IDENTIFICATION OF IMMUNOGENIC EPITOPES OF THE 170-KDA SUBUNIT ADHESINOF ENTAMOEBA-HISTOLYTICA IN PATIENTS WITH INVASIVE AMEBIASIS

Entamoeba histolytica causes amebic dysentery (AD) and liver abscess ( ALA). Little is known about protective immunity to amebiasis, and stud ies in this area have been complicated by the paucity of defined ameba antigens. We examined the proliferative responses of peripheral blood mononuclear cells (PBMC) from patients with AD and ALA to a recombina nt protein containing a portion of the 170 kDa adhesin of E. histolyti ca (170CR), and to two synthetic peptides (1 and 2) derived from the 1 70 kDa sequence that were predicted to contain T cell epitopes. A sign ificant number of patients with AD and ALA had PBMC that proliferated to 170CR molecule, and several individuals with ALA and AD had T cells that recognized one or both peptides. Contrarily, individuals from a non-endemic region for amebiasis did not respond to 170CR protein, or to both peptides. In regard to antibody response, nine of fifteen pati ents with ALA showed antibodies to 170CR protein. These same patients had antibodies to peptide 2. We identified peptides from 170-kDa adhes in that may contain both T and B cell epitopes recognized by some pati ents with invasive amebiasis. These peptides may be valuable reagents in studies of the immune response to amebiasis.