Week 2 Flashcards
What are the 3 main inflammatory cytokines?
-TNFalpha
-IL-1
IFNgamma
What are the 2 names of direct anti-microbial molecules tissue cells can make?
- defensins
- cathelicidins
Where are dendritic cells found?
- skin, lymph nodes, spleen, within/underneath mucosal epithelia
- also in thymus (present self-antigens to developing T cells)
How many types of receptors do lymphocytes have? macrophages? neutrophils?
- lymphocytes- 1 kind of receptor (all identical)
- Macrophages and neutrophils have many different receptors on cell surface
How many days does it take to induce the adaptive immune system?
- 7-10 days
- rare B and T lymphocytes with identical antigen recognition sequences must find each other to proliferate
- another 1-5 days to develop memory
What parts of the body/ job do B cells protect? T cells?
- B cells: protect extracellular spaces (tissue fluids, blood, secretions) by releasing antobodies = humoral immunity
- T cells: survey surfaces of cells looking for mutations= cell-mediated immunity
What CD molecule is expressed on all T cells?
CD3 (part of the T cell receptor)
What CD molecules are found on all B cells?
- CD79a and CD79b
- both part of B cell receptor complex
Do MHC class 1 and 2 present to T cells, B cells, or both?
- only to T cells (MHC 1 to CD8 and MHC 2 to CD4)
- B cell receptors see antigen and secrete antibodies
What 2 Ig molecules can activate complement?
2 IgGs or 1 IgM molecule
GM makes “classic” cars - classic complement pathway
Which is the only antibody that can cross the placenta?
IgG
Which Ig is the B cell antigen receptor?
IgD
Which Ig is mostly in secretions and has a chain called the “Secretory Component”. What does it do?
- IgA
- Secretory component makes it resistant to digestive enzymes
Which Ig attaches to mast cells and controls mediators of inflammation?
-also role in parasite resistance
- IgE
- causes mast cells to make prostaglandins, leukotrienes, and cytokines
- mast cells degranulate releasing histamine
What would cause increased reticulocytes?
-blood loss or hemolytic processes
(normal reticulocyte count if immune system destroys red cell precursors)
-should correspond with hematocrit (low hematocrit should increase reticulocytes)
What causes macrocytic cells? (MCV>100)
- B12, folic acid deficiency
- drugs that impair DNA synthesis
What causes microcytic cells? (MCV<80)
- iron deficiency
- Thalassemia trait
- Anemia of chronic disease
- Sideroblastic anemias
With low serum B12, what can be detected as elevated in serum?
-elevated serum methylmalonic acid levels
What are common lab findings with iron deficiency?
- decreased Hgb
- microcytic MCV
- decreased serum iron
- increased or normal TIBC
- decreased iron saturation
Which is more severe: Thalassemia alpha or beta?
-alpha
What’s the pathogenesis of Anemia of Chronic Disease?
- cytokine production causes:
- decreased EPO production
- suppression of erythroid progenitors
- blocking transferrin iron release
- normal/increased ferritin
What is the order of complement activation in Classical Pathway?
C1, C4, C2, C3, C5, C6, C7, C8, C9
What defective parts of the complement pathway result in meningococcal infections?
- Membrane attack complex (C5-C9)
- Alternative pathway (Factor B and D, properdin)
What type of enzyme does the proteolytic steps of Classical complement pathway?
-serine esterases
What parts of complement are covalently attached to surface by thioester bonds?
C4b and C3b
What results from absence or mutation in C1 inhibitor of complement classic pathway?
hereditary angioedema
-Tx: anabolic steroids to increase C1 INH synthesis
C4b interacts with which complement receptors on white cells?
CR1
What is the classical pathway C3 convertase called?
C4b2a
What are the 2 ways to form C4b2a?
- Classic: C1q interaction with C1r and C1s
- MBL: MASP-1 and MASP-2
What is the name of the alternative pathway C3 convertase?
-What stabilizes it?
C3bBb
-Stabilized by Properdin
What are the 2 C5 convertases?
- C4b2aC3b
- C3bBbC3b
Binding of C5b-7 to what prevents membrane insertion of MAC?
S protein
What does Vitronectin (CD59/ Protectin) do and where is it located?
-on self membranes to inhibit binding of C9 and its polymerization (saves it from MAC)
What is an example of a fluid phase inhibitor of C3 Convertase?
Factor H
- if it sees C3bBb floating around, it binds and dissociates Bb to inactivate it
- “Decay acceleration of the convertase”
- Factor H also can be cofactor for cleavage by Factor I (if by sialic acid residue= on host cell)
What can result from deficiency in DAF (CD55) and CD59?
- complement mediated intravascular hemolysis in paroxysmal nocturnal hemoglobinuria (PNH)
- increased RBC MAC-mediated lysis
What parts of complement pathway are inflammatory mediators?
C3a and C5a
- bind anaphylatoxin receptors
- CD88 = C5a receptor
What receptor is for clearing immune complexes?
Which for augmentation of humoral immunity?
-CR1 for clearing ICs
-CR2 (CD21) for augmentation of humoral immunity (C3 fragments interact with complement receptors)
-CR1 (CD35) on RBCs
CR2 (CD21) on B cells
What should you always do if you see nucleated RBCs?
-bone marrow biopsy
What do you add to H antigen to make A antigen? B?
A: N-acetylgalactosamine
B: galactose
What causes Febrile Transfusion Reactions?
-recipient antibodies against donor WBC
What happens in Graft vs. Host disease?
- donor lymphocytes attack host
- usually fatal
- prevent by irradiating products
