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Activation of polymorphonuclear leukocytes by spermatozoa
Abstract:
Human spermatozoa activated human polymorphonuclear leukocytes (PMN) in the presence of serum. Activation of PMN was studied by measuring the emission of chemiluminescence by the PMN. The amount of chemiluminescence emitted depended on the number of spermatozoa and the serum concentration, and the presence of antibody or complement. Spermatozoa were able to activate PMN in the presence of heat-inactivated serum (only antibody, no complement), serum obtained from a patient with agammaglobulinemia (without antibodies and only complement as opsonin), and in MgEGTA agammaglobulinemic serum (only the alternative pathway of complement intact). In the presence of heat-inactivated agammaglobulinemic serum no significant chemiluminescence was observed. It was concluded that spermatozoa activate the alternative pathway of complement. Dead spermatozoa were more able to activate PMN than viable spermatozoa.
Insights
Human sperm activate immune cells called polymorphonuclear leukocytes (PMN) via the complement system. Dead sperm were more effective activators than live sperm, highlighting a role for complement activation in immune responses.
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.