Branches of Immunity and Acute phase reactants Flashcards
Branches of immunity
Natural and Adaptive
Resist infection through normal body functions; No prior exposure needed; Response unchanged with repeated exposures
Natural immunity
Specific to each pathogen; Memory cells increase response upon re-exposure
Adaptive immunity (Acquired, specific)
Parts of Natural Immunity
External and internal defense mechanisms.
External defense system
Anatomical barriers (skin, mucous membranes, cilia) prevent microorganisms from entering.
Biochemical barriers in external defense
Lactic acid in sweat, lysozymes in tears and saliva.
Role of normal flora
Competes with pathogens for nutrients.
Internal defense mechanism
Recognizes specific molecular components of pathogens.
Cellular defense: Phagocytes and NK cells
Phagocytes kill extracellular organisms; NK cells kill intracellular organisms.
Immunity that includes Acute phase reactants, interferons (A and B), defensins, and complement proteins aid in immunity.
Humoral defense
1st line of defense (external, natural)
Skin, mucous membranes
2nd line of defense (internal, natural)
Phagocytes, complements
3rd line of defense (internal, adaptive)
Lymphocytes and antibodies (T cells and B cells)
Acute phase reactants increase by at least _____ during infection, trauma, or injury
0.25
Acute phase reactants are primarily produced by the ___________
Hepatocytes; Liver
Cytokines involved in acute phase reactant production
Interleukin-1 (IL-1), interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α)
Discovery of C-reactive protein
Discovered by Tillet and Francis in 1930
C-reactive protein was originally thought to be an ______
Antibody to the C-polysaccharide of pneumococcus
Structure of C-reactive protein
Consists of five identical subunits held together by noncovalent bonds
C-reactive protein functions
Capable of opsonization, agglutination, precipitation, and activation of complement by the classical pathway.
Main substrate of C-reactive protein
Phosphocholine.
CRP concentration for low cardiovascular disease risk
<1 mg/dL.
CRP concentration for average cardiovascular disease risk
1 – 3 mg/dL.
CRP concentration for high cardiovascular disease risk
> 3 mg/dL.
Has a high affinity for HDL cholesterol, transported by HDL to the site of infection, contributes to localized inflammation in coronary artery disease
Serum Amyloid A
Mediation of inflammation with major functions: opsonization, chemotaxis, and lysis of cells
Complement proteins
Migration of phagocytes to the site of injury
Chemotaxis
Major component of the alpha band in serum electrophoresis; general plasma inhibitor of proteases and counteracts neutrophil invasion during inflammation
Alpha-1-antigen
Binds irreversibly to free hemoglobin from intravascular hemolysis; acts as an antioxidant to protect against oxidative damage
Haptoglobin
Strengthens clots, stimulates endothelial cell adhesion/proliferation, creates a barrier to prevent microbial spread, increases blood viscosity, promotes RBC and platelet aggregation
Fibrinogen
Principal copper-transporting protein in plasma; converts toxic Fe2+ to nontoxic Fe3+
Ceruloplasmin
What acute phase protein increases by 1000x within 4-6 hours and functions in opsonization and complement activation?
C-reactive protein
Acute phase protein increases by 1000x within 24 hours and functions in cholesterol removal?
Serum amyloid A
Acute phase protein increases by 2-5x within 24 hours and functions as a protease inhibitor?
Alpha-1 antitrypsin
Acute phase protein increases by 2-5x within 24 hours and is involved in clot formation?
Fibrinogen
Acute phase protein increases by 2-10x within 24 hours and binds hemoglobin?
Haptoglobin
Acute phase protein increases by 2x within 48-72 hours and binds copper while oxidizing iron?
Ceruloplasmin
Acute phase protein increases by 2x within 48-72 hours and is involved in opsonization and lysis?
Complement C3
