Developmental interrelationship of specific Lyt 123 and Lyt 1 cell sets in expression of antibacterial immunity to Listeria monocytogenes.

Lyt phenotypes of peritoneal exudate T lymphocytes from Listeria monocytogenes-immune mice were determined with respect to their capacity to confer protection upon local or systemic transfer. It is shown that, locally, Lyt 1 T cells provide protection, whereas only unselected native populations, containing adequate numbers of Lyt 123 T cells, were effective in transferring systemic protection. When Lyt 1 T cells were the crucial cell type (local transfer), admixture of Lyt 123-containing peritoneal exudate T-lymphocyte-enriched cells did not enhance protection, save for slight additive effects. Likewise, when Lyt 123-containing peritoneal exudate T lymphocyte-enriched cells were the crucial cell type (systemic transfer), admixture of various numbers of Lyt 1 cells was without marked effect. A change in Lyt phenotype from Lyt 123 to Lyt 1 paralleled by an increase of protective capacity upon local transfer was observed when sensitivity of early and late exudate T cells to anti-Lyt 2.2 antiserum plus complement treatment was investigated. The data suggest that (i) the propensity of specific T cells to enter exudates is associated with the Lyt 123 phenotype, (ii) the actual effector cell of antibacterial protection is an Lyt 1 T cell, and (iii) a developmental interrelation exists between Lyt 123 T cells and Lyt 1 T cells in T-cell-dependent protection of mice against L. monocytogenes.