Ch 6 Flashcards
Type 1 hypersensitivity mediated by which cell?
Mast cells
Type II hypersensitivity is mediated by which mediator?
Antibody
What is an example of Type II hypersensitivity?
Mismatched blood transfusion haemolysis
The process of which humans recognise self vs non self cells is called?
Self tolerance
The leading cause of death in HIV patients is
Opportunistic TB
What is the definition of ‘Window Period of HIV infection’?
The time between HIV infection and seroconversion (usually 2-3 weeks post infection)
Immunotherapy: how does this treatment achieve its effect?
Stimulates IgG to combine with antigens
Which cells are involved in rejection of an organ transplant?
T cells
What is the most useful marker in determining severity of HIV infection?
CD4+ counts
What is the role of HAART therapy in HIV?
Slows progression of disease
What are the components of the innate immune system?
- Epithelial barrier eg skin
- Monocytes/macrophages
- Phagocytes and dendritic cells, NK cells
- Complement
5.plasma cells
What is the function of dendritic cells?
They phagocytose antigens and present the peptides to be recognised by T cells
What is the difference between TOLL like receptors vs NOD like receptors (location, function)?
- TOLL: located on plasma membrane, detect microbial molecules
- NOD: in the cytosol, detects molecules associated with necrotic cells, microbes
What is the role of TOLL like receptors?
Recruit leukocytes
Which pathways do TLR are able to recruit leukocytes?
- NF-KB (cytokine secretion and exp of adhesion molecules)
- IRF (Interferon regulatory factors) - produce Type 1 interferon/cytokines
What is the role of RIG-like receptors?
Detect viral nucleic acids–> produce antiviral cytokines (IFN A)
What is an interferonopathy?
Excessive production of IFN, leads to systemic inflammation (STING: stimulator of interferon genes)
Flare up associated with gout is an example of which receptor activation?
NOD like receptor
What is the function of NK cells? 2
- Detect IgG coated targets and destroy them
- Secrete cytokines eg IFN G to activate macrophages
What receptor does NK cells express?
CD16 (an IgG receptor)
How is NK cells regulated (self tolerance)? 2
- Type I MHC molecules on healthy cells
- Interleukins
Which interleukin activates NK cells to kill?
IL-12
Which interleukins stimulate proliferation of NK cells? 2
IL2 and IL15
What are the 2 types of adaptive immunity?
- Humoral immunity (extra cellular, B cell)
- Cellular immunity (Intracellular, T cells)
What are the components of adaptive immunity?
Lymphocytes and their cytokines
Antibodies/immunoglobulins
What is the role of Helper T cells?
Activate B cells to make antibodies and activate other leukocytes eg phagocytes
CD8+ cells recognise antigens presented by MHC ___ cells
I
CD4+ cells respond to antigen presented on MHC ___cells
II
What proteins do at cells express to assist their functional responses?
CD3, CD4, CD8, CD28
What is the role of CD4+ T cells?
Secrete cytokines to assist macrophages and B lymphocytes to fight infection
What is the role of CD8+ T cells?
Cytotoxic: they directly kill host cells
What Ig (2) do all B cells express to bind antigen?
IgM and IgD
Active B cells that produce antibodies are called ___
Plasma cells
What are the primary lymphoid organs? 2
Thymus (T cells)
Bone marrow (B cells)
What are the secondary lymphoid organs?
LN
Spleen
Mucosal and cutaneous lymphoid tissues
The primary co stimulators (2) for T cells that is recognised by CD28 receptor?
CD80 and CD86
CD4+ T cells differentiate to effector cells known as (2)
Th1 and Th2
What do Th1 secrete?
IFN G
What does Th2 secrete?
IL-4
What is the role of Th2 cells?
Secrete IL-4 to turn B cells into IgE secreting plasma cells
What is the mechanism of Immediate Type I hypersensitivity?
IgE antibody –> mast cell release of vasoactive amines
What are examples of Type I hypersensitivity?
Allergies
Asthma
Anaphylaxis
What is the mechanism of Type II Hypersensitivity?
Antibody mediated: production of IgG and IgM which binds to cell/tissues
This gets phagocytosed/lysis by activated complement
What are 2 examples of Type II hypersensitivity?
- Haemolytic anemia
- Good pastures syndrome
What is Type III hypersensitivity?
Deposition of antibody complexes onto target tissues
What is an example for Type III hypersensitivity? 3
- lupus
- Glomerulonephritis
- Serum sickness
Fibrinoid necrosis is likely associated with (type of hypersensitivity)
III
What is Type VI hypersensitivity?
Activated T cell lymphocytes: release of cytokines (CD4+) and T cell mediated cytotoxicity (CD8+)
Oedema and/or granuloma formation is part of (Type of Hypersensitivity)
VI
What are 4 examples of Type VI hypersensitivity?
- Type I diabetes
- Contact dermatitis
- TB
- Multiple sclerosis
The propensity to develop a hypersensitivity reaction is called?
Atopy
Graves disease is an example of (hypersensitivity type)
Type II
Myasthenia gravis is (type of hypersensitivity)
Type II
Post streptococcal glomerulonephritis is an example of (hypersensitivity)?
Type III
Type VI hypersensitivity involved which T cell?
CD4+ T cell
Delayed hypersensitivity is also known as
Type VI
Type VI hypersensitivity: which Th is involved?
Th1 (secrete IL-12) -primary
Th17 (IL-17 and IL-22)
What is the role of IL-12 in Type VI hypersensitivity?
To amplify Th1 response
Immune tests: diagnosis of fungal/bacterial or coccidioidomycosis
Complement fixation (IgM/IgG to detect titers of certain antigens)