First Aid: Immunology Flashcards
What are the two parts of a lymph node’s medulla?
Medullary Sinuses: Connect with efferent lymph drainage and contain macrophages.
Medullary Cords: packed with lymphocytes and plasma cells.
Which type of cell is in the follicular center of a spleen sinusoid?
B Cell
Which type of cell is in the periarterial lymphatic sheath of a spleen sinusoid?
T Cell
Which type of cell is in the spleen red pulp?
RBCs
Which type of cells are in the marginal zone of a spleen?
Antigen Presenting Cells
Which infections are postsplenectomy patients more susceptible to?
SHiNE SKiS: Strep Pneumo, H. Influenza B, Neisseria meningitidis, E. Coli, Salmonella, Klebsiella, Strep Group B
What can be seen on a blood smear of a postsplenectomy patient?
Howell-Jolly Bodies (Nuclear remnants), Target Cell, Thrombocytosis
What is especial about the epithelial cells of the thymus?
Epithelial Reticular Cells in Hassall Corpuscles express AIRES which upregulates every plasma proteins for the negative selection of T Cells.
What are TLR and what do they do?
They are Toll Like Receptor of the innate immune system that recognize PAMPs.
Which type of antigen do MHC Class I present?
Endogenously expressed proteins (ie. viral) to cytotoxic CD8+ T Cells
Which type of antigen do MHC Class II present?
Exogenous protein to CD4+ T Helper Cells. MHC II are only in APC.
What is the quarteary structure of MHC I & II?
MHC I is a dimer with the alpha subunit doing the antigen presentation and beta2 microglobulin carrier the complex to the cell sruface. MHC II has an alpha and a beta subunit and the antigen presentation takes places in a groove between them.
Where does MHC II load its antigen?
In the RER after delivery by TAP.
Which HLA subtype is the most associated with disease? Which diseases?
HLA B27 is associated with Psoriasis, Ankylosing spondylitis, arthritis of Inflammatory bowel disease, Reactive arthritis (Reiter’s syndrome).
Which two diseases is HLA Subtype D4 associated with?
Rheumatoid Arthritis and DM Type I. (1 rheum has 4 walls.)
What are the three signals that induce Natural Killer Cell to kill?
Non-specific signals on cell surfaces. Lack of MHC I. Has an Fc receptor CD16 which allows it to kill cells with bound Ig.
Which cytokines enhance Natural Killer Cell activity?
IL-2 (Proliferation), IL-12, TNF (makes more IL-2 receptors), INF-alpha, INF-beta (both INF are non-specific “kill” signals.)
How does a Natural Killer Cell kill?
Using perforin to create a hole in the membrane followed by a release of Granzyme B.
What mechanism does a B Cell use to improve antigen affinity?
Somatic hypermutation
What role do activated CD4+ T Cells have?
Helper T Cells. They can only help. Seriously, they don’t do anything else.
What are the five different types of mature CD4+ T Cells?
Th1 (Macrophage activator), Th2 (Eosinophil, Mast cell and Plasma cell recruiter), Th17(Neutrophil recruiter), ThFC (B Cell activator, phenotypic switch), Treg (T Cell activation inhibitor)
What is the co-stimulatory signal required for T Cell activation?
B7 on APC surface binds CD28 on T Cell surface.
What is the co-stimulatory signal required for B Cell activation?
CD40 on the B Cell surface bind CD40L on the T helper surface.
What do Th1 cells do?
Secrete INF-gamma which activates macrophages and CTL.
What do Th2 cells do?
Secrete IL-4, IL-5, IL-6 and IL-13 to recruit eosinophils in induce IgE secretion.
Describe the feedback loop between macrophages and T cells.
Th1 cells secrete INF-gamma which stimulate macrophages. Macrophages release IL-12, which stimulate Th1 cells.
What are Th1 cells inhibited by?
IL-4 and IL-10 from Th2 cells.
What are Th2 cells inhibited by?
INF-gamma from Th1 cells.
What do Treg cells do?
When activated they secrete IL-10 and TGF-beta which are anti-inflammatory.
What are the 4 Cs of the Fc region?
C- terminal
Complement binding
Constant
Carbohydrate side chains
What is the function of IgG?
Serum antibody. Crosses placenta. Secondary to IgM. Monomer.
What is the function of IgM?
Serum antibody. Pentamer. Primary response before IgM.
What is the function of IgA?
Mucosa antibody. Does not bind compliement.
What is the function of IgE?
Type I Hypersensitivity. On the surface of mast cells and basophils. Monomer. Antihelmithic.
Which lymph nodes drain the foregut, midgut and hindgut?
Celiac, Superior Mesenteric and Inferior Mesenteric. Just like the arterial supply.
What are the two lymphatic drainage ducts and what do they drain?
Right Lymphatic Duct - Right side of the body above the diaphragm.
Thoracic Duct - Everything else and drains into the subclavian and jugular junction.
Which three proteins regulate serum iron during disease?
Ferritin increases as intracellular stores increase. Hepcidin increases and prevents ferritin from releasing iron. Transferrin is sequestered by macrophages to decrease iron transfer.