;">bacterial petri dishes</td>
			<td style="width:191px;"></td>
			<td style="width:107px;"></td>
			<td>any brand should be appropriate</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:353px;">2 ml cyrovials</td>
			<td style="width:191px;"></td>
			<td style="width:107px;"></td>
			<td>any brand should be appropriate</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:353px;">UV spectrometer</td>
			<td style="width:191px;"></td>
			<td style="width:107px;"></td>
			<td>any brand should be appropriate</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:353px;">safety engineered needles</td>
			<td style="width:191px;"></td>
			<td style="width:107px;"></td>
			<td>any brand should be appropriate</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:353px;">C57BL6/J</td>
			<td style="width:191px;">Jackson laboratories</td>
			<td style="width:107px;">Stock#000664</td>
			<td>Order for arrival at 7 wks</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:353px;">Bleach</td>
			<td style="width:191px;"></td>
			<td style="width:107px;"></td>
			<td>For decontamination</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:353px;">70% Ethanol</td>
			<td style="width:191px;"></td>
			<td style="width:107px;"></td>
			<td>For decontamination</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:353px;">Glass beads</td>
			<td style="width:191px;"></td>
			<td style="width:107px;"></td>
			<td>any brand should be appropriate</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:353px;">Centrifuge</td>
			<td style="width:191px;"></td>
			<td style="width:107px;"></td>
			<td>rotor, buckets, bucket covers.</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:353px;">Microcentrifuge</td>
			<td style="width:191px;"></td>
			<td style="width:107px;"></td>
			<td>any brand should be appropriate</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:353px;">Sterile Glycerol</td>
			<td style="width:191px;"></td>
			<td style="width:107px;"></td>
			<td>any brand should be appropriate</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:353px;">Pipette Tips</td>
			<td style="width:191px;"></td>
			<td style="width:107px;"></td>
			<td>any brand should be appropriate</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:353px;">Pipette</td>
			<td style="width:191px;"></td>
			<td style="width:107px;"></td>
			<td>any brand should be appropriate</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:353px;">Surgical instruments</td>
			<td style="width:191px;"></td>
			<td style="width:107px;"></td>
			<td>any brand should be appropriate</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:353px;">70 micron strainers</td>
			<td style="width:191px;"></td>
			<td style="width:107px;"></td>
			<td>any brand should be appropriate</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:353px;">3 ml syringe</td>
			<td style="width:191px;"></td>
			<td style="width:107px;"></td>
			<td>any brand should be appropriate</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:353px;">Pipette gun</td>
			<td style="width:191px;"></td>
			<td style="width:107px;"></td>
			<td>any brand should be appropriate</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:353px;">Filtration Units</td>
			<td style="width:191px;"></td>
			<td style="width:107px;"></td>
			<td>any brand should be appropriate</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:353px;">Trypan Blue</td>
			<td style="width:191px;"></td>
			<td style="width:107px;"></td>
			<td>Dilute 1 to 9 in ddH20, any brand should be appropriate</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:353px;">Hemocytometer</td>
			<td style="width:191px;"></td>
			<td style="width:107px;"></td>
			<td>any brand should be appropriate</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:353px;">Round bottomed plates</td>
			<td style="width:191px;"></td>
			<td style="width:107px;"></td>
			<td>any brand should be appropriate</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:353px;">FACs tubes</td>
			<td style="width:191px;">BD</td>
			<td style="width:107px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:353px;">BD LSR II</td>
			<td style="width:191px;">BD</td>
			<td style="width:107px;"></td>
			<td>Any flow cytometer could be used for acquisition that has an appropriate laser configuration and filter set to discriminate the fluorochormes</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:353px;">Flowjo software</td>
			<td style="width:191px;">Treestar</td>
			<td style="width:107px;"></td>
			<td>Used for data analysis. Other types of data analysis software will also be appropriate</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:353px;">Multichannel pipettor (0-300 &#181;l)</td>
			<td style="width:191px;">Eppendorf</td>
			<td style="width:107px;"></td>
			<td>Used for washing cells and adding antibodies during flow cytometry staining</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:353px;">Acetic Acid</td>
			<td style="width:191px;"></td>
			<td style="width:107px;"></td>
			<td>Used for washing glass beads, any brand should be appropriate</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:353px;">Microbank Bacterial Preservation System</td>
			<td style="width:191px;">Pro-lab Diagnositics</td>
			<td style="width:107px;"></td>
			<td>Used as an alternative to glycerol stocks for long-term storage of bacteria</td>
		</tr>
	</tbody>
</table>

experimental infection with listeria monocytogenes as a model for studying host interferon-&#947; responses

李斯特菌是革兰氏阳性细菌是食源性疾病的人类的原因。与此病原体的小鼠实验性感染一直对先天性和适应性免疫细胞和特定细胞因子的抗细胞内病原体宿主免疫中的作用非常翔实。 李斯特杆菌亚致死感染期间由先天细胞的IFN-γ生产是活化的巨噬细胞和病原体1-3的早期控制很重要。此外，IFN-γ的生产由自适应存储器淋巴细胞是用于在再感染4吸先天细胞活化重要的。 单增李斯特菌感染模型从而作为一个伟大的工具调查，旨在提高IFN-γ生产的新疗法是否在体内的IFN-γ反应产生影响，并有生产性生物效应，如增加细菌清除或改善生存鼠标从感染。这里描述的是用于如何进行C57BL / 6J小鼠用单增李斯特菌的EGD株腹膜内感染和流式细胞测量IFN-γ的生产由NK细胞，NKT细胞，和自适应淋巴细胞由流动的基本协议。另外，程序被描述为:（1）生长和用于接种制备的细菌，（2）测量在脾脏和肝脏，以及端点（3）测量动物存活的细菌负荷。还提供了有代表性的数据来说明这个感染模型如何可以用来测试特定剂对IFN-γ反应， 单增李斯特菌 ，并从该感染的小鼠的存活率的影响。

图3显示在24小时后的感染细胞计数的IFN-γ染色一些典型流脾NK和NKT细胞与病原体的10 5 CFU。该图还示出了表2中记载的染色面板的选通策略。 图4示出在一个实验中，其中雄性小鼠用PPARα拮抗剂IS001或媒介物对照处理得到的一些有代表性的数据，感染10 5 CFU 单增李斯特菌，然后24小时后分析在NK和NKT细胞的IFN-γ 。该...

Watch this Scientific Journal Video about Experimental Infection with Listeria monocytogenes as a Model for Studying Host Interferon-Î³ Responses at JoVE.com

Experimental Infection with Listeria monocytogenes as a Model for Studying Host Interferon-&#947; Responses

这个协议描述如何接种C57BL / 6J小鼠李斯特菌的EGD株（单增李斯特菌），并测量干扰素γ（IFN-γ）的反应由自然杀伤（NK）细胞，天然杀伤T（NKT）细胞，和自适应T淋巴细胞后感染。该协议还介绍了如何进行生存研究，小鼠感染后有修改的LD 50剂量的病原体。

实验性感染<em&gt;李斯特菌</em&gt;作为研究主机干扰素γ响应模型

L. monocytogenes is a gram-positive bacterium that is a cause of food borne disease in humans. Experimental infection of mice with this pathogen has been ...

experimental-infection-with-listeria-monocytogenes-as-model-for

Universidad de Cartagena UDEC

Research

JoVE Journal

Immunology and Infection

13.5K 次观看.  University of Toronto. 这个协议描述如何接种C57BL / 6J小鼠李斯特菌的EGD株（单增李斯特菌），并测量干扰素γ（IFN-γ）的反应由自然杀伤（NK）细胞，天然杀伤T（NKT）细胞，和自适应T淋巴细胞后感染。该协议还介绍了如何进行生存研究，小鼠感染后有修改的LD 50剂量的病原体。 

视频: Experimental Infection with Listeria monocytogenes as a Model for Studying Host Interferon-γ Responses

Measuring Bacterial Load and Immune Responses in Mice Infected with Listeria monocytogenes

Listeria monocytogenes (Listeria) is a Gram-positive facultative intracellular pathogen1. Mouse studies typically employ intravenous injection of Listeria, which results in systemic infection2. After injection, Listeria quickly disseminates to the spleen and liver due to uptake by CD8&alpha;+ dendritic cells and Kupffer cells3,4. Once phagocytosed, various bacterial proteins enable Listeria to escape the phagosome, survive within the cytosol, and infect neighboring cells5. During the first three days of infection, different innate immune cells (e.g. monocytes, neutrophils, NK cells, dendritic cells) mediate bactericidal mechanisms that minimize Listeria proliferation. CD8+ T cells are subsequently recruited and responsible for the eventual clearance of Listeria from the host, typically within 10 days of infection6.
Successful clearance of Listeria from infected mice depends on the appropriate onset of host immune responses6	. There is a broad range of sensitivities amongst inbred mouse strains7,8. Generally, mice with increased susceptibility to Listeria infection are less able to control bacterial proliferation, demonstrating increased bacterial load and/or delayed clearance compared to resistant mice. Genetic studies, including linkage analyses and knockout mouse strains, have identified various genes for which sequence variation affects host responses to Listeria infection6,8-14. Determination and comparison of infection kinetics between different mouse strains is therefore an important method for identifying host genetic factors that contribute to immune responses against Listeria. Comparison of host responses to different Listeria strains is also an effective way to identify bacterial virulence factors that may serve as potential targets for antibiotic therapy or vaccine design.
We describe here a straightforward method for measuring bacterial load (colony forming units [CFU] per tissue) and preparing single-cell suspensions of the liver and spleen for FACS analysis of immune responses in Listeria-infected mice. This method is particularly useful for initial characterization of Listeria infection in novel mouse strains, as well as comparison of immune responses between different mouse strains infected with Listeria. We use the Listeria monocytogenes EGD strain15 that, when cultured on blood agar, exhibits a characteristic halo zone around each colony due to &beta;-hemolysis1 (Figure 1). Bacterial load and immune responses can be determined at any time-point after infection by culturing tissue homogenate on blood agar plates and preparing tissue cell suspensions for FACS analysis using the protocols described below. We would note that individuals who are immunocompromised or pregnant should not handle Listeria, and the relevant institutional biosafety committee and animal facility management should be consulted before work commences.

Measuring Bacterial Load and Immune Responses in Mice Infected with Listeria monocytogenes

Listeria monocytogenes is a model organism for studying immune responses and genetic susceptibility to intracellular bacteria in mice. This method enables one to measure bacterial load and generate single-cell suspensions of the liver and spleen from mice for FACS analysis to determine changes in immune cells due to Listeria infection.

测量细菌感染小鼠和免疫反应李斯特菌</em

Listeria monocytogenes (Listeria) is a Gram-positive facultative intracellular pathogen1. Mouse studies typically employ intravenous injection of ...

科研

免疫与感染

Introducing Shear Stress in the Study of Bacterial Adhesion

During bacterial infections a sequence of interactions occur between the pathogen and its host. Bacterial adhesion to the host cell surface is often the initial and determining step of the pathogenesis. Although experimentally adhesion is mostly studied in static conditions adhesion actually takes place in the presence of flowing liquid. First encounters between bacteria and their host often occur at the mucosal level, mouth, lung, gut, eye, etc. where mucus flows along the surface of epithelial cells. Later in infection, pathogens occasionally access the blood circulation causing life-threatening illnesses such as septicemia, sepsis and meningitis. A defining feature of these infections is the ability of these pathogens to interact with endothelial cells in presence of circulating blood. The presence of flowing liquid, mucus or blood for instance, determines adhesion because it generates a mechanical force on the pathogen. To characterize the effect of flowing liquid one usually refers to the notion of shear stress, which is the tangential force exerted per unit area by a fluid moving near a stationary wall, expressed in dynes/cm2. Intensities of shear stress vary widely according to the different vessels type, size, organ, location etc. (0-100 dynes/cm2). Circulation in capillaries can reach very low shear stress values and even temporarily stop during periods ranging between a few seconds to several minutes 1. On the other end of the spectrum shear stress in arterioles can reach 100 dynes/cm2 2. The impact of shear stress on different biological processes has been clearly demonstrated as for instance during the interaction of leukocytes with the endothelium 3. To take into account this mechanical parameter in the process of bacterial adhesion we took advantage of an experimental procedure based on the use of a disposable flow chamber 4. Host cells are grown in the flow chamber and fluorescent bacteria are introduced in the flow controlled by a syringe pump. We initially focused our investigations on the bacterial pathogen Neisseria meningitidis, a Gram-negative bacterium responsible for septicemia and meningitis. The procedure described here allowed us to study the impact of shear stress on the ability of the bacteria to: adhere to cells 1, to proliferate on the cell surface 5and to detach to colonize new sites 6 (Figure 1). Complementary technical information can be found in reference 7. Shear stress values presented here were chosen based on our previous experience1 and to represent values found in the literature. The protocol should be applicable to a wide range of pathogens with specific adjustments depending on the objectives of the study.

During the infection process, a key step is the adhesion of pathogens with host cells. In most instances this adhesion step occurs in the presence of mechanical stress generated by flowing liquid. We describe a technique that introduces shear stress as an important parameter in the study of bacterial adhesion.

在细菌粘附的研究剪应力

During bacterial infections a sequence of interactions occur between the pathogen and its host. Bacterial adhesion to the host cell surface is often the ...

The Citrobacter rodentium Mouse Model: Studying Pathogen and Host Contributions to Infectious Colitis

This protocol outlines the steps required to produce a robust model of infectious disease and colitis, as well as the methods used to characterize Citrobacter rodentium infection in mice. C. rodentium is a gram negative, murine specific bacterial pathogen that is closely related to the clinically important human pathogens enteropathogenic E. coli and enterohemorrhagic E. coli. Upon infection with C. rodentium, immunocompetent mice suffer from modest and transient weight loss and diarrhea. Histologically, intestinal crypt elongation, immune cell infiltration, and goblet cell depletion are observed. Clearance of infection is achieved after 3 to 4 weeks. Measurement of intestinal epithelial barrier integrity, bacterial load, and histological damage at different time points after infection, allow the characterization of mouse strains susceptible to infection.
The virulence mechanisms by which bacterial pathogens colonize the intestinal tract of their hosts, as well as specific host responses that defend against such infections are poorly understood. Therefore the C. rodentium model of enteric bacterial infection serves as a valuable tool to aid in our understanding of these processes. Enteric bacteria have also been linked to Inflammatory Bowel Diseases (IBDs). It has been hypothesized that the maladaptive chronic inflammatory responses seen in IBD patients develop in genetically susceptible individuals following abnormal exposure of the intestinal mucosal immune system to enteric bacteria. Therefore, the study of models of infectious colitis offers significant potential for defining potentially pathogenic host responses to enteric bacteria. C. rodentium induced colitis is one such rare model that allows for the analysis of host responses to enteric bacteria, furthering our understanding of potential mechanisms of IBD pathogenesis; essential in the development of novel preventative and therapeutic treatments.

The Citrobacter rodentium Mouse Model: Studying Pathogen and Host Contributions to Infectious Colitis

Citrobacter rodentium infection provides a valuable model to study enteric bacterial infections as well as host immune responses and colitis in mice. This protocol outlines the measurement of barrier integrity, pathogen load and histological damage allowing for the thorough characterization of pathogen and host contributions to murine infectious colitis.

"<em&gt;枸橼酸rodentium</em&gt;鼠标产品型号:研究感染性结肠炎的病原体和宿主的贡献

This protocol  outlines the steps required to produce a robust model of infectious disease and  colitis, as well as the methods used to characterize ...

Oral Transmission of Listeria monocytogenes in Mice via Ingestion of Contaminated Food

L. monocytogenes are facultative intracellular bacterial pathogens that cause food borne infections in humans. Very little is known about the gastrointestinal phase of listeriosis due to the lack of a small animal model that closely mimics human disease. This paper describes a novel mouse model for oral transmission of L. monocytogenes. Using this model, mice fed L. monocytogenes-contaminated bread have a discrete phase of gastrointestinal infection, followed by varying degrees of systemic spread in susceptible (BALB/c/By/J) or resistant (C57BL/6) mouse strains. During the later stages of the infection, dissemination to the gall bladder and brain is observed. The food borne model of listeriosis is highly reproducible, does not require specialized skills, and can be used with a wide variety of bacterial isolates and laboratory mouse strains. As such, it is the ideal model to study both virulence strategies used by L. monocytogenes to promote intestinal colonization, as well as the host response to invasive food borne bacterial infection.

Oral Transmission of Listeria monocytogenes in Mice via Ingestion of Contaminated Food

This paper describes a novel method for oral infection of mice using Listeria monocytogenes-contaminated food. The protocol can readily be adapted for use with other food borne bacterial pathogens.

口头传播的<em&gt;单核细胞增生李斯特氏菌</em小鼠通过食入被污染的食物

L. monocytogenes are facultative intracellular bacterial pathogens that cause food borne infections in humans. Very little is known about the ...

Imaging InlC Secretion to Investigate Cellular Infection by the Bacterial Pathogen Listeria monocytogenes

Bacterial intracellular pathogens can be conceived as molecular tools to dissect cellular signaling cascades due to their capacity to exquisitely manipulate and subvert cell functions which are required for the infection of host target tissues. Among these bacterial pathogens, Listeria monocytogenes is a Gram positive microorganism that has been used as a paradigm for intracellular parasitism in the characterization of cellular immune responses, and which has played instrumental roles in the discovery of molecular pathways controlling cytoskeletal and membrane trafficking dynamics. In this article, we describe a robust microscopical assay for the detection of late cellular infection stages of L. monocytogenes based on the fluorescent labeling of InlC, a secreted bacterial protein which accumulates in the cytoplasm of infected cells; this assay can be coupled to automated high-throughput small interfering RNA screens in order to characterize cellular signaling pathways involved in the up- or down-regulation of infection.

Imaging InlC Secretion to Investigate Cellular Infection by the Bacterial Pathogen Listeria monocytogenes

Listeria monocytogenes is a Gram positive bacterial pathogen frequently used as a major model for the study of intracellular parasitism. Imaging late L. monocytogenes infection stages within the context of small-interfering RNA screens allows for the global study of cellular pathways required for bacterial infection of target host cells.

成像InlC的分泌由细菌病原体调查感染蜂窝<em&gt;单核细胞增生李斯特氏菌</em

Bacterial intracellular  pathogens can be conceived as molecular tools to dissect cellular signaling  cascades due to their capacity to exquisitely ...

Porphyromonas gingivalis as a Model Organism for Assessing Interaction of Anaerobic Bacteria with Host Cells

Anaerobic bacteria far outnumber aerobes in many human niches such as the gut, mouth, and vagina. Furthermore, anaerobic infections are common and frequently of indigenous origin. The ability of some anaerobic pathogens to invade human cells gives them adaptive measures to escape innate immunity as well as to modulate host cell behavior. However, ensuring that the anaerobic bacteria are live during experimental investigation of the events may pose challenges. Porphyromonas gingivalis, a Gram-negative anaerobe, is capable of invading a variety of eukaryotic non-phagocytic cells. This article outlines how to successfully culture and assess the ability of P. gingivalis to invade human umbilical vein endothelial cells (HUVECs). Two protocols were developed: one to measure bacteria that can successfully invade and survive within the host, and the other to visualize bacteria interacting with host cells. These techniques necessitate the use of an anaerobic chamber to supply P. gingivalis with an anaerobic environment for optimal growth.
The first protocol is based on the antibiotic protection assay, which is largely used to study the invasion of host cells by bacteria. However, the antibiotic protection assay is limited; only intracellular bacteria that are culturable following antibiotic treatment and host cell lysis are measured. To assess all bacteria interacting with host cells, both live and dead, we developed a protocol that uses fluorescent microscopy to examine host-pathogen interaction. Bacteria are fluorescently labeled with 2&#39;,7&#39;-Bis-(2-carboxyethyl)-5-(and-6)-carboxyfluorescein acetoxymethyl ester (BCECF-AM) and used to infect eukaryotic cells under anaerobic conditions. Following fixing with paraformaldehyde and permeabilization with 0.2% Triton X-100, host cells are labeled with TRITC phalloidin and DAPI to label the cell cytoskeleton and nucleus, respectively. Multiple images taken at different focal points (Z-stack) are obtained for temporal-spatial visualization of bacteria. Methods used in this study can be applied to any cultivable anaerobe and any eukaryotic cell type.

Porphyromonas gingivalis as a Model Organism for Assessing Interaction of Anaerobic Bacteria with Host Cells

This article presents two protocols: one to measure anaerobic bacteria that can successfully invade and survive within the host, and the other to visualize anaerobic bacteria interacting with host cells. This study can be applied to any cultivable anaerobe and any eukaryotic cell type.

牙龈卟啉单作为模式生物的评价厌氧细菌的相互作用与宿主细胞

Anaerobic bacteria far outnumber aerobes in many human niches such as the gut, mouth, and vagina. Furthermore, anaerobic infections are common and ...

RNA Purification from Intracellularly Grown Listeria monocytogenes in Macrophage Cells

Analysis of the transcriptome of bacterial pathogens during mammalian infection is a valuable tool for studying genes and factors that mediate infection. However, isolating bacterial RNA from infected cells or tissues is a challenging task, since mammalian RNA mostly dominates the lysates of infected cells. Here we describe an optimized method for RNA isolation of Listeria monocytogenes bacteria growing within bone marrow derived macrophage cells. Upon infection, cells are mildly lysed and rapidly filtered to discard most of the host proteins and RNA, while retaining intact bacteria. Next, bacterial RNA is isolated using hot phenol-SDS extraction followed by DNase treatment. The extracted RNA is suitable for gene transcription analysis by multiple techniques. This method is successfully employed in our studies of Listeria monocytogenes gene regulation during infection of macrophage cells 1-4. The protocol can be easily modified to study other bacterial pathogens and cell types.

RNA Purification from Intracellularly Grown Listeria monocytogenes in Macrophage Cells

Here we describe a method for bacterial RNA isolation from Listeria monocytogenes bacteria growing inside murine macrophages. This technique can be used with other intracellular pathogens and mammalian host cells.

RNA纯化在细胞内生长<em&gt;李斯特菌</em&gt;巨噬细胞

Analysis of the transcriptome of bacterial pathogens during mammalian infection is a valuable tool for studying genes and factors that mediate infection. ...

Methodologies for Studying B. subtilis Biofilms as a Model for Characterizing Small Molecule Biofilm Inhibitors

This work assesses different methodologies to study the impact of small molecule biofilm inhibitors, such as D-amino acids, on the development and resilience of Bacillus subtilis biofilms. First, methods are presented that select for small molecule inhibitors with biofilm-specific targets in order to separate the effect of the small molecule inhibitors on planktonic growth from their effect on biofilm formation. Next, we focus on how inoculation conditions affect the sensitivity of multicellular, floating B. subtilis cultures to small molecule inhibitors. The results suggest that discrepancies in the reported effects of such inhibitors such as D-amino acids are due to inconsistent pre-culture conditions. Furthermore, a recently developed protocol is described for evaluating the contribution of small molecule treatments towards biofilm resistance to antibacterial substances. Lastly, scanning electron microscopy (SEM) techniques are presented to analyze the three-dimensional spatial arrangement of cells and their surrounding extracellular matrix in a B. subtilis biofilm. SEM facilitates insight into the three-dimensional biofilm architecture and the matrix texture. A combination of the methods described here can greatly assist the study of biofilm development in the presence and absence of biofilm inhibitors, and shed light on the mechanism of action of these inhibitors.

Methodologies for Studying B. subtilis Biofilms as a Model for Characterizing Small Molecule Biofilm Inhibitors

This study presents the development of reproducible methodologies to study biofilm inhibitors and their effects on Bacillus subtilis multicellularity.

方法学研究<em&gt;乙。枯草</em&gt;生物膜作为模型的表征小分子抑制剂生物膜

This work assesses different methodologies to study the impact of small molecule biofilm inhibitors, such as D-amino acids, on the development and ...

Listeria monocytogenes Infection of the Brain

Listeria monocytogenes is an intracellular bacterial pathogen that is frequently associated with food-borne infection. The ability of&#160;L. monocytogenes to cross the blood-brain barrier (BBB) is concerning as it can lead to life-threatening meningitis and encephalitis. The BBB protects the brain microenvironment from various toxic metabolites and microbial pathogens found in the blood following infection, and therefore supports brain homeostasis. The mechanisms by which L. monocytogenes present in the bloodstream cross the BBB to cause brain infections are not fully understood and there is also a lack of a robust model system to study brain infections by L. monocytogenes. Here, we present a simple mouse infection model to determine whether bacteria have crossed the BBB and to quantitate the burden of bacteria that have colonized the brain in vivo. In this method, animals were infected intravenously with L. monocytogenes and were humanely euthanized by exposure to CO2 followed by cervical dislocation. Cardiac perfusion of the animals was performed prior to harvesting infected organs. Blood was collected before perfusion and the number of bacteria per organ or mL of blood was determined by plating dilutions of the blood or organ homogenates on agar plates and counting the number of colonies formed. This method can be used to study novel receptor-ligand interactions that enhance infection of the brain by L. monocytogenes and can be easily adapted for the study of multiple bacterial pathogens.

Listeria monocytogenes Infection of the Brain

During infection, Listeria monocytogenes is capable of crossing the blood-brain barrier to colonize the brain. In this protocol, we demonstrate how to assess bacterial colonization of organs following infection of mice. A procedure to perform whole organ perfusion for specific determination of bacterial numbers in the brain parenchyma is provided.

李斯特菌脑部感染

Listeria monocytogenes is an intracellular bacterial pathogen that is frequently associated with food-borne infection. The ability of&#160;L. ...

Using a Bacterial Pathogen to Probe for Cellular and Organismic-level Host Responses

There are a variety of strategies bacterial pathogens employ to survive and proliferate once inside the eukaryotic cell. The so-called 'cytosolic' pathogens (Listeria monocytogenes, Shigella flexneri, Burkholderia pseudomallei, Francisella tularensis, and Rickettsia spp.) gain access to the infected cell cytosol by physically and enzymatically degrading the primary vacuolar membrane. Once in the cytosol, these pathogens both proliferate as well as generate sufficient mechanical forces to penetrate the plasma membrane of the host cell in order to infect new cells. Here, we show how this terminal step of the cellular infection cycle of L. monocytogenes (Lm) can be quantified by both colony-forming unit assays and flow cytometry and give examples of how both pathogen- and host-encoded factors impact this process. We also show a close correspondence of Lm infection dynamics of cultured cells infected in vitro and those of hepatic cells derived from mice infected in vivo. These function-based assays are relatively simple and can be readily scaled up for discovery-based high-throughput screens for modulators of eukaryotic cell function.

We describe both in vitro and in vivo infection assays that can be used to analyze the activities of host-encoding factors.

实验性感染

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测量细菌感染小鼠和免疫反应李斯特菌

在细菌粘附的研究剪应力

"

口头传播的

成像InlC的分泌由细菌病原体调查感染蜂窝

牙龈卟啉单作为模式生物的评价厌氧细菌的相互作用与宿主细胞

RNA纯化在细胞内生长

方法学研究

李斯特菌脑部感染

细菌病原体在细胞和有机水平宿主反应探针中的应用