DIFFERENCES IN THE LYMPHOPROLIFERATIVE PATTERN TO LEISHMANIA-MEXICANAANTIGENS RECOGNIZED BY IMMUNIZED AND INFECTED MICE

Immunity to leishmanial infection depends primarily on the activities initiated by T lymphocytes which have been sensitized to a diverse poo l of parasitic antigens. In this study, the pattern of the lymphoproli ferative responses of lymph node and spleen cells isolated from BALB/c and C57BL/6 mice previously infected with Leishmania mexicana was het erogeneous. However, we observed more pronounced responses to antigen fractions with molecular masses of 63 and 10-15 kDa, based on T cell i mmunoblotting. Responses were stronger and more persistent in the inte rmediate resistant C57BL/6 strain, as compared to the more evanescent response in the highly susceptible BALB/c mice. Similar responses in t erms of immunodominant fractions were also consistently seen in total and T lymphocytes isolated from BALB/c mice which had been immunized w ith a soluble extract of Leishmania mexicana. These results are discus sed in terms of general requirements for an effective vaccine against human leishmaniasis.