Effect of passive immunization with mouse Anti-BCG 64 kDa protein on ehrlich ascites carcinoma cells

Abstract

Cancer is one of the leading causes of death now-a-days. There are various treatment options for cancer and each has its own side effects because most of the therapeutic agents of cancer are non-selective and may cause destruction of both cancer as well as normal cells. Therefore, search for a highly specific therapeutic molecule is still going on. As it is known that, immune molecules are highly specific in terms of antigenantibody reactions, so immunotherapy might be a better and more specific choice for cancer therapy compared to conventional molecules in use. Moreover, to handle any emergency cancer cases, there must be instant treatment option through passive immunization. Surface protein antigenic similarity of a 64 kDa Mycobacterium bovis BCG surface protein has been reported in the literature. BCG 64 kDa shares a common 64 kDa antigenic determinant with various mouse and guinea pig cancer cells and is cross reactive to one of these cancer cell antigens. The anti-BCG 64 kDa antibody has also been shown to have anti-cancer effects against various solid tumors of experimental animals having cross reactive antigen. However, there is no such report of similar experiment on malignant ascites cell lines. Considering the above facts, this study was undertaken to assess the effects of anti-64kDa antibody on Ehrlich Ascites Carcinoma (EAC) cells. In this study, mouse anti-BCG 64 kDa antibody showed anticancer effect on EAC cell, when compared to control. Animals from experimental group showed increased life span and a plummeted rate of weight gain than negative control. Animals transplanted with EAC cells were treated by two methods. In one method, animals received regular treatment till day 7 and showed 49.2% increase in life span compared to negative control. The other method was cyclic treatment (5 days, treatment, 5 days pause) where life span was increased up to 33.47% compared to negative control. Furthermore, reduced cell growth rate was observed in EAC cell bearing mice treated with anti-BCG 64 kDa containing serum. To confirm the cross reactivity between anti-BCG 64 kDa antibody and EAC cell antigen, whole cell extracts of EAC cells were immunoblotted with BCG 64 kDa immunized mice sera and a 64 kDa band was observed. All these data suggest us that, water soluble BCG 64 kDa surface antigen shares common antigenic determinants with malignant ascites cells and has anti-cancer activity in mice in terms of survival and rate of weight gain. Considering all these results, we conclude that the anti-BCG 64 kDa antibody containing serum could be considered as an effective cancer treatment option.