Jimmy1. Introduction to the Immune system: Lectures 1 and 2 Hugh Brady [email_address] Recommended textbook: Janeway’s Immunobiology (7 th Ed) 2008, Garland Science 48. T and B cell responses are initiated in secondary lymphoid organs - lymph nodes and spleen Haematopoiesis B cells Neutrophils etc T cell development 60. Antigens are the molecules recognized by the immune response Epitopes are sites within antigens to which antigen receptors bind 61. An antibody binds an antigen directly whereas a T-cell receptor binds a complex of antigen fragment and self molecule 85. MHC class I molecules present antigen derived from proteins in the cytosol 87. MHC class II molecules present antigen originating in intracellular vesicles