[Mycobacterium vaccae influences the kinetics of Th1/Th2 cells and expression of iNOS in a marine model of experimental tuberculosis].
OBJECTIVE
To investigate the immunoregulative mechanism of Mycobacterium vaccae by way of molecular pathology.


METHODS
BALB/C mice were randomly divided into three groups: tuberculosis model (A); mice were challenged with H37Rv by their tail veins and then immunized by M. vaccae (B); control mice (N). Immunohistochemistry and pathological slices stained with HE were evaluated to investigate the correlation between the expression of IFN-gamma, IL-4 and iNOS and the type and magnitude of tissue injury.


RESULTS
A predominance of Th1 cells was observed manifested by a high percentage of IFN-gamma positive cells in the inflammatory infiltrate and granulomas demonstrated by immunohistology peaked 6 weeks after infection (0.058 +/- 0.010), and there was a significant increase compared with N group (0.005 +/- 0.020, P < 0.01). This was followed by a chronic advanced phase characterized by pneumonia local necrosis with a Tho balance due to an equivalent proportion of IFN-gamma and IL-4 positive cells in the lung lesions. The iNOS expression was increased in acute phase and decreased in chronic phase. B group had localized lung lesions, proliferate and lymphoid nodules were predominant, there was less necrostic change. A predominance of Th1 cells was observed during the infection changed over time and there was no Tho balance phase occurred. iNOS expression had a higher level during the wholecourse of infection.


CONCLUSIONS
M. vaccae can enhance the protective immunological response by inducing Th1 response and inhibiting Th2 response.
Zhang
L
L
Beijing Chest Hospital, Beijing 100095, China.
Ma
W
W
Da
J
J
D000818:Animals; D001428:Bacterial Vaccines / Q000276:immunology*; D005260:Female; D007150:Immunohistochemistry; D007371:Interferon-gamma / Q000096:biosynthesis; D015847:Interleukin-4 / Q000096:biosynthesis; D008168:Lung / Q000473:pathology; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D019001:Nitric Oxide Synthase / Q000032:analysis*; D052247:Nitric Oxide Synthase Type II; D018417:Th1 Cells / Q000276:immunology*; D018418:Th2 Cells / Q000276:immunology*; D014376:Tuberculosis / Q000276:immunology / Q000628:therapy*
D001428:Bacterial Vaccines; C080550:Mycobacterium w vaccine; D015847:Interleukin-4; D007371:Interferon-gamma; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; C496317:Nos2 protein, mouse