Suppression of antigen-specific lymphocyte activation in modeled microgravity

Various parameters of immune suppression are observed in lymphocytes from a stronauts during and after a space flight. it is difficult to ascribe this suppression to microgravity effects on immune cells in crew specimens, due to the complex physiological response to space flight and the resultant eff ect on in vitro immune performance. Use of isolated immune cells in true an d modeled microgravity in immune performance tests, suggests a direct effec t of microgravity on in vitro cellular function. Specifically, polyclonal a ctivation of T-cells is severely suppressed in true and modeled microgravit y. These recent findings suggest a potential suppression of oligoclonal ant igen-specific lymphocyte activation in microgravity. We utilized rotating w all vessel (RWV) bioreactors as an analog of microgravity for cell cultures to analyze three models of antigen-specific activation. A mixed-lymphocyte reaction, as a model for a primary immune response, a tetanus toroid respo nse and a Borrelia burgdorferi response, as models of a secondary immune re sponse, were all suppressed in the RWV bioreactor. Our findings confirm tha t the suppression of activation observed with polyclonal models also encomp asses oligoclonal antigen-specific activation.