Antigen presenting cell activation immune response

It is reasonable to presume that the immunogenic and adjuvant activity of lipospheres may be the result of a combination of factors. These factors may include a focused and enhanced delivery of the antigen to an antigen-presenting cell (macrophage) and protection of the antigen from metabolic destruction at other sites in the body that do no participate in the immune response. 

To initiate a T-cell immune response, antigen presenting cells have to display antigenic peptides com-plexed with the major histocompatibility complex (MHC) on their cell surface. The T-cell receptor of CDS cells is specific for the peptide-MHC class I complex while the CD4 cell receptor binds the peptide-MHC class II complex. This binding of the peptide-MHC II complex stimulates CD4 cell proliferation and subsequent lymphokine release. This CD4 cell response can initiate a delayed hypersensitivity reaction. However CD4 activation and the production of various lymphokines is also needed for the generation of cytotoxic T-cells and for the differentiation of plasma cells from B-lymphocytes and the antibody response by these plasma cells. For their role in also the humoral immune response CD4 cells are called T-helper cells. 

Figure 11.2. Antigen presentation and activation of - and B-cell-mediated immune responses. (Adapted from Ada [57]).

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