title: Dynamic culture in a rotating-wall vessel bioreactor differentially inhibits murine T-lymphocyte activation by mitogenic stimuli upon return to static conditions in a time-dependent manner.
abstract: Depressed immune function is a well-documented effect of spaceflight. Both in-flight studies and ground-based studies using microgravity analogs, such as rotating wall vessel (RWV) bioreactors, have demonstrated that mitogen-stimulated T lymphocytes exhibit decreased proliferation, IL-2 secretion, and activation marker expression in true microgravity and the dynamic RWV-culture environment. This study investigates the kinetics of RWV-induced T lymphocyte inhibition by monitoring the ability of Balb/c mouse splenocytes to become activated under static culture conditions after concanavalin A (Con A) stimulation in an RWV. Splenocytes were stimulated with Con A and cultured for up to 24 h in the RWV before being allowed to "recover" under static culture conditions in the continued presence of Con A. The T-lymphocyte fraction of splenocytes was assayed during the recovery period for IL-2 secretion, expansion of the T-lymphocyte population, and expression of the activation marker CD25. Our results indicate that CD25 expression was not affected by any duration of RWV exposure. In contrast, proliferation and IL-2 secretion were inhibited by >8 and 12 h of exposure, respectively. Culture in the RWV for 24 h resulted in a near-complete loss of cellular viability during the recovery period, which was not seen in cells maintained in the RWV for 16 h or less. Taken together, these results indicate that for up to 8 h of RWV culture activation is not significantly impaired upon return to static conditions; longer duration RWV culture results in a gradual loss of activation during the recovery period most likely because of decreased T-cell viability and/or IL-2 production.
authors.affiliation: School of Biomedical Engineering, Science, and Health Systems, Drexel University, Commonwealth Hall 7-721, 3142 Chestnut St., Philadelphia, PA 19104, USA.
authors.forename: D M
authors.initials: DM
authors.lastname: Simons
authors.forename: E M
authors.initials: EM
authors.lastname: Gardner
authors.forename: P I
authors.initials: PI
authors.lastname: Lelkes
mesh_terms: D000818:Animals; D019149:Bioreactors; D049109:Cell Proliferation; D002470:Cell Survival; D002478:Cells, Cultured; D003208:Concanavalin A / Q000494:pharmacology; D007376:Interleukin-2 / Q000378:metabolism; D007700:Kinetics; D008213:Lymphocyte Activation; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008934:Mitogens / Q000494:pharmacology*; D012399:Rotation; D013154:Spleen / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D013601:T-Lymphocytes / Q000187:drug effects* / Q000378:metabolism; D018474:Weightlessness Simulation / Q000295:instrumentation
chemical_list: D007376:Interleukin-2; D008934:Mitogens; D003208:Concanavalin A