Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.27.1 (RNase)
 16,360 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We have investigated the pathogenesis of the polyclonal hypogammaglobulinemia associated with BALB/c plasmacytomas TEPC-183 and SPQC-11 to gain insight into the hypogammaglobulinemia observed in human myeloma. With pokeweed mitogen-driven IgM biosynthesis by mouse splenocytes as the indicator system for suppression, we found that a protein extract of asscites cells obtained from these tumor-bearing animals could suppress immunoglobulin production, whereas like extracts from a non-suppressing plasmacytoma, modified RPC-5, caused no suppression in vitro. Extracts of tumor ascites depleted of mononuclear phagocytes by iron carbonyl treatment showed little suppressor activity. The active extract was not cytotoxic and contained no mycoplasma or common murine viruses. Furthermore, the active suppressor factor appears to be a low m.w. protein that is not affected by treatment with ribonuclease. These results and others are consistent with the idea that the hypogammaglobulinemia of myeloma is due to the formation of immunoregulatory macrophage-like cells which synthesize a suppressor substance.
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PMID:Hypogammaglobulinemia in experimental myeloma: the role of suppressor factors from mononuclear phagocytes. 85 68

BALB/c mice with the plasmacytoma MOPC 104E producing monoclonal IgM-lambda with antibody activity to alpha-1,3 dextran were found to have B lymphocytes with surface immunoglobulins with the immunochemical characteristics of 104E IgM capable of binding alpha-1,3 dextran. RNA extracted from this plasmacytoma induced the synthesis of such surface immunoglobulins on normal B lymphocytes in vitro and in vivo. Injection of 200 mug of MOPC 104E RNA into normal mice 72 hr prior to the administration of the antigen kept the immune response to dextran-S intact, but suppressed that to other antigens, such as DNP-Ficoll and LPS, T cell-independent antigens, and SRBC and BSA which are T cell-dependent. The effect of the RNA was abolished by RNase but not by pronase and DNase. RNA extracted from LPC-1 tumour (gamma2a-k without known antibody activity) significantly suppressed the immune response to dextran-S and to other antigens in normal mice. Thus, opposite effects of MOPC 104E RNA on the response to specific and non-specific antigens strengthen the hypothesis that the immune deficiency in plasmacytoma bearing mice is due to the conversion of normal surface immunoglobulin of a population of B lymphocytes to the idiotype of the respective myeloma globulin.
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PMID:Surface immunoglobulins of lymphocytes in plasmacytoma. V. The effect of RNA-rich extract from mouse plasmacytoma MOPC 104E on the immune response. 127 83

The antitumor action of bovine seminal ribonuclease was evaluated with a quantitative assay based on the production of tumor foci in the spleens of mice injected with plasmacytoma cells. The antitumor action depended on the integrity of the catalytic site, and on the dimeric structure of the enzyme. A working hypothesis is proposed, based on these results, and on previous results obtained studying the antitumor action of seminal RNAase in vitro on cell cultures. According to this hypothesis, the antitumor action is based on the ability of seminal RNAase to interact at specific receptor sites on the tumor cell membrane, as well as on its RNA degrading ability.
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PMID:The antitumor action of seminal ribonuclease tested with the plasmacytoma spleen colonization assay. 222 56