Growth Inhibition of Human Melanoma Cells by C-Reactive Protein (CRP) Activated Lymphocytes 1

Summary When human melanoma cells were grown in tissue culture with allogeneic lymphocytes at a ratio of 50 lymphocytes to one melanoma cell, the growth curve was altered so that doubling time of melanoma cell count increased by 14% over controls. CRP alone did not alter the growth curve; but when CRP (20 μg/ml) was added to lymphocytes and melanoma cells (50:1), no increase in melanoma cell numbers occurred. Rather, there was a decrease in melanoma cells and loss of viability so that, at 72 hr, 75% of the original inoculum was dead. It was concluded that CRP stimulated normal lymphocytes to destroy melanoma cells. The suggestion is made that lymphocyte activation is the normal physiological function of CRP. The author wishes to acknowledge the technical assistance of Mr. E. Benes.