Screening of an antigen target for immunocontraceptives from cross-reactive antigens between human sperm and Ureaplasma urealyticum.
Epidemiologic studies indicated that some infertile men who were infected with Ureaplasma urealyticum displayed positive antisperm antibodies in their serum and/or semen. The purpose of this study was to investigate the possible mechanism of antisperm antibodies production after infection with U. urealyticum and to analyze the relationship between U. urealyticum and infertility. The existence of cross-reactive antigens (61, 50, and 25 kDa) between U. urealyticum and human sperm membrane proteins was confirmed. Among the cross-reactive antigens, the urease complex component UreG of U. urealyticum was determined. By searching the Swiss-Prot protein database, a pentapeptide identity (IERLT) between UreG and human nuclear autoantigenic sperm protein (NASP) was found. Furthermore, using Western blot analysis and enzyme-linked immunosorbent assay, the cross-reaction between the NASP and UreG was verified. Both anti-rUreG antibody and the antiserum against the synthetic peptide NASP393-408 containing the pentapeptide inhibited mouse sperm egg binding and fusion. After immunization by rUreG or the synthetic peptide, 81.2 and 75% female mice became sterile, respectively. The effect on fertility in mice immunized with the synthetic peptide was reversible. These findings proved for the first time that it was feasible to screen antigens for immunocontraceptives from cross-reactive antigens between sperm and microorganisms which induce infertility.
Shi
Jianli
J
Department of Histology and Embryology, Shanghai Jiao Tong University School of Medicine, 280 South Chongqing Road, Shanghai, China 200025.
Yang
Zhengmin
Z
Wang
Min
M
Cheng
Guoyan
G
Li
Ding
D
Wang
Yifei
Y
Zhou
Yuancong
Y
Liu
Xiaolong
X
Xu
Chen
C
D000818:Animals; D000907:Antibodies, Bacterial; D000941:Antigens / Q000276:immunology*; D000942:Antigens, Bacterial / Q000276:immunology*; D001324:Autoantigens / Q000235:genetics / Q000276:immunology; D001426:Bacterial Proteins / Q000276:immunology; D015153:Blotting, Western; D002352:Carrier Proteins / Q000276:immunology; D003269:Contraception, Immunologic; D003429:Cross Reactions; D004797:Enzyme-Linked Immunosorbent Assay; D005307:Fertilization in Vitro; D006801:Humans; D007248:Infertility, Male / Q000209:etiology; D008297:Male; D008565:Membrane Proteins / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C; D009687:Nuclear Proteins / Q000235:genetics / Q000276:immunology; D010455:Peptides / Q000276:immunology; D028044:Phosphate-Binding Proteins; D011817:Rabbits; D017386:Sequence Homology, Amino Acid; D013094:Spermatozoa / Q000276:immunology*; D016869:Ureaplasma Infections / Q000150:complications / Q000276:immunology; D016990:Ureaplasma urealyticum / Q000276:immunology*
D000907:Antibodies, Bacterial; D000941:Antigens; D000942:Antigens, Bacterial; D001324:Autoantigens; D001426:Bacterial Proteins; D002352:Carrier Proteins; D008565:Membrane Proteins; C489390:NASP protein, human; D009687:Nuclear Proteins; D010455:Peptides; D028044:Phosphate-Binding Proteins; C082270:ureG protein, Bacteria