1. Antigen Processing & Presentation

2. MHC antigens codominate53

3. Mixed Lymphocyte Reaction38

4. Self MHC Restriction of T Cells
CD4+ & CD8+ cells
Antigen must be in cleft of MHC
MHC polymorphism
~500 antigens/cleft
Self MHC Restriction of T Cells

5. Haplotype Restricted Cytotoxicity56

6. “Antigen Pulse” “Antigen pulsed” macrophages
T helper (CD4+) cells can only be stimulated by macrophages with the same MHC Class II
Cytotoxic (CD8+) T cells can only be stimulated by macrophages with the same MHC Class I
“Antigen Pulse”

7. T Cell Activation

8. MHC I: Biological function44

9. MHC II: Biological function47

10. MHCII: Biologogical function (2)46

11. MHCII: Function 50

12. Role of Antigen Presenting Cells
Immunize with native protein
Boost with native protein
B cell & T cell response
Boost with denatured antigen
T cell response only
2 different mechanisms APC for cell mediated & humoral
Role of Antigen Presenting Cells

13. Antigen Presenting Cells
Professional APC
Dendritic cells
Macrophages
B Cells
Non Professional APC
Fibroblasts
Glial cells
Thymic epithelial cells
Vascular endothelial cells

14. Lot MHC-II
co-stimulate
activate T helpers
Dendritic cells

15. Macrophages Engulf microbe first co express with B7 membrane protein
digest antigen
bind to MHC-II
co express with B7 membrane protein
Macrophages

16. Constitutively express MHC-II
activated
then express B7
B Cells

17. Two Presentation Pathways
Cytosolic-
MHC-I
endogenous antigens
Endocytic -
MHC-II
exogenous antigens
Two Presentation Pathways

18. Cytosolic Pathway: Endogenous Antigens
Ubiquitin & ATP
Bind to peptide
proteasomes
Bind ubiquitin
peptide transport
Assembly of peptides in MHC-I
Rough Endoplasmic reticulum
Export to membrane
Cytosolic Pathway: Endogenous Antigens

19. TAP proteins Transports associated with Antigen Processing
TAP-1 TAP-2
Transfer Peptides from proteosome to RER
TAP proteins

20. TAP-1 TAP-2

21. Calnexin & MHC-1

22. Assembly in RER TAP-1 TAP-2 transport into ER Bind to Calnexin MHC-I
Add peptide to MHC-I
Release calnexin
Transport to Gogli
Assembly in RER

23. Endogenous Pathway MHC-i

24. Endocytic Pathway: Exogenous Antigens
endocytic vesicles
peptide transport
Assembly of peptides in MHC-II
Endocytic Pathway: Exogenous Antigens

25. Endocytic Route From Outside- phagocytosis From Inside Fuse
Make MHC-II
Bind Invariant chain
CLIP- digests invariant chain
Fuse
MHC-II & clipped I & peptide
peptide displaces clipped I chain
Endocytic Route

26. Invariant chain & MHC-II

27. Exogenous Pathway MHC-II

28. THANKS