To distinguish and define the differentiative and communicative relations of Ly123 and Ly1 cells in generating specific helper-effector (HE) (Ly1:HE) and specific suppression-inducing (SI) (Ly1:SI) cells, these two functional sets were generated from various combinations of congenic genetically marked sets of cortisone-resistant nylon-purified thymocytes (CRNPT) by culture on antigen-primed macrophages (M phi) (the (T-M phi culture system). It was thus shown that Ly1:HE and Ly1:SI cells are produced by differentiation from antecedent Ly123 cells. Ly1:HE and Ly1:SI are separate Ly1 populations; generationof Ly1:HE cells requires the presence of Ly1 cells, whereas the generation of Ly1:SI cells does not. Although the Ly23 CRNPT set, which is included when Ly123 cells are positively selected with Lty-2 antiserum is ruled out as a precursor source of Ly1:SI cells, the possibility of a communicative role for Ly23 cells in generating Ly1:SI cells remains to be investigated. The role of the Ly1 set required for the generation of Ly1:HE cells from CRNPT is communicative, not differential; and it is not a precursor source of Ly1:HE or Ly1:SI cells in the CRNPT population. It remains to be seen whether the use of additional phenotypic markers will distinguish subsets of Ly123 and Ly1 cells engaged in these several functions.

This content is only available as a PDF.