IDENTIFICATION OF AN IMMUNODOMINANT 32-KILODALTON MEMBRANE-PROTEIN OFLEISHMANIA-DONOVANI INFANTUM PROMASTIGOTES SUITABLE FOR SPECIFIC DIAGNOSIS OF MEDITERRANEAN VISCERAL LEISHMANIASIS

Sera from 35 patients suffering from Mediterranean visceral leishmania sis (caused by Leishmania donovani infantum) and 59 patients with vari ous forms of cutaneous leishmaniasis prevalent in the sub-Mediterranea n countries (caused by Leishmania major, L. donavani infantum, or Leis hmania tropica) were tested by immunoblotting and enzyme-linked immuno sorbent assay (ELISA) with both membrane and soluble antigens prepared from L. donovani infantum parasites. Control sera were from healthy c hildren (n = 41), adults with nonleishmanial diseases (n = 40), and pa tients with Chagas' disease (n = 12). A P32 antigen present in the mem brane preparation from L. donovani infantum parasites was recognized b y 95% of serum specimens from patients,vith Mediterranean visceral lei shmaniasis but not by serum specimens from patients,vith cutaneous lei shmaniasis or sera from control individuals. An ELISA with electroelut ed P32 antigen was found to have a specificity and sensitivity of 94% in the serodiagnosis of Mediterranean visceral leishmaniasis. Healthy children with asymptomatic Leishmania infection were seronegative for the P32 antigen by ELISA. These results suggest that antibodies to P32 antigen develop only in patients with visceral leishmaniasis and that the P32 ELISA may be useful in areas where the disease is endemic for discriminating between patients with this disease and those with othe r clinical conditions.