Immunology Flashcards
Where are MHC Class I proteins expressed?
Ubiquitous - surface of nucleated cells
Where are MHC Class II proteins expressed?
Antigen-presenting cells; dendritic cells, macrophages, B cells
Immune function of MHC Class I proteins…
Cytotoxicity
Immune function of MHC Class II proteins…
Immune regulation, coordination & activation of other immune cells
Distribution of Igs in serum (abundance)
IgG, IgA, IgM, IgE, IgD (GAMDE)
What are antibodies?
Soluble, secreted glycoproteins that bind specifically to antigens
Immune reactant in Type 1 Hypersensitivity Reactions?
IgE
Immune reactant in Type 2 Hypersensitivity Reactions?
IgG or IgM
Immune reactant in Type 3 Hypersensitivity Reactions?
IgG & IgM
Immune reactant in Type 4 Hypersensitivity Reactions?
T cells
In what form are the antigens involved in Type 1 Hypersensitivity Reactions?
Soluble
In what form are the antigens involved in Type 2 Hypersensitivity Reactions?
Cell-bound
In what form are the antigens involved in Type 3 Hypersensitivity Reactions?
Soluble
In what form are the antigens involved in Type 4 Hypersensitivity Reactions?
Soluble or cell-bound
What is the mechanism of action of a Type 1 Hypersensitivity reaction?
Allergen-specific IgE antibody binds to the Fc receptor on mast cells.
Cross-linking of IgE causes degranulation of mast cells
What is the mechanism of action of a Type 2 Hypersensitivity reaction?
IgG or IgM antibodies bind to cellular antigen leading to complement activation & cell lysis.
IgG can also mediate with CT cells, NKCs, macrophages & neutrophils
What is the mechanism of action of a Type 3 Hypersensitivity reaction?
Ag-Ab complexes are deposited in tissues. Complement activation leads to inflammatory mediators & recruits neutrophils, enzymes released damage tissues
What is the mechanism of action of a Type 4 Hypersensitivity reaction?
TH1 cells secrete cytokines → activate macrophages & CT cells
Give some examples of a Type 1 Hypersensitivity reaction?
Anaphylaxis, seasonal hay-fever, food & drug allergies
Give some examples of a Type 2 Hypersensitivity reaction?
RBC destruction after transfusion with mismatched blood type or haemolytic disease of new-born
Give some examples of a Type 3 Hypersensitivity reaction?
Post-streptococcal glomerulonephritis, rheumatoid arthritis, systemic lupus erythematosus
Give some examples of a Type 4 Hypersensitivity reaction?
Contact dermatitis, Type1 diabetes mellitus, multiple sclerosis
Red Blood Cell & Mast Cell lineage…
Haematopoietic Stem Cell → Common Myeloid Progenitor → RBCs & MCs
Neutrophils, Basophils, & Eosinophils lineage…
Haematopoietic Stem Cell → Common Myeloid Progenitor → Myeloblast → Neutrophils, Basophils, Eosinophils
