Complement responsible for activation of bacterial lysis is –
**Question:** Complement responsible for activation of bacterial lysis is -
A. Complement System
B. Antibody-dependent cell-mediated cytotoxicity (ADCC)
C. Complement C3
D. Complement C5
**Core Concept:** The complement system is a part of the host's immune response that helps in the clearance of pathogens, particularly bacteria, by enhancing phagocytosis and directly lysing bacteria. The complement system comprises of a cascade of proteins that can be activated via three pathways: classical, alternative, and lectin.
**Why the Correct Answer is Right:** Complement C3 is a key component of the complement system. When activated, it cleaves into several fragments, including C3a and C3b. C3b is responsible for opsonization (marking bacteria for phagocytosis) as well as direct bacterial lysis through the formation of the membrane attack complex (MAC) on the bacterial surface.
**Why Each Wrong Option is Incorrect:**
A. Antibody-dependent cell-mediated cytotoxicity (ADCC) is a process in which antibodies bind to antigens on the surface of pathogens. However, it is not directly responsible for bacterial lysis.
B. Complement C5 is a crucial component of the complement system, but it is not directly responsible for bacterial lysis. Complement C3b plays a more significant role in bacterial lysis.
C. Complement C3 is a critical component of the complement system, as explained previously.
**Clinical Pearl:** A well-functioning complement system helps in the rapid clearance of bacteria from the body, contributing to the overall defense mechanism against infections. Understanding the role of complement components like C3 is essential for medical students and healthcare professionals to appreciate the intricacies of the immune response and its implications in clinical practice.