1. K4.2  : 95% in mouse  : 60% in human IMMUNOGLOBULIN CLASSES

3. Opsonisation agglutination neutralisation antibody-dependent cell-mediated cytotoxicity complement activation mast cell degranulation protection of the neonate Different immunoglobulin and their function

4. IgG Structure –Monomer (7S) IgG1, IgG2 and IgG4 IgG3

5. IgG Structure Properties –Major serum Ig –Major Ig in extravascular spaces –Placental transfer –Fixes complement –Binds to Fc receptors Phagocytes - opsonization K cells - ADCC

6. IgM Structure –Pentamer (19S) –Extra domain (C H4 ) –J chain CH4 J Chain

7. IgM Structure Properties –3rd highest serum Ig –First Ig made by fetus and B cells –Fixes complement

8. Fixation of C1 by IgG and IgM Abs C1r C1s C1q C1r C1s C1q No activationActivation

9. IgM Structure Properties –3rd highest serum Ig –First Ig made by fetus and B cells –Fixes complement Tail Piece –Agglutinating Ig –Binds to Fc receptors –B cell surface Ig

10. IgA Structure –Serum - monomer –Secretions (sIgA) Dimer (11S) J chain Secretory component J Chain Secretory Piece

11. IgA Structure Properties –2nd highest serum Ig –Major secretory Ig –Does not fix complement unless aggregated –Binds to Fc receptors on some cells

12. IgD Structure –Monomer –Tail piece Tail Piece

13. IgD Structure Properties –4th highest serum Ig –B cell surface Ig –Does not bind complement

14. IgE Structure –Monomer –Extra domain (C H4 ) CH4

15. IgE Structure Properties –Least common serum Ig –Allergic reactions –Parasitic infections –Does not fix complement

16. 14 B. IgG heavy chain variability ~200 variable region segments (V) ~50 diversity regions (D) 4 joining segments (J) 5 constant regions (C)

17. 15 VDJC DNA of precursor cell (not to scale) random gene rearrangement B-cell DNA mRNA transcription and splicing translation C. Developmental gene rearrangements

18. 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.

19. 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.

20. 21 immunized mouse antibody producing B-cells mutant myeloma cells fusion hybridomas cell mixture

21. 22 well containing selective medium test supernatant for antibody of interest dilute retest for antibody of interest