Question

The immune system is self-restricted and the self-restriction is seen with immunological responses that involve both the MHC class I and the MHC class II molecules. Define MHC class I and class II restriction, which molecules and cells are involved and which stage of the immune response (stages 1 – 8 in figure 1-7) the class I and class II restriction occurs (pick a stage from figure 1-7, state that stage, and describe the MHC restriction taking place (class I or II and the cells and molecules). Then describe an experiment which shows MHC class I restriction and then an experiment showing MHC class II restriction. Be sure to define, describe and name all antigens, animals, cell, purification systems and assays (readouts) used.

VERVIEW FIGURE Innate arn tion between Innate and Adaptive Immunity in Resolving an Infection Primary lymphoid organs Lymphocyte Development (Ch. 6, 7, 8, 9) Thymus Bone 4 Innate Epithelial Immunity cell barrier (Ch. 4, 5) Blood flow IN Infection Secondary lymphoid organ (e.g. lymph node Lymphatic flow IN Effector Responses (Ch. 12) Lymphatic flow OUT Lymphocyte Activation and Differentiation (Ch. 10, 11) Cut or splinter Mucosal Infectious ImmunityAgents (Ch. 13) Memory Cells (Ch. 10, 11) (Ch. 17)

Answer 1

class 1 MHC genes express glycoproteins and MHC molecules, sometimes referred to as MHC antigens on nearly all nucleated cells. each MHC class 1 gene codes for a transmembrane glycoprotein of approximate molecular weight 43 k da, which is referred to as the alpha or heavy chain. it comprises three extracellular domains alpha 1 alpha 2 alpha 3. the alpha 3 domain is highly conserved and interacts with CD8 membrane molecule present on Tc cells. the highest levels of class 1 molecules are expressed by lymphocytes whereas fibroblasts, liver hepatocytes and neural cells expresses very low levels of class 1 MHC molecules.

the T cell molecule CD4 binds to the invariant portion of all MHC class 2 molecules. class 2 MHC gene express MHC molecule constitrutively only on antigen presenting cells.APCs are professional and non professional APCs. professional APCs are Dendritic cells, macrophages, and B lymphocytes. non professional antigen presenting cells are like fibroblasts, thymic epithelial cells, glial cells can be induced to express class 2 MHC molecules or a co stimulatory signal.