Cell-mediated reactivity to antigens shared by Moloney-virus-induced lymphomas (LSTRA) and certain 3-methylcholanthrene-induced mouse sarcomas

Urotherapy for patients with cancer

Cancer cells release various antigens, some of which appear in the urine. Oral autourotherapy is suggested as a new treatment modality for cancer patients. It will provide the intestinal lymphatic system with the many tumor antigens against which antibodies may be produced. These antibodies may be pierced through the blood stream and attack the tumor and its cells.

Detection of a novel lymphocyte protein-tyrosine kinase by renaturation in polyacrylamide gels

Protein kinase activity, including activity specific for the phosphorylation of tyrosine residues, can be detected among particulate fraction proteins of T cell lymphomas after separation by SDS-polyacrylamide gel electrophoresis. Putative protein kinases are detected by renaturation of enzyme activity directly within the gel following removal of detergent. LSTRA, a cell line that exhibits elevated levels of protein-tyrosine kinase activity, was found to express a predominant protein-tyrosine kinase of molecular weight 30,000. This same enzyme was present in T lymphocytes and other T lymphoid cell lines. Studies involving rapid preparation of protein fractions, limited proteolysis and one-dimensional peptide mapping did not demonstrate a direct relationship between the phosphorylated 30,000 dalton protein and the predominant 56,000 dalton phosphotyrosine containing protein that is observed following phosphorylation of LSTRA cell particulate fractions in vitro.

Covalently bound myristate in a lymphoma tyrosine protein kinase

The murine lymphoma cell line LSTRA expresses high levels of a membrane-associated tyrosine protein kinase, which we now show to be acylated by [3H]myristate in vivo. This [3H]myristate-labeled tyrosine protein kinase is immunoprecipitated from detergent extracts of postnuclear particulate fractions with an antibody directed against its single site of tyrosine phosphorylation. This site has an amino acid sequence also found in the transforming proteins of the Rous sarcoma and Y73 viruses. Preincubation of the antibody with a peptide containing the same sequence completely blocks this immunoprecipitation. The [3H]myristate linkage to the protein is stable in boiling 2% NaDodSO4/0.125 M Tris Cl, pH 6.7/5% 2-mercaptoethanol, which suggests an amide rather than an ester linkage. Analogous attempts to label with [3H]palmitate show negligible incorporation into either nonnuclear particulate proteins or immunoprecipitated proteins. Chemical characterization of the immunoprecipitated protein isolated by NaDodSO4/PAGE verifies that the 3H label is in protein-associated myristate. Sonicated 5% NaDodSO4 extracts of LSTRA and YAC-1 (another murine lymphoma line) cells contain quite different distributions of myristoylated proteins.

Production of T-cell lines with inhibitory or stimulatory activity against syngeneic tumors in vivo. A preliminary report

We obtained Thy-I-positive cells directly from growing methylcholanthrene-induced (MCA-1510) sarcomas using fluorescence-activated cell sorting, then cultured these lymphocytes in medium containing Interleukin-2 and tested their activity in vivo against various MCA-sarcoma lines with the Winn assay. We found that cultured T cells from small MCA-1510 tumors (17 days after transplantation) significantly inhibited the growth of that particular sarcoma, but not of three other MCA-tumor lines tested, while cultured T cells from large MCA-1510 sarcomas (41 days after transplantation) significantly enhanced the growth of that tumor, but not of an unrelated tumor, MCA-1460. The former cells were primarily Lyt-1+, 2+ while the latter were primarily Lyt-1+, 2+.

Suppressor pathways in tumor immunity: a requirement for Qa-1 positive tumor-bearer spleen T cells in suppression of the afferent immune response to tumor antigens

Spleen cells from mice bearing large methylcholanthrene (MCA)-induced sarcomas were injected intravenously into mice challenged in the hind footpads with heavily-irradiated cells from the same or a different sarcoma. As measured by [3H]-thymidine incorporation on day 5 or 6, cellular proliferation in the draining popliteal lymph nodes of these mice was significantly depressed as compared to control animals receiving normal spleen cells or medium intravenously. The suppression was found to be mediated by a Qa-1-positive, Thy-1 positive cell. It was relatively resistant to cyclophosphamide treatment (100 mg/kg). Furthermore, it had both antigen-specific and non-specific components. The findings are discussed in relation to a suppressor activator cell-suppressor acceptor cell pathway in the immunoregulation of tumor immunity.

Cell-mediated suppression of tumor immunity has a non-specific component. I. Evidence from transplantation tests

We have first demonstrated that the growth of a transplanted, 3-methyl-cholanthrene-induced BALB/c sarcoma, MCA-1425, in specifically immune syngeneic mice, was facilitated when the MCA-1425 tumor cells were injected together with either a mixture of irradiated MCA-1425 cells and thymus cells from mice immune to MCA-1425 or a mixture of irradiated cells from an antigenically different BALB/c sarcoma, MCA-1460, and thymus cells from mice immune to MCA-1460. We then performed Winn assays to study the induction of an immune response that could prevent the outgrowth of MCA-1425 cells in irradiated syngeneic recipients. Tumor immunity was found to be suppressed, if the mice immunized by a subcutaneous transplant of MCA-1425 cells and used as lymphocyte donors, were injected intraperitoneally with cells from either a different sarcoma, MCA-1460, or from 12-day BALB/c embryos. We tentatively attribute our finding to antigen-non-specific suppressor effector cells and postulate that an antigen-specific event is often involved in their induction.

Cell-mediated suppression of tumor immunity has a non-specific component. II. Evidence from cell culture experiments

In vitro studies were performed to search for cells in the thymus of BALB/c mice with MCA-induced sarcomas which could suppress either a secondary immune response to MuLV-associated tumor antigens present on a Moloney leukemia virus-induced lymphoma, LSTRA, or a primary cytotoxic response to C57BL/6 alloantigens. They showed that thymocytes from mice with sarcomas were suppressive in both systems, and that suppression was independent of whether or not the sarcomas expressed MuLV antigen gp70. Furthermore, normal thymocytes, when combined with mitomycin-C-treated cells from any of several different MCA-induced sarcomas, suppressed the in vitro generation of a secondary cytolytic response to LSTRA. We postulate that exposure of mice to certain tumor antigens induces cells which, in the presence of the same tumor antigens which are not detectably present on the tumor cells inducing the response.

T-T hybridoma product specifically suppresses tumor immunity

Culture supernatants of spleen or thymus cells from BALB/c mice bearing transplanted, syngeneic, methylcholanthrene-induced sarcomas suppress T lymphocyte-mediated lysis of cells from the tumor borne by the donor of the spleen or thymus cells. On this basis, we hybridized thymus cells from mice bearing sarcoma MCA-1490 with cells from the T lymphoma BW5147. The hybrids (hybridomas) formed were tested for production of factors that could suppress T lymphocyte-mediated lysis of MCA-1490 cells. One hybridoma, and a clone derived from it, produced factors that suppressed the lysis of MCA-1490 cells in vitro. In addition, these factors enhanced the growth of MCA-1490 in immune mice and prevented the destruction of MCA-1490 cells by immune lymphocytes in tumor neutralization (Winn) assays. In vitro lysis of cells from another MCA-induced sarcoma by immune lymphocytes was not suppressed. The suppressor factors did not affect the proliferative response of BALB/c lymphocytes to mitogens or the generation of a cytotoxic response to C57BL/6 alloantigens. Neither did they inhibit the generation of primary or secondary cytotoxic responses to murine leukemia virus-related antigens present on a BALB/c lymphoma line, LSTRA. Although our findings suggest that these suppressor factors are specific for MCA-1490, their specificity for antigens restricted to this tumor needs further definition.

Changes in tumor-specific antigen expression during passage in vitro and in vivo of newly derived methylcholanthrene-induced sarcomas of BALB/C mice

The characteristics of tumor antigens of the transplantation type, TATA, were studied in a series of methylcholanthrene-induced sarcomas in pedigreed BALB/cAN mice. Each of the six sarcomas exhibited unique TATA when assayed for tumor rejection in syngeneic hosts. In three instances, however, in sarcomas CI-I, CII-5 and CII-7, TATA activity was lost during early in vivo passages. This activity was reestablished invivo from the in vitro-passaged lines in CI-I and CII-7 and these sarcomas along with CI-3, CI-4 and CII-10 maintained a stable TATA phenotype throughout the 50 transplant passages; TATA was lost permanently, however, in CII-5. These results indicate a dimorphic nature of early-passage neoplasms. No cross-reacting antigens were detected among these sarcomas, including also Meth A, a sarcoma well characterized as to its membrane antigens; nor was any evidence obtained for the existence of alien (inappropriate) H-2 antigens employing tumor rejection assays in F1 hybrids of BALB/c with strains bearing several haplotypes and also with studies of H-2 serology. In three sarcomas, some evidence was obtained for the existence of alloantigens of the non-H-2 type since it was found that (BALB/c X DBA/2)F1 hybrids could not be immunized by respective sarcomas. These findings suggest the existence on these sarcomas of a tumor antigen that is expressed normally in DBA/2 mice, although no definitive evidence has been obtained. Assays for MuLV, for the viral structural proteins gp70 and p30 and for reverse transcriptase showed that three sarcomas were positive and three others, as well as Meth A, were negative. MuLV and its antigens had no influence on tumor rejection activity nor could the cross-reactivity observed in the radioisotopic footpad assay (IFP) be related to MuLV.