Enrichment of antigen-specific helper and suppressor T cells

Abstract

LYMPHOCYTES are known to differ on the basis of their antigen specificity, as postulated by Burnet¹, and experimentally confirmed by a variety of techniques^2–5. Although there are many problems involved in purifying cells reactive to a given antigen there have been successful reports. These include the purification of rosette-forming cells⁶, the separation of cells binding fluoresceinated antigen on a cell sorter⁷, and the recovery of cells which have bound to an antigen matrix⁸ or a cell surface^8–10. The use of gelatin^8,11 substrates has proved to be successful in the purification of B lymphocytes, with enrichment of antigen-specific cells estimated in the order of 100-fold^11,12. Because antigen-binding T cells bind better at 37 °C than at 4 °C (refs 13 and 15), collagen gels were used in this study, as gelatin melts at 37 °C. A procedure for the enrichment of antigen-specific T cells should provide an essential step in the approach to many problems of understanding T cells and their function, such as the nature of T-cell receptors on subpopulations of T cells, the nature of mediators of T-cell function (especially antigen-specific mediators) and the mechanisms and control of T-cell activation. Here we describe a method for the selective enrichment of T cells reactive to protein or synthetic polypeptide antigens, and demonstrate the selectivity and specificity of the procedure by cross absorption experiments. The general applicability of the procedure was verified by using T cells immunised in vivo or in vitro, and by demonstrating 100-fold enrichment with different subpopulations of T cells, namely carrier-specific helper and carrier-specific suppressor cells involved in the in vitro antibody response.