RECOMBINANT VACCINIA INTERLEUKIN-2 INFECTED TUMOR-CELL VACCINES IN IMMUNOTHERAPY OF MURINE COLON ADENOCARCINOMA

A recombinant vaccinia virus (vCF13) containing and expressing the gen e for human interleukin (IL)-2 (vCF13) was compared to a recombinant v accinia transfection control strain containing the LacZ gene at the sa me insertion site (vTFCLZ-1) for their ability to augment the immunoge nicity of murine colon adenocarcinoma cell lines CT26 and CA51 in Balb /c mice. Both recombinant vaccinia strains abolished tumorigenicity of 10(5) CT26 or CA51 tumor cells. vCF13-infected tumor cells that secre ted human IL-2 as measured by both CTLL-2 and enzyme-linked immunosorb ent assays induced delay in tumorigenesis when administered in two wee kly subcutaneous injections 1 week prior to challenge with 10(5) uninf ected tumor cells. Although three of five vCF13-CT26 immunized mice de veloped tumors by day 14 after challenge, intralesional injection of t hese tumors with vCF13 induced rapid regression, whereas all five tumo rs that developed in vTFCLZ-1 immunized mice showed no response to int ralesional vTFCLZ-1. These preliminary results provide support for the potential utility of recombinant vaccinia/IL-2 in tumor immunotherapy .