Hi Mar,
I had a question about the exogenous pathway (MHCII). Could you tell me if this is correct?
1.the pathogen is engulfed by a phagocytic cell and degraded in the lysosome
2.the MHCII associated with the antigen
3.exocytosis of the complex to plasma membrane
4.Helper T cell CD4 binds to MHCII-antigen
This looks about right. There is a diagram on page 167 of the BioBiochem CC that should halp with this.
And also, after CD4 binds, is perforin released (as it happens in the endogenous pathway) to lyse the cell?
This seems reasonable as you would want to lyse the cell containing the invader. I am not 100% sure on this, but I cannot find any literature saying that this is not the case.