Class Notes (834,728)
Canada (508,699)
IMIN200 (114)
All (14)


2 Pages
Unlock Document

Immunology and Infection
All Professors

LECTURE #8 – T CELL DEVELOPMENT After studying lecture #8, you should be familiar with the following concepts. 1. The T Cell Receptor (TCR). T cells detect foreign antigen through the TCR. Each TCR is a heterodimer composed of an α and a β chain. Each chain contains a variable and a constant region. The variable region is responsible for antigen recognition. The TCR is permanently anchored in the plasma membrane and has no effector functions. Similar to the BCR, a TCR is generated through somatic recombination. V, J and C gene segments form the α chain and separate V, D, J and C gene segments form the β chain. Upon successful formation of an α chain at one locus recombination is shut off at the other α locus. This is referred to as allelic exclusion and it ensures that each T cell expresses a single α chain. Allelic exclusion also occurs at the β chain locus and during BCR rearrangement. 2. TCR – MHC interactions. The TCR interacts with antigenic peptides presented by MHC molecules (either class I or class II). The α chain and the β chain of the TCR interact with the peptide. Additional TCR residues interact with the MHC. The variable region of the TCR mediates TCR-MHC interactions. Stable formation of a TCR/MHC complex requires additional interactions of CD4 or CD8 on the T cell with the presenting MHC molecule. CD4 interacts with an invariant region of MHC II molecules and CD8 interacts with invariant regions of MHC I molecules. Thus, the class of cell presenting the antigen (i.e. MHC I or MHC II) determines the nature of the responding T cell (CD4 or CD8). 3. CD4 and CD8 T cells. CD4 T cells are also referred to as helper T cells. They interact with other immune cells such as B cells or macrophages and drive their activation. CD8 T cells are also known as
More Less

Related notes for IMIN200

Log In


Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.