The Eker renal tumor rat. General immune status in relation to a varying tumor burden.

Evidence was obtained that the response of blood lymphocytes to phytohemagglutinin was reduced in some but not all rats with massive hereditary renal tumors (less than 50 mm mean diameter). Erythrocyte-antibody sensitized, complement dependent (EAC) rosette formation by sensitized spleen cells was also depressed in these animals, but plaque forming cell activity was essentially normal. Lesser tumor growth was associated with general cell-mediated and humoral immune responses which were within the range found for non-tumor-bearing syngeneic rats.