Recent Advances in Thymic Hormone Research

Sztein, Marcelo B.; Goldstein, Allan L.

doi:10.1007/978-1-4684-5242-6_10

Cited by 1 publication

(6 citation statements)

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“…TF5, bovine kidney fraction 5 (KF5), and synthetic thymosin a1 were provided by Alpha 1 Biomedicals (Washington, DC) and were prepared as described (16,20,21). The TF5 preparation was endotoxin-free as determined by the Limulus and rabbit pyrogen assays.…”

Section: Methodsmentioning

confidence: 99%

“…Thymic hormones exhibit immunoreconstitutive effects in vivo and in vitro (12)(13)(14)(15)(16). In vitro, thymic hormones enhance proliferative responses of both murine and human lymphocytes (12)(13)(14)(15)(16).…”

mentioning

confidence: 99%

“…In vitro, thymic hormones enhance proliferative responses of both murine and human lymphocytes (12)(13)(14)(15)(16). In vivo, injection of thymosin a1, a synthetic peptide originally isolated in its native form from thymosin fraction 5 (TF5), a partially purified calf thymus preparation (12)(13)(14)(15)(16), increases IL-2 production in vitro and the response to IL-2 of spleen cells from old mice in response to mitogens (17). Further, TF5 increases in vitro IL-2 production by human lymphocytes in response to phytohemagglutinin (PHA) (18,19).…”

mentioning

confidence: 99%

“…Thymosin et, Enhances PHA-Induced IL-2R Expression. Experiments were performed in order to determine whether thymosin a1, which has been shown to have immunoregulatory activities in other systems (12)(13)(14)(15)(16)(17)21), is able to modulate IL-2R expression on human lymphocytes stimulated by suboptimal PHA concentration. A representative experiment of five with similar results is included in Fig.…”

mentioning

confidence: 99%

“…TF5 Modulation of IL-2R Expression Induced by Monoclonal Antibody OKT3. The lymphoproliferative responses to specific antigens have been shown to be enhanced by thymic hormones (12)(13)(14)(15)(16). These responses involve activation through the T-cell antigen receptor, IL-2 production, and IL-2R expression.…”

mentioning

confidence: 99%

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Modulation of interleukin 2 receptor expression on normal human lymphocytes by thymic hormones.

Sztein¹,

Serrate²,

Goldstein³

1986

Proc. Natl. Acad. Sci. U.S.A.

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The expression of interleukin 2 receptors (IL-2R) is a critical step leading to normal lymphocyte proliferation. Since thymosin fraction 5 (TF5), a thymic hormone preparation, enhances lymphoproliferative responses of human cells, we examined the effects of TF5 on the expression of IL-2R on mitogen-stimulated human lymphocytes. TF5 significantly increased the percentage and antigen density of cells expressing IL-2R after stimulation with an optimal concentration of phytohemagglutinin (PHA) when the cells from the same donor exhibited suboptimal responses to PHA alone. The same effect was observed with a suboptimal PHA concentration and with OKT3 monoclonal antibody stimulation. Thymosin eq, a synthetic polypeptide originally isolated in its native form from TF5, was also able to increase IL-2R expression in response to PHA, suggesting that it is the active species in TF5. The enhancement of IL-2R expression was paralleled by increased proliferative responses. Increased IL-2R expression appears to be the direct effect of thymic hormones, since abrogation of interleukin 2 production by cyclosporin A did not affect TF5-mediated enhancement of PHA-induced IL-2R expression. These results point to a physiological role of thymic hormones in the maintenance of normal levels of IL-2R expression. This immunoregulatory activity of thymic hormones might be relevant in the treatment of conditions where there is decreased IL-2R expression, such as the acquired immune-deficiency syndrome, or in the restoration of normal IL-2R expression to lymphocytes from aged individuals.

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Section: Methodsmentioning

confidence: 99%