A T cell can only become activated after being physically or chemically stimulated by the abnormal targetcell in a process called
A) costimulation.
B) opsonization.
C) sensitization.
D) neutralization.
E) precipitation.

Question

Quizplus · Accepted Answer

T cells require two signals to become activated and initiate an immune response. The first signal is provided by the presentation of an antigen by an antigen-presenting cell (APC). The second signal is costimulation, which occurs when the T cell receptor on the T cell interacts with a costimulatory molecule on the APC. Without costimulation, the T cell will not become activated, even if it has been sensitized to the antigen. Therefore, option A, costimulation, is the correct choice. Options B, D, and E describe other processes that are not directly involved in T cell activation. Option C, sensitization, is a necessary step in T cell activation but does not describe the mechanism by which activation occurs.

A T Cell Can Only Become Activated After Being Physically