Decreased Vβ8.2 T-cells in neonatal rats exposed prenatally to Staphylococcal enterotoxin B are further deleted by restimulation in an in vitro cultured thymus.

Staphylococcal enterotoxin B (SEB) administration during adulthood can cause the anergy or deletion of variable portion of the ? chain (V?)?expressing T cells. However, the effect of maternal SEB administration during pregnancy on the thymocytes of neonatal rats remains to be elucidated. In the present study, pregnant rats at gestational day 16 were intravenously injected with 15 µg SEB. The present study revealed that prenatal exposure of SEB significantly increased the proportion of cluster of differentiation (CD)4?single positive (SP) T cells and decreased the proportions of CD8?SP, CD4+ V?8.2+ and CD8+ V?8.2+ T cells in the thymus of neonatal rats between day 0 and 5 after delivery. In an in vitro cultured thymus, SEB restimulation significantly increased the proportion of double positive cells and decreased the proportions of CD4?SP, CD8?SP, CD4+ V?8.2+ and CD8+ V?8.2+ T cells. Furthermore, the decreased V?8.2+ T?cells in neonatal rats exposed prenatally to SEB were further deleted by SEB restimulation in an in vitro cultured thymus. These data suggested the special response pattern of the remaining SEB?specific T cells to SEB restimulation in neonatal rats exposed prenatally to SEB.