Vaccine immunogenicity

[dtordrup]

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