Immunoadherence and complement in cancer-bearing mice.

Shortly after grafting of Ehrlich ascites carcinoma cells, the serum of tumour-bearing mice loses the capacity to mediate immunoadherence phenomena, because of a sharp decrease in the concentration of C3b and C3d, while the cellular receptors for such factors are unaffected by tumour growth. It is suggested that complement is consumed through the alternative pathway which is activated during the inflammatory responses accompanying tumour growth.