Question

Which one of the following is an acute phage protein ?

• A. Complement
• B. Antigen
• C. Antibody
• D. CRP

Hint:

CRP (C-Reactive Protein) is the classic biomarker of acute inflammation, synthesized in high amounts during the acute phase response of the host.

Answer 1

The Correct Option is D

Step 1: Understanding the Concept:
During the early phases of tissue injury, inflammation, or infection, the host liver synthesizes and releases specialized proteins into the blood to help coordinate the innate immune response.
Note: The term "acute phage protein" in the question is a typographical error in the original examination paper and refers to acute phase protein (APP).

Step 2: Detailed Explanation:
C-Reactive Protein (CRP) is a classic, highly sensitive, major acute phase protein (APP) present in vertebrates, including teleost fishes.
Following infection, tissue damage, or inflammatory stimuli, the concentration of CRP in the plasma rises rapidly (often within hours).
It acts as a pattern recognition receptor, binding to the phosphorylcholine expressed on the surface of dead cells and pathogenic bacteria, which activates the classical complement pathway and enhances phagocytosis (opsonization).
Let us review the other choices:
1. Complement (A): A complex biochemical system consisting of multiple serum proteins, but it is not categorized as a major diagnostic acute phase protein in the same class as CRP.
2. Antigen (B): Any foreign molecule (typically a macromolecule) that triggers an immune response.
3. Antibody (C): A specific immunoglobulin produced by plasma B cells during adaptive immune responses.

Step 4: Final Answer:
Therefore, CRP is a major acute phase (phage) protein.