Abstract
A method for cloning soluble antigen-specific proliferating human T lymphocytes directly from peripheral blood cells of individuals recently primed with the antigen is described. The soluble antigen was keyhole limpet hemocyanin. After expansion in liquid culture, these cells were shown to be antigen specific and to require HLA-DR-histocompatible presenting cells. Recloning of small numbers of these cells in soft agar under conditions of high plating efficiency yielded true clones (i.e., derived from a single cell) which retained specificity for the original stimulating antigen as shown by blastogenic responses measured by incorporation of [3H]thymidine. However, antigen-specific stimulation of clones was demonstrated only in the presence of an HLA-DR-compatible cooperating cell population together with the relevant antigen. Cells that manifested only HLA-A or B locus identity with the T-cell clone were not effective as presenting cells. Other antigens, such as tetanus toxoid, to which the donor of the clone or of the presenting cells was immune failed to stimulate the clone.