A novel immunohistochemical technique for demonstration of specific binding of human monoclonal antibodies to human cryostat tissue sections.

We describe a novel immunohistochemical technique which permits the detection of specific binding of human monoclonal antibodies (MAb) to cryostat sections of human tissues. The technique overcomes the problem of background staining caused by the presence of endogenous immunoglobulins in tissue sections. This is achieved by the formation of a molecular complex of the primary antibody (a human MAb), horseradish peroxidase-conjugated goat anti-human immunoglobulin, and normal human serum. This complex is then incubated with cryostat sections of human tissue, and binding of the complex is demonstrated using diaminobenzidine/hydrogen peroxide. The method is suitable for immunohistochemical screening of small samples of tissue culture supernatant for the presence of human MAb of potential interest, and for determining the pattern of binding of such MAb to a wide range of normal and pathological human tissues.

Immunodetection of human tumour-associated cell-bound antigens by human monoclonal antibodies.

A novel cellular enzyme-linked immunoassay has been developed to detect specific binding of human monoclonal antibodies to target tumour cells obtained by enzymatic disaggregation of surgically resected human colorectal carcinomas. Cell preparations derived from human tissues contain endogenous immunoglobulin. The method described is designed to detect specific binding of a human monoclonal antibody while minimising extraneous background signals caused by the presence of endogenous immunoglobulins in the preparation. This is achieved by first generating immune complexes, which are then incubated with the target cells. The assay is well suited for rapid screening of large numbers of tissue culture supernatants and could be adapted for cells of other tumours. Small quantities of target cells and supernatant are used and the assay can be completed within 5 h.