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Updated: Jul 6, 2026
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Medium-throughput Screening Assays for Assessment of Effects on Ca2+-Signaling and Acrosome Reaction in Human Sperm
Published on: March 1, 2019
Fas receptor is not present on ejaculated human sperm
S Perticarari1, G Ricci, R Boscolo
1Clinical Analysis Unit, Department of Laboratory Medicine, Institute of Child Health IRCCS Burlo Garofolo, Via dell'Istria 65/1, 34137 Trieste, Italy.
Human Reproduction (Oxford, England)
|April 15, 2008
Summary
Fas (CD95) is not detected on human ejaculated sperm, despite its role in germ cell apoptosis. This study found no correlation between Fas on sperm and apoptotic markers, suggesting Fas is not a reliable indicator of sperm apoptosis.
Area of Science:
- Reproductive Biology
- Immunology
- Cell Biology
Background:
- Apoptosis regulates male germ cell numbers.
- Fas expression is observed in apoptotic spermatocytes and spermatids.
- The presence of Fas (CD95) on ejaculated human sperm and its relation to apoptosis were investigated.
Purpose of the Study:
- To determine if Fas (CD95) is present on ejaculated human sperm.
- To investigate the relationship between Fas on sperm and the apoptotic marker Syto16.
- To assess the role of Fas in sperm apoptosis.
Main Methods:
- Semen samples from 77 infertile men were analyzed using flow cytometry before and after preparation.
- Multiparameter flow cytometry assessed sperm concentration, viability, apoptosis, leukocytes (CD45), and Fas (CD95).
- Indirect immunofluorescence confirmed flow cytometry findings.
Main Results:
- Mean CD95 positive cells were <1% with no difference between normozoospermic and non-normozoospermic men.
- No correlation was found between apoptotic sperm and CD95 positive cell concentration.
- Leukocytes, not sperm, expressed significant CD95, which was upregulated by activating anti-Fas antibody and betulinic acid.
Conclusions:
- No detectable quantity of Fas (CD95) was found on human ejaculated sperm.
- Fas expression is primarily on leukocytes in semen, not on sperm.
- Betulinic acid induced apoptosis in sperm, but not via Fas.
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