结核菌H37Ra在小鼠体内诱导的免疫应答及其保护力

目的:研究结核菌H37Ra免疫小鼠后产生的特异性免疫应答以及保护效果.方法:BALB/c小鼠随机分为H37Ra组、BCG组和生理盐水(NS)组,免疫8周后处死部分小鼠,取脾淋巴细胞经体外培养、PPD刺激后,MTT法检测淋巴细胞的刺激指数,ELISA法检测培养上清液中IFN-γ和IL-4水平.另一部分免疫小鼠经腹腔感染结核分枝杆菌(Mycobacterium tuberculosis,MTB)毒株H37Rv,4周后处死,测定小鼠脏器重量指数.取稀释的小鼠脾脏和肺脏匀浆接种于改良罗氏培养基,培养21天后计数脏器荷菌量.结果:H37Ra和BCG免疫小鼠脾淋巴细胞刺激指数、IFN-γ和IL-4水平均显著高于NS对照组.感染4周后H37Ra和BCG组小鼠脏器重量指数较NS对照组均显著降低.H37Ra组小鼠脾脏和肺脏荷菌量与NS对照组比较分别下降了1.228log10CFU和0.954log10CFU,差异有显著性(P<0.05),与BCG组之间差异均无显著性.结论:H37Ra免疫小鼠后可以诱导产生Th1型免疫应答,能够抵抗毒株H37Rv的攻击,且免疫效果与BCG相当.     

结核分枝杆菌ESAT6-CFP10融合蛋白诱导的小鼠免疫应答及其保护力

目的:研究结核分枝杆菌(MTB)ESAT6-CFP10融合蛋白诱导的小鼠体液和细胞免疫应答以及对MTB感染小鼠的保护能力。方法:用预先转移到硝酸纤维素膜条的ES-AT6-CFP10融合蛋白采用皮下包埋的方法免疫小鼠。用MTB培养上清滤液蛋白(CFP)作为抗原,用ELISA法测定免疫小鼠血清特异性抗体的滴度。末次免疫后,取部分免疫小鼠脾淋巴细胞,体外用ESAT6-CFP10融合蛋白刺激后,以MTT比色法检测淋巴细胞增殖反应,同时检测免疫小鼠IFN-γ和IL-2水平及脾细胞杀伤效应。另一部分免疫的BALB/c小鼠经尾静脉感染MTB毒株H37Rv,4周后计数脾脏中的细菌数。结果:ESAT6-CFP10融合蛋白免疫小鼠血清特异性抗体的滴度为1∶6400。淋巴细胞刺激增殖指数为1.90±0.15,明显高于生理盐水组(0.90±0.15);IFN-γ和IL-2的含量分别为1.792±19ng/L和0.211±11ng/L,显著高于生理盐水对照组,但不及BCG免疫组;同时融合蛋白诱导的脾细胞杀伤率为36%。与生理盐水免疫组(细菌负荷6.51±0.13)相比较,融和蛋白免疫的BALB/c小鼠,对攻击感染后MTB在脾脏中增殖有显著作用(细菌负荷为5.24±0.15,P<0.05),但与BCG免疫组相比脾脏中细菌负荷减少甚微。结论:ESAT6-CFP10融合蛋白可作为新型结核疫苗的候选组分。     

藤黄微球菌Rpf结构域多肽诱导小鼠免疫应答的实验研究

目的:研究藤黄微球菌Rpf结构域多肽的免疫学特性.方法:用原核表达的藤黄微球菌Rpf结构域多肽免疫哌BALB/c小鼠3次,每次间隔2周.用ELISA法检测免疫小鼠血清中特异性抗体滴度.分离免疫小鼠的脾淋巴细胞,体外用抗原再刺激后,用MTT比色法检测免疫小鼠脾淋巴细胞的增值指数.ELISA方法检测淋巴淋巴细胞悬液中IFN-γ、IL-10和IL-12产生水平.另一部分免疫的小鼠经尾静脉感染MTB毒株H37Rv,4周后,计数脾脏细菌负荷数.结果:藤黄微球菌Rpf结构域多肽免疫小鼠血清特异性抗体滴度为1∶128 000,淋巴细胞增殖指数为(2.10±0.12),明显高于生理盐水对照组(0.90±0.21).ELISA方法检测Rpf结构域多肽免疫组IFN-γ,IL-10和IL-12水平为(1 126±36) ng/L,(368±13)ng/L和(289±14)ng/L,明显高于生理盐水对照组(P<0.01).与生理盐水免疫组(细菌负荷6.64±0.13)相比较,Rpf结构域多肽免疫的BALB/c小鼠,对攻击感染后抗MTB在脾脏中增殖有明显作用(细菌负荷为5.03±0.11,P<0.05).结论:藤黄微球菌Rpf结构域多肽有可能作为新型结核疫苗的候选组分.     

结核分枝杆菌MPT64重组母牛分枝杆菌免疫学特性

目的:研究结核分枝杆菌MPT64重组母牛分枝杆菌疫苗免疫学特性.方法:用分泌表达MPT64的重组母牛分枝杆菌疫苗免疫BALB/c小鼠,ELISA法检测免疫小鼠的特异性抗体滴度和抗体亚类.分离免疫小鼠脾淋巴细胞,检测淋巴细胞增殖、IFN-γ和IL-12产生水平、CD4+细胞和CD8+细胞数、脾淋巴细胞特异性CTL杀伤效应.毒株攻击后对脾脏细菌负荷计数.结果:MPT64重组母牛分枝杆菌疫苗免疫可诱导小鼠高水平的体液免疫应答,免疫小鼠脾淋巴增殖明显,IFN-γ和IL-12含量增加,CD4+和CD8+细胞百分比明显增加,CTL杀伤效应明显,对MTB H37Rv攻击后有一定的保护作用.结论:MPT64重组母牛分枝杆菌疫苗可诱导小鼠有效的体液和细胞免疫应答,有可能作为新型TB疫苗候选.     

LC3-LpqH增强Ag85B抗结核分枝杆菌DNA疫苗的免疫保护作用

目的探讨微管相关蛋白轻链3-脂蛋白前体-LpqH(LC3-LpqH)DNA佐剂对Ag85B抗结核分枝杆菌(MTB)DNA疫苗免疫保护作用的影响。方法分别用纯化的pCMV-Ag85B、pCMV-LpqH/pCMV-Ag85B、pCMV-LC3-LpqH/pCMV-Ag85B、pCMV质粒DNA对BALB/c小鼠进行3次肌肉注射免疫。末次免疫2周后,ELISA检测血清中抗Ag85B IgG亚型及滴度。Ag85B刺激下培养各组小鼠脾脏淋巴细胞,ELISA检测血清白细胞介素2(IL-2)、干扰素-γ(IFN-γ)、IL-4、IL-10分泌水平。末次免疫3个月后,用MTB标准毒株H37Rv尾静脉注射感染小鼠,计数肺和脾脏MTB载量并观察肺组织病理变化。结果与Ag85B免疫组相比,LC3-LpqH/Ag85B免疫组抗Ag85B的IgG2a水平显著提高,而IgG1水平显著降低,并伴随IL-2、IFN-γ分泌增加及IL-4、IL-10减少,肺和脾脏内MTB载量降低,肺组织病变程度减轻。结论 LC3-LpqH可显著增强Ag85B抗MTB疫苗的Th1型免疫应答,并显示较好的免疫保护效应。     

两株登革2型病毒E基因重组质粒免疫BALB/c小鼠产生特异性抗体水平的比较

目的 用含登革2型病毒(Dengue type 2 virus,DEN2)B株和NGC株E基因部分序列pcDNA3.1重组质粒初次和加强免疫BALB/c小鼠,观察免疫小鼠体液免疫应答的差异.方法 用两株含DEN2 E基因部分序列(1～476 bp)的pcDNA3.1重组质粒与含有佐剂的重组质粒共同免疫BALB/c小鼠,初次免疫后第14天、28天分别加强免疫1次,共免疫3次.收集初次免疫后第14、28、42、70和98天外周血标本,间接ELISA法测定小鼠血浆特异性IgM/IgG类抗体水平,细胞病变抑制法检测特异性抗体水平.结果 不同DEN2毒株E基因部分序列的pcDNA3.1重组质粒初次和加强免疫BALB/c小鼠诱导特异性IgM、IgG类抗体的产生存在差异,B株重组质粒加强免疫小鼠后特异性抗体效价水平较高并持续较长时间.结论 DEN2两毒株E基因部分序列重组质粒免疫小鼠后诱生的特异性抗体类别、水平存在差异.     

活菌H37Ra与灭活菌H37Rv感染小鼠腹腔巨噬细胞的实验研究

目的:探讨小鼠腹腔接种结核分枝杆菌活菌H37Ra、灭活菌H37Rv后,诱导巨噬细胞免疫物质的表达差异,探讨活菌H37Ra及灭活菌H37Rv作为新的结核候选疫苗的可行性。方法:分别培养BALB/c小鼠腹腔巨噬细胞,用活菌H37Ra,灭活菌H37Rv感染10小时后用抗酸染色方法,观察各组巨噬细胞吞噬情况并计算吞噬率。将活菌H37Ra、灭活菌H37Rv、生理盐水分别接种BALB/c小鼠腹腔,免疫30天后取小鼠腹腔巨噬细胞,RT-PCR法检测小鼠腹腔巨噬细胞IL-12P40、TNFα-、IFNγ-的基因转录水平;ELISA法检测细胞因子IL-12P40、TNFα-、IFNγ-的表达;Griess法、化学法检测小鼠腹腔巨噬细胞分泌NO、H2O2水平;流式细胞仪检测IFNγ-诱导的CD40L的变化情况。结果:巨噬细胞对活菌H37Ra和灭活菌H37Rv的吞噬率分别为(55.71±8.42)%、(14.82±2.12)%。与灭活菌相比,活菌H37Ra有更强的被吞噬能力(P<0.01)。活菌H37Ra免疫小鼠腹腔巨噬细胞后能显著诱导巨噬细胞的IL-12P40、TNF及IFNγ-基因的转录;细胞因子IL-12P40、TNFα-、IFNγ-、NO及H2O2高水平分泌;同时活菌H37Ra刺激IFNγ-诱导的巨噬细胞表面CD40L的高表达。结论:活的结核分枝杆菌H37Ra能显著诱导小鼠腹腔巨噬细胞产生更多的保护性免疫物质,有利于免疫应答,有可能作为新的结核候选疫苗,而灭活菌H37Rv不能显著激活小鼠腹腔巨噬细胞分泌保护性免疫物质,不宜作为新的结核候选疫苗。     

外源质粒DNA经胃肠道途径对小鼠免疫基因的调控作用

目的:研究外源质粒DNA经胃肠道途径对小鼠免疫基因表达的调控作用。方法:给BALB/c小鼠灌胃质粒pcDNA3200μg,分别在灌胃后4h和18h分离脾脏,提取脾脏总RNA。利用Affymetrix基因表达谱芯片对灌胃质粒pcD-NA3后的BALB/c小鼠脾脏进行基因表达谱研究。采用Genmmapp和MAPPFinder软件进行功能聚类分析。结果:灌胃质粒pcDNA3后,大量与免疫应答相关的基因发生上调,这些基因包括转录因子、细胞因子和细胞因子受体、主要组织相容性基因、蛋白酶体基因、补体分子基因和细胞凋亡相关基因;下调的基因主要是免疫球蛋白基因。MAPPFinder分析结果显示大量免疫应答过程发生上调。结论:外源质粒DNA通过胃肠道途径可调控大量免疫基因的表达,对相关基因及免疫应答过程的研究有助于在分子水平上深入了解外源质粒DNA的胃肠道作用机制。     

pCMV-LC3-Ag85B重组质粒DNA疫苗对结核的免疫保护作用

目的构建结核分枝杆菌Ag85B抗原基因与微管相关蛋白轻链3(LC3)基因融合的DNA疫苗,探究其抗结核分枝杆菌保护效应。方法构建pCMV-LC3-Ag85B重组质粒并转染RAW264.7细胞,Western blot法检测目的蛋白的表达水平。分别以pCMV、pCMV-Ag85B、pCMV-LC3-Ag85B质粒免疫BALB/c小鼠。末次免疫2周后,Ag85B刺激下培养各组小鼠脾脏淋巴细胞,ELISA检测IL-2、IFN-γ、IL-4、IL-10分泌水平。末次免疫3个月后,用H37Rv标准株尾静脉注射感染小鼠,计数肺和脾脏结核分枝杆菌载量。结果 pCMV-LC3-Ag85B在RAW264.7细胞的表达水平与质粒浓度呈剂量依赖性。与pCMV-Ag85B免疫组相比,pCMV-LC3-Ag85B免疫组的IL-2、IFN-γ分泌显著增加,而肺和脾脏内结核分枝杆菌载量降低。结论 pCMV-LC3-Ag85B可显著增强Th1型免疫应答,并显示较好的抗结核分枝杆菌免疫保护效应。     

登革2型病毒43株NS1基因重组质粒DNA的免疫原性及保护作用研究

目的 研究以pcDNA3.1为载体的登革2型病毒43株（D2－43）NS1基因重组DNA的免疫原性及对登革病毒感染所致小鼠神经毒的免疫保护作用。方法 将纯化的pcDNA-NS1重组质粒DNA采用肌肉多点注射途径免疫3周龄BALB／c小鼠，剂量为每只100μg/次，检测了免疫鼠血清抗体滴度及特异性细胞毒作用。并以D2－43病毒脑内攻击6周龄BALB/c小鼠产生的神经毒症状为实验模型，对pcDNA-NS1的免疫保护作用进行了初步探讨。结果 用间接ELISA测得pcDNA-NS1免疫后抗体滴度为1：800，在补体存在下，对D2－43病毒感染的BHK－21细胞特异性杀伤率可达到61．6％。由免疫的BALB／c小鼠脾制备的效应细胞在体外可特异性地杀伤D2－43感染的P－815细胞（H－2^d)。当效靶比（E／T）为20：1时，pcDNA-NS1质粒免疫后的特异性CTL杀伤百分率为22．6％。将100 LD50的D2－43病毒经脑内攻击BALB／c小鼠，结果表明免疫pcDNA-NS1组小鼠存活率最高（90．9％）；与免疫pcDNA3.1对照组比较，P值＜0．05。结论 pcDNA-NS1质粒免疫BALB／c小鼠不仅可诱导体液免疫，还可诱导特异性细胞免疫。初步结果还显示，用含NS1基因的重组质粒DNA免疫的小鼠能免受致死剂量登革病毒的攻击，为登革热新型疫苗的研究奠定了基础。     

Paucibacillary tuberculosis in mice after prior aerosol immunization with Mycobacterium bovis BCG

To develop a murine model of paucibacillary tuberculosis for experimental chemotherapy of latent tuberculosis infection, mice were immunized with viable Mycobacterium bovis BCG by the aerosol or intravenous route and then challenged six weeks later with virulent Mycobacterium tuberculosis. The day after immunization, the counts were 3.71 +/- 0.10 log(10) CFU in the lungs of aerosol-immunized mice and 3.65 +/- 0.11 and 4.93 +/- 0.07 log(10) CFU in the lungs and spleens of intravenously immunized mice, respectively. Six weeks later, the lungs of all BCG-immunized mice had many gross lung lesions and splenomegaly; the counts were 5.97 +/- 0.14 and 3.54 +/- 0.07 log(10) CFU in the lungs and spleens of aerosol-immunized mice, respectively, and 4.36 +/- 0.28 and 5.12 +/- 0.23 log(10) CFU in the lungs and spleens of intravenously immunized mice, respectively. Mice were then aerosol challenged with M. tuberculosis by implanting 2.37 +/- 0.13 log(10) CFU in the lungs. Six weeks after challenge, M. tuberculosis had multiplied so that the counts were 6.41 +/- 0.27 and 4.44 +/- 0.14 log(10) CFU in the lungs and spleens of control mice, respectively. Multiplication of M. tuberculosis was greatly limited in BCG-immunized mice. Six weeks after challenge, the counts were 4.76 +/- 0.24 and 3.73 +/- 0.34 log(10) CFU in the lungs of intravenously immunized and aerosol-immunized mice, respectively. In contrast to intravenously immunized mice, there was no detectable dissemination to the spleen in aerosol-immunized mice. Therefore, immunization of mice with BCG by the aerosol route prior to challenge with a low dose of M. tuberculosis resulted in improved containment of infection and a stable paucibacillary infection. This model may prove to be useful for evaluation of new treatments for latent tuberculosis infection in humans.     

Impact of iron loading and iron chelation on murine tuberculosis

Objective: To demonstrate in a mouse model of tuberculosis that excess iron load enhances the growth of Mycobacterium tuberculosis and to assess whether or not iron chelation may abrogate the effect of iron loading on Mycobacterium tuberculosis growth in the mouse model.
Methods: In the first experiment, female BALB/C mice were infected intravenously with 5.4 × 10⁴ CPU of M. tuberculosis H37Rv per mouse. Before infection, half of them were treated for 2 weeks with 50 mg/kg polymaltose ferric hydroxide, a source of iron. In a second experiment, female BALB/C mice were infected intravenously with 9 × 10⁴ CPU per mouse and half of them were iron loaded for 2 weeks before infection. Both iron-loaded and non-iron-loaded mice were treated with desferrioxamine (DFO), an iron chelator, or isoniazid. At each sacrifice, mice and their spleens were weighed, lung lesions were noted, and the number of M. tuberculosis CFU determined by quantitative cultures of spleen and lungs.
Results: In the first experiment, the number of CFU was significantly higher in the spleen of iron-treated mice than in non-iron-loaded mice at days 14 and 28 after infection. In the second experiment, iron loading enhanced the multiplication of M. tuberculosis in the spleen but not in the lungs, DFO displayed a modest but significant effect on the multiplication of M. tuberculosis in iron-loaded mice, and isoniazid therapy was effective in both iron-loaded and non-iron-loaded mice.
Conclusions: Iron loading of BALB/C mice enhanced the multiplication of M. tuberculosis in the spleens but not in the lungs. DFO exhibited significant activity against M. tuberculosis in iron-loaded mice, and isoniazid therapy was strongly bactericidal in both iron-loaded and non-iron-loaded mice.     

Tuberculosis DNA vaccine encoding Ag85A is immunogenic and protective when administered by intramuscular needle injection but not by epidermal gene gun bombardment

Immunogenicity and protective efficacy of a DNA vaccine encoding Ag85A from Mycobacterium tuberculosis were compared in BALB/c and C57BL (B6 and B10) mice immunized by intramuscular (i.m.) needle injection or epidermal gene gun (gg) bombardment. In BALB/c mice, gg immunization could induce elevated antibody and cytotoxic T lymphocyte responses with plasmid doses 50-fold lower than those required for i.m. immunization. Interleukin-2 (IL-2) and gamma interferon (IFN-gamma) secretion, however, was much lower in gg-immunized than in i.m.-immunized BALB/c mice. On the other hand, C57BL mice reacted only very weakly to gg immunization, whereas elevated Ag85A-specific antibody, IL-2, and IFN-gamma responses (significantly higher than in BALB/c mice) were detected following vaccination by the i.m. route. Antibody isotypes were indicative of Th2 activation following gg injection of BALB/c and of Th1 activation following i.m. injection of C57BL mice. Finally, C57BL but not BALB/c mice were protected by i.m. Ag85A DNA immunization against intravenous M. tuberculosis challenge, as measured by reduced numbers of CFU in spleen and lungs, compared to animals vaccinated with control DNA. Gene gun immunization was not effective in either BALB/c or C57BL mice. These results indicate that i.m. DNA vaccination is the method of choice for the induction of protective Th1 type immune responses with the Ag85A tuberculosis DNA vaccine.     

Immunization of mice with mycobacterial culture filtrate proteins.

Culture filtrate proteins were obtained from Mycobacterium tuberculosis cultures after 7 days growth in Proskauer and Beck medium. The protein yield increased substantially to peak about the time the number of viable organisms reached its maximum level (day 8). Examination of the protein concentrate by SDS-PAGE revealed the presence of at least 12 separate protein bands varying from 10 to 90 kD. Mice were injected subcutaneously with 20 micrograms of M. tuberculosis culture filtrate (MTCF) protein suspended in saline or Freund's complete or incomplete adjuvant. The vaccinated mice were subjected to an aerogenic challenge with 10(3) colony-forming unit (CFU) M. tuberculosis Erdman and a significant reduction in the number of viable organisms was observed in the spleens and lungs determined over a 21-day period compared with age-matched normal controls. Mice immunized with the same culture filtrate proteins bound to nitrocellulose particles also showed some resistance to the virulent challenge, suggesting that individual antigens present in the culture filtrate were able to induce a protective T cell-mediated immune response in appropriately immunized mice.     

Immunogenicity and protective efficacy of the Mycobacterium tuberculosis fadD26 mutant

The Mycobacterium tuberculosis fadD26 mutant has impaired synthesis of phthiocerol dimycocerosates (DIM) and is attenuated in BALB/c mice. Survival analysis following direct intratracheal infection confirmed the attenuation: 60% survival at 4 months post-infection versus 100% mortality at 9 weeks post-infection with the wild-type strain. The fadD26 mutant induced less pneumonia and larger DTH reactions. It induced lower but progressive production of interferon (IFN)-gamma, interleukin (IL)-4 and tumour necrosis factor (TNF)-alpha. Used as a subcutaneous vaccine 60 days before intratracheal challenge with a hypervirulent strain of M. tuberculosis (Beijing code 9501000), the mutant induced a higher level of protection than did Bacille Calmette-Guérin (BCG). Seventy per cent of the mice vaccinated with the fadD26 mutant survived at 16 weeks after challenge compared to 30% of those vaccinated with BCG. Similarly, there was less tissue damage (pneumonia) and lower colony-forming units (CFU) in the mice vaccinated with the fadD26 mutant compared to the findings in mice vaccinated with BCG. These data suggest that DIM synthesis is important for the pathogenicity of M. tuberculosis, and that inactivation of DIM synthesis can increase the immunogenicity of live vaccines, and increase their ability to protect against tuberculosis.     

Genetically susceptible mice remain proportionally more susceptible to tuberculosis after vaccination

DBA/2 mice are much more susceptible to infection with Mycobacterium tuberculosis than major histocompatibility complex-compatible BALB/c mice. It is shown here that, although vaccination provided mice of both strains with a capacity to reduce the level of infection in their lungs, vaccinated DBA/2 mice remained much more susceptible in this organ than vaccinated BALB/c mice. Consequently, the former mice developed more lung pathology and died much earlier than the latter. On the other hand, colony-forming unit counts and histology suggest that vaccination provided mice of both strains with an increased and equal ability to express immunity in the liver and spleen, thereby indicating that they possessed equal systemic levels of vaccine-induced immunity at the time of M. tuberculosis challenge. The results indicate that inefficient expression of immunity in the lungs is likely to prove an obstacle to successful vaccination against tuberculosis in resistant and susceptible mouse strains, but more so in the latter strains.     

DNA vaccine encoding ESAT-6 enhances the protective efficacy of BCG against Mycobacterium tuberculosis infection in mice

ESAT-6 is a protein produced by virulent Mycobacterium tuberculosis but absent in Mycobacterium bovis bacillus Calmette-Guerin (BCG) and is considered as a promising vaccine subunit against tuberculosis. The protective efficacy of a new strategy based on the combination of DNA vaccine encoding ESAT-6 (DNA-E6) and BCG immunization was investigated in the present study. BALB/c mice were immunized with DNA-E6, BCG, DNA-E6 plus BCG, vector plus BCG or vector alone. Three weeks after the last immunization, antigen-specific interferon (IFN)-gamma secreted upon stimulation with BCG-PPD or ESAT-6 protein by splenocytes of the different groups was determined by an ELISA. The immunized mice were challenged intravenously with low-dose virulent M. tuberculosis H37Rv and bacterial load of the infected mice was measured in the spleen and lung 6 weeks later. Pathological changes in the lung were observed by haematoxylin-eosin (HE) or acid-fast staining. Our study demonstrated that ESAT-6-specific IFN-gamma was improved in mice vaccinated with DNA-E6 plus BCG, compared with those mice immunized with BCG alone. The combination of DNA-E6 and BCG resulted in the maximum reduction in bacterial load in both the lung and spleen, and only slight pathological changes were detected in the lung. These results suggested that the combination of DNA-E6 and BCG vaccination could be a better strategy against M. tuberculosis infections in human.     

Mycobacterium bovis BCG immunization induces protective immunity against nine different Mycobacterium tuberculosis strains in mice

Recent preclinical and epidemiologic studies have suggested that certain Mycobacterium tuberculosis genotypes (in particular, Beijing lineage strains) may be resistant to Mycobacterium bovis BCG vaccine-induced antituberculosis protective immunity. To investigate the strain specificity of BCG-induced protective responses in a murine model of pulmonary tuberculosis, C57BL/6 mice were vaccinated with BCG vaccine and then challenged 2 months later with one of nine M. tuberculosis isolates. Four of these strains were from the W-Beijing lineage (HN878, N4, NHN5, and ChS) while four were non-Beijing-type isolates (C913, CDC1551, NY669, and NY920). As a control, the WHO standard M. tuberculosis Erdman strain was evaluated in these vaccination/challenge experiments. To assess the protective responses evoked by BCG immunization, organ bacterial burdens and lung pathology were assessed in vaccinated and naïve mice at 4, 12, and 20 weeks postchallenge as well as during the day of infection. At 4 weeks after the aerosol challenge with each of these strains, significantly reduced bacterial growth in the lungs and spleens and significantly improved lung pathology were seen in all vaccinated animals compared to naïve controls. After 12 weeks, reduced organ bacterial burdens were detected in vaccinated animals infected with six of nine challenge strains. Although lung CFU values were lower in vaccinated mice for only three of nine groups at 20 weeks postchallenge, significantly decreased lung inflammation was seen in all immunized animals relative to controls at 20 weeks postchallenge. Taken together, these data demonstrate that BCG vaccination protects against infection with diverse M. tuberculosis strains in the mouse model of pulmonary tuberculosis and suggest that strain-specific resistance to BCG-induced protective immunity may be uncommon.