Investigation Of Immunocontraceptive Vaccine Baesd On Epitomics

Safe and effective contraception methods are required for the conduct of national policy of family planning and the development of harmonious society.Seeking safe and effective methods of contraception has been one of the important research interests in the field of human reproductive health.It is therefore possible to screen or produce some reproduction-related antigens,to prepare contraceptive vaccines.To obtain safe,effective,convenient,and reversible contraceptive vaccine,many methods and technologies have been developed.For instance,the "modified peptide biosynthesis method" is employed to identify the minimum motif of each epitope recognized by antibody,which open the new field for immunocontraception vaccine.Firstly,the sperm specific proteins(tNASP,Izumo 1,SPESP),which have immunocross reactive antigens with Uu,were usedas targets to design epitopes for vaccines.After screening and validating B-cell epitope(BCE)of those sperm specific proteins,P6(YSFYRV)from Izumo 1 Ig-like domain specifically binds to egg membrane was found.Vaccination using p6 has similar contraceptional effect compared to using BCE polyvalent chimeric peptides constructed by sperm specific proteins(tNASP,Izumo 1,SPESP).In addition,P6 is highly homologous among the different species.In human and mouse,the specific expression of P6 in sperm makes it a suitable antigen for contraceptive vaccines according to WHO standards.Secondly,we chose protein UreG,which has cross reactivity with sperm proteins in the Uu coding proteins,as a target protein.By linear epitome studies,we identified linear epitope and the minimum base sequences in UreG protein,such as KRPLIIG,RILLNT,DLAPY,LKSR and RLQLAL.We found that although KRPLIIG and LKSR epitopes have contraceptive effect in animal experiments and could be potential target antigens for contraceptive vaccines,but their safety need to be investigated furth.This study helps to further clarify the exact mechanisms of sperm-oocyte fusion and provides new insights into immunocontraception and the treatment of infertility.