Immunology

Question 0

Describe how the immune system response maybe altered in order to decrease plaque formation

Answer 0

Decrease Th1 or the cytokines that stimulate differentiation into Th1 such as IL-12,18.
Increase stimulation of Th2 cells or IL-4 which stimulates its differentiation
Increase Treg which produce anti- inflammatory cytokines IL-10 and TBF- beta

Question 1

Describe in detail the steps of plaque formation

Answer 1

1. Inflamed endothelium due to oxidized LDL (develop a vaccine Ab against this)
2. Expression of adhesion molecules by endothelium to bind WBC, Cell response to local pro-inflammatory cytokines.
3. Monocytes become macrophages, and then after consuming LDLs, foam cells
4. CD4 cells recruited (release more inflammatory cytokines: TNFa, and IFN gamma).
5. Cytokines stimulate smooth muscle production.
6. Fibrous cap covering a plaque may be weakened by these cytokines (as well as other stressors) and rupture
7. Clotting

Question 2

What is a granuloma and how is it maintained? How might it be compromised?

Answer 2

Collection of organized macrophages that fuse into multi nuclear giant cells, with them are lymphocytes, DC, fibroblasts and collagen.

MO secret cytokines to maintain the granuloma; TNFa is critical.

Anti rheumatic drugs or those targeting pro-inflammatory cytokines could potentially reopen granuloma by decreasing TNFa.

Question 3

How does BALT protect mucosal surfaces?

Answer 3

CD4+ bind to B cells via CD40 and CD40 L. CD4 cells will produce TGF beta which will stimulate the production of IgM class switching to IgA. IgA helps maintain the immune system in these areas.

Question 4

Which immunoglobulin is primarily found in secretions and which is primarily found in serum?

Answer 4

IgA secretions

IgG serum

Question 5

How do Ag activate an immune response leading to IgA dimerization?

Answer 5

Ag is transported across epithelium by an M cell and then bound by MHC complex of MO which present the peptide to CD4+ cells. These activated B-cells which become plasma cells and provide the J chain needed to dimerize these immunoglobulins. Dimerized IgA then bind to a receptor on epithelial cells and when secreted out the other side retain a secretory piece with them.

Question 6

How does IgA act to protect mucosal surfaces?

Answer 6

Inhibits entry of pathogens through mucosa