Inhibited interferon-gamma but normal interleukin-3 production from rats flown on the space shuttle.

Rats were flown on Space Shuttle SL-3 for 1 week. When spleen cells were removed from these rats and challenged with concanavalin-A, interferon-gamma production was severely inhibited, while interleukin-3 production was unaffected compared to ground-based control rats. These data indicate that there is a defect in interferon-gamma production in rats that have been exposed to spaceflight. This defect could contribute to, and be one reason for, immunosuppression observed after spaceflight.