Tissue reactivity of IgG eluted from human carcinomas

Mixed haemagglutination with tissue sections was used to study the tissue reactivity of IgG eluted from human carcinomas. IgG eluted from 21 of 29 tumours, bound to the autologous tissue. The binding was mediated through the Fab-portion, and the bound IgG had an intact Fc-portion. Most eluted IgG bound to the autologous tissue, but binding was also seen to other carcinomas of the same type as well as to other types. In addition, the IgG bound to several cancer-free tissues. Accordingly, the eluates of the 21 tumours contained IgG with a broad tissue reactivity. The eluates of a) the remaining 8 tumours, b)normal tissue, and c) liver tissue from patients with non-malignant diseases, contained IgG which did not bind to any tissue. The IgG associated with these tissues was probably non-specifically bound or bound to receptors in vivo.