Inhibitory effect of somatostatin on human T lymphocytes proliferation.
Somatostatin (SOM) was originally described as a growth hormone release inhibiting factor, but SOM and its specific receptors (SOM-r) have been shown to be expressed on both normal and activated T and B lymphocytes and other immunocompetent cells. In the present study we have demonstrated that SOM strongly inhibits the proliferation of human T lymphocytes when stimulated by PHA, Con A or alloantigens. However, SOM was most effective when the T cells were stimulated by an alloantigen rather than a polyclonal activator such as PHA and ConA. Moreover, SOM strongly inhibited the expression of activation markers such as CD69 and CD25 that are expressed on T lymphocytes during alloantigen stimulation. SOM also inhibited both CD28 and CD2 mediated T cell proliferation. Whereas proliferation of T cells induced by the engagement of CD3 antigen using specific mAbs was only marginally affected. Our results would support the concept that in humans SOM plays a key role in the modulation of T cell activation by interfering with the antigen-independent pathways CD2 and CD28.
Department of Pharmacology, School of Medicine, University of Milan, Italy.
C
C
Casnici
D
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Lattuada
C
C
Perego
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P
Franco
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O
Marelli
D000328:Adult; D000945:Antigens, Differentiation, T-Lymphocyte / Q000378:metabolism; D006801:Humans; D007519:Isoantigens; D008213:Lymphocyte Activation / Q000187:drug effects*; D008934:Mitogens / Q000494:pharmacology; D013004:Somatostatin / Q000494:pharmacology*; D013601:T-Lymphocytes / Q000187:drug effects* / Q000378:metabolism
D000945:Antigens, Differentiation, T-Lymphocyte; D007519:Isoantigens; D008934:Mitogens; D013004:Somatostatin