ANTIBODY-RESPONSE AGAINST A LEISHMANIA-DONOVANI AMASTIGOTE-STAGE-SPECIFIC PROTEIN IN PATIENTS WITH VISCERAL LEISHMANIASIS

The antibody response against an amastigote-specific protein (A2) from Leishmania donovani was investigated. Sera from patients with trypano somiasis and various forms of leishmaniasis were screened for anti-A2 antibodies, Sera from patients infected only with L. donovani or Leish mania mexicana specifically recognized the A2 recombinant protein, The se results were consistent with karyotype analyses which revealed that the A2 gene is conserved in L. donovani and L. mexicana strains. The potential of this antigen in diagnosis was further explored by screeni ng a series of sera obtained from patients in regions of the Sudan and India where L. donovani is endemic, The prevalence of anti-A2 antibod ies was determined by Western blotting for all samples. Enzyme-linked immunosorbent assay (ELISA) and an immunoprecipitation assay were also performed on some of the samples. Anti-A2 antibodies were detected bg ELISA in 82 and 60% of the samples from individuals with active visce ral leishmaniasis (kala-azar) from the Sudan and India, respectively, while the immunoprecipitation assay defected the antibodies in 92% of the samples from India, These data suggest that the A2 protein mag be a useful diagnostic antigen for visceral leishmaniasis.