1. October 27, 2014

2. ANIMELLE IN PANGRATTATO CON CARCIOFI (Breaded sweetbreads with artichokes) Ingredients: 4 Tbs. white bread crumbs, 2 beaten eggs, salt, pepper, 6 Tbs. butter, 1 1/2 lb. sweetbreads, 8 baby artichokes, 2 garlic cloves, 1 tsp. olive oil, 1 sprig minced parsley. Sift the bread crumbs. Beat the eggs in a bowl together with salt pepper, and 1 tsp. oil. Blanch the sweetbreads. Cut them in equal pieces, dust with flour, immerse them in egg and then bread crumbs In a very hot pan, fry the sweetbreads in 4 Tbs. of butter, drain on paper towels and arrange on pre-heated platter. Clean the artichokes, cut them in quarters and put in a saucepan with a little oil, 2 garlic cloves, parsley, salt, pepper. Cover the saucepan, cook over medium heat for 6-7 minutes. Remove from heat, add the remaining butter, stir and pour on top of the sweetbreads. Serve immediately

3. FETAL PIG 1.Thymus Gland 2.Left Atrium 3.Coronary Artery 4.Left Ventricle 5.Pericardial Sac 6.Lobes of Lung 7.Diaphragm 8.Liver 9.Small Intestine

4. Figure 5-1 Thymus-dependent lymphocytes = T cells

5. The nude (nu/nu) mouse Thymic “nude” mice have a severe combined immunodeficiency (SCID). The can make neither helpers or killers. There are other types of SCIDs such as the failure to make lymphoid cells in the bone marrow.

7. DiGeorge’s syndrome 22q11.2 deletion syndrome includes cardio-facial syndrome, congenital thymic aplasia.

8. TBX1 encodes transcription factors that control pharyngeal segmentation Heterozygous deletion: 22 subtelomeric region and 22q11.2

9. Involution of the older thymus (fat takes over) Infected with a virus that sends the thymus into hyperdrive, Cronin’s vampires have super-immune systems and seeming immortality.

10. T cell developmental events in the thymus 1.Rearrangement of TCR beta genes. Failure = apoptosis. (Allelic exclusion) 2.Rearrangement of TCR alpha genes. Failure = apoptosis. (Allelic exclusion) 3. Expression of CD4 and CD8 (double-positive T cells) 4.Positive selection for TCRs that bind self MHC (rescue). Failure = apoptosis. 5. Positive selection determines T cell phenotype (CD4 or CD8) 6.Negative selection for TCRs that bind self antigen peptides. Success = apoptosis.

11. Figure 5-5 Red apoptotic cells, blue macrophages Cortical apoptosis: TCR failure and negative selection

12. …have successfully made a unique TCR idiotype …be able to recognize foreign peptides presented by self MHC proteins (self restriction) …choose either a killer or a helper (CD8 + or CD4 + ) major. …not recognize self peptides presented by self MHC proteins (self tolerance; don’t do irreparable damage to oneself Saturday night.) Thymic education: The successful graduate of Thymusburg College will… 95-98% of the entering class flunks out!! Do Great Immuno

13. Figure 5-3 http://www.bio.davidson.edu/courses/Immunology/hyperhuman/Thymus/thymus10_0.html Histology of the thymus

14. Figure 5-18 Review http://www.bio.davidson.edu/courses/Immunology/Flash /Main.html

15. The Riddle of the Thymus How can a single T- cell receptor pass both positive and negative selection? In other words, how can a T-cell recognize self MHC + self and survive only to recognize self MHC + self and die? ????

16. Answer: Strength of binding. Positive selection depends on moderate binding. Moderate binding leads to rescue/survival. No or weak binding leads to apoptosis. Negative selection depends on strong binding (affinity and avidity). Strong binding leads to apoptosis. Ha, Ha!

18. Positive selection of T cell type T cell recognizes self MHC protein with either CD4 or CD8. The other receptor is lost and the cell becomes a single positive cell (helper or killer).