loocking for information

[bonello]

I'm in 3rd year of medecine and I have a comprehension problem.
How does the hla1-tcr,cd3,cd4 interaction work
cd3 is the transduction protein (with itam regions)
tcr regions: cdr1,2 recognize hla 1 on alpha 3 (almost 
unvariant,little polymorphism) domain.
and recognize the antigenic peptide (interacting with hla1 alpha 1 and 
alpha 2 domains) with it proper cdr3 .
With whath and where does the cd4 interact  in the activation 
system.HOw does she come close to the cdr-cd" complex?
thanks for answering at my e-mail address /
roland.bonello at wanadoo;fr