[Establishment and evaluation of a Chinese rhesus model of tuberculosis].

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.

CD4+ T cell depletion does not affect the level of viremia in chronically SHIVSF162P3N-infected Chinese cynomolgus monkeys.

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.

SIV Infection Impairs the Central Nervous System in Chinese Rhesus Macaques.

The central nervous system (CNS) impairment is a consequence seen in SIV infection of rhesus macaques of Indian-origin, which is more common in infected macaques with rapid disease progression than in those with conventional disease progression. Here, we investigated the CNS damages in SIVmac239-infected Chinese rhesus macaques. We demonstrated that SIV infection of Chinese macaques could cause neuropathological impairments, which was evidenced by appearance of SIV-RNA positive cells, the infiltration of activated macrophages and abundant multinucleated giant cells (MNGCs) in the different regions of the brains. The animals with high viremia and short survival time (average of 16 weeks, rapid progression, RP) had severer neuropathological changes than those with conventional progression (CP). As compared with the RP animals, CP macaques had lower viremia and much longer survival time (average of 154 weeks). These findings indicate that SIVmac239 infection of Chinese rhesus macaque can be used as a suitable animal model and alternative resource for nueroAIDS research.

SIV Infection Facilitates Mycobacterium tuberculosis Infection of Rhesus Macaques.

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.

Azithromycin inhibits neutrophil accumulation in airways by affecting interleukin-17 downstream signals.

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.

M. tuberculosis H37Rv infection of Chinese rhesus macaques.

Mycobacterium tuberculosis is the most common communicable infectious disease worldwide and the top killer of human immunodeficiency virus (HIV)-infected people. Because of common dual HIV and M. tuberculosis infections, the emergence of multidrug-resistant M. tuberculosis strains, the lack of effective vaccination, the morbidity, and the mortality of M. tuberculosis infection are increasing sharply. Therefore, there is an urgent need for vaccine and drug development against M. tuberculosis infection. These require appropriate animal models that closely resemble human disease. To this end, we infected Chinese rhesus macaques with the M. tuberculosis H37Rv strain. Bronchoscopy was used to inoculate nine monkeys with different doses of M. tuberculosis H37Rv strain. Regardless of the M. tuberculosis dose, all monkeys were infected successfully. This was shown by clinical, laboratory, and histopathology assessments. Among nine infected monkeys, six developed acute rapid progressive tuberculosis and the remaining animals mirrored early-stage chronic disease. These data, taken together, demonstrate that Chinese rhesus macaques are highly susceptible to M. tuberculosis infection and develop similar manifestations of disease that are seen in humans. This model affords new opportunities for studies of M. tuberculosis disease pathology and therapeutics.