Leishmania major: common antigen responsible for induction of delayed-type hypersensitivity response in guinea pigs

The cellular response to Leishmania major (L. major) was evaluated in vivo by delayed-type hypersensitivity (DTH) skin test reaction using leishmanin as antigen. Our previous study had shown the development of species-specific DTH reaction in sensitized guinea pigs by application of a single purified antigen from promastigotes and filtered culture supernatants of L. major. This study has shown that purified antigen is common in both stages of the life cycle and filtered culture supernatant of L. major. The common antigen was purified and analyzed from soluble Leishmania antigen (SLA) of amastigotes, promastigotes, and filtered culture supernatant of L. major by specific monoclonal antibody coupled to sepharose-4B. The purified antigen, which gave a single band of 56 kDa on sodium dodecyl sulfate polyacrylamide gel (SDS-PAGE) electrophoresis, elicited DTH response in guinea pigs sensitized with L. major. It was almost of the same degree as that produced by whole SLA. These results show that DTH inducer antigen is present in both stages of the life cycle and filtered culture supernatant of L. major.