In eukaryotes, end-binding (EB) proteins serve as a hub for orchestrating microtubule dynamics and are essential for cellular dynamics and organelle movements. EB proteins modulate structural transitions at growing microtubule ends by recognizing and promoting an intermediate state generated during GTP hydrolysis. However, the molecular mechanisms and physiochemical properties of the EB1 interaction network remain elusive. Here we show that EB1 formed molecular condensates through liquid-liquid phase separation (LLPS) to constitute the microtubule plus-end machinery. EB1 LLPS is driven by multivalent interactions among different segments, which are modulated by charged residues in the linker region. Phase-separated EB1 provided a compartment for enriching tubulin dimers and other plus-end tracking proteins. Real-time imaging of chromosome segregation in HeLa cells expressing LLPS-deficient EB1 mutants revealed the importance of EB1 LLPS dynamics in mitotic chromosome movements. These findings demonstrate that EB1 forms a distinct physical and biochemical membraneless-organelle via multivalent interactions that guide microtubule dynamics.

Chronically SHIVSF162P3N-infected cynomolgus monkeys were used to determine the effects of the antibody-mediated acute CD4+ T cell depletion on viral load as well as on the immunological factors associated with disease progression. Compared with the control animals, CD4+ T cell-depleted animals with SHIV infection showed (i) little alteration in plasma viral load over the period of 22 weeks after the depletion; (ii) increased CD4+ T cell proliferation and turnover of macrophages at the early phase of the depletion, but subsequent decline to the basal levels; and (iii) little impact on the expression of the inflammatory cytokines and CC chemokines associated with disease progression. These findings indicate that the antibody-mediated acute CD4+ T cell depletion had minimal impact on plasma viral load and disease progression in chronically SHIVSF162P3N-infected cynomolgus monkeys. Future investigations are necessary to identify the key factor(s) related to the immune activation and macrophage infection during the CD4 deletion in chronic viral infection.

目的建立中国恒河猴SHIVKU-1艾滋病模型,观察感染SHIVKU-1的中国恒河猴中枢神经系统损伤的病理改变特点。方法用SHIVKU-1感染2只中国恒河猴（编号WSH01和WSH02）,分别于感染后第72周和第70周出现严重艾滋病症状时执行安乐死。取脑组织的不同部位行常规病理切片,进行HE染色检查和免疫组织化学染色检查。结果 WSH01恒河猴感染晚期出现站立困难、行动迟缓、左半身控制能力丧失等明显的神经艾滋临床症状。WSH02恒河猴感染晚期全身耗竭,严重腹泻。HE染色检查WSH01恒河猴小脑、脑干、枕叶中可见多核巨细胞浸润和神经胶质小结形成;大脑皮层小胶质细胞增生;海马回神经元细胞减少、排列无序。病理诊断为艾滋病脑炎。WSH02猴仅在脑组织中观察到部分小胶质细胞结节,未见其他明显的神经病理损伤。免疫组化检查观察到在实验猴脑组织有两种主要的损伤形式,分别为典型的血管周病变和弥散性病变;大量活化巨噬细胞和小胶质细胞浸润和激活,多核巨细胞形成（CD68,CD163,Iba-1）;损伤部位SHIVKU-1病毒蛋白P28强阳性（SIV p28）;WSH01恒河猴海马回神经元细胞明显减少且排列无序（MAP2）。结论中国恒河猴SHIVKU-1感染导致中枢神经系统损伤,脑组织各部位表现出不同程度的病理改变,以大量巨噬细胞/小胶质细胞浸润、激活,并伴有病毒显著增殖为主。

Hepatitis C virus (HCV) is a major cause of human chronic liver disease and hepatocellular carcinoma. Our recent studies showed that α1,6-fucosyltransferase (FUT8), a key glycosyltransferase, was the most up-regulated glycosyltransferase after the HCV infection of human hepatocellular carcinoma Huh7.5.1 cells. Here, we further studied the effects and possible mechanism of FUT8 on the proliferation of HCV and chemotherapy-resistance of HCV-infected Huh7.5.1 cells. The effects of FUT8 on the proliferation and drug resistance of HCV-infected Huh7.5.1 cells were analyzed by flow cytometry analysis (FCM), quantitative real-time polymerase chain reaction (qRT-PCR), Western blot analysis and lactate dehydrogenase (LDH) release assay. Results: We found that FUT8 not only promoted Huh7.5.1 proliferation by activating PI3K-AKT-NF-κB signaling, but also stimulated the expression of the drug-resistant proteins P-glycoprotein (P-gp) and multidrug resistance related protein 1 (MRP1) and enhanced the 5-fluorouracil (5-FU) chemo-resistance of Huh7.5.1 cells. Silencing of FUT8 reduced the cell proliferation and increased the 5-FU sensitivity of HCV-infected Huh7.5.1 cells. Inhibition of P-gp and MRP1 increased the 5-FU drug sensitivity in HCV infected Huh7.5.1 cells. HCV-induced FUT8 promotes proliferation and 5-FU resistance of Huh7.5.1 cells. FUT8 may serve as a therapeutic target to reverse chemotherapy resistance in HCV-infected Huh7.5.1 cells.

Animal models are crucial for the study of severe infectious diseases, which is essential for determining their pathogenesis and the development of vaccines and drugs. Animal experiments involving risk grade 3 agents such as SARS CoV, HIV, M.tb, H7N9, and Brucella must be conducted in an Animal Biosafety Level 3 (ABSL-3) facility. Because of the in vivo work, the biosafety risk in ABSL-3 facilities is higher than that in BSL-3 facilities. Undoubtedly, management practices must be strengthened to ensure biosafety in the ABSL-3 facility. Meanwhile, we cannot ignore the reliable scientific results obtained from animal experiments conducted in ABSL-3 laboratories. It is of great practical significance to study the overall biosafety concepts that can increase the scientific data quality. Based on the management of animal experiments in the ABSL-3 Laboratory of Wuhan University, combined with relevant international and domestic literature, we indicate the main safety issues and factors affecting animal experiment results at ABSL-3 facilities. Based on these issues, management practices regarding animal experiments in ABSL-3 facilities are proposed, which take into account both biosafety and scientifically sound data.

Nonalcoholic steatohepatitis (NASH) is a common clinical condition that can lead to advanced liver diseases. Lack of effective pharmacotherapies for NASH is largely attributable to an incomplete understanding of its pathogenesis. The deubiquitinase cylindromatosis (CYLD) plays key roles in inflammation and cancer. Here we identified CYLD as a suppressor of NASH in mice and in monkeys. CYLD is progressively degraded upon interaction with the E3 ligase TRIM47 in proportion to NASH severity. We observed that overexpression of Cyld in hepatocytes concomitantly inhibits lipid accumulation, insulin resistance, inflammation and fibrosis in mice with NASH induced in an experimental setting. Mechanistically, CYLD interacts directly with the kinase TAK1 and removes its K63-linked polyubiquitin chain, which blocks downstream activation of the JNK-p38 cascades. Notably, reconstitution of hepatic CYLD expression effectively reverses disease progression in mice with dietary or genetically induced NASH and in high-fat diet-fed monkeys predisposed to metabolic syndrome. Collectively, our findings demonstrate that CYLD mitigates NASH severity and identify the CYLD-TAK1 axis as a promising therapeutic target for management of the disease.

Non-alcoholic steatohepatitis (NASH) is an increasingly prevalent liver pathology that can progress from non-alcoholic fatty liver disease (NAFLD), and it is a leading cause of cirrhosis and hepatocellular carcinoma. There is currently no pharmacological therapy for NASH. Defective lysosome-mediated protein degradation is a key process that underlies steatohepatitis and a well-recognized drug target in a variety of diseases; however, whether it can serve as a therapeutic target for NAFLD and NASH remains unknown. Here we report that transmembrane BAX inhibitor motif-containing 1 (TMBIM1) is an effective suppressor of steatohepatitis and a previously unknown regulator of the multivesicular body (MVB)-lysosomal pathway. Tmbim1 expression in hepatocytes substantially inhibited high-fat diet-induced insulin resistance, hepatic steatosis and inflammation in mice. Mechanistically, Tmbim1 promoted the lysosomal degradation of toll-like receptor 4 by cooperating with the ESCRT endosomal sorting complex to facilitate MVB formation, and the ubiquitination of Tmbim1 by the E3 ubiquitin ligase Nedd4l was required for this process. We also found that overexpression of Tmbim1 in the liver effectively inhibited a severe form of NAFLD in mice and NASH progression in monkeys. Taken together, these findings could lead to the development of promising strategies to treat NASH by targeting MVB regulators to properly orchestrate the lysosome-mediated protein degradation of key mediators of the disease.

Nat. Med. 23, 439–449 (2017); published online 20 February 2017; corrected after print 26 July 2017 In the version of this article initially published, the authors inadvertently left out information in the Online Methods section regarding a second injection of AAV8-CFLAR(S1) 7 weeks after the first injection in the monkey experiments to ensure stable expression of CFLAR(S1) in the livers of the monkeys that received the injections.

Tuberculosis (TB) is a serious disease around the world, and protein based subunit vaccine is supposed to be a kind of promising novel vaccine against it. However, there is no effective adjuvant available in clinic to activate cell-mediated immune responses which is required for TB subunit vaccine. Therefore, it is imperative to develop new adjuvant. Here we reported an adjuvant composed of dimethyl dioctadecylammonium (DDA), Poly I:C and cholesterol (DPC for short). DDA can form a kind of cationic liposome with the ability to deliver and present antigen and can induce Th1 type cell-mediated immune response. Poly I:C, a ligand of TLR3 receptor, could attenuate the pathologic reaction induced by following Mycobacterium tuberculosis challenge. Cholesterol, which could enhance rigidity of lipid bilayer, is added to DDA and Poly I:C to improve the stability of the adjuvant. The particle size and Zeta-potential of DPC were analyzed in vitro. Furthermore, DPC was mixed with a TB fusion protein ESAT6-Ag85B-MPT64(190-198)-Mtb8.4-Rv2626c (LT70) to construct a subunit vaccine. The subunit vaccine-induced immune responses and protective efficacy against M. tuberculosis H37Rv infection in C57BL/6 mice were investigated. The results showed that the DPC adjuvant with particle size of 400 nm and zeta potential of 40 mV was in good stability. LT70 in the adjuvant of DPC generated strong antigen-specific humoral and cell-mediated immunity, and induced long-term higher protective efficacy against M. tuberculosis infection (5.41 ± 0.38log10CFU) than traditional vaccine Bacillus Calmette-Guerin (BCG) (6.01 ± 0.33log10CFU) and PBS control (6.53 ± 0.26log10CFU) at 30 weeks post-vaccination. In conclusion, DPC would be a promising vaccine adjuvant with the ability to stimulate Th1 type cell-mediated immunity, and could be used in TB subunit vaccine.

Altered T-cell homeostasis, such as expansion of CD8+ T cells to the secondary lymphatic compartments, has been suggested as a mechanism of HIV/simian immunodeficiency virus (SIV)-pathogenesis. However, the role of immune activation of CD8+ T cells in the CD4/CD8 turnover and viral replication in these tissues is not completely understood. In this study, we compared the expression of immune activation markers (CD69 and HLA-DR) on CD8+ T cells in the peripheral blood and lymph nodes (LNs) of SIV-infected/uninfected Chinese rhesus macaques. SIV-infected macaques had significantly higher percentages of CD8+CD69+ and CD8+HLA-DR+ T cells in all these anatomical compartments than uninfected macaques. LNs that located close to the gastrointestinal (GI) tract (colon, mesenteric, and iliac LNs) of SIV-infected macaques had profoundly lower numbers of CD4+ T cells, but no significant difference in expression of activation marker (CD8+CD69+ and CD8+HLA-DR+) as compared with the peripheral lymphatic tissues (axillary and inguinal LNs). The CD4/CD8 ratios were negatively correlated with the activation of CD8+ T cells in the overall LNs, with further associations with CD8+HLA-DR+ in GI LNs while CD8+CD69+ in peripheral LNs. These observations demonstrate that the increase of CD8+ T cell activation is a contributing factor for the decline of CD4/CD8 ratios in GI system.

Regulatory T cells (Tregs), which could be down-regulated by IL-28B, were reported to suppress T-cell-mediated immunity. The aim of this study was to investigate the role of IL-28B on the immune responses and protective efficacy of a tuberculosis (TB) subunit vaccine. First, a recombinant adenoviral vector expressing mouse IL-28B (rAd-mIL-28B) was constructed; then C57BL/6 mice were immunized with subunit vaccine ESAT6-Ag85B-Mpt64(190-198)-Mtb8.4-HspX (EAMMH) and rAd-mIL-28B together thrice or primed with Mycobacterium bovis bacillus Calmette-Gue'rin (BCG) and boosted by EAMMH and rAd-mIL-28B twice. At last the immune responses were evaluated, and the mice primed with BCG and boosted by subunit vaccines were challenged with virulent Mycobacterium tuberculosis H37Rv to evaluate the protective efficacy. The results showed that rAd-mIL-28B treatment significantly down-regulated the frequency of Tregs at 4 weeks after the last immunization but did not increase the Th1-type immune responses. Moreover, in the regimen of BCG priming and EAMMH boosting, rAd-mIL-28B treatment did not increase the antigen-specific cellular and humoral immune responses, and consequently did not reduce the bacteria load following H37Rv challenge. Instead, it induced more serious pathology reaction. In conclusion, IL-28B down-regulates Tregs following EAMMH vaccination but does not improve the protective immune responses.

目的 探讨不同地理分布的恒河猴亚种在结核分枝杆菌感染实验中的反应差异,为在结核疫苗评价中选择合适的动物模型提供依据. 方法 通过纤维支气管镜定量感染湖北、广西恒河猴,建立急性感染结核病模型.在不同的时间点检测血液、血生化(包括C反应蛋白)、血沉等指标,并对组织细菌载量、肺组织和淋巴结病理切片进行对比分析.结果 湖北恒河猴的血液学指标在感染期间均呈下降趋势,在第16、20周(感染后期)均低于广西恒河猴,但血沉值在12、16、20周呈上升趋势,均高于广西恒河猴.两组恒河猴血液中性粒细胞在第12周(湖北猴1.1×1010/L,广西猴4.7×109/L)、淋巴细胞第4周(湖北猴1.7×109/L,广西猴6.8×109/L)和嗜碱性粒细胞在感染前(湖北猴4.3×107/L,广西猴2.0×108/L)差异有统计学意义(P＜0.01),血小板在16周(湖北猴3.8×1011/L,广西猴4.5×109/L)、20周(湖北猴4.1×1011/L,广西猴4.9×109/L)差异有统计学意义(P＜0.01).湖北恒河猴左肺细菌载量(4.52 lgCFU/g)低于广西恒河猴(6.30 lgCFU/g)(P＜0.05).与广西恒河猴相比较,湖北恒河猴左、中、上肺有明显结核结节. 结论 在MTB的急性感染实验中,湖北和广西恒河猴的血液学指标、部分组织的细菌载量和病理改变均存在差异.

Continuous high global tuberculosis (TB) mortality rates and variable vaccine efficacy of mycobacterium Bacille Calmette-Guérin (BCG) emphasize the need for improved vaccines and drugs against TB, which require clinically relevant animal models for evaluation. We infected a total of 24 Chinese rhesus macaques with varying doses (CFU of 25, 100 and 500) of Mycobacterium tuberculosis (M.tb) Erdman strain via bronchoscopy. Regardless of the M.tb doses, all animals were infected successfully with minor differences in clinical progression; as evidenced by clinical manifestations, laboratory analyses, bacterial burden in infected tissues and histopathology evaluations. Rhesus macaques of Chinese origin are highly susceptible to infection with M.tb Erdman strain and develop acute TB disease, which is similar to that in humans. Pathologically, Chinese rhesus macaques recapitulated the complete spectrum of granulomatous lesions seen in human TB disease. These data indicate that low-dose infection of rhesus macaques of Chinese origin is a suitable model for acute M.tb infection.

Tuberculosis (TB) is a common opportunistic infection and the leading cause of death for human immunodeficiency virus (HIV)-infected patients. Thus, it is necessary to understand the pathogenetic interactions between M.tb and HIV infection. In this study, we examined M.tb and/or simian immunodeficiency virus (SIV) infection of Chinese rhesus macaques. While there was little evidence that M.tb enhanced SIV infection of macaques, SIV could facilitate M.tb infection as demonstrated by X-rays, pathological and microbiological findings. Chest X-rays showed that co-infected animals had disseminated lesions in both left and right lungs, while M.tb mono-infected animals displayed the lesions only in right lungs. Necropsy of co-infected animals revealed a disseminated M.tb infection not only in the lungs but also in the extrapulmonary organs including spleen, pancreas, liver, kidney, and heart. The bacterial counts in the lungs, the bronchial lymph nodes, and the extrapulmonary organs of co-infected animals were significantly higher than those of M.tb mono-infected animals. The mechanistic studies demonstrated that two of three co-infected animals had lower levels of M.tb specific IFN-γ and IL-22 in PBMCs than M.tb mono-infected animals. These findings suggest that Chinese rhesus macaque is a suitable and alternative non-human primate model for SIV/M.tb coinfection studies. The impairment of the specific anti-TB immunity is likely to be a contributor of SIV-mediated enhancement M.tb infection.

To search for more effective tuberculosis (TB) subunit vaccines, antigens expressed in different growth stages of Mycobacterium tuberculosis (M. tuberculosis), such as RpfE (Rv2450c) produced in the stage of resuscitation, Mtb10.4 (Rv0288), Mtb8.4 (Rv1174c), ESAT6 (Rv3875), Ag85B (Rv1886c) mainly secreted by replicating bacilli, and HspX (Rv2031c) highly expressed in dormant bacilli, were selected to construct six fusion proteins: ESAT6-Ag85B-MPT64190-198-Mtb8.4 (EAMM), Mtb10.4-HspX (MH), ESAT6-Mtb8.4, Mtb10.4-Ag85B, ESAT6-Ag85B, and ESAT6-RpfE. The six fusion proteins were separately emulsified in an adjuvant composed of N,N'-dimethyl-N, N'-dioctadecylammonium bromide (DDA), polyribocytidylic acid (poly I:C) and gelatin to construct subunit vaccines, and their protective effects against M. tuberculosis infection were evaluated in C57BL/6 mice. Furthermore, the boosting effects of EAMM and MH in the adjuvant of DDA plus trehalose 6,6'-dimycolate (TDM) on BCG-induced immunity were also evaluated. It was found that the six proteins were stably produced in E. coli and successfully purified by chromatography. Among them, EAMM presented the most effective protection against M. tuberculosis. Interestingly, the mice that received EAMM+MH had significantly lower bacterial counts in the lungs and spleens than the single protein vaccinated groups, and had the same effect as those that received BCG. In addition, EAMM and MH could improve BCG-primed protective efficacy against M. tuberculosis infection in mice. In conclusion, the combination of EAMM and MH containing antigens from both replicating and dormant stages of the bacilli could induce robust immunity against M. tuberculosis infection in mice and may serve as promising subunit vaccine candidate.

This study investigated the therapeutic effects of interleukin (IL)-2 and granulocyte-macrophage colony-stimulating factor (GM-CSF) co-administrated with antibacterial agents isoniazid (INH) and rifampin (RIF) to treat a mouse model of tuberculosis (TB) infection. A drug-susceptible TB strain, H37Rv was used to infect mice and the effectiveness of IL-2 and GM-CSF was initially evaluated based on survival rate, bacterial counts in lungs and spleens and the pathological condition of the lungs. Next, the therapeutic effect of the immunotherapy regimen was assessed in multidrug-resistant strain OB35-infected mice. In the H37Rv infection model, IL-2 and GM-CSF monotherapies reduced bacterial numbers in the lungs by 0.82 (P < 0.01) and 0.58 (P < 0.05) lg colony-forming units (CFU), respectively, and in the spleens by 1.42 (P < 0.01) and 1.22 (P < 0.01) lg CFU, respectively, compared with the untreated group. Mice receiving immunotherapy developed fewer lesions in the lungs compared with mice receiving antibacterial therapy alone. In the OB35 infection model, immunotherapy with either cytokine resulted in a significant reduction of bacterial load in the lungs and spleens and less severe lesions in the lungs compared with the untreated or antibacterial therapy treated mice. Notably, mice receiving immunotherapy with both cytokines had a 30% survival rate which was higher than that in other treated groups, and had significantly less CFUs in the lungs and spleens (1.02 and 1.34 lg CFU) compared with antibacterial therapy alone (P < 0.01). This study demonstrated that immunotherapy with both IL-2 and GM-CSF may be useful to treat multidrug resistant tuberculosis (MDR-TB).

BACKGROUND:Azithromycin can reduce neutrophil accumulation in neutrophilic pulmonary diseases. However, the precise mechanism behind this action remains unknown. Our experiment assessed whether azithromycin inhibits neutrophil accumulation in the airways by affecting interleukin-17 (IL-17) downstream signals.METHODS:Mice were pretreated with azithromycin before murine IL-17A (mIL-17) stimulation. After the mIL-17 stimulation, the levels of six neutrophil-mobilizing cytokines were determined by enzyme-linked immunosorbent assay (ELISA) tests in bronchoalveolar lavage (BAL) fluid; IL-6, CXC chemokine ligand-1 (CXCL-1), CXCL-5, macrophage inflammatory protein-2 (MIP-2), granulocyte colony-stimulating factor (G-CSF), and granulocyte macrophage colony-stimulating factor (GM-CSF). The number of neutrophils in BAL fluid were evaluated by cytospin preparations.RESULTS:(1) Azithromycin pretreatment significantly inhibited both the release of three neutrophil-mobilizing cytokines (MIP-2, CXCL-5 and GM-CSF) and the accumulation of neutrophils in airways caused by mIL-17 stimulation. (2) The levels of three neutrophil-mobilizing cytokines (IL-6, MIP-2 and GM-CSF) were positively correlated with the numbers of neutrophil in BAL fluid.CONCLUSIONS:Azithromycin can inhibit neutrophil accumulation in the airways by affecting IL-17 downstream signals. This finding suggests that macrolide antibiotic application might be useful in prevention of neutrophilic pulmonary diseases characterized by high levels of IL-17.

OBJECTIVE:To establish and evaluate the Chinese rhesus model of tuberculosis.METHODS:Twelve Chinese rhesus macaques, randomly divided into 3 groups, were inoculated with 2 different doses of Mycobacterium tuberculosis H(37) Rv strain via both bronchoscopic and intratracheal instillation into the lungs. Clinical observation and laboratory examinations were performed, including erythrocyte sedimentation rate, C-reactive protein, tuberculin skin test and X-ray examination. Histopathological assessments were performed in the 24th week postinfection. Statistical analysis was performed by ANOVA in the 3 groups.RESULTS:After infection all the animals manifested fever, weight lose, lack of appetite, coughing and other symptoms of tuberculosis. The temperature gradually increased and reached a peak [(40.1 ± 0.2)°C] at the 8th week postinfection. The weight decreased significantly at 24th week postinfection (-5.5 ± 5.6)%. Erythrocyte sedimentation rate elevated significantly at the 6th to 8th week postinfection (36 ± 40) mm/1 h. C-reactive protein was significantly increased at the 6th to 24th week after infection (75.8 ± 49.8) mg/L. The positive rate of tuberculin skin test was 100%. In Group I (bronchoscopic instillation, 20 CFU) the disease developed slowly, and the main manifestation of chest X-ray was patchy shadows. In group II (bronchoscopic instillation, 100 CFU) and group III (intratracheal instillation, 100 CFU) the disease developed rapidly, and the main manifestation of chest X-ray was patchy and nodular lesions during the 4th to the 12th week postinfection, but became large patchy and consolidation lesions during the 12th to the 24th week postinfection. Tuberculosis granuloma and caseous necrosis, similar to the pathological changes of human tuberculosis, were found in the lungs, mediastinal lymph nodes, kidney and spleen. The results of acid-fast stain were positive. The most serious pathological manifestations were observed in group II, followed by group III and group I. The highest bacterial load of the right lung was seen in group II, followed by group I and group III.CONCLUSIONS:A chinese rhesus model of tuberculosis was successfully developed via both bronchoscopic and intratracheal instillation. Their clinical manifestations, disease progression and pathological changes were similar to human primary tuberculosis and hematogenous disseminated tuberculosis.

Objectives: To evaluate regimens using bacillus Calmette-Guerin (BCG) or recombinant BCG (rBCG) overexpressing Ag85B for priming, followed by boosting with a modified vaccinia virus Ankara strain (MVA) and/or adenovirus vector (AD) expressing an Ag85B-ESAT6 fusion protein.Methods: Cellular and humoral immune responses were determined after subcutaneous vaccination, which was employed to trigger systemic immunity against intravenous infection in a mouse model of tuberculosis (TB). Bacterial loads and lung histology were evaluated.Results: The relative IgG2a and IgG1 antibody levels indicated that the viral-vectored vaccines generated a T-helper type 1 (Th1)-biased response after two doses of viral boost vaccinations. Boosting BCG-primed mice with viral vaccines induced a Th1 immune response that included both CD4 and CD8 T-cells generating antigen-specific interferon-gamma (IFN-gamma) and CD8 T cytotoxic activity. Only mice vaccinated with two different viral boosters after BCG priming exhibited a significant reduction in bacterial burden in the lung after challenge. Histology examinations confirmed the attenuation of lung damage and more compact granulomas. After mycobacteria priming, boosting with AD85B-E6 followed by MVA85B-E6 afforded better protection than the reverse order of administration of the viral vectors.Conclusions: This study demonstrates the potential of multiple heterologous viral booster vaccines, although the exact correlates of protection and optimal regimens should be further investigated for the rational design of future vaccine strategies. (C) 2012 International Society for Infectious Diseases. Published by Elsevier Ltd. All rights reserved.