Immunology Flashcards
Medullary region of lymph nodes contains what types of cells?
Reticular cells
Macrophages
What is present on blood smear in a person with splenectomy?
Howell jolly bodies
Target cells
Thrombocytosis
What are the features of the innate immune system?
Fast, Nonspecific, No memory
PMNs, Macs, NKs, Dendritic cells, Complement
MHC 1 features?
HLA [A, B ,C]
On all nucleated cells expect RBCs
heavy chain + B2 microglobulin
MHC II features?
HLA [DP, DQ, DR]
Only Ag presenting cells
2 alpha chains 2 beta chains
What are the associations with HLA-B27?
Psoriasis
Ankylosing spondylitis
IBD
Reiters syndrome
What HLA is associated with Celiac disease?
HLA DQ2/8
What HLA is associated with MS, SLE, and Goodpasteurs?
HLA DR2
*Notice its an MHC II cause caused by antibodies
What HLA is associated with DM and Graves? RA? Pernicious anemia?
DM= HLA DR3 RA = HLA DR4 Per = HLA DR5
What cells use perforins and granzymes to induce apoptosis in virally infected cells and Tumor cells in the absence of MHC 1 on the surface?
NK cells
What cytokines activate NK cells?
IL-2
IL-12
IFN- alpha & Beta
WHat are the key features of the Innate immune system that “recognize” pathogens?
TLRs
PAMPs (LPS, ssRNA, flagella)
What is the mechanism of Antigen loading onto MHC 1?
Antigen “PEPTIDES” loaded in RER after delivery via TAP transporter
What is the mechanism of Antigen loading onto MCH II?
Loaded following Invariant chain in acidified Endosome
What is the co-stimulatory signal required to activate T cells?
B7 on APC —> CD28 on Tcell
**B7 on macs and dendritic cells
What is the costimulatory signal that induces B cell class switching?
CD40 L on Tcell –> CD40r on Bcells
What cytokines do Th1 secrete?
IFN gamma to activate Macrophages and CTLs
What cytokines do Th2 secrete?
IL-4 –> IgE
IL-5–> IgA + Eosinophils
IL-6 –> Acute phase proteins
IL-13 –> Igs
What is the macrophage Lymphocyte reaction needed for Granulomas?
Macs release IL-12 –> T-cells differentiate into Th1 cells.
Th1 secrete IFN g to activate macs
What is the function of Regulatory Tcells?
Maintain specific immune tolerance by suppressing CD4/ CD8 cells
*Once activated= Anti-inflammatory
secrete IL-10, TGFbeta
What are the Surface markers for Treg cells?
CD3
CD4
***CD25
What are the anti-inflammatory cytokines?
IL-10
TGF beta
What are the Fab and Fc portions of Antibodies?
Fab = Antigen binding site, Variable site, Ag specificity site Fc= Constant, Complements binding site
What processes cause antibody diversity?
Recombination of VJ regions
Heavy chain rearrangement
Somatic hypermutation= Germinal centers
Addition of Nucleotides to DNA during recombination
What are the features of IgG?
Most abundant Ig
Crosses placenta
Opsonizes bacteria
Neutralizes toxins/ viruses
What are the features of IgA?
Monomer in circulation
Dimer when Secreted
Crosses epithelial cells via TRANSCYTOSIS
Features of IgE?
Binds Mast cells and basophils
Immunity against worms via Eosinophils
LOWEST concentration in serum due to rapid binding via Mast cells
What are the Acute phase reactants “Unregulated” during inflammation?
Serum amyloid A
CRP= opsonin, fixes complement
Ferritin= sequesters IRON
Fibrinogen= Coagulation, endo repair, ESR
Hepcidin= Prevents release of IRON by ferritin
What Acute phase reactants are “Down-regulated” during inflammation?
Albumin= Conserve AAs
Transferrin
What activates the Activators for Complement:
Classical pathway
Alternative pathway
Lectin pathway
Classical= IgM + IgG Alternative = Microbe Surface Lectin = Mannose
What are the functions of:
C3a
C3b
C5a
C3a + C5a = Anaphylaxis
C3b = Opsonin + Clear ICs
C5a = PMN chemotactic
What inhibit Complement activation on self cells?
DAF
C1 esterase inhibitor
What is the flow of the Alternative complement system?
C3b + B/D –> C3 convertase –> C3b (C5 convertase)
What is the flow of the Lectin pathway?
MBL-> C1 complex -> C4b {C3 convertase}
What is the flow of the Classical pathway?
C1 complex -> C2b + C4b= C3 convertase
What is the main difference btwn Classical and Alternative pathways?
Classical = C1 + C2 + C4 Alternative = C3 + B/D
Low C4 levels will be seen when what complement pathway is activated?
Classical == IgM + IgG
C1 esterase inhibitor deficiency?
Hereditary Angioedema
ACE CI
C3 deficiency?
Recurrent Pyogenic sinus infections
Inc susceptibility to T3HS rxn
GPI anchored DAF def?
PNH
What are the functions of IL-1?
Fever
Activate endothelial cells to express adhesion molecules
What are the functions of IL-12?
Induces Th1 differentiation
Activates NKs
What are the functions of TNF alpha?
Septic shock
Endothelial activation
Leukocyte recruitment
Vascular leakage
What cytokine function like GM-CSF?
IL-3
What cytokine suppresses Th2, and has Antiviral & antiTumor properties via NK cell activation?
IFN gamma
What are the functions of IL-5?
IgA
Eosinophil growth and differentiation
What are the mechanism of IFN actions?
Induce Ribonuclease that inhibit viral protein synthesis
Degrade viral mRNA {alpha & beta}
Gamma= increases MHC I + II expression & activates NK cells
What cells express CD28?
T cells
What cells express CD21? What is this a receptor for?
B cells
EBV receptor
What cells express CD14?
Macs
**also have Fc & C3b receptors
What cells express CD56 and CD16?
NK cells
What is the unique marker for NK cells?
CD56
What bacteria classically undergo Antigen variation?
Borrelia = relapsing fever
gonorrhea (PILUS protein)
Salmonella (flagella)
Trypanosomes
Endotoxins and LPS directly stimulate?
Macrophages via CD14
NO Th cells involvement
**Unlike SuperAgs that activate T cell receptors
For what can Passive immunity be given?
Tetanus
Botulinum
HBV
Rabies
Features of T1 HS?
IgE + immediate
Asthma, hay fever, drugs
Mast cells = First release Histamine/ Eos chemotactic
Late; release PGs and LTs
What are the 3 mechanisms of T2HS cell destruction?
Opsonization
Complement
ADCC via NK cells
Direct vs Indirect coombs?
Direct= Detect Abs that HAVE bound pts cells Indirect= Detect Abs that CAN bind pt serum
Serum sickness and arthus reactions are examples of what?
T3HS
Serum sickness= 5days post Foreign protein causing Abs to form and bind it. Deposit in tissue and activate Complement
Arthus= Ag-Ab complexes in Skin= necrosis
Blood transfusion reactions symptoms & Rx: Allergic reaction?
Urticaria
Wheezing
Fever
Rx: Anti-histamines
Blood transfusion reactions symptoms & Rx: Anaphylactic reaction?
Dyspnea = Bronchospasms
Hypotension
Respiratory arrest/ shock
Blood transfusion reactions symptoms & Rx: Febrile nonhemolytic rxn?
Fever
headache
chills
Flushing
Blood transfusion reactions symptoms & Rx: Acute hemolytic rxn?
Hypotension Tachypnea Tachycardia Flank pain Hemoglobulinemia Jaundice
Auto-antibodies and diseases: Anti-CCP Anti-Topo1 Anti-mitochondrial Anti-endomysial Anti-Transglutaminase Anti-Jo1/SRP/ Mi-2 Anti-smooth muscle Anti-glutamate Decarboxylase
CCP= RA Topo1= Scleroderma Mito= Primary biliary cirrhosis Endomysial= Celiac Transglutaminase= Celiac Jo1/ SRP/ Mi2= Polymyositis/ Dermatomyositis Smooth muscle= AI hepatitis Glutamate dc= T1 DM
Pt that has recurrent TB or disseminated TB has what def?
IL-12 or INF gamma
Pt with coarse face, Staph abscesses, Eczema, and Increased IgE?
Jobs syndrome = Hyper IgE
- *Th1 cells fail to produce IFN gamma
- PMNs inability to respond to chemotactic
Pt with cerebellar defect, spider angiomas, IgA def and increase AFP?
Ataxia-telangiectasia= DNA repair defect
Pt with thrombocytopenia, recurrent infections, and Eczema. What is the underlying cause of his symptoms? What is seen on Ig differential?
Wiskott aldrich = T cells unable to reorganize **ACTIN cytoskeleton
**Inc IgE + IgA but Low IgM
Pt with neutrophilia but inability to form pus has what defect?
Leukocyte adhesion def =
Def= LFA1 Integrins or CD18
**Delayed umbilical cord seperation
Pt with a recent kidney transplant presents with rash, jaundice, diarrhea, and hepatosplenomegaly. what is the dx?
Graft vs Host
Main mediators of Rejection:
Hyperacute
Acute
Chronic
Hyperacute= Abs (occlude BVs, necrosis) Acute= CTLs (vasculitis, infiltrate) Chronic= CTL recog MHC1 presentation as nonself (FIBROSIS, vascular damage, Irreversible)
