HUMORAL IMMUNOSTIMULATION I. INCREASED UPTAKE OF [I~SI]IoDODEOXYLrRIDINE AND [3H]THr~mINE INTO TNP-CELLS TREATED WITH ANTI-TNP ANTIBODY* BY WILLIAM T. SHEARER,$

Evidence to support an irnmunostimulafion theory of tumor growth has recently been reviewed by Prehn (1, 2). Basically the immunostimulation theory proposes that both humoral and cellular immune responses can, under certain conditions, facilitate tumor growth by direct effect upon the tumor cells. Enhancement of tumor cell growth, on the other hand, is thought to be due to an enhancing antibody which acts by blocking cell-mediated immunity and thus indirectly facilitates tumor cell growth (3). The immunity effect proposed by Prehn is a biphasic one; that is, mild immune response to tumor cells accelerates tumor cell growth, whereas a strong immune response is cytotoxic (1, 2, 4).