Hi!
I have a couple of questions regarding the induction of lasting immunity by vaccination:
1) To induce BOTH a cellular and humoral response by vaccination, is it sufficient for antigen presenting cells to endocytose, digest and display peptides in the MHC-II complex? This would present antigens to CD4+ helper cells, but I am not sure whether the following cascade would be enough to induce a strong response both from cytotoxic T cells and antibody secreting B cells..
The alternative, I suppose, would be to have a vaccine that also entered the cytoplasm of cells, thereby gaining access to the MHC-I complex, which is recognized by CD8+ cytotoxic T cells. Any thoughts?
2) Related to above, what is the importance of cross-priming (transportation of vesicles containing antigen peptides to dendritic cells) in the induction of cellular and humoral responses? For instance, a certain recombinant BCG is able to escape the endosome, thereby causing presentation of antigens by MHC-I, apoptosis of the host cell AND cross priming, but I am not sure of the relative contributions of these effects to immunity.
Any and all feedback would be much appreciated )
Cheers, David
