Figure 18.3 Antigen presentation after DNA vaccination:

Following DNA vaccination communication between surfaces of the T-cell and the antigen presenting cells (Co-stimulatory molecules) as well as recognition of MHC class I complex by the T-cell receptor is must for a successful antigen presentation to a naïve T cell to stimulate the cell. Co-stimulatory molecules are absent in muscle cells and hence they do not behave like efficient antigen presenting cells. Usually if a naïve T-cell confronts a cell carrying a right antigen- MHC Class I complex in the absence of the co-stimulatory molecules or antigen presenting cells then the T-cells turn insensitive to this antigen if there is any repeated exposure to the same antigen.