INDUCTION OF CYTOKINES IN MICE WITH PARAINFLUENZA PNEUMONIA

The possible involvement of cytokines in the acute viral pneumonia ind uced by the murine parainfluenza type 1 virus, Sendai virus, was studi ed. Cytokine profiles for both the respiratory tract and the draining mediastinal lymph node (MLN) of virus-infected C57BL/6J mice were quan tified by using the single-cell cytokine (ELISPOT) assay with freshly isolated cell populations and enzyme-linked immunosorbent assay for lu ng lavage fluids and culture supernatants. Maximal levels of interleuk in 2 (IL-2), gamma interferon (IFN-gamma), tumor necrosis factor, IL-6 , and IL-10 were detected at the inflammatory site 7 to 10 days after infection, about the time that virus is cleared from the lung. The fre quencies of cells producing IL-2, IL-4, IL-6, IL-10, IFN-gamma, and tu mor necrosis factor were much higher for the bronchoalveolar lavage (B AL) cell population than for the MLN cell population. Cytokine product ion after in vitro restimulation of MLN cells was dominated by IL-2 an d IFN-gamma, with low levels of IL-10 and IL-6 also being present, Mos t of the cytokine was produced by the CD4(+) cells, although the CD8() subset was also involved, No IL-4 was found in the BAL fluid or in c ulture supernatants from restimulated BAL or MLN cells, although a hig h frequency of IL-4 producing cells was demonstrated in the BAL popula tion by ELISPOT analysis.