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The immunogenicity of leukemia L1210 in DBA/2 Ha and 6C3HED lymphosarcoma tumor cells in C3H/f mice was significantly increased after treatment with V. cholerae neuraminidase. DBA/2 Ha and C3H/f mice repeatedly immunized with neuraminidase-treated tumor cells rejected subsequent challenge of 10(7) or 10(6) untreated tumor cells, respectively. Based on the 51Cr microcytotoxicity assay, both strains of mice showed strong complement-dependent antibody titers and cell-mediated immunity. Sera and splenic lymphocytes from immunized C3H/f mice neutralized the tumorigenicity of 6C3HED lymphosarcoma and protected the recipient C3H/f mice against the disease. Immune lymphocytes pretreated with anti-theta sera lost their ability to neutralize the tumorigenicity of lymphosarcoma, and they failed to be stimulated by T-cell mitogens. We studied the effectiveness of chemoimmunotherapy in DBA/2 Ha mice with leukemia L1210. A single near optimal dose of BCNU 2 days after implantation of 10(6) tumor cells increased the survival time. A single immunization with 2 X 10(7) neuraminidase-treated L1210 tumor cells 4 days after cytoreductive therapy increased survival and resulted in cures for 50% of animals. Immunization of mice with neuraminidase-treated tumor cells and MER produced indefinite survival in a larger percentage of mice than did either treatment alone. AKR mice with spontaneous leukemia treated with combination chemotherapy sustained an 180% increase in life-span. Combination chemotherapy plus immunization with neuraminidase-treated syngeneic or allogeneic (Gross virus-induced) E2G leukemia cells were highly effective in prolonging the life-span of the immunized leukemic AKR mice. The experimental data led to clinical trials in acute myelocytic leukemia with neuraminidase-treated a-logeneic myeloblasts. Patients with acute myelocytic leukemia were randomized into two groups after remission induction. The median remission duration of patients on sustaining chemotherapy alone was 19 weeks (8 patients), whereas six of nine patients who received neuraminidase-treated allogeneic myeloblasts remain in remission 79-132 weeks. Statistical analysis of the remission duration and survival of patients who received chemoimmunotherapy versus the control group shows highly significant differences.

A double-blind longitudinal study for the presence of human immunodeficiency virus type 1 (HIV-1) neutralizing antibodies (NAb) in the sera of 36 patients with acquired immune deficiency syndrome (AIDS), 149 prodromal homosexual subjects, and 33 heterosexual subjects has been carried out. All AIDS patients and 68% of prodromal homosexual subjects (101/149) were found to be HIV-1 antibody positive by Western blot assay. All heterosexual subjects were HIV-1 antibody negative. Neutralizing antibody(s) was determined by testing the protective activity of sera against HIV-1 infection of human T-cell line H9. Study subjects were divided into NAb(+) (antibody titer, greater than 1:40) and NAb(-) (antibody titer, less than 1:40) groups. During the 24-month observation period 2 of 80 (3%) HIV-1(+) NAb(+) individuals progressed to AIDS and died, as compared to 5 of 21 (24%) of HIV-1(+) NAb(-) subjects who progressed to AIDS. Similarly, among the NAb(+) AIDS patients 8 of 23 (35%) died, while 10 of 13 (77%) of the NAb(-) patients died during the course of the study. In addition, the absence or reduction of HIV-1 p17 and p24 antibodies directed against HIV-1 antigens as well as the low titer or absence of NAb appears to be closely related to the clinical progression of the disease. These studies suggest that a decrease in the virus neutralization capacity of the sera and a decrease or complete loss of HIV-1 p17 and p24 antibodies may be useful as prognostic indicators for the progression of disease in HIV-1-seropositive patients.

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In 1973 PBB's were accidentally mixed into animal feed, resulting in marked toxic effects. Meat and dairy products were widely consumed in Michigan. To determine the impact of PBB's, 55 exposed Michigan farm residents, 11 Michigan chemical workers and 46 non-exposed Wisconsin farmers were examined. Abnormalities included decreased number of T-lymphocytes with concomitant increase of lymphocytes with no detectable surface markers, "null cells", and altered lymphocyte function. Data obtained from skin testing using standard recall antigens, showed no consistent correlation between the delayed cutaneous hypersensitivity response and the impaired lymphocyte function. PBB (hexa) in separated white blood cells and red cells was positively identified and quantified by gas chromatography-mass spectrometry. PBB and immunological abnormalities were not detected in non-exposed Wisconsin dairy farm residents.

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