Where we’re going • Structure of the TCR- alpha and beta chains (αβ) • The γδTcells- know a bit about them • The CD3 components and signal transduction-cover much, responsible for just a few concepts. • Alloreactivity
Review of TCR’s • Th and Tc; Th respond to MHC II Ag presentation, help B and Tc cells. CD4 coreceptor • Tc respond to MHC I Ag presentation (endogenous), and kill virus-infected/cancerous cells. CD8
Both alpha and beta are somewhat like the H chain Short tails- need CD3!
γδTcells- something different LOW diversity Many w/ no CD4/CD8 Gut Phospholipid antigens
The delta’s are LOST! This happens first
The joint is CD3- the others vary, but not as much. Not somatic hypermutation This is weird!!
Short tails = needs help for signal transduction Help provided by CD3- a complex Opposites attract! Immunoreceptor tyrosine-based activation motif!
Alloreactivity • It’s what gets you in tissue rejection • Contradicts MHC restriction! • Large # of T cells react- 1-5%! • Lots of theories, but clearly there’s a somewhat non-specific binding that sets off the T cell.
Things to know • Structure of the TCR- alpha and beta chains (αβ) • The γδTcells- know a bit about them • The CD3 components and signal transduction- ITAMS, B7-CD28, CD4,CD8 • Alloreactivity