Human sperm cells express CD44.
OBJECTIVE
To determine whether CD44 is expressed by human sperm cells.


METHODS
Prospective study.


METHODS
Assisted conception unit and university research laboratory.


METHODS
Fourteen normal fertile donors.


METHODS
None.


METHODS
Enzyme-linked immunoassay was used to measure the concentration of CD44 in samples of human sperm cells. Immunocytochemistry using a fluorescent antibody system was used to confirm and localize the expression of CD44 on sperm membranes. Western blotting was used to identify CD44 protein in extracts of lysed sperm cells.


RESULTS
The presence of CD44 was identified in suspensions of pure sperm cells by ELISA. The mean sperm count was 66 million per milliliter (range, 60 million-75 million per milliliter) and the mean concentration of CD44 was 0.013 ng per 10(6) sperm (range, 0.012 ng-0.015 ng per 10(6) sperm). Use of a fluorescently labeled antibody to CD44 confirmed the presence of CD44 on sperm membranes. CD44 expression was mostly localized in the acrosome region. Western blotting using a specific monoclonal antibody to CD44 identified a variant of CD44 with an approximate molecular weight of 73 kDa.


CONCLUSIONS
The expression of CD44 on the surface of human sperm membranes was confirmed by three independent methods.
Bains
Rani
R
Division of Biomedical Sciences, School of Health Sciences, University of Wolverhampton, Wolverhampton, United Kingdom.
Adeghe
Jude
J
Carson
Ray J
RJ
D015153:Blotting, Western; D002462:Cell Membrane / Q000378:metabolism; D004797:Enzyme-Linked Immunosorbent Assay; D005455:Fluorescent Antibody Technique; D006801:Humans; D018960:Hyaluronan Receptors / Q000378:metabolism*; D008297:Male; D011446:Prospective Studies; D013094:Spermatozoa / Q000378:metabolism*
D018960:Hyaluronan Receptors