Sera from rabbits immunized with sonicates of Mycobacterium bovis BCG were passed through an immunoadsorbent made of a soluble BCG extract to make partially purified antibodies to BCG. These antibodies were in turn used to prepare an immunoadsorbent through which the BCG extract was passed. The partially purified antigenic material was radiolabeled and subjected to electrophoresis in acrylamide gels. One of the radiolabeled fractions isolated (BCG-C) was found to bind to antibodies to BCG and H37Rv, but not to antibodies in sera from rabbits immunized with other mycobacterial species or Nocardia asteroides . The reaction between BCG-C and the partially purified antibodies to BCG was inhibited by small amounts of different BCG antigens. Cultures obtained from 25 patients with tuberculous diseases, other bacterial cultures, and various bacterial extracts were tested for their capacity to inhibit this reaction. Each of 13 mycobacteria identified as M. tuberculosis inhibited this reaction. Equivalent numbers of 12 strains of mycobacteria other than M. tuberculosis and high concentrations of other bacterial extracts did not inhibit, indicating that determinants of BCG present in M. tuberculosis were not detected in the other mycobacteria or in non-acid-fast bacteria. The use of sequential purification procedures could be of potential clinical value in quickly differentiating between M. tuberculosis and a variety of other mycobacteria.
A water-soluble, oil-free supernatant fraction of sonically treated BCG (BCG-SS) was shown to be an immunological adjuvant and a mitogen. When BCG-SS and sheep erythrocytes (SRBC) were injected intravenously into mice, the plaque-forming cell (PFC) response was 10 times greater than that induced by injection of SRBC alone. Circulating antibody responses to SRBC and to bovine serum albumin were also enhanced by BCG-SS. The in vitro enhancement of PFC and circulating antibody responses did not require mineral oil or exogenous lipids. In vitro PFC responses by normal mouse spleen cells were also greatly increased in the presence of BCG-SS. Anti-theta serum-treated spleen cells from mice that had been lethally irradiated and reconstituted with normal bone marrow cells also gave a higher PFC response to SRBC in the presence of BCG-SS. This suggests that BCG-SS can stimulate B lymphocytes to develop an immune response when T lymphocytes are severely depleted or absent. BCG-SS also stimulated the uptake of 125IUdR by normal spleen cell cultures, indicating that it is a mitogen.
This study was undertaken to investigate the antigenic relationships between human malignant melanoma cells and Mycobacterium bovis (BCG). Rabbits were immunized with sonicates of BCG or with malignant melanoma cells from different patients and the resulting antisera were tested for their capacity to bind radiolabeled soluble extracts prepared from BCG and melanoma cells. The binding of antibodies to radiolabeled antigens was studied by precipitation of radiolabeled antigen-antibody complexes by anti-rabbit immunoglobulin. Antibodies in sera from rabbits immunized with either BCG (anti-BCG) or melanoma cells (anti-melanoma) bound both the labeled BCG and melanoma antigens. Control antisera, from rabbits immunized with human acute or chronic lymphatic leukemia cells or with normal human spleen cells, did not bind significant amounts of radiolabeled BCG. Antibodies in sera from rabbits immunized with normal spleen cells bound small but significant amounts of radiolabeled melanoma antigens. Binding by anti-BCG and anti-melanoma to the radiolabeled antigens was studied before and after absorption of antisera with cells from human melanoma, leukemia, guinea pig hepatoma, and normal human spleen cells. Inhibition studies using unlabeled BCG extracts also were carried out. The absorption and inhibition studies confirmed that the binding reactions were specific and that antigens from five melanoma patients shared antigenic determinants with BCG.
The performance characteristics of the Gen-Probe Probe Competition Assay (PCA) used in conjunction with the Gen-Probe PACE 2 and 2C direct detection assays for Chlamydia trachomatis were examined. Data collected by five public health laboratories by using the Gen-Probe PACE 2 were pooled and analyzed. Of 25,081 endocervical and male urethral specimens tested by the PACE 2 assay, 773 were tested by PCA. Of 334 specimens initially positive by the PACE 2 assay with an initial PACE 2 result of greater than 2,000 relative light units (RLU), 333 (99.7%) were positive by PCA while 242 of 339 (71.4%) specimens with an initial result between the cutoff and 2,000 RLU were positive by PCA, and 35 of 100 (35%) specimens with initial results between 200 RLU and the cutoff were positive by PCA. An additional 10,938 specimens were tested by the PACE 2C assay. Of these, positive PCA results were obtained for 187 of 188 (99.5%) specimens with initial results of greater than 2,000 RLU, 99 of 163 (60.7%) of specimens in the range of cutoff to 2,000 RLU, and 12 of 100 (12%) in the range of 200 RLU to the cutoff. These results indicate that specimens greater than 2,000 RLU do not require a supplemental test and that additional positive results can be obtained by testing specimens with an initial result below the cutoff.
The incidence and possible clinical relevance of immune complexes in sera from children with acute leukemias was investigated. Determinations were made in sera obtained at three-month intervals from individual patients over a two-year period. Two tests, the Clq binding and the polyethylene glycol precipitation assays, were employed. At time of diagnosis, immune complexes were found in sera from 6 of 41 patients (15%) with acute lymphoblastic leukemia (ALL). Three of 6 patients with T-cell leukemia had immune complexes at diagnosis as compared to 3 of 35 with null-ceH leukemia. Only 1 of the 6 patients with T-cell leukemia had a white blood cell count of less than 50,OOO/pl3. Of the patients followed for six months or more, 34% had immune complexes during therapy and the incidence of relapse was unrelated to the presence or absence of immune complexes. Fifty-two percent of patients that remained in remission during the period of study and 5 of 8 patients that relapsed (63%) had immune complexes at one time or another suggesting that the presence of immune complexes by themselves did not portend either a favorable or an unfavorable prognosis. Sera taken at the time of diagnosis from children with acute non-lymphoblastic leukemia (ANLL) had a higher incidence (36%) of immune complexes than similar sera from ALL patients (15%). Antibodies in sera from leukemia patients at diagnosis had a lower capacity to bind a BCG antigen than did sera from contfol subjects. Eleven of 17 patients that had BCG immunotherapy had a humoral antibody response to BCG. There was no relation between an antibody response to BCG and a favorable clinical response.
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