During an experiment, an investigator gently abrades the skin from the flank of a mouse, creating a 1 × 2-cm skin window. A glass cover slip is then placed over the area so that cells attracted to the site attach to the cover slip for assessment. Two hours later, an extravasation of cells from the vasculature is noted on the cover slip. Which of the following complement components is the direct cause of the enhanced vascular permeability and chemoattraction in the abraded skin area in this experiment? (A) C1q (B) C4b (C) C5a (D) C7 (E) C9

The complement components that is the direct cause of the enhanced vascular permeability and chemoattraction in the abraded skin area in this experiment is C5a. The correct option is C.

Explanation:

When the investigator gently abrades the skin from the flank of a mouse, creating a 1 × 2-cm skin window, the investigator caused a mild tissue damage which leads to a complex series of events resulting in the repair of the damaged tissue. These events are collectively called an INFLAMMATION. Inflammation can therefore be defined as the reaction of vascularized living tissue to local injury.

There are many compounds that triggers specific aspects of inflammation and they are collectively called inflammatory mediators. An example is the Complement component 5a. It has the following functions in mediating inflammatory response:

- enhances vascular permeability

- it has the ability to attract other cells to the site of the abraded skin area (a chemoattractant).