The Complement System

These flashcards cover essential vocabulary and concepts related to the complement system as presented in the lecture notes.

Complement System

A part of the immune system that enhances the ability to clear pathogens from the body.

C3 Convertase

An enzyme complex that cleaves C3 into C3a and C3b, central to the complement activation pathways.

Anaphylatoxins

Small fragments generated during complement activation (C3a, C4a, C5a) that promote inflammation and recruit immune cells.

Opsonization

The process by which pathogens are marked with complement proteins (such as C3b) to enhance their uptake and clearance by phagocytes.

Membrane Attack Complex (MAC)

A structure formed by complement proteins (C5b, C6, C7, C8, C9) that creates pores in the cell membranes of pathogens, leading to cell lysis.

C1 Inhibitor (C1 INH)

A regulatory protein that inhibits the activation of the classical pathway by preventing the proteolytic activity of C1r and C1s.

Factor H

A complement regulatory protein that binds to C3b, preventing the formation of C5 convertase and aiding in C3b degradation.

Decay Accelerating Factor (DAF)

A protein that disrupts the stability of C3 and C5 convertase, preventing complement activation on host cells.

Complement Deficiencies

Disorders resulting from low levels or dysfunction of complement proteins leading to increased susceptibility to infections.

CH50 Test

A functional test that measures the activity of the classical complement pathway by evaluating the serum's ability to lyse antibody-sensitized erythrocytes.