Comparative effect of rat and fetal calf serum on measurement of the natural tumoricidal activity of rat lymphocytes,macrophages and polymorphonuclear cells

Summary The effect of rat serum versus fetal calf serum on the in vitro natural cytolytic activity of rat lymphocytes, macrophages and polymorphonuclear cells against syngeneic tumour cells was compared. The cytolysis level mediated by the three varieties of effector cells was lower when rat serum was used instead of fetal calf serum to supplement the culture medium. This could explain in part the discrepancies found between in vitro and in vivo studies.