Fc receptors for IgG and antigen presentation on MHC class I and class II molecules

Antigens internalized through specific membrane receptors are presented to helper CD4+ T cells antigen concentrations 10(3) to 10(4) fold lower than a ntigens internalized by fluid phase. B lymphocyte antigen receptors, mannos e receptors and receptors for the Fc region of immunoglobulins promote both internalization and immunoglobulins, low antigen concentration. Thus, bind ing to specific membrane receptors concentrate antigens on antigen presenti ng cells and mediates efficient uptake. Is this 'quantitative' concentratio n of antigens on antigen presenting cells the end of the story? Or may 'qua lity', i.e. selective intracellular antigen targeting, somehow influence th e efficiency or specificity of MHC class I and class II-restricted antigen presentation?