Alterations of humoral, cell mediated and antibody dependent cell mediated cytotoxic responses during the course of amoebic infection in guinea pigs.

The cellular and antibody dependent cellular cytotoxic (ADCC) responses of splenic lymphocytes and peritoneal macrophages obtained from animals at variable intervals after inoculation were studied against trophozoites of axenic E histolytica (NIH:200). Cytotoxic responses of effector cells from infected animals were compared with those of effector cells from vaccine stimulated and unstimulated uninfected control animals. Cellular and antibody-dependent cellular cytotoxic responses of the effector cells from animals during the establishment and acute phase of infection were significantly suppressed, compared with unstimulated uninfected and vaccinated (FI amoebic proteins stimulated) effector cells. The effector cells from animals recovered from infection showed enhanced cytotoxic responses against trophozoites of E histolytica. The suppressed cytotoxic response was accompanied by impairment of cytotoxic cell activities and lack, or very low level of anti-FI antibodies in the sera of animals during the establishment phase of infection. With the rise in anti-FI antibodies in the sera of animals ADCC could be induced effectively against trophozoites of E histolytica, which seem to result in clearance of amoebic infection.