Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0153470 (Spleen)
 4,015 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A humoral factor extracted from calf thymus (THF) restores the immunocompetence of spleen cells from neonatally thymectomized (NTx) mice to induce an in vitro graft-vs-host (GVH) response. This acquistion of immunocompetence consists of a series of biochemical events, the first of which involves an obligatory rapid increase in adenyl cyclase acitivity and in intracellular levels of cyclic AMP. Protein synthesis occurs as a further step in the events leading to induction of immunocompetence by THF and could be blocked by cycloheximide with the consequent abolishment of the immunocompetence of the lymphoid cells tested. The induction of competence by THF is accompanied by a simultaneous reduction in DNA synthesis resulting from the increase in intracellular cyclic AMP levels. These steps have been studied in the absence of antigenic stimulation which is not required for the induction of competence by THF. Spleen extracts prepared by a similar procedure as THF were found to be devoid of the properties described above.
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PMID:Intracellular events involved in the induction of immune competence in lymphoid cells by a thymus humoral factor. 23 96

Spleen cells from LAF1 mice primed with photo-oxidized antigen B exhibit helper T-cell activity when assayed in an adoptive transfer system with spleen cells from mice primed with timothy pollen extract and treated with anti-thy 1.2 serum and complement. These helper cells, when placed in culture with antigen B, secrete a soluble antigen B-specific helper factor (THF) that requires the presence of normal spleen cells or cells that do not adhere to nylon wool in order to exhibit T cell-replacing activity. The THF has been partially purified over an immobilized antigen adsorbent. The eluted THF exhibits a mol. wt of 65,000 by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE), and contains 5% carbohydrate by weight. The THF is I-Ak-positive and Ig-negative.
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PMID:Antigen B-specific helper factor from timothy grass pollen: isolation and partial characterization. 679 10

The effect of in vivo treatment with THF (thymus humoral factor) on the response of mouse lymphocytes to mitogens was investigated. Different preparations of THF were tested by daily i.m. injections into normal mice. Spleen, peripheral lymph node and thymus cells were tested for reactivity to several mitogens at various intervals after initiation of treatment. Our results indicate that the administration of THF to normal mice causes an inhibitory trend in the response of spleen cells to T-cell mitogens. It was found that the response of spleen cells to phytohemagglutinin (PHA) and concanavalin A (Con A) was strongly depressed after 7 days of treatment with 50 micrograms of THF. This was followed by a recovery of the response to normal levels after 14 days of treatment. The response of spleen cells to lipopolysaccharide (LPS) a B-cell mitogen, did not change throughout 14 days of treatmnent with THF. Lymph node cells of THF-treated mice behaved qualitatively in a similar manner to spleen cells, while thymus cells from THF-treated mice showed a significantly increased response to Con A. In contrast to normal mice, the injection of THF into mice with an impaired reactivity to PHA, such as thymectomized mice and tumor-bearing mice, caused an augmentation of the mitogenic response of spleen cells. These results suggest that in vivo administration of THF causes regulatory changes in the lymphocyte reactivity to T-cell mitogens.
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PMID:Regulatory action of THF on T-cell reactivity to mitogens. 696 74