Immunoregulatory activity in adult rat testicular interstitial fluid: Roles of interleukin-1 and transforming growth factor β

Mark P. Hedger, David J. Nikolic-Paterson, Paul Hutchinson, Robert C. Atkins, David M. De Kretser

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Studies on the effect of rat testicular interstitial fluid (IF) on T- cell function have reported both stimulatory and inhibitory actions. Specific cytokines produced within the testis, particularly interleukin-1 (IL-1) and transforming growth factor β (TGFβ), may contribute to these apparently conflicting observations. In proliferation assays employing lectin- or antibody-activated thymocytes or mature T cells in vitro, adult rat testicular IF stimulated T-cell activation and/or proliferation at low assay doses and was inhibitory at higher doses. The stimulatory activity was blocked by recombinant IL-1 receptor antagonist. The inhibitory activity was not affected by a polyspecific TGFβ antiserum. The biological characteristics of the inhibitor were distinct from those of a similar, but considerably less potent, activity in platelet-depleted serum. These data demonstrate that rat testicular IF contains biologically significant concentrations of IL-1 but has a predominantly inhibitory action on T-cell responses. The factor predominantly responsible for this inhibitory activity displays a relatively large apparent molecular weight, is protease sensitive and partially heat labile, but does not appear to be one of the known mammalian TGFβ isoforms.

Original languageEnglish
Pages (from-to)927-934
Number of pages8
JournalBiology of Reproduction
Issue number4
Publication statusPublished - Apr 1998

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