Antibody response of patients harbouring different zymodemes of Entamoeba histolytica to homologous and heterologous antigens.

Entamoeba histolytica isolates characterized into four zymodemes were used as antigens in the IFAT; with 17 sera obtained from patients harbouring different amoebic isoenzyme groups. The method of cultivation used was found to influence the ease of reading the IFAT. Reactivity of serum samples, obtained from the selected patients (i.e. with varied forms of amoebiasis), against homologous and heterologous antigens did not reveal any antigenic differences among amoebic zymodemes. The present result is an advance on our knowledge and corroborates previous findings. However, since the clinical spectrum of the disease may vary and diagnosis based on history may not necessarily be complete, it is suggested that the present result should be taken as tentative until reactivity of the antigens (from different zymodemes) against specifically raised sera in 'animal models' is known.