Aim: 

In the last two decades previous experiments performed in space have shown that in vitro T lymphocytes activation is remarkably reduced in microgravity conditions. In order to study T cells behaviour during simulated microgravity we focused our attention on chemokine receptors modulation. Chemokines are a family of molecules that regulate several biologic functions through activation of their cognate receptors, (e.g. lymphocyte chemotaxis, lymphocyte homing and differentiation, virus-host interactions). We investigated CCR7, CCR5, CCR4 e CXCR3 expression.

Methods: 

Human peripheral blood leukocytes (PBMC) were isolated by Hystopaque 1077 density gradient centrifugation, and T cells were purified using high affinity CD3+ T-cell enrichment columns. T cells, activated with a final concentration of 5 mg/ml Con A with 4 mg/ml anti-CD28 antibody and unactivated controls, were incubated at 1 × g or at RPM (0 × g) for 72 h at 37°C. The chemokine receptors expression were analyzed on a BD-LSR cytofluorimeter using the CELLQuest™ software (Becton Dickinson).

Results: 

Preliminary data have shown a CXCR3 up-regulated, (especially in unstimulated cells) in simulated low g conditions, respect to the ground controls, in both PBMC and T cell. On other hand, no changes were observed in CCR4, CCR5 and CCR7 expression.

Conclusion: 

Several aspects remained to be elucidated to explain the mechanisms by which CXCR3 is up-regulated on T lymphocyte during simulated microgravity conditions. At present we are performing RT- PCR experiments on CXCR3 genes modulation in modelled microgravity conditions. Research supported by Italian Space Agency.