Croatia - Immunology Flashcards
What cytokine(s) do CD4+ Th1 lymphocytes produce?
- IFN-gamma
- IL-2
- TNF-alpha
What cytokine(s) do CD4+ Th17 lymphocytes produce?
- IL-17 (A&F)
- IL-21
- IL-22
What cytokine(s) do CD4+ Th2 lymphocytes produce?
IL-4, IL-5, IL-9, IL-13
What cytokine(s) do CD4+ regulatory T cells produce?
IL-10
TGF-beta
IL-35
What cytokine(s) do(es) Th1 cells produce?
IFN-gamma
IL-2
TNF-alpha
What is the the primary target of Th1 lymphocytes?
cell-mediated/cyotoxic responses against viruses or intracellular pathogens
Against which type of pathogens are Th2 lymphocytes particularly effective?
extracellular pathogens (large pathogens), helps to stimulate antibody responses
Against which type of pathogens are Th17 lymphocytes particularly effective?
fungi
What is the function of T-reg cells?
switches off responses that are no longer required, maintains tolerance
What cells do Th2 lymphocytes stimulate? Through what cytokine(s)?
B cells
IL-4, IL-5, IL-9, IL-13
Why are some dogs more susceptible to intracellular pathogens such as leishmania based on their immune system function?
A more susceptible dog may have a Th2 mediated response, and since antibodies can’t get inside the macrophage where the organism is. Animals who appropriately activate a Th1 response will be able to kill the organisms.
What type of lymphocytes are primarily involved in the pathogenesis of allergy?
Th2 lymphocytes –> stimulate B lymphocytes –> become plasma cells –> secrete IgE
What cytokine produced by Th2 lymphocytes is chemotactic for eosinophils?
IL-5
What cytokine(s) produced by Th2 lymphocytes is/are important in B cell stimulation?
IL-4, IL-5, IL-9, IL-13
What are components of the innate immunity of the skin?
- dry environment
- keratin
- microflora
- epidermal barrier
- antimicrobial peptides
- secretions: enzymes, lipids, polyreactive IgA, complement
What are pathogen-associated molecular patterns?
highly conserved microbial structures – not easily altered by microbes to avoid detection
e.g. sugars, proteins, lipids, nucleic acid motifs
What type of antigenic molecules do dendritic cells recognize? Via what receptors?
pathogen-associated molecular patterns
microorganism-associated molecular patterns
damage-associated molecular patterns
VIA pattern recognition receptors (toll-like receptors)
What are NOD-like receptors?
nucleotide-binding oligomerization domain receptors
intracytoplasmic toll-like receptors of dendritic cells
activates caspase-1
converts prol-IL-1beta to active IL-1beta (proinflammatory)
What are the three signals required for activation of a naive Th0 lymphocyte?
1) recognition of antigenic peptide-MHC II complex by the T-cell receptor/recognition of MHC II by the T cell CD4 molecule
2) other surface interactions
3) cytokines produced by the APC binding to receptors on the T cell membrane
What cytokine produced by Th2 helper cells is chemotactic for mast cells?
IL-4
What is the mechanism for which exposure to parasites can be protective for development of allergy?
increases the production of T regulatory cells
T/F: Immune complex formation is a normal mechanism for antigen clearance from the body.
True
What are possible reasons that a serology test could give a false negative?
- test sensitivity was too low to detect antibody
- antibody response has been suppressed or not yet developed (neonatal, immunodeficient, immunosuppressed)
- testing too soon after antigen exposure
What are possible reasons that a serology test could give a false positive?
- exposure to a cross-reactive antigen or vaccine
- persistent antibody post exposure
- technical problem with assay
T/F: Normal animals can have a positive ANA.
True (should be a low titer) – due to physiologic autoantibodies trying to clean up cellular debris
What is a typical ANA result for an animal with SLE?
Should be a high titer
T/F: SLE is the only autoimmune condition with a positive ANA.
False - low-titred ANA common in many chronic inflammatory, infectious & neoplastic diseases; SLE should have a high titer
-30-50% of dogs with autoimmune diseases such as AIHA, IMPA, PF may have a high-titered ANA
What is different between the IgE measured in a serology test vs. an IDAT?
IDAT measures mast-cell bound IgE at the tissue of interest, serology measures circulating allergen-specific IgE
What does IL-4 do? What cell(s) produce it?
Th2 cells & mast cells produce
- stimulates B cell growth and differentiation: enhances IgG and IgE responses, promotes MHC II expression
- activates mast cells
- activates macrophages (alternative - M2 - activation)
- suppresses Th17 cells
- suppresses Th1 activation (antagonized IFN-gamma and IL-2)
What does IL-13 do? What cell(s) produce it?
Th2 cells produce
- stimulates B cell growth
- suppresses macrophage functions
- similar function to IL-4 because its receptor shares a common alpha chain with the IL-4R
- required for optimal induction of IgE
What does IL-5 do? What cell(s) produce it?
Th2 cells & mast cells produce
- stimulates B cell growth
- promotes differentiation of activated B cells into plasma cells
- stimulates IgM and IgG production
- enhances IL-4-induced IgE production
- stimulates IgA production in mucosal B cells
- mobilizes and activates eosinophils
What does IL-9 do? What cell(s) produce it?
Th2 cells produce
-T-cell growth factor
What are the functions of Th17 cells?
- mediate inflammation
- B-cell helpers
What does IL-17 do? What cell(s) produce it?
Th17 cells produce
- protective response to extracellular bacteria
- assist in clearance of fungi
- recruits granulocytes
- stimulates production of GM-CSF => neutrophilia
- promotes recruitment and survival of macrophages
- stimulates production of proinflammatory cytokines (IL-1, IL-6, GM-CSF, TNF-alpha) and antibacterial peptides from many cell types
What is the function of IFN-gamma?
has some antiviral activity
- activates cells through the JAK-STAT pathway
- promotes macrophage activation
- suppresses Th2 cells
- enhances NK cell activity
What cells produce IFN-gamma?
Th1 cells
CD8+ cytotoxic T cells
NK cells
(lesser amounts from antigen-presenting cells, B cells, and natural killer T cells)
What cell(s) produce IL-2?
CD4+ Th1 cells
-some also produced by CD8+ T cells, NK T cells, dendritic cells, mast cells
What is the function of IL-2?
- potent stimulator of T cell proliferation
- stimulates IFN-gamma production
- stimulates antibody production by B cells
- enhances cytotoxicity of CD8+ and NK cells
- promotes T cell differentiation into Th1 and Th2 subset
- inhibits Th17 differentiation
- activates macrophages: induces TNF production, enhances IFN-gamma activation
