Pathology fun

The Roles of MHC Molecules In Adaptive Immune Responses MHC molecules enable T-lymphocytes to recognize epitopes of antigens and discriminate self from non-self. Unlike B-cell receptors on B-lymphocytes that are able to directly bind epitopes on antigens, the T-cell receptors (TCRs) of  T-lymphocytes  can only recognize epitopes - typically short chains of amino acids called peptides - after they are bound to MHC molecules. Epitope-Specific Receptors on the surface of B- and T-Lymphocytes. B-lymphocytes have B-cell receptors that recognize epitopes directly on antigens. T-lymphocytes have TCR molecules that recognize epitopes only after they have been placed on cells of the body by way of MHC molecules. The MHC genes are the most polymorphic genes in the human genome, possessing many alleles for each gene. The MHC genes are co-dominantly expressed so that an individual expresses the alleles inherited from each parent. In this way, the number of MHC molecules that bind peptide for prese

  Adaptive immunity Have you ever wondered how your recovery time for the common cold, the flu, or small infections seems to get shorter after you’ve been exposed and successfully recovered the first time? The adaptive immune system, also called  acquired immunity , uses specific antigens to strategically mount an immune response. Unlike the innate immune system, which attacks only based on the identification of general threats, the adaptive immunity is activated by exposure to pathogens and uses an immunological memory to learn about the threat and enhance the immune response accordingly. The adaptive immune response is much slower to respond to threats and infections than the innate immune response, which is primed and ready to fight at all times. Cells of the adaptive immune system Unlike the innate immune system, the adaptive immune system relies on fewer types of cells to carry out its tasks:  B cells  and  T cells . Both B cells and T cells are lymphocytes that are derived from s