Trophoblast/leukocyte-common antigen is expressed by human testicular germ cells and appears on the surface of acrosome-reacted sperm.
The murine monoclonal antibody H316 reacts with a cell-surface antigen of human trophoblast, leukocytes, certain epithelia, and several malignant cell types. We have found that the H316 antibody also recognizes an antigen synthesized by pre- and post-meiotic human testicular germ cells and is expressed in the acrosomal region of methanol-fixed testicular, epididymal, and ejaculated sperm. The antigen is poorly expressed on the surface of fresh ejaculated motile sperm, but is detectable on most viable sperm after a 6-h incubation in medium containing human serum albumin (HSA), or 60-min incubation with the calcium ionophore A23187 (both treatments induce sperm acrosomal changes termed capacitation and acrosome reaction). We found that antigen recognized by H316 is immunoprecipitated as a single, broad 50 kDa band from radiolabeled ionophore-treated sperm extracts and that preincubation of HSA-capacitated sperm with this antibody causes a moderate, but significant, inhibition of hamster egg penetration. These data indicate that the antigen recognized by the H316 monoclonal antibody is synthesized by testicular germ cells and is surface-expressed on capacitated/acrosome-reacted sperm populations. Its potential as a human sperm acrosome reaction marker, and possible biological role in sperm-egg or sperm-lymphocyte interactions, warrants further investigation.
Anderson
D J
DJ
Department of Obstetrics, Gynecology and Reproductive Biology, Harvard Medical School, Boston, Massachusetts 02115.
Michaelson
J S
JS
Johnson
P M
PM
D000911:Antibodies, Monoclonal / Q000276:immunology; D000943:Antigens, Differentiation; D000954:Antigens, Surface / Q000032:analysis; D001324:Autoantigens; D004591:Electrophoresis, Polyacrylamide Gel; D004822:Epididymis / Q000166:cytology; D005455:Fluorescent Antibody Technique; D006649:Histocompatibility Antigens; D006801:Humans; D007150:Immunohistochemistry; D007519:Isoantigens; D007525:Isoelectric Focusing; D017493:Leukocyte Common Antigens; D008297:Male; D008854:Microscopy, Electron; D008970:Molecular Weight; D011233:Precipitin Tests; D011863:Radioimmunoassay; D013075:Sperm Capacitation; D013087:Spermatids / Q000276:immunology*; D013094:Spermatozoa / Q000276:immunology* / Q000648:ultrastructure; D013737:Testis / Q000166:cytology
D000911:Antibodies, Monoclonal; D000943:Antigens, Differentiation; D000954:Antigens, Surface; D001324:Autoantigens; D006649:Histocompatibility Antigens; D007519:Isoantigens; C055067:trophoblast-lymphocyte cross-reactive antigens; D017493:Leukocyte Common Antigens