免疫球蛋白4

nullImmunoglobulin GeneticsImmunoglobulin GeneticsImmunoglobulin Genetics HistoryImmunoglobulin Genetics HistorySame C region could associate with many V regions IgG Ab with different specificities Same V region could associate with many C regions Same idiotype on IgG and IgM Ab V and C regions coded for by separate genes Light Chain Gene Families Germ line gene organizationLight Chain Gene Families Germ line gene organizationLight Chain Gene Families Gene rearrangement and expressionLight Chain Gene Families Gene rearrangement and expressionHeavy Chain Gene Family Germ line gene organizationHeavy Chain Gene Family Germ line gene organizationHeavy Chain Gene Family Gene rearrangement and expressionHeavy Chain Gene Family Gene rearrangement and expressionHeavy Chain Gene Family Gene rearrangement and expressionHeavy Chain Gene Family Gene rearrangement and expressionMechanism of DNA RearrangementsMechanism of DNA RearrangementsRecombination signal sequences (RSS) Nonmer Heptamer 1 or 2 turn signals Rag-1 and Rag-2Order of Ig Gene ExpressionOrder of Ig Gene ExpressionOrder of Ig Gene ExpressionOrder of Ig Gene ExpressionOrder of Ig Gene Expression Explains:Order of Ig Gene Expression Explains:Why an individual B cell only produces one kind of Ig with one kind of heavy and one kind of light chain Why an individual B cell makes only makes antibodies of one specificity Why there is allelic exclusionOrigin of Antibody Diversity HistoryOrigin of Antibody Diversity HistoryDefinition – Diversity (repitoire) is the total of all the Ab specificities that an organism is capable of expressing Theories Germ line theory Somatic mutation theoryOrigin of Antibody Diversity Current conceptsOrigin of Antibody Diversity Current conceptsMultiple V genes V-J and V-D-J joining Junctional diversity N region insertions Amino acid sequences not encoded in the germ line null-GTCAATG-GTCAATG-+Break DNATdT adds nucleotidesLigateN region insertionIntronJDJJJDDDGeneration of N region insertionsOrigin of Antibody Diversity Current conceptsOrigin of Antibody Diversity Current conceptsMultiple V genes V-J and V-D-J joining Junctional diversity N region insertions Somatic mutation Combinatorial association MultispecificityGeneration of DiversityGeneration of Diversity Ag independent process Clonal selectionT Cell Antigen ReceptorT Cell Antigen ReceptorHeterodimer of an  and a  chain Gene structure and expression of the  chain is analogous to the immunoglobulin heavy chain Gene structure and expression of the  chain is analogous to the immunoglobulin light chain No somatic mutation in T cells