cd4 on APC?

[macpherson at molbiol.ox.ac.uk]

In article <800821391snz at davemac.demon.co.uk>, Dave McNeill <dave at davemac.demon.co.uk> writes:
> Simple question(?):- Why do macros, FDCs and other APC express CD4? 
> -- 
> Dave McNeill

Expression of CD4 is species restricted - murine macrophages do not express 
it, some rat macrophages and DC do.  Activated T cells may express MHC class 
II and this could possibly interact with CD4 as an adhesion molecule or ?? for 
signalling.

Gordon MacPherson