SURFACE EXPRESSION OF ONLY GAMMA-DELTA AND OR ALPHA-BETA-T-CELL RECEPTOR HETERODIMERS BY CELLS WITH 4 (ALPHA, BETA, GAMMA, DELTA) FUNCTIONAL RECEPTOR CHAINS

Surface expression of TCR dimers by cells synthesizing three or four distinct types of receptor chains was analyzed. Cells containing intact .gamma., .alpha., and .beta. chains had only .gamma..delta. dimers on the cell surface. In human PEER cells, addition of a functional .alpha. chain led to the loss of .gamma..delta. dimer expression and expression of only .alpha..beta. dimers. This result was not due to transcriptional down-regulation of the .gamma. or .delta. loci. In murine cells expressing all four chains, both .gamma..delta. and .alpha..beta. dimers could be demonstrated on a single cell. No other chain combinations (.alpha..gamma., .alpha..delta., .beta..gamma., or .beta..delta.) were detected. Thus, there is stringent control of assembly and/or transport of TCR heterodimers, such that functional receptors consist only of .alpha..beta. and .gamma..delta. pairs, and no additional repertoire diversity is generated by cross pairing.