Heterologous protection in murine cutaneous leishmaniasis

Mice immunized with a glycolipid antigen (GL) of Leishmania major plus adjuvant are relatively resistant to subsequent infection with this protozoan parasite. The GL is affinity purified on the monoclonal antibody WIC-79.3 which is L. major-specific and does not react with L. donovani. When another monoclonal, WIC-108.3, which cross-reacts with several Leishmania species, is used to affinity purify GL from L. donovani, the eluted material can partially protect genetically resistant mice against L. major. Thus, GL cross-reactions may in part underlie the known protective effects of crude L. donovani antigens against L. major infection. Experiments with live parasites of the L. major isolate LRC-L119, that is non-pathogenic in mice, that does not survive long in macrophages in vitro, and that has not been shown to contain any WIC-79.3 reactive GL, indicated that this isolate will very effectively protect mice against subsequent infection. This raises the possibility that GL is only one of at least two different classes of vaccinating antigen capable of protectively immunizing mice in this cutaneous leishmaniasis model.