PREFERENTIAL USAGE OF THE FC RECEPTOR-GAMMA CHAIN IN THE T-CELL ANTIGEN RECEPTOR COMPLEX BY GAMMA/DELTA T-CELLS LOCALIZED IN EPITHELIA

zeta and eta chains of the T cell antigen receptor (TCR) complex and the gamma chain of Fc receptors (FcR gamma) constitute a family of proteins important for the expression of, and signal transduction through, these receptors in hematopoietic cells. In zeta-deficient mice, TCR expression was reduced in most T cells. By contrast, CD8 alpha alpha(+) TCR-gamma/delta(+) intestinal intraepithelial lymphocytes in these mice expressed a normal level of TCR. Biochemical analysis of the TCR complex in these cells from zeta-deficient as well as normal mice revealed the predominant usage of FcR gamma. Furthermore, gamma/delta(+) T cells in epithelia of the skin and female reproductive organs from zeta-deficient mice also showed relatively high TCR expression, indicating the usage of FcR gamma. These observations demonstrate the preferential usage of FcR gamma by gamma/delta(+) T cells localized in epithelia of normal mice.