ASGSB 1998 Annual Meeting Abstracts

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LYTIC VIRUS REPLICATION IN ASTRONAUTS DURING SPACE FLIGHT.   R.P. Stowe¹, D.L. Pierson², and A.D.T. Barrett¹. ¹Dept. of Pathology, University of Texas Medical Branch, Galveston, and ²Life Sciences Research Laboratories, NASA/JSC, Houston, TX.

The majority of humans are infected with Epstein-Barr virus (EBV) early in life and thereafter carry the virus in a latent form. Reactivation of latent EBV may be an important threat to crew health during extended space missions. Control of EBV replication in vivo is mediated primarily by cytotoxic T-cells, and severe clinical symptoms have been associated with reactivation of EBV in patients with defective cellular immunity. Using a space analog of prolonged isolation (Australian Antarctic expedition), we have previously shown increased antibody responses to EBV lytic proteins associated with decreased delayed-type hypersensitivity. In this study, we investigated the effects of short-space flight on latent EBV reactivation. Peripheral blood samples were collected from 16 astronauts before Launch (L-10 and L-3) and again upon Return (R+0 and R+3). The samples were analyzed for EBV antibodies to structural (viral capsid antigen-VCA) and nonstructural (early antigen-EA) proteins, human (h) and/or viral (v) interleukin (IL)-10, and IL-6. The VCA geometric mean titer was significantly increased (p<0.05) at L-10 as compared to baseline (annual physical) samples. In two astronauts, 4-fold decreases in VCA titers were observed at R+0 followed by a 4-fold increase at R+3. Plasma levels of hIL-10/vIL-10 were generally elevated at R+0. Three astronauts exhibited high hIL-10/vIL-10 levels (11.5-15.4 pg/ml) which positively correlated with either 4-fold increases in EA titers or high VCA/EA titers. IL-6 was significantly elevated at landing indicating an acute stress response to atmospheric reentry. These results indicate that lytic replication of EBV, as reflected by rising EA/high VCA antibodies, occurs during short-space flights and may pose a significant health risk on longer Lunar/Mars expeditions.

(Supported by NASA GSRP Grant NGT-51666, Houston Advanced Research Center, and UTMB Sealy Center on Aging)

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