Fc receptor‐bearing cells as a reliable marker for quantitation of host lymphoreticular infiltration of progressively growing solid tumors

Abstract

Disaggregated cell suspensions made from transplanted solid tumors, either chemically-induced fibrosarcomas, or spontaneous mammary carcinomas, can contain very high numbers of F_c receptor-bearing cells which are of host origin. Because most types of lymphoreticular cells have F_c receptors, and because T cells—most of which are F_c receptor-negative—appear to infiltrate such tumors only to a very limited degree, the possibility that F_c receptor cells could serve as a reliable and simple marker for host lymphoreticular cell infiltration of solid tumors was tested. This was accomplished by comparing the ratios of F_c rosetting cells to serologically detectable host cells in H2^d or H2^k haplotype tumor cell suspensions grown in (H2^d × H2^k) F₁ hybrid mice, where host cells could be distinguished from tumor cells by treatment with the appropriate anti-H2 serum. Ratios of 0.8 to 1.08 were obtained for four different tumors including the SaD/2 fibrosarcoma, a CBA spontaneous fibrosarcoma, and the T1699 and CaD/2 mammary carcinomas. Analysis of the results showed that enumeration of F_c rosettes was a reliable host cell marker for at least three of the four tumors tested. The mean non-malignant host cell content of the various tumors, as assessed by anti-H2 cytotoxicity tests, ranged from 23% to 41%.