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antibody response. The objective of this study was to develop adjuvants which can enhance antibody resnonse a~ainst two antigens, B-hCG and LHR;~, linked to a carrier, tetanus toxoid. The antigen-carrier conjugates were adsorbed on alum. The adsorption increased the immunogenicity as compared with the antigen in saline. More than 30 substances were tested for their adjuvanticity to increase the antibody titres over and above the alum adsorbed Cormulation. Four of them were found promising for primary response. A lipidic non-toxic emulsion gave a good secondary immune response.

APPLICATION OF MONOCLO~AL Ah~IBODIES TO HUMAN CHORIONIC C/]NA[X)- TROPIN IN ENZYME-]ZgftrNOASSAYS.

Eric WCNG, Vinoent I]3M, Evelyn LGW, Albert F. CHEN and Chi- Yu Gregory LEE. Department of Obstetrics and Gynaecology, The --

University of British Columbia, Vancouver, Canada.

To develop sensitive enzyme-immunoassays for human chorionic gonado- tropin (HCG), we have raised monoclonal antibodies specific to ~ -subunit of HCG by an improved hybridoma technique. Following successive immunizations with ~ -subunit of HCG partially purified by sodium dodecylsulfate acrylamide gel electrophoresis, spleen cells of immunized mice were fused with NS-I myel- cma cells. The hybrid cells were cultured initially in a semi-solid selection mediu~n containing methylcellulose in petri-dishes. Visible colonies were removed and subcultured, seven to ten days after cell fusions. By microplate enzyme-ir~nunoassay and sodium dodecylsulfate gel/protein blot radioir~uno- binding method, about one dozen of hybrid cell lines were shown to produce antibodies that bind both HCG and ~-HCG and exhibit little cross-reactivity to LH and FSH. To perform a sandwich solid-phase enzyme-immunoassay, each

-HCG-specific monoclonal antibody was coated on nylon balls (2 mm in diameter), nitrocellulose filters or microtiter plates. A quantitative irm~m~ assay was proceeded by incubating HCG at proper concentrations and then horse radish peroxidase-labeled ~-HCG monoclonal antibodies as the second antibodie~ Pairs of menoclonal antibodies that bind nenoverlapping antigenic dc~ains of HCG were selected for this sandwich inmunoassay. This irmmnoassay procedure is highly specific to HCG and permits facile and quantitative determinations of 1 ng/ml HCG in biological fluids.