In: Biology
Which of the following three signals are required for the activation of naïve T cells?
a. TCR bound to MHC-Ag complex, costimulation, and granzymes
b. TCR bound to MHC-Ag complex, costimulation, and cytokines
c. NF-kB, NFAT, and PI3-Akt signaling
d. CD40 bound to CD40L, CD80 bound to CD28, and IL-12 production
e. IL-1, IL-6, and TNF
The answers is (b ) TCR bound to MHC Ag complex, costimulation and cytokines.
Activation of T helper cells require generation of three specific signals.
Activated T helper cells secretes increased amount of IL-2 as well as IL-2 receptor.IL-2 binds to its receptors on the same T helper cells and also on other T helper cells and induces the naive T helper cells to proliferate and differentiate. It is activated and becomes lymphoblast cells which subsequently differentiate into memory and effector T helper cells.
The three specific signals are -
Following the signal generation , there is initiation of the signal transduction at the CD 4 molecule which interacts with the CD3 molecule and it causes the transmission of signal leading to activation of T helper cells. Following this , there is differentiation of naive T helper cells into memory and effector T helper cells.