1. MOLECULAR BASIS OF ANTIGEN RECOGNITION BY B CELLS AND ANTIBODIES

2. The immunoglobulin G (IgG) molecule COMPLEMENT ACTIVATION BINDING TO CELLS DEGRADATION TRANSPORT ANTIGEN BINDING

3. IgG is built from twelve similar shaped immunoglobulin domains

4. The three-dimensional structure of immunoglobulin C and V domains

5. There are discrete regions of hypervariability in V domens Distinct regions of high variability and conservation led to the concept of a FRAMEWORK (FR), on which hypervariable regions were suspended. Most hypervariable regions coincided with antigen contact points - the COMPLEMENTARITY DETERMINING REGIONS (CDRs)

6. The hypervariable regions of antibody V domains lie in discrete loops at one end of the domain structure CDR: complementarity-determining region

7. Within the V domain, sequence variability is localized to three complementarity-determining regions (CDRs). CDRs form three loops that are clustered at one end of the domain. In the antibody molecule the CDRs of the heavy and light chains form a variable surface that binds antigen.

8. Mechanisms of epitope recognition Linear and discontinuous epitopes Multivalent Antigens Polymeric Antibodies Epitope binding mechanisms

9. The nature of antigenic determinants

10. Two kinds of multivalent antigen

11. IgM is secreted as a pentamer of immunoglobulin monomers

12. IgA molecules can form dimers

13. Transcytosis of dimeric IgA antibody across epithelia is mediated by the poly-Ig receptor (pIgR)

14. IgG is a highly flexible molecule

15. Different hinge structures distinguish the four subclasses of IgG

16. Each human immunoglobulin isotype has specialized functions correlated with distinctive properties

17. Maternal IgG is transported by the neonatal Fc receptor (FcRn) across the placenta to the fetus

18. IgG half-life FcRn is also present in the adult and involved in protecting IgG from degradation Accounts for the long (3 week) half-life of IgG compared to other Ig isotypes Therapeutic agents that are fused to IgG Fc regions take advantage of this property e.g. Enbrel (TNFR-Fc) Half-life in serum IgG - 21 days IgA - 6 days IgM - 5 days IgE - 2.5 days

19. The receptor FcRn transports IgG from the bloodstream into the extracellular spaces of tissues

20. Epitopes can bind to pockets, grooves, extended surfaces, or knobs in antigen-binding sites

21. The noncovalent forces that hold together the Ag-antibody complex

22. Pentameric IgM and dimeric IgA are synthesized in association with the same J chain. A poly-Ig receptor (pIgR) is responsible for the transcytosis of dimeric IgA across epithelia. FcRn receptors: - transport IgG across the placenta. - transport IgG from the bloodstream into the extracellular spaces of tissues. - protect IgG from degradation. Antigens are bound to antibodies through noncovalent bonds.

23. B cell antigen receptor complex

24. Cross-linking of B-cell receptors by antigens initiates a cascade of intracellular signals ITAM: immunoreceptor tyrosine-based activation motif

25. Signal transduction by the BCR complex

26. Structure and function of the B-cell co-receptor

27. Signals generated from the B-cell receptor and co-receptor combine to activate B cells in response to surface and soluble antigens

28. B cell activation requires - cross-linking of surface immunoglobulin - signals from the B-cell co-receptor (or from PRR-s) - helper T cells (in the case of protein antigens)

29. Production of a mouse monoclonal antibody

30. Possible use of monoclonal antibodies - Identifying cell types Immunohistochemistry Characterization of lymphomas with CD (cluster of differentiation) markers - Isolation of cells Isolation of CD34+ stem cells for autologous/allogeneic transplantation (from peripheral blood) - Blood group determination (with anti-A, anti-B, and anti-D monoclonals) - Identification of cell surface and intracellular antigens Cell activation state - Therapeutic usage of monoclonal ABs CD20+ anti-B-cell monoclonals in non-Hodgkin lymphoma Prevention of organ rejection after transplantation Anti-inflammatory antibodies (autoimmune diseases)

31. Monoclonals in tumor therapy 1.„Naked MAb”, unconjugated antibody Anti-CD20 (rituximab – Mabthera/Rituxan, chimeric): B-cell Non-Hodgkin lymphoma Anti-CD52 (campath – Mabcampath, humanized): chronic lymphoid leukaemia Anti-ErbB2 (trastuzumab – Herceptin, humanized): breast cancer Anti-VEGF (bevacizumab – Avastin, humanized): colorectalis tu. (+ Lucentis!) Anti-EGFR (cetuximab – Erbitux, chimeric): colorectalis tu. (+ Vectibix, rekomb. human) 2.Conjugated antibody Anti-CD20 + yttrium-90 isotope (ibritumomab- Zevalin) Anti-CD20 + iodine-131 (tositumomab – Bexxar)

32. Monoclonal antibodies as treatments for disease

33. The antibodies made by a hybridoma cell line are all identical and are therefore called monoclonal antibodies. Monoclonal antibodies are applied in: - research - diagnostic tests - therapeutic treatments