Related Experiment Videos
Implication of sperm head agglutination induced by a V3 peptide (fragment 307-330, HIV-1 envelope protein gp120)
1Department of Obstetrics and Gynecology, Taipei Medical College and Yang-Ming University, Taiwan, Republic of China.
Abstract:
Human semen is the main vehicle for the transmission of human immunodeficiency virus (HIV); therefore, the interaction of HIV with the sperm is worthy of study. The motile sperm head fixation method was used as an in vitro model system to demonstrate the interaction of sperm with the peptide of HIV envelope protein. A micropipette loaded with semen was put into phosphate-buffered saline (PBS) containing V3 peptide (HIV-1IIIB envelope protein, fragment 307-330) or C2 peptide (HIV-1IIIB envelope protein, fragment 254-274). The V3 peptide caused a significant number of head-to-head binding sperm while the C2 peptide did not. This V3 peptide carries a high positive charge, which may overcome the electrostatic resistance on the cell to bring the sperm together. An HIV-CD4+ cell attachment inhibitor, dextran sulfate (DS, molecular weight about 5000), enhanced the sperm head agglutination induced by the V3 peptide. DS is presumed able to bind with specific sites near the V3 domain of gp120 to induce conformational change so as to prevent the binding of anti-V3 monoclonal antibodies or CD4+ cells to the V3 domain. This study suggests that DS interacts directly with the V3 peptide to enhance the sperm head agglutination.
Insights
Human immunodeficiency virus (HIV) transmission involves semen. Researchers studied HIV envelope protein V3 peptide interactions with sperm, finding V3 peptide causes sperm head-to-head binding, enhanced by dextran sulfate.
Area of Science:
- Virology
- Immunology
- Reproductive Biology
Background:
- Human semen is a primary vector for human immunodeficiency virus (HIV) transmission.
- Understanding the interaction between HIV and sperm is crucial for preventing sexual transmission.
Purpose of the Study:
- To investigate the interaction between sperm and specific peptides of the HIV envelope protein in vitro.
- To determine the role of the V3 peptide and dextran sulfate in sperm-HIV interactions.
Main Methods:
- Utilized a motile sperm head fixation method as an in vitro model.
- Exposed sperm to V3 peptide and C2 peptide in phosphate-buffered saline (PBS).
- Assessed the effect of dextran sulfate (DS) on V3 peptide-induced sperm agglutination.
Main Results:
- The V3 peptide significantly induced head-to-head binding of sperm.
- The C2 peptide did not cause significant sperm binding.
- Dextran sulfate enhanced the V3 peptide-mediated sperm head agglutination.
Conclusions:
- The positively charged V3 peptide may overcome electrostatic repulsion to aggregate sperm.
- Dextran sulfate likely interacts with the V3 peptide, enhancing sperm agglutination.
- These findings provide insights into potential mechanisms of HIV transmission via semen.