hypersensitivity & autoimmunity

Question 1

contrast mechanisms of type I, II, III, IV

Answer 1

type I = IgE mediated
type II = IgG mediated
type III = IgG class 
type IV = cells rather than antibodies

Question 2

how do allergens induce immediate immune responses during early phase allergy

Answer 2

some mediators released by mast cells and basophil cause eosinophil and neutrophil chemotaxis

Question 3

understand relationship between antibodies (IgE and IgG) and Fc receptors

Answer 3

interaction between bound antibodies and the cell surface Fc receptor activates immune cell to kill the microbe

Question 4

define atopy

Answer 4

genetic trait to have predisposition to anaphylaxis

Question 5

understand differences between type II, III antibody mediated hypersensitivity

Answer 5

both result from same class of antibody = IgG
difference between them lies in form of antigens that generate a response - type II distinguished in location of antigens , type II = cell bound, type III = soluble
also, type II can also involve IgM antibodies 

type II may occur in response to host cells or to non-self cells as occurs in blood transfusion reactions

Question 6

understand factors mediated by T cells to cause tissue damage and autoimmune disease

Answer 6

mutations in T cell specific genes such as FOXP3 and CTLA4

Question 7

contrast systemic and organ specific autoimmune disease

Answer 7

organ specific affect particular targets in the body
systemic engages multiple organs
both types can coexist in same patient, either sequentially or concurrently, sustained by presence of antibodies directed against corresponding autoantigens

Question 8

chemotaxis

Answer 8

cell movement is directed in response to an extracellular chemical gradient

factors that regulate chemotaxis are often mutated in cancer