Biochem and Immunology Insights

  Structure of the immune system The immune system are organised into specific structures. Classified as ü     Primary organs (bone marrow, thymus) ü     Secondary organs (lymph nodes, spleen, mucosa-associated lymphoid tissue): —   Bone marrow : All the cells of the immune system are derived from stem cells in the bone marrow. 1.      Thymus —   Located in the thorax —   In the cortex - thymocyte (immature T-cells) dev`t occurs Immature T-cells enter the cortex, proliferate, mature It involves T-cell receptor v   gene rearrangement v     positive selection v   and pass on to the medulla. —   In Medulla – additional negative selection to remove auto-reactive T-cells from the mature cells occurs —   From the medulla mature T lymphocytes enter   circulation 2. Lymph Node The node is made up of three components: a)      Lymphatic sinuses ...

A NTIBOD Y STRUCTURE AND PROPERTIES   Immunoglobulins are glycoprotein molecules that are produced by plasma cells (B-Cells) in response to an immunogen and which function as antibodies   Antibody structure   Heavy and Light Chains:   All Ig have a four chain structure as their basic unit. composed of: v   two identical light chains (23kD) and v   two identical heavy chains (50-70kD) v   Disulfide bonds v   Inter-chain disulfide bonds - The 2 light chains and the 2 heavy chains are held together by inter-chain disulfide bonds and by non-covalent interactions v     Intra-chain disulfide binds - Within each of the polypeptide chains there are also intra-chain disulfide bonds IMMUNOGLOBULIN CL A SSES The Ig can be divided into five different classes, based on differences in the amino acid sequences in the constant region of the heavy chains (CH) . All Ig within a given class will have very similar heavy chain co...