A comparative study of different isolated fractions of Entamoeba histolytica in amoebic liver abscess.

Fifty six patients with amoebic liver ubscess were assessed for antibody production and lymphokine release using different antigenic fractions such as sephadex G-200 eluted fraction-I (F-I), shed of bile salt treated amoebae (SBSTA), amoebic membrane glycoprotein (AMG), amoebic RNA and whole amoebic lysate (WAL). Antibody production in response to WAL, F-I, SBSTA, AMG and RNA was assessed by indirect haemagglutination assay. Five and 53 fold increased titres of IHA was observed with F-I and SBSTA respectively compared to WAL. The difference between mean titres of F-I, SBSTA and WAL was found to be highly significant (P < 0.001). Amoebic RNA did not show pronounced antibody titres. Lymphokine release by T lymphocytes in response to F-I, SBSTA, AMG, RNA and WAL was assessed by leukocyte migration inhibition (LMI) test. A highly increased release of LMIF by RNA, AMG, F-I and SBSTA was observed compared to whole amoebic lysate. The difference between the means of the purified fractions and WAL, to release of LMIF was found to be highly significant (P 0.001). These findings suggest that SBSTA, F-I and AMG fractions might have an important role as a potent antigen in inducing humoral and cell mediated immunity in patients with amoebic liver abscess and these findings also confirm the multiple antigenicity of E. histolytica.