Lymphoid structures Flashcards
What is the function of lymph nodes?
Filtration by macrophages, storage of T and B cells
What are primary follicles?
Lymph nodes that are dormant
What are secondary follicles?
Lymph nodes that are actively producing B and T cells
What cells are contained within the medulla of a lymph node?
Lymphocytes and plasma cells
What cells are contained within the paracortex of the lymph node?
T cells
Where does lymph drain from the head and neck?
Cervical lymph nodes
What are the lymph nodes that drain the lungs?
Hilar lymph nodes
What are the lymph nodes that drain the trachea and the esophagus?
Mediastinal lymph nodes
What are the lymph nodes that drain the Upper limb, breast, and skin above the umbilicus?
Axillary lymph
What are the lymph nodes that drain the liver, stomach, spleen, pancreas, and upper duodenum?
Celiac
What are the lymph nodes that drain the colon from the splenic flexure to the upper rectum?
Inferior mesenteric
What are the lymph nodes that drain the tests, ovaries, kidneys, and uterus?
Para-aortic nodes
What are the lymph nodes that drain the anal canal (below the pectinate line), and skin below the umbilicus?
Superficial inguinal
What are the lymph nodes that drain the dorsolateral foot and posterior calf?
Popliteal
What part of the spleen houses T cells?
WhiTe pulp
What part of the spleen houses B cells?
Red pulp
What is contain within the marginal zone of the spleen ( the area between the white and red pulp)?
APCs and B cells
Asplenic pts are susceptible to infections with which bacteria? (6)
Strep pneumoniae HIB N. Meningitidis E. Coli Salmonella GBS
(SHiNE SKiS)
What are Howell–Jolly bodies, and in what condition are they seen in?
DNA inclusions in RBCs, caused by splenectomy
Why is there thrombocytosis in pts who are asplenic?
Spleen normally removes platelets
What is the site of maturation for B cells, and T cells?
B cells = bone
T cells = Thymus
Is adaptive immunity inheritable?
No
TLRs and PAMPs are key in the innate immune response, or the adaptive?
Innate
What are the gene loci for MHC class I?
HLA-A, B, and C
What are the gene loci for MHC class II?
HLA-DR, DP, DQ
CD4 binds to MHC I or II?
II
CD8 binds to MHC I or II?
I
Which MHC class is responsible for presenting endogenously synthesized antigens, class I or II?
I
Which MHC class is responsible for presenting exogenously synthesized antigens to Th cells, class I or II?
II
Which class of MHC loads peptides in the RER?
I
Which class of MHC proteins loads peptides following the release of invariant chain in acidified endosome?
II
HLA haplotype A 3 is associated with what disease?
Hemochromatosis
What is the HLA haplotype that is associated with Psoriatic arthritis, ankylosing spondylitis, IBD, and reactive arthritis?
B27
What is the HLA haplotype that is associated with celiac disease?
DQ2/DQ8
What is Goodpasture syndrome?
Autoimmune attack of BM or lungs and kidneys
What is the HLA haplotype that is associated with Goodpasture syndrome, MS, and SLE?
DR2
What is the HLA haplotype that is associated with DM I, SLE, and Grave’s disease?
DR3
What is the HLA haplotype that is associated with RA?
DR4 (“There are 4 walls in a ‘room’”)
What is the HLA haplotype that is associated with pernicious anemia?
DR5
Pernicious anemia is caused by what?
B12 deficiency
What are two protein/enzyme that NK cells utilize to kill tumor cells?
Perforin and granzymes
NK cells are activated by which ILs? (4)
IL2, IL12, IFN beta and alpha
What is the role of Th 4 cells?
Help B cells make antibodies and produce cytokines
What is the role of CD8 T cells?
Kill infected cells
Positive selection of T cells occurs in which part of the thymus? What is positive selection?
Cortex
T cells expressing TCRs capable of binding self MHC survive
Negative selection of T cells occurs in which part of the thymus? What is negative selection?
Medulla
T cells bindings too tightly with self antigens die
What is the cytokine that induces CD4 T cells to differentiate into Th1 cells? Th2? Th17? Treg?
Th1 = IL 12 Th4 = IL2 Th17 = TGF-beta + IL6 Treg = TGFbeta
What are the three types of APCs?
B cells
Macrophages
Dendritic cells
What are the costimulatory signals involved in T cell activation?
B7 and CD28
CD40 receptor on B cells binds to what ligand on Th cells?
CD40 ligand
What are the steps of T cell activation?
Dendritic cell presentation via MHC II to Th.
Th cell presents to CD8 T cells
What are the steps of B cell activation?
Th cell stimulated, then B cell activation. Work together to achieve full activation
What determines the class switching from IgM?
Th cell cytokines
Th1 cells secrete what cytokine?
IFN-gamma
Th2 cells secrete what cytokines (4)?
IL 4, 5, 6, 13
Th1 cells do what?
Activate Macrophages and CTLs
Th2 cells do what?
Recruits eosinophils for parasite defense and promote IgE production
Th1 cells are inhibited by what two cytokines?
IL4 and IL10
Th2 cells are inhibited by what cytokine?
IFN-gamma
Macrophages release what cytokine to stimulate T cells to differentiate into Th1 cells?
IL12
Th1 cells release what cytokine to stimulate macrophages?
IFN-gamma
What are the proteins that CTLs release to destroy cells?
Perforin and granzymes
What is the role of regulatory T cells?
Suppressing CD4 and CD8 T cells
Transcription factor FOXP3 is found in what immune cells?
Tregs
What part of IgM and IgG fixes complement?
Fc portion
What parts of antibodies recognize antigens?
Variable portions of the heavy and light chains
Which chain contributes to both Fc and Fab portions of an antibody? What part of the antibody does the other contribute?
Heavy chain contributes both
Light portion only contributes to Fab portion
What part of the antibody determines the isotype of the antibody (Fc or Fab region)?
Fc region
What are the four Cs of the Fc portion of antibodies?
Constant
Carboxy terminal
Complement binding
Carbohydrate side chains
How is antibody diversity generated?
random recombination of V(D)J genes
True or false: IgG crosses the placenta
True
True or false: IgA fixes complement
False
True or false: IgM crosses the placenta
False
What is the function of IgD?
Unknown
Which antibody mediates Type I hypersensitivities, by binding to mast cells and basophils?
IgE
What is the primary antibody?
IgM
What is the secondary antibody?
IgG
Which antibody can be found as a dimer, and crosses mucus membranes?
IgA
Which antibody can be found as a pentamer, and is the main antibody found on immature B cells?
IgM
What are thymus independent antigens?
Antigens that lack a peptide component
What are thymus dependent antigens?
Antigens that contain a protein component, allowing for class switching, and all the goodies that come with adaptive immunity
What organ produces acute phase reactant proteins?
Liver
Prolonged elevation of serum amyloid A can lead to what?
Amyloidosis
What is the role of CRP?
Opsonizes, fixes complement
What is the role of ferritin?
Binds and sequesters Fe
What is the role of fibrinogen?
Coagulation factor.
What is the role of hepcidin?
Prevents the release of Fe bound by ferritin
What are the two acute phase reactants that are downregulated in inflammation?
Albumin
Tranferrin
What is the role of albumin?
Transport protein for bunches of stuff
What is the role of transferrin?
Fe sequestration
The MAC complex defends against what type of bacteria?
Gram negative
What is the classic pathway for complement activation?
IgG or IgM binds to bacteria (GM makes classic cars)
What is the alternative pathway for complement activation?
Microbe surface molecules
What is the Lectin pathway for complement activation?
Complement fixes mannose
What is the function of C3b?
Binds bacteria (b for binds)
What is the function of C3a, C4a, and C5a?
anaphylaxis
What is the function of C5a?
PMN chemotaxis
What complements combine to form the MAC complex?
C5b-9
What are the two primary opsonins in bacterial defense?
C3b and IgG
True or false: C3b helps clear immune complexes
True
What are the two inhibitors of complement, that prevent hemolysis of RBCs?
Decay accelerating factor + C1 esterase inhibitor
C1 esterase inhibitor deficiency leads to what? What type of medication is contraindicated in this disease?
Hereditary angioedema
ACE inhibitors
C3 deficiency causes what?
Increases the risk of bacterial infections
C5-C9 deficiency leads to a predisposition to develop infection from what genus of bacteria?
Neisseria
Decay accelerating factor (DAF) deficiency leads to what?
Complement mediated lysis of RBCs and nocturnal hemoglobinuria
What is the functions of IL1-6?
IL-1 = Fever IL-2 = T cells production IL-3 = Bone marrow stimulation IL-4 = IgE production IL-5 = IgA production IL-6 = acute phase protein stimulation
(“Hot T-bone stEAC)
What is the role of IL8?
Chemotaxis for PMNs
What is the role of IL-12?
T cell differentiation into Th1 cells
What is the chemokine that mediates septic shock?
TNF-alpha
What is the chemokine that activates NK cells to kill virus infected cells?
IFN-gamma
What is the role of IL-10?
Modulates inflammatory response. (inhibits T cells)
What is interferon?
Glycoproteins synthesized by cells to alert nearby cells of infection.
What are the two enzymes that are upregulated with exposure to Interferon?
RNAase L
Protein kinase
All nucleated cells have MHC class I or II?
I
What is the role of the TCR protein found on T cells?
T cell receptor–binds to MHC complexes
What is the role of CD3 on T cells?
Associated with TCR for activation
What is the role of CD28 on T cells?
Binds B7 on APCs
What is the protein that B7 on APCs binds to, that is present on T cells?
CD28
What is the protein on Th cells and APCs that allow for Th cells activation?
CD40 and CD40 ligand
CD8 or CD4 to CTLs?
CD8
What is the CD protein that is a receptor for Epstein Barr virus?
CD21 (beer at the bar when 21)
What is the role of CD16 on NK cells?
Binds Fc portion of IgG
What is the CD protein that is unique to NK cells?
CD56
What is clonal anergy?
Inactivation of T cells when exposed to Self-protein without other costimulatory molecules
What is the MOA of superantigens on Strep pyogenes and Staph Aureus?
Cross-link Beta region of T cell receptors to MHC II on APCs, leading to massive release of cytokines.
Which is a more severe mutation for the Flu, antigenic shift or drift?
Shift
What are the four bacterial/virus exposures where giving passive abs is indicated?
Tetanus
Botulinum
HBV
Rabies
Which is a live attenuated, and which is an inactivated vaccine: sabin and salk polio?
Sabin = Live attenuated Salk = Inactivated
What is a type I hypersensitivity?
Antigen cross linking of IgE on presensitized mast cells
What are the chemokines that are produced in the delayed Type I hypersensitivity?
Leukotrienes
What is a Type II hypersensitivity?
IgM and IgG bind to antigen on self cells
What is a Type III hypersensitivity?
Immune complexes (antigen+antibody+complement)
What is serum sickness?
Type III hypersensitivity d/t ab introduction or drugs
What is Arthus reaction?
Local, subacute type III hypersensitivity when injecting antigen in the skin.
What is a type IV hypersensitivity?
T-cell mediated activation of macrophages (NO antibody involvement)
Which type of hypersensitivity does NOT involve antibodies?
IV
Transplant rejections are what type of hypersensitivity?
IV
TB skin tests are what type of hypersensitivity?
IV
Poststreptococcal Glomerulonephritis is what type of hypersensitivity?
III
What is pemphigus vulgaris?
type III attack against desmosomes, causing painful blisters