免疫球蛋白的结构与功能的关系免疫球蛋白的结构与功能的关系.pptVIP

Immunoglobulin Structure-Function Relationship 免疫球蛋白的结构与功能的关系 Antibodies are Proteins that Recognize Specific Antigens 抗体能够特异性的识别抗原 Epitopes（抗原决定簇 ）: Antigen Regions that Interact with Antibodies Consequences of Antibody Binding抗体结合效应 CH3 CH2 Fb Fv Fv Fv Fb Fv Hinge Elbow CH3 CH2 Fb Fv Flexibility and motion of immunoglobulins 30 strongly neutralising McAb 60 strongly neutralising McAb Fab regions 60 weakly neutralising McAb Fab regions Human Rhinovirus 14 - a common cold virus 30nm Models of Human Rhinovirus 14 neutralised by monoclonal antibodies Electron micrographs of Antibodies and complement opsonising Epstein Barr Virus (EBV) Negatively stained EBV EBV coated with a corona of anti-EBV antibodies EBV coated with antibodies and activated complement components Antibody + complement- mediated damage to E. coli Healthy E. coli Electron micrographs of the effect of antibodies and complement upon bacteria Non-covalent forces in antibody - antigen interactions Electrostatic forces Attraction between opposite charges Hydrogen bonds Hydrogens shared between electronegative atoms Van der Waal’s forces Fluctuations in electron clouds around molecules oppositely polarise neighbouring atoms Hydrophobic forces Hydrophobic groups pack together to exclude water (involves Van der Waal’s forces) Why do antibodies need an Fc region? Detect antigen Precipitate antigen Block the active sites of toxins or pathogen-associated molecules Block interactions between host and pathogen-associated molecules The (Fab)2 fragment can - Inflammatory and effector functions associated with cells Inflammatory and effector functions of complement The trafficking of antigens into the antigen processing pathways but can not activate Structure and function of the Fc region CH3 CH2 IgA IgD IgG CH4 CH3 CH2 IgE IgM The hinge region is replaced by an additional Ig domain Fc structure is common to all specificities of antibody within an ISOTYPE (although there are allotypes) The structure ac