河南师范大学：《生物化学》课程PPT教学课件（英文版）Section D ——-Antibodies

Section D- Antibodies D1 The immune system D2 Antibody structure D3 Polyclonal and monoclonal antidies D4 Antibody synthesis D5 Antibodies as tools

D1 The immune system D2 Antibody structure D3 Polyclonal and monoclonal antidies D4 Antibody synthesis D5 Antibodies as tools Section D ---Antibodies

D1 The Immune System Functions The immune system has two main function to recognize invading pathogens and then to trigger pathways that will destroy them. The humoral immune system relies on B lymphocytes to produce soluble antibodies that will bind the foreign antigens. The cellular immune system uses killer T lymphocytes that recognize and invading cells directl

• Functions The immune system has two main function to recognize invading pathogens and then to trigger pathways that will destroy them. The humoral immune system relies on β lymphocytes to produce soluble antibodies that will bind the foreign antigens. The cellular immune system uses killer T lymphocytes that recognize and invading cells directly. D1 The Immune System

Primary and secondary Immune responses The primary immune responses occurs on initial contract with a foreign and results in production of immunoglobulin M(gM) and then immunoglobulin G (IgG). If the same antigens encountered again, immuno logical memory leads to a secondary immune responses that produces a much more rapid and larger increase in specific IgG production

Primary and secondary immune responses • The primary immune responses occurs on initial contract with a foreign and results in production of immunoglobulin M (lgM) and then immunoglobulin G (lgG). If the same antigens encountered again, immuno￾logical memory leads to a secondary immune responses that produces a much more rapid and larger increase in specific IgG production

Structure of Immunoglobulin M Constant regions Variable reglons Disulphide bonds

容 Structure of Immunoglobulin G1 Site for attachment Disulphide to phagocytic cells bonds Sites fol attachment to antigen Site for attachment to complement variable region Constant region

Primary and secondary immune responses The primary immune response occurs on initial contact with a foreign antigen and results in production of immunoglobulin M and then IgG. If the same antigen is encountered again, immunological memory leads to a secondary immune sponse that produces a much more rapid and larger increase in specific IgG production

Primary and secondary immune responses • The primary immune response occurs on initial contact with a foreign antigen and results in production of immunoglobulin M and then IgG. • If the same antigen is encountered again,immunological memory leads to a secondary immune rsponse that produces a much more rapid and larger increase in specific IgG production

Primary and secondary immune responses PRIMARY RESPONSE SECONDARY RESPONSE Total antibody-Plateau Decline 15 days 10 days 15 days First exposure econd exposure to antigen (→ Plasma cell ( B cells ◎+ ◎→◎ o→◎◎→◎ ◎+-0-0 O+◎+0

Primary and secondary immune responses

Clonal selection theory A large number of antibody-producing cells exist in an animal even before it encounters a foreign antigen, each cell producing only one specific antibody and displaying this on its cell surface. An antigen binds to cells that display antibodies with appropriate binding sites and causes proliferation of those cells to form clones of cells secreting the same anti body in high concentration

Clonal selection theory • A large number of antibody-producing cells exist in an animal even before it encounters a foreign antigen, each cell producing only one specific antibody and displaying this on its cell surface. An antigen binds to cells that display antibodies with appropriate binding sites and causes proliferation of those cells to form clones of cells secreting the same antibody in high concentration

Clonal selection Antigen receptor Antigen 有 Variety of B cells Cell proliferation Clone of plasma cells Clone of memory cells 上 Antibodies secreted into circulation Copynghto Pearson Education, Inc publishing as Benjamin Cummings

Clonal selection

Self-tolerance Cells that produce antibody that reacts with normal body com ponents are killed early in fetal life so that the adult animal normally is unable to make antibodies against self, a condition called self-tolerance

Self-tolerance • Cells that produce antibody that reacts with normal body components are killed early in fetal life so that the adult animal normally is unable to make antibodies against self, a condition called self-tolerance