RESPIRATORY SYNCYTIAL VIRUS TRIGGERS SYNTHESIS OF IL-6 IN BALB C MOUSE ALVEOLAR MACROPHAGES IN THE ABSENCE OF VIRUS-REPLICATION/

Cytokines produced by alveolar macrophages are likely involved in the regulation of the immune response arising from respiratory syncytial v irus (RSV) infection. Both infectious and UV-inactivated RSV were effe ctive in inducing BALB/c mouse alveolar macrophages to synthesize incr eased levels of IL-6 mRNA and secreted IL-6 protein. No increase in IL -1 beta (either mRNA or secreted protein) was observed. The augmented production of IL-6 was activated by purified virus and was reduced by pretreating virus with virus-neutralizing antiserum, demonstrating a r equirement for virus in the enhanced IL-6 response. The results sugges t that the exposure of BALB/c alveolar macrophages to small quantities of RSV (in the absence of detectable virus replication) is sufficient to trigger IL-6 production, The finding that UV-inactivated virus was effective in triggering IL-6 production by mouse alveolar macrophages is similar to that reported in human alveolar macrophages, providing further validation of the BALB/c mouse as a useful animal model for hu man RSV infection. (C) 1997 Academic Press.