Which of the complement fragments is inflammatory?


a. C3a
b. C4a
c. C5a
d. all of the above

Verified step by step guidance

1. Understand the role of complement fragments in the immune system, particularly their involvement in inflammation.
2. Recall that complement fragments such as C3a, C4a, and C5a are known as anaphylatoxins, which can induce inflammation.
3. Consider the individual roles of C3a, C4a, and C5a in promoting inflammation by causing degranulation of mast cells and basophils, leading to the release of histamine and other inflammatory mediators.
4. Recognize that each of these fragments (C3a, C4a, C5a) contributes to the inflammatory response, but C5a is particularly potent in attracting neutrophils and enhancing phagocytosis.
5. Conclude that all the options (C3a, C4a, C5a) are involved in inflammation, suggesting that the correct answer is likely 'd. all of the above'.

Key Concepts

Complement System

The complement system is a part of the immune system that enhances the ability of antibodies and phagocytic cells to clear pathogens from an organism. It consists of a series of proteins that, when activated, can lead to inflammation, opsonization, and cell lysis. Understanding how these proteins interact is crucial for identifying their roles in immune responses.

Inflammatory Mediators

Inflammatory mediators are substances that promote inflammation, a key part of the immune response. In the context of the complement system, certain fragments like C3a and C5a act as anaphylatoxins, which can increase vascular permeability and attract immune cells to sites of infection or injury, thus playing a significant role in the inflammatory process.

Anaphylatoxins

Anaphylatoxins are small peptide fragments generated during the complement activation process, specifically C3a, C4a, and C5a. These fragments are known for their ability to induce inflammation by promoting the release of histamine from mast cells and attracting leukocytes to the site of infection. Recognizing which fragments function as anaphylatoxins is essential for understanding their inflammatory roles.