The objective of this project is to seek detailed knowledge about immune responses to antigens associated with rat colon cancer, and on one hand to develop methods to stimulate those responses that lead to tumor rejection establishing immunotherapeutic and prophylactic procedures and on the other hand to investigate the feasibility of using sequential assays of humoral antitumor antibodies for diagnostic purposes. Special emphasis will be put on lymphocyte separation with two-phase CCD technique, affinity to liposomes and Sepharose beads containing magnetique ferrofluids and cell sorting on the basis of fluorescense. Detergent solubilized tumor membrane antigens contained in liposome vesicles are studied as targets in in vitro assays for tumor antigen and antitumor antibodies, as immunogen and in in vivo immunization and in vitro sensitization of lymphocytes. Attempts are made to develop monoclonal antibodies to antigens associated with colorectal carcinomas of the rat. These antibodies are to be used as reagents in in vitro assays and for preparative purposes.