Skip to main content
Ch. 15 - Innate Immunity
Chapter 12, Problem 15.4a

The alternative complement activation pathway involves ________________.


a. factors B, D, and P
b. the cleavage of C5 to form C9
c. binding to mannose sugar
d. recognition of antigens bound to specific antibodies

Verified step by step guidance
1
Identify the key components involved in the alternative complement activation pathway.
Understand that the alternative pathway is part of the innate immune system and does not require antibodies for activation.
Recognize that the alternative pathway is triggered by the spontaneous hydrolysis of complement component C3.
Note that factors B, D, and P (properdin) are crucial in stabilizing the C3 convertase complex in the alternative pathway.
Eliminate options that involve specific antibodies or mannose-binding, as these are related to the classical and lectin pathways, respectively.

Verified Solution

Video duration:
3m
This video solution was recommended by our tutors as helpful for the problem above.
Was this helpful?

Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Complement System

The complement system is a crucial part of the immune response, consisting of a series of proteins that enhance the ability of antibodies and phagocytic cells to clear pathogens. It can be activated through three pathways: classical, lectin, and alternative, each leading to the formation of a membrane attack complex that can lyse pathogens.
Recommended video:
Guided course
05:15
Review of the Complement System

Alternative Pathway Activation

The alternative complement activation pathway is initiated by the spontaneous hydrolysis of complement component C3, leading to the formation of C3b. This pathway does not require antibodies and is activated by the presence of pathogens, allowing for a rapid immune response.
Recommended video:
Guided course
04:40
1) Alternative Pathway

Role of Factors B and D

Factors B and D are essential components in the alternative pathway of complement activation. Factor B binds to C3b, and Factor D cleaves Factor B to form the C3 convertase, which amplifies the complement response by generating more C3b, thus enhancing opsonization and pathogen clearance.
Recommended video:
Guided course
03:55
Introduction to B Lymphocytes