Complement Proteins as Soluble Pattern Recognition Receptors for Pathogenic Viruses

Area of Science:

• Immunology
• Virology
• Biochemistry

Background:

• The complement system is a vital component of innate immunity, essential for pathogen elimination through classical, alternative, and lectin pathways.
• Complement activation against viruses leads to effector functions like opsonisation, phagocytosis, and direct viral lysis via the membrane attack complex.

Purpose of the Study:

• To review complement-dependent and -independent interactions between specific complement components and viruses.
• To explore viral strategies for subverting complement recognition and activation, thereby impacting viral pathogenesis.

Main Methods:

• Literature review focusing on interactions between complement components (C1q, C4b-binding protein, properdin, factor H, Mannose-binding lectin, Ficolins) and viruses.
• Analysis of viral mechanisms to inhibit the complement system.

Main Results:

• Individual complement components can neutralize viruses independently of cascade activation.
• Viruses have evolved diverse mechanisms to evade or inhibit complement, aiding their survival and disease progression.

Conclusions:

• Complement plays a dual role in antiviral defense, capable of direct neutralization and immune modulation.
• Understanding viral evasion strategies is crucial for developing therapies targeting complement-host-pathogen interactions.