Immunology Flashcards
Type 1 T helper (Th1) cells produce which cytokines and role?
Type 1 T helper (Th1) cells produce interferon-gamma, interleukin-2, and tumour necrosis factor-beta, which activate macrophages and are responsible for cell-mediated immunity and phagocyte-dependent protective responses.
Type 2 T helper (Th2) cells produce which cytokines and role?
type 2 Th (Th2) cells produce IL-4, IL-5, IL-10, and IL-13, which are responsible for strong antibody production, eosinophil activation, and inhibition of several macrophage functions, thus providing phagocyte-independent protective responses.
What does interleukin 3 do?
IL-3: stimulates the differentiation of multipotent hematopoietic stem cells into myeloid progenitor cells.
What does interleukin 3 do?
IL-3: stimulates the differentiation of multipotent hematopoietic stem cells into myeloid progenitor cells.
Which cells express CD4
T helper cells
monocytes,macrophages, anddendritic cells
CD4 is a single-chain molecule composed of four immunoglobulin-like domains and binds to a conserved site on the β2 domain of the class II MHC molecule well away from the site where the TCR binds
Prognosis of tree nut and peanut allergies
20% peanut allergies resolve
9% tree nut allergies resolve
20% get worse with time
Leukocyte adhesion Disorder 1
Clinical features and Ix
LAD I is an autosomal recessive disorder caused by a mutation in the integrin beta-2 gene which codes for the CD18 subunit. It classically presents with omphalitis and delayed cord separation. Blood results will reveal leucocytosis. Flow cytometry to confirm the diagnosis will reveal absent or low CD18 and absent CD11.
Features of CVID
CVID is a disorder with
Low levels of most/all Ig classes
Lack of B lymphocytes or plasma cells capable of producing antibodies
Frequent bacterial infections
With CVID, patients are prone to recurrent infections: URTI/LRTI (H influenzae, S pneumoniae, M catarrhalis, S aureus, PCP, M pneumoniae), OM, sinusitis, diarrhea and malabsorption from Giardia lamblia infection (Rx metronidazole).
C3 deficiency
C3 deficiency would predispose to serious pyogenic (pus-forming) infections
Terminal pathway (C5-C9) deficiency
Terminal pathway (C5-C9) deficiency results in lack of MAC formation, predisposing to Neisserial infections.
Features of phagocytic disorder
recurrent fungal, opportunistic, pyogenic, etc. infections
Encapsulated organisms
(YESSomeNastyKillersHavePrettyBigCapsules)
Yersinia pestis
Escherichia coli
meningeal strains only
Salmonella typhi
Streptococcus pneumoniae andStreptococcus pyogenes
Neisseria meningitidis
Klebsiella pneumoniae
Haemophilus influenzaetype B(B polysaccharide)
Pseudomonas aeruginosa
Bordetella pertussisandBacillus anthracis(contains poly D-glutamate capsule)
Cryptococcus neoformans
only encapsulated fungal pathogen
Causes of Leukocyte Adhesion Deficiency I-III
LAD I is caused by CD18 deficiency or defects.
LAD II is caused by the absence of fucosylated carbohydrate ligands which leads to defective rolling of hematopoietic cells.
LAD III is caused by a defect in integrin activation.
Note: Delayed separation of the umbilical cord is seen in LAD I and LAD III but is NOT a feature of LAD II.
Most common trigger for erythema multiforme
HSV infection
Cytokines produced by Th1 and Th2
Th1 - IFN gamma, IL2
Th2 - IL 4, 5, 6, 13, 21
