Human Tumor-Associated Antigens Detected by Serological Techniques: Analysis of Autologous Humoral Immune Responses to Primary and Metastatic Human Sarcomas by an Enzyme-linked Immunoabsorbant Solid-Phase Assay (ELISA)

An enzyme-linked immunoabsorbant solid-phase assay was developed for measuring humoral immune responses to human sarcoma-associated antigens, and binding of autologous sera to 1-butanol extracts of fresh sarcomas was determined. Binding of autologous sarcoma patients’ sera was reproducible and significantly greater than normal sera. Extensive quantitative competitive binding inhibition tests with normal tissue were unable to completely remove binding to autologous tumor extracts by sera from five of eight patients, thus demonstrating a quantitatively distinct specificity present on tumor tissue. An antibody in autologous sera recognizing a determinant on normal adult tissue was also identified. Autologous humoral immune responses to soluble 1-butanol extracts of paired primary and metastatic human sarcomas from six patients from this group were assessed. Antibody binding was observed to both primary and metastatic tumor extracts; however, binding was significantly greater to the primary extracts in 14 of 16 autologous serum tumor combinations tested. Absorption and competitive binding inhibition studies demonstrated the presence of common sarcoma-associated antigens in extracts of both the primary tumor and its metastasis from all patients studied. Two individual metastases from the same patient also possessed antigens recognized in that patient’s primary tumor extract in two cases. Autologous sarcoma patients’ sera recognize sarcoma-associated antigens common to both the primary tumor and its metastasis.