An overview of complement systems in teleosts

Area of Science:

• Immunology
• Comparative Biology
• Aquatic Animal Health

Background:

• The complement system is a vital part of innate immunity, comprising ~35 proteins and activated via classical, alternative, and lectin pathways.
• Mammalian complement activation leads to C3 cleavage, forming C3-convertase, initiating cascades that generate the membrane attack complex.
• While extensively studied in mammals, the teleost complement system remains less understood, particularly its roles in immune responses.

Purpose of the Study:

• To review and summarize current knowledge of teleost complement components involved in phagocytosis, chemotaxis, and cell lysis.
• To compile characterized complement components and regulators across various teleost species.
• To analyze the role of complement regulators in pathogen infection and the influence of complement receptors on teleost immune responses.

Main Methods:

• Literature review and synthesis of existing research on teleost complement systems.
• Compilation and analysis of data on characterized teleost complement components and regulators.
• Review of studies on complement receptors and their impact on teleost immunity.

Main Results:

• Identified and characterized complement components in various teleost species.
• Provided a comprehensive compilation of teleost complement regulators and their association with pathogen infection.
• Reviewed the influence of complement receptors on teleost immune responses, including phagocytosis, chemotaxis, and cell lysis.

Conclusions:

• The review offers new insights into the teleost complement system's role in recognition and defense.
• Understanding teleost complement is essential for developing novel immune strategies in aquaculture.
• Future research directions proposed for molecular evolution, structure, and function of teleost complement components.