A Comparative Study Of Different Probe Labeling Of Human Sperm Mannose Receptor

Fertilization is one of most important reseach area in the field of fertility control and life science. It is a very complete multiple-steps procedure and its molecμlar machenism is still not fully understood. Human sperm mannose receptor (hsMR) might be the key molecular related in sperm recognition, binding and fusion to oocyte.It has been investigated in localization, function and some respects in biochemistry for hsMR . The molecular characteristic of hsMR however is not yet defined. Several investigations showed the molecular weight of hsMR varied from 27KDa to 160KDa. It is well know that hsMR recognized and binded to D-mannose and might related in sperm and oocyte interaction. Recently, furthermore, a few reports indicated that hsMR might be the same to human macrophage mannose receptor (hmMR) or CD206, and might be important in mediating HIV-1 to infect spermatozoa. However, in respect of evolution, mannose receptor of sperm should not be only for mediating the virus infection but should be for fertilization or other physiological functions. Did CD206 equal to hsMR? Did CD206 has a role in mediating spem-oocyte interaction? Based these questions, we detected the molecular in protein dot-blotting, SDS-PAGE , western-blotting and fluorescence immunocytochemistry utilized D-Mannosylated albumin (DMA) and anti-CD206 antibody, respectively.Results: Dot-blotting assay showed that DMA and anti-CD206 specific bound to the blot of ConA or CD206 respectively. Western-blotting of protein from human sperm extracts showed a band of 72KDa protein was labelled by DMA but no band by anti-CD206. This confirmed that there is a kind of mannose binding molecular but not CD206. Fluorescence immunocytochemistry indicated that acrosome-reacted sperm was labelled with DMA-FITC at equatorial segment or acrosome area but without any anti-CD206. Conclusion:Mannose receptor on human sperm head is a kind of 72KDa protein but is not equal to human macrophage mannose receptor (hmMR) or CD206.1. There are two mannose-binding proteins on human spermatozoa with 27Kda or 72Kda of molecular weight respectively;2. 27KDa protein(might be SAP) may be the protein from the male genital tract and attached to spermatozoa(espectialy on tail). While, the 72Kda protein might be the one expressed on equatorial segment of sperm after acrosome reaction and mediating sperm-oocyte interaction and so call hsMR;3. There is no homologous human macrophage mannose receptor on human spermatozoa.