The Effects of Levamisole, CORYNEBACTERIUM PARVUM, and Unblocked Lymphocytes on Mice Injected with Herpes Virus Type 2-transformed Cells

The association between herpes simplex virus type-2 and carcinoma of the cervix is becoming increasingly strong (Rawls, et al., 1976 ; Rapp and Duff, 1974; Hollingshead, et al-, 1973). This study demonstrates the ability of certain known immunostimulators to beneficially· alter the immune status of mice injected with HSV-2 transformed cells. Balb/c mice were randomly divided into 6 groups. Group 1 mice were used as negative controls and received no tumor cell injection. All other groups received subcutaneous injections of 1 x 106 cells/ mouse. Tumor therapy by means of irrmunostimulation was started for each group of mice 1 day after the initial tumor cell injection and proceeded on a weekly basis for a total of 7 weeks before sacrifice. Group 1 non-injected mice received no tumor therapy. Group 2 mice were used as positive controls and also received no immuno stimulatory therapy. Mice in group 3 received 200 μgm of levamisole, a non-specific immune stimulator. Group 4 mice were given 300 μgm of heat and formalin killed Corynebacterium parvum which is known to non specifically stimulate macrophage populations. Mice in group 5 received unblocked lymphocytes at a concentration of 4 x 106 cells/ mouse. Group 6 mice received a combination therapy of levamisole, C. parvum and unblocked lymphocytes. Weekly measurements of tumor volume were made using vernier calipers. At the time of sacrifice specific cytotoxicity tests were performed. These included the antibody-dependent cell-mediated cytotoxicity (ADCC) test, the blocking factor (BF) assay and the cytolytic T-lymphocyte (CTL) test. The lymphocyte transformation test using phytohemagglutinin, a T-cell mitogen, was also performed at the time of sacrifice, using mouse spleen cells. Levamisole was unable to significantly stimulate the immune status of group 3 animals and showed no apparent benefit in reducing tumor volume. Unblocked lymphocytes administered to group 5 mice may have had some stimulatory effect upon the immune status of the tumor mice, but it was not significant. Tumor volume was the greatest for group 5 mice and significantly higher than for those mice treated only with C. parvum (group 4) or the combination therapy (group 6). ADCC and BF cytotoxicity results did tend to indicate that C. parvum alone and in combination with levamisole and unblocked lymphoctyes was able to stimulate the immune responses, of group 4 and 6 animals. Tumor volumes were the lowest for these 2 groups. Combination group 6 mice had the lowest tumor incidence also. It was concluded from this study that the combination of levamisole, C. parvum and unblocked lymphocytes did have an enhancing effect upon the immune status of tumor hosts, which may actually aid in lowering tumor incidence and progression