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This Article Full Text Full Text (PDF) All Versions of this Article: 79/3/525    most recent biolreprod.107.064386v2 biolreprod.107.064386v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Google Scholar Articles by Foulds, L. M. Articles by Hedger, M. P. PubMed PubMed Citation Articles by Foulds, L. M. Articles by Hedger, M. P. Agricola Articles by Foulds, L. M. Articles by Hedger, M. P.

Molecular Identification of Lyso-Glycerophosphocholines as Endogenous Immunosuppressives in Bovine and Rat Gonadal Fluids¹

Monash Institute of Medical Research,⁴ Australian Research Council Special Research Centre for Green Chemistry,⁵ and Department of Biochemistry and Molecular Biology,⁶ Monash University, Clayton, Victoria 3800, Australia

ABSTRACT

The ability of the gametes to escape detection by the immune system is vital to successful human reproduction. Furthermore, the observed capacity of the testis in some species to support tissue grafts without rejection (immunological privilege) indicates that spermatogenic cells are protected by local immunoregulatory mechanisms. One of these mechanisms involves targeting T cells for inactivation and destruction within the testicular environment. Although the fluids of the testis and ovary surrounding the developing gametes contain soluble factors that inhibit T cells, the identity of the molecule(s) responsible for this activity has been unknown. Using a specific T-cell proliferation assay to monitor bioactivity, these molecules were purified from bovine ovarian follicular fluid by methanol extraction and sequential reverse-phase HPLC (RP-HPLC). All purified active fractions coincided with the elution position on RP-HPLC of several small molecules ranging in size from 496 to 522 Da. The same molecules were localized to the immunosuppressive fractions of rat testicular interstitial fluid. The active molecules were identified, using capillary electrophoresis electrospray ionization mass spectroscopy, as lyso-glycerophosphocholines (lyso-GPCs), namely, 1-palmitoyl-sn-glycero-3-phosphocholine, 1-oleoyl-sn-glycero-3-phosphocholine, a 18:2a/lyso-GPC (putatively, 1-linoleoyl-sn-glycero-3-phosphocholine), and a 20:4a/lyso-GPC (putatively, 1-arachidonyl-sn-glycero-3-phosphocholine). Comparison of the bioactivity and mass spectroscopy profiles of two of the purified molecules with their synthetic standards confirmed the identification. These molecules inhibit T-cell proliferation in response to activation and induce apoptosis of these cells in a time- and dose-dependent manner. The emergence of gonadal lyso-GPCs as potential regulators of critical immune events opens up new avenues of inquiry into the origins of autoimmune infertility and more generally into mechanisms of peripheral immunoregulation and the development of novel immunosuppressives.

apoptosis, immunology, interstitial cells, ovary, testis

³ These authors contributed equally to this work.

¹ Supported by a Program Grant (14786) from the NHMRC of Australia and an Australian Research Council (ARC) Special Research Centre Grant. M.P.H. and A.I.S. were supported by NHMRC Fellowships 143788 and 182814, respectively.

Correspondence: ²Mark P. Hedger, Monash Institute of Medical Research, Monash University, Clayton, Victoria 3800, Australia. FAX: 61 3 9594 7111; e-mail: mark.hedger{at}med.monash.edu.au