Basic Immunology Flashcards
Compare and contrast MHC I and MHC II.
MHC I is composed of three alpha chains and beta-two-microglobulin. Processes intracytosolic antigens and interacts mainly with CD8+ cells.
MHC II is composed of two alpha and two beta chains. Processes extracellular antigens and interacts mainly with CD4+ cells.
What are the co-stimulatory receptors for MHC interactions?
CD4 / CD8
CD80 / CD86
CD28 / B7
Compare and contrast the stimulus pathways to produce IgM and IgG.
B-cells can be directly recognize and be stimulated against free-floating antigens»_space; IgM formation.
IgG formation requires induction via T-helper cells interacting with APCs (which includes B-cells). Need CD40+CD154 interaction for isotype switching.
What is the immunophenotype of B-memory cells?
CD19+
CD27+
Surface IgM/IgD NEGATIVE
What IgG subclasses can fix complement?
IgG 1 + 3 fix complement well.
IgG 2 is not very good at it.
IgG 4 cannot fix complement.
What is the difference between a linear and a conformational epitope?
Conformational epitopes arise from disjointed amino acids that come into proximity in 3d space.
What is the Cipellini effect?
Expression of an allele affects the expression of another allele in trans (example: C allele reduces expression of trans D)
What patient factors contribute to their tendency to form alloantibodies?
Disease state, degree of inflammation
Certain HLA types (eg, DRB*15)
Antigen makeup
What is transfusion-related immunomodulation, and what causes it?
Transfusion may reduce immune activity, slightly increasing infection risk. This is thought to be due to donor factors including TGFb and soluble HLA/FasL.
What is a “NET”
Neutrophil extracellular trap; a web-like apparatus composed of DNA and AMPs.
What heme malignancies DECREASE risk of alloimmunization?
Lymphoid neoplasms
