Immune responses Flashcards
Actue-phase reactants are mainly produced by
liver
APR are induced by
IL-6
Opsonin that fixes complement and facilitates phagocytosis
C-reactive protein
Function of ferritin
Binds and sequesters iron to inhibit microbial iron scavenging
APR that correlates with ESR
Fibrinogen
APR that dicreases iron absorption by degrading ferroportin and iron release from macrophages
Hepcidin
Acute phase reactants: upregulated
C reactive protein Ferritin Fibrinogen Hepcidin Serum Amyloid A Procalcitonin
Prolonged elevation can lead to amyloidosis
Serum amiloyd A
Acute phase reactants: downregulated
Albumin
Transferrin
System of hepatically synthesized plasma proteins that play a role in innate immunity and inflammation
Complement
Membrane attack complex defends against
Gram - bacteria
Pathways of complement activation
- Classic pathway: IgG or IgM mediated
- Alternative pathway: microbe surface molecules
- Lectin pathway: mannose or other sugars on microbe surface
C3b function
Opsonization: C3B Binds Bacteria
C3a, C4a, C5a function
Anaphylaxis: A
C5a function
Neutrophil chemotaxis
C5bC9 function
Cytolisis by membrane attack complex
Opsonins
C3b: binds bacteria
IgG
Opsonin function
Greek: prepare for eating=enhance fagocytosis
Secondary function of C3b
Clearing immune complexes
Inhibitors of complement, preventing complement activation on self cells
DAF: decay accelerating factor: CD55
C1 esterase inhibitor
C3 deficiency
- Increases risk of severe recurrent pyogenic sinus and respiratory tract infections
- Susceptibility to type III hypersensitivity reactions
C5-C9 deficiencies
Susceptibility to recurrent Neisseria bacteriemia
C1 esterase inhibitor deficiency
Hereditary angioedema due to unregulated activation of kallikrein that increases bradykinin
Low C4 levels
ACE inhibitors are contraindicated (bradykinin causes dry cough)
CD55 (DAF) deficiency
Complement mediated lysis of RBCs and paroxysmal nocturnal hemoglobinuria
Hereditary angioedema
C1 esterase inhibitor deficiency
Inerleukines: hot t-bone steak
Il1: fever IL2: stimulates T cells IL3: stimulates bone marrow IL4: Stimulates IgE production IL5: Stimulates IgA production IL6: Stimulates akute-phase protein production
Major chemotactic factor for neutrophils
IL-8
IL-12 functions
Induces differentiation of T cells into Th1 cells
Activates NK cells
Tumor necrosis factor alpha function
Activates endothelium
WBC recruiment
Vascular leak
Causes cachexia in malignancy
Tumor necrosis factor alpha
Maintains granulomas in Tuberculosis
Tumor necrosis factor alpha
Cytokines secreted by macrophages
1, 6,8,12,TNFalpha
IL that funcitions like GM-CSF
IL.3
Secreted by T cells in response to antigen/IL-12 from macrophages; stimulates them to phagocyte pathogens; Inhibits differentiation of Th2 cells
Interferon gamma
Attenuate immune response
TGF beta
IL-10
Enhances class switching to IgE and IgG
IL-4 (Th2)
Enhances class switching to IgA Stimulates eosinphils
IL-5
Increases MCH expression and antigen presentation by all cells
Interferon gamma
Respiratory (oxidative burst)
Activation of phagocyte NADPH oxidase complex which utilizes 02 releasing ROS
Deficiency of NADPH oxidase
Chronic granulomatous disease
Patients with NADPH oxidase are at risk of
Infection by catalase positive species:
- S.aureus
- Aspergillus
Protein in P aeruginosa that generates ROS to kill competing microbes
Pyocyanin
Part of innate host defense against RNA and DNA viruses, synthesed by virus infected cells that act locally on uninfected cells
Interferon alpha and beta
Binds do B7 of APC
CD28 in T cells
Cytotoxic T cells coreceptors for HIV
CXCR4
CCR5
Co receptor for EBV in B cells
CD21: you can drink beer at the bar when you are 21
Marker for NK
CD56
Hematopoietic stem cells, cell surface marker
CD34
State during which a cell cannot become activated by exposure to its antigen
Anergy
T and B cells become anergic when
Exposed to their antigen without costimulatory signal
Bacteria that can produce superantigens
S pyogenes
S aureus
Superantigens effect
Cross-link te beta region of the T cell receptor to the MHC class II on APCs: activate Cd4+: massive release of cytokines
Antigenic variation examples
- Bacteria: salmonella, Borrelia recurrentis (relapsing fever), N gonorrhoeae (pilus protein)
- Viruses: inflenza, HIV, HCV
- Parasites: trypanosomes
Receiving preformed antibodies is a form of
Passive immunity
Treatment in non-vaccinated After exposure to:
Tetanus toxin, Botulinum toxin , HBV, Varicella, Rabies virus, diphteria
Preformed antibodies (passive)
Duration of passive immunity
Short span of antibodies: 3 weeks
Vaccines are a for of ____ immunity
Active: humoral (B cells) or cellular (T cells)
Types of vaccine
- Live attenuated vaccine
2. Inactive or killed vaccine
Live attenuated vaccines that can be given to HIV patients who have a CD4 account >200/mm3
MMR: triple vírica
Varicella
Examples of Live attenuated vaccine
BCG: Bacilo Calmette-Guerin: tbc Measles Mups Polio: Sabin Rotavirus Rubella Varicella Yellow fever
Live attenuated vaccine induce a
Cellular and humoral response
Inactivated or killed vaccine induce a
Humoral response
Examples of inactivated vaccines
Rabies Influenza Polio: Salk Hepatitis A RIP always
Hypersensitivity types
ACID Type I: Anaphylactic and Atopic:. antigen-IgE Type II: Citotoxic: antibody mediated Type III: Immune complex Type IV: Delayed, cell mediated
Hypersensitivity antibody mediated types
I, II, III
Free antigen cross links IgE on presintized mast cells and basophils
Hypersensitivity type I
Antibodies bind to cell surface antigens
Hypersensitivity type II
Hypersensibility type I tests
Skin test
Blood test: ELISA
Hypersensibility type II tests
Direct Coombs test
Indirect Coombs test
Direct coombs test detects
Antibodies Directly attached to RBC
Indirect Coombs test detects
Presence of unbound Antibodies in the serum