Regulation of the Immune System- L11 Flashcards Preview

Immunology > Regulation of the Immune System- L11 > Flashcards

Flashcards in Regulation of the Immune System- L11 Deck (14):
1

Tolerance

Lack of response to a specific antigen

2

2 major mechanisms of tolerance induction

1. Deletion of reactive cells
2. Inactivation of reactive cells: Anergy

3

Clonal deletion in T cells

-Occurs in thymus
-Tight association of autoreactive TCR to MHC presented antigen on thymic dendritic cells causes apoptosis

4

Clonal anergy in T cells

T cells become inactivated if an appropriate co-stimulatory signal is not received

5

Generation of T regs

Active process, suppresses autoreactivity

6

Mechanisms of tolerance in T cells

1. Clonal deletion
2. Clonal anergy
3. Functional deletion
4. Generation of suppressor or T reg cells
5. Blocking of presentation or activation

7

Mechanisms of tolerance in B cells

1. Clonal deletion
2. Clonal abortion/clonal anergy
3. Functional deletion

8

T regs

FoxP3+CD25+CD4+T cells that actively suppress pathological and physiological immune responses

9

IPEX

Syndrome where FoxP3 is lost and T regs cannot differentiate. Patients with IPEX develop many autoimmune disorders.

10

Mechanisms of regulation by T regs

-Direct contact with target cells
-Cytokine mediated suppression of T cells
-Cytokine mediated suppression of pAPC function

11

B7:CTLA4

Stop signal for T cells, binding inactivates them

CTLA4 expressed by T cells, B7 by APCs.

12

Protein antigens can induce

-Humoral immunity
-Cell mediated immunity
-Class switching
-Affinity maturation
-Generation of memory cells

13

Polysaccharide and lipid antigens can induce

-Humoral immmunity
-Can NOT induce CMI
-This is why we don't have long-lived immunity to encapsulated bacteria!!!!

14

How can antibody itself regulate the immune response?

-It can sequester antigen and prevent other B cells from being activated by it
-Can cross link Ig and Fc receptors to inactivate

Ex: preventing an Rh response