Both B and gamma delta TCR+ lymphocytes regulate alpha beta TCR+ lymphocytes involved in superantigen specific responses

Endogenous. superantigens. (SAg) presented by MHC class II IA molecules ind uce slow-evolving negative selection of alpha beta T cells. The role of bot h B and gamma delta T cells on the regulation of these SAg-specific alpha b eta T cell responses was addressed in IA(b+) IEb- C57BL/6 mice bearing gene tically induced B cell and gamma delta T cell deficiencies. B lymphocytes w ere required in the negative selection of V beta5(+)/V beta 12(+) CD4(+) T cells. In contrast, gamma delta T cells positively stimulated the utilizati on of the same SAg-responsive alpha beta T cell subsets. These differences started in mature CD4(+) thymocytes and extended to naive T cell pools for B cell negative selection, and up to memory T cells for gamma delta T cell influences. The levels of SAg-responsive T cells did not vary between C57BL /6 and double deficient (B cell and gamma delta T cell-deficient) congenic mice, implying that both B and gamma delta T cells acted through independen t mechanisms.