EFFECT OF SPACE-FLIGHT ON CYTOKINE PRODUCTION AND OTHER IMMUNOLOGICALPARAMETERS OF RHESUS-MONKEYS

During a recent flight of a Russian satellite (Cosmos #2229), initial experiments examining the effects of space flight on immunologic respo nses of rhesus monkeys were performed to gain insight into the effect of space flight on resistance to infection, Experiments were performed on tissue samples taken from the monkeys before and immediately after flight, Additional samples were obtained approximately 1 month after flight for a postflight restraint study, Two types of experiments were carried out throughout this study. The first experiment determined th e ability of leukocytes to produce interleukin-l and to express interl eukin-2 receptors. The second experiment examined the responsiveness o f rhesus bone marrow cells to recombinant human granulocyte-macrophage colony-stimulating factor (GM-CSF), Human reagents that cross-reacted with monkey tissue were utilized for the bulk of the studies, Results from both studies indicated that there were changes in immunologic fu nction attributable to space flight, Interleukin-l production and the expression of interleukin-2 receptors was decreased after space flight . Bone marrow cells from flight monkeys showed a significant decrease in their response to GM-CSF compared with the response of bone marrow cells from nonflight control monkeys, These results suggest that the r hesus monkey may be a useful surrogate for humans in future studies th at examine the effect of space flight on immune response, particularly when conditions do not readily permit human study.