Generation of Listeria monocytogenes-specific T cells mediating delayed footpad reaction and protection in neonatally thymectomized mice but not in nude mice.

Neonatally thymectomized (NTx) mice, sham-operated control mice and congenitally athymic nude mice were immunized with viable Listeria monocytogenes and their spleen cells examined for the capacity to transfer both delayed footpad reaction and protection against challenge at the site of local transfer. Cells from immune NTx mice conferred significant degrees of delayed footpad reaction and protection comparable to sham mice, while cells from immune nude (nu/nu) mice did not. This ability was completely eliminated by the treatment of cells with anti-Thy1, anti-Lyt1 or anti-L3T4 antibody plus complement but not with anti-Lyt2 antibody plus complement. These results indicated that NTx mice can normally mount the immunity to L. monocytogenes by generating Lyt1+2-, L3T4+ T cells. Immune competence of NTx mice and thymus dependency of various immune responses are discussed.