Opsonisation agglutination neutralisation antibody-dependent cell-mediated cytotoxicity complement activation mast cell degranulation protection of the neonate Different immunoglobulin and their function
IgG Structure –Monomer (7S) IgG1, IgG2 and IgG4 IgG3
IgG Structure Properties –Major serum Ig –Major Ig in extravascular spaces –Placental transfer –Fixes complement –Binds to Fc receptors Phagocytes - opsonization K cells - ADCC
IgE Structure Properties –Least common serum Ig –Allergic reactions –Parasitic infections –Does not fix complement
14 B. IgG heavy chain variability ~200 variable region segments (V) ~50 diversity regions (D) 4 joining segments (J) 5 constant regions (C)
15 VDJC DNA of precursor cell (not to scale) random gene rearrangement B-cell DNA mRNA transcription and splicing translation C. Developmental gene rearrangements
19 polyclonal many antibodies that recognize many epitopes monoclonal one antibody that recognizes one epitope various classesone class making specific antibodies requires purified antigen specific antibody can be made with impure antigen difficult reproducibilityhigh reproducibility A.
20 B. Monoclonal antibody production B-cells do not survive in culture B-cell fused to myeloma cells produce hybridomas which survive in culture and produce antibody Fusion is inefficient so a selection for hybridomas is used.