Selection and enrichment of antigen-specific T lymphocyte populations.

Antigen-specific T lymphocytes bind in vitro to cells carrying alloantigens or to macrophages bearing antigen to which the lymphocytes were sensitized. This phenomenon is the basis of present procedures for the isolation and enrichment of antigen-specific T lymphocytes. The antigen-mediated adherence permits the removal of T cells with other specificities, which do not bind to the antigen-containing monolayer. The subsequent activation and multiplication of the antigen-bound cells further increases the proportion of the antigen-specific lymphocytes in culture. The selected cells, which are derived from a small fraction of the initial lymphocyte population, proliferate until they comprise up to 30% of the original total cell number. Another factor favoring enrichment is that unactivated cells do not survive well in culture whereas antigen-specific activated cells maintain their viability. Indeed, the selected cells can be maintained for a few weeks in culture. The activity of the selected lymphocytes is elevated toward the antigen used for enrichment, but lowered, or absent, toward other antigens. The progeny of the antigen-adherent lymphocytes are thus seen to be enriched for one antigen-specific subpopulation, and deprived of lymphocytes committed to other antigens. Cells obtained by this procedure should prove to be very useful for the functional analysis of T lymphocytes.