Human sperm-specific peptide vaccine that causes long-term reversible contraception

Area of Science:

• Immunology
• Reproductive Biology
• Vaccinology

Background:

• Human sperm possess a novel dodecamer peptide sequence, YLP(12), crucial for oocyte binding.
• This peptide is an epitope of a 50 +/- 5-kDa membrane protein found on sperm acrosomes and tails.

Purpose of the Study:

• To investigate the immunocontraceptive potential of the YLP(12) peptide in a murine model.
• To assess the efficacy and reversibility of a vaccine based on the YLP(12) peptide.

Main Methods:

• A vaccine was created by conjugating synthetic YLP(12) with the binding subunit of recombinant cholera toxin.
• Female mice were vaccinated via intramuscular or intranasal routes.
• Fertility and antibody responses were monitored over time, with reversibility tested via intravaginal peptide administration.

Main Results:

• Vaccination induced a long-term, sperm-specific immune response in serum and the vaginal tract, leading to a contraceptive state.
• Fertility was fully restored at 305-322 days as antibody reactivity decreased.
• The contraceptive effect was completely reversed by intravaginal administration of the YLP(12) peptide.

Conclusions:

• The sperm-specific YLP(12) peptide is a promising candidate for a contraceptive vaccine.
• The induced antibodies interfere with prefertilization events, including sperm capacitation, acrosome reaction, and sperm-oocyte binding.
• The contraceptive effect is long-lasting but reversible, offering a potential new approach to birth control.