Isoantibodies to Human Cancer Cells in Healthy Recipients of Cancer Homotransplants

Abstract

Summary Homotransplants of nine cancer cell lines and two normal cell cultures were made in 20 healthy male volunteers. Each man was given only one cell type. Sera collected before and 2, 4 and 6 weeks after implantation were studied using the tanned erythrocyte agglutination technique with antigens prepared as saline extracts of freshly harvested cells of 10 cancer cell lines and 8 cell lines of normal origin. All pretransplantation sera gave negative tests. Two recipients of normal cell transplants produced no antibody which could be detected with normal cell test antigens, and very rarely showed low level reaction with cancer cell antigens. All 18 recipients of cancer cell lines had antibody in the 2- and 4-week serum specimens but seldom in the 6-week serum. These sera reacted against the cell type transplanted and almost equally well against other cancer cell lines of various types. Several reacted with the “transformed” FL amnion cell line but reactions with other cells of normal origin were rare. Reproducibility of titers on repeated tests was good. Following adsorption of these sera with fresh cell suspensions prepared from tissue cultures, blood, or tissue specimens, they were retested against cancer cell antigens. In most instances antibody titers were not significantly affected when the adsorbing cells were normal but disappeared when cancer cells were used. The data demonstrate that the 10 cancer cell lines which were studied contain an antigen or antigens in common which were foreign to the transplant recipients and rarely detectable in the normal cell lines and normal tissues which were studied. These results are consistent with the concept of human cancer-specific antigens common to the cancers of many individuals. There are, however, other plausible explanations. These are discussed and the need for caution in interpretation of antigenic analyses based on antibody formation to homografts (or heterografts) is stressed.