GENE-EXPRESSION AND PRODUCTION OF TUMOR-NECROSIS-FACTOR-ALPHA, INTERLEUKIN-1, INTERLEUKIN-6, AND GAMMA-INTERFERON IN C3H HEN AND C57BL/6N MICE IN ACUTE MYCOPLASMA-PULMONIS DISEASE/

Studies were conducted to determine whether the production of various cytokines is associated with Mycoplasma pulmonis disease expression. S usceptible C3E/HeN and resistant C57BL/6N mice were inoculated intrana sally with 10(7) CFU of virulent M. pulmonis UAB CT or avirulent M. pu lmonis UAB T. Expression of genes for tumor necrosis factor alpha (TNF -alpha), interleukin lot (IL-1 alpha), IL-1 beta, IL-6, and gamma inte rferon (IFN-gamma) in whole lung tissue and TNF-alpha gene expression in bronchoalveolar lavage (BAL) cells was determined by reverse transc ription-PCR using specific cytokine primers at various times postinocu lation. In addition, concentrations of TNF-alpha, IL-1, IL-6, and IFN- gamma were determined in BAL fluid and serum samples at various times postinoculation. Our results shelved that there was a sequential appea rance of cytokines in the lungs of infected mice: TNF-alpha, produced primarily by BAL cells, appeared first, followed by IL-1 and IL-6, whi ch were followed by IFN-gamma. Susceptible C3H/HeN mice had higher and more persistent concentrations of TNF-alpha and IL-6 in BAL fluid tha n did resistant C57BL/6N mice, indicating that TNF-alpha and possibly IL-6 are important factors in pathogenesis of acute M. pulmonis diseas e in mice. Serum concentrations of IL-6 were elevated in C3H/HeN mice, but not C57BL/6N mice, following infection with M. pulmonis, suggesti ng that IL-6 has both local and systemic effects in M. pulmonis diseas e.