Activation of polymorphonuclear leukocytes by spermatozoa

Area of Science:

• Immunology
• Reproductive Biology
• Complement System

Background:

• Human spermatozoa can interact with and activate immune cells.
• Polymorphonuclear leukocytes (PMN) are key immune cells involved in inflammatory responses.
• The complement system is a crucial part of innate immunity, involving various proteins and pathways.

Purpose of the Study:

• To investigate the mechanism by which human spermatozoa activate PMN.
• To determine the role of serum components, including antibodies and complement, in sperm-mediated PMN activation.
• To elucidate which complement pathway is involved in sperm-induced PMN activation.

Main Methods:

• Measurement of chemiluminescence emitted by PMN as an indicator of activation.
• Incubation of PMN with human spermatozoa in the presence of different serum preparations (normal, heat-inactivated, agammaglobulinemic, MgEGTA-treated).
• Assessment of the influence of sperm viability on PMN activation.

Main Results:

• Spermatozoa activated PMN in the presence of serum containing antibodies, complement, or only the alternative complement pathway.
• Activation was dependent on sperm concentration, serum concentration, and the presence of antibody or complement.
• Heat-inactivated agammaglobulinemic serum (lacking both antibodies and complement) did not induce significant PMN activation.
• Dead spermatozoa demonstrated a greater capacity to activate PMN compared to viable spermatozoa.

Conclusions:

• Human spermatozoa activate the alternative pathway of the complement system.
• Spermatozoa-mediated PMN activation is dependent on complement activation.
• Sperm viability influences the extent of PMN activation, suggesting a role for damaged sperm in immune responses.