Le. Bermudez et M. Petrofsky, Host defense against Mycobacterium avium does not have an absolute requirement for major histocompatibility complex class I-restricted T cells, INFEC IMMUN, 67(6), 1999, pp. 3108-3111
The role of CD8(+) T cells was evaluated in a mouse model of disseminated M
ycobacterium avium infection. C57BL/6J and C57BL/6J beta(2)(-/-) (beta(2)(-
/-)) mice were infected intravenously, and the number of viable bacteria in
each liver and spleen was determined. No significant difference between th
e number of bacteria in the two strains of mice was observed at 2, 4, 6, an
d 8 weeks after infection. Histopathological examination of granulomas from
C57BL/6J and beta(2)(-/-) mice did not show any difference either in the n
umber of organisms per granuloma or in the size of the granulomas, Investig
ation of the cytokine profile in the spleen demonstrated that the beta(2)(-
/-) strain of mice produced a significantly lower amount of gamma interfero
n at 8 weeks after infection and significantly increased concentrations of
tumor necrosis factor alpha compared with that from the wild-type mouse. In
terleukin-12 and transforming growth factor beta(1) levels did not differ b
etween the two strains of mice at 2, 4, 6, and 8 weeks. Although previous w
ork had found that host response against Mycobacterium tuberculosis involve
s major histocompatibility complex class I-restricted T cells, our results
indicate that chronic deficiency of CD8(+) T cells does not lead to a diffe
rent expression of the disease and that if CD8(+) T cells are involved in t
he host response, their function can be assumed by other immune cells.