T-cell recruitment regulated by prostaglandin-mediated system and its role in immune response

The dynamics of the number of T cells in spleen and the level of prostaglandin E2 in plasma were investigated serially in mice injected with Corynebacterium parvum. In the first few days, the level of plasma PGE2 increased but decreased to lower than the normal level thereafter. The absolute number of T cells in the spleen began to increase after the PGE2 level dropped. But such an increase of T cells was not observed in ATx mice challenged with C. parvum. Moreover, replenishing the mice with exogenous PGE2 in the period of low PGE2 halted selectively the increase of T cells in the spleen. This enlarged T cell subset responded to PHA, expressed Lyt-1+2+, and was sensitive to PGE2. And this T-cell subpopulation exerted a suppressive effect on antibody response in low PG environment, but lost its inhibitory effect in high PG milieu. These results suggested that an immature T cell subset is recruited from the thymus in a low PG state and participates as regulator cells in immune response at peripheral lymphoid organs.