Control of growth and vascularity of B16 melanoma by syngeneic lymphocytes

We have studied the participation of syngeneic lymphocytes in the subcutaneous growth and vascularization of B16 melanoma tumors. Subcutaneous tumors in animals, lymphocyte depleted by thymectomy and x-irradiation, exhibit slow, poorly vascularized growth as compared to normal or lymphocyte reconstituted controls. This condition may be reversed by administration of lymphocytes to lymphocyte deficient hosts either prior to tumor cell injection or while the animal is tumor bearing. The results are discussed in terms of lymphocyte induced angiogenesis.