Isolation and characterization of recombinant antigens from Leishmania aethiopica that react with human antibodies

A genomic expression library of Leishmania aethiopica was constructed in lambda gt11 and screened with patient sera and sera from healthy people living in an area of endemicity. Forty-five recombinant clones were isolated and partly characterized. Clone-specific antibodies were prepared and used with sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Western immunoblot analysis to estimate the molecular masses of the parasite-derived antigens containing the reactive epitope(s). Antigens with apparent molecular masses of 90, 85, 63, 50, 41, 25 and 24 kDa as well as several antigens with lower molecular masses were detected. The clone-specific antibodies from patients with diffuse cutaneous leishmaniasis reacted with high-molecular-weight antigens (30,000 less than Mr less than 90,000), whereas antibodies from patients with localized cutaneous leishmaniasis recognized low-molecular-weight antigens (Mr less than 25,000). Nine different purified recombinant antigens were obtained from lysogens in Escherichia coli Y1089 by immunoaffinity chromatography on anti-beta-galactosidase columns and were subsequently tested with patient sera. It is suggested that some of these recombinant antigens might be used for immunodiagnostic purposes.