Immunological enhancement of primary tumor development and its prevention

While it has been known for decades that the growth of tumor transplants ca n be enhanced immunologically, the potential significance of these previous findings to the development of primary tumors and the mechanisms of tumor enhancement has remained obscure. This review will summarize recent experim ents indicating that primary turner development, can De enhanced by active immunization. The evidence suggests that antibodies, B cells and CD4(+) T c ells can play a critical role in enhancing the development of primary tumor s, whereas endogenous interferon-gamma (IFN gamma) can counteract enhanceme nt. Thus, we envision two possible functions of IFN gamma: (i) preventing B cell and antibody enhancement and (ii) counteracting tumor promotion indep endent of T and B cells.