Immunotherapy - Dra. Viterbo Flashcards
3 main components of Innate Immune System
- MECHANICAL COMPONENTS (skin/epidermis, mucus)
- BIOCHEMICAL COMPONENTS (antimicrobial peptides and proteins, complement, enzymes, interferons, acidic pH, free radicals)
- CELLULAR COMPONENTS (neutrophils, macrophage, NK, NKT)
Complement components enhance macrophage and neutrophil phagocytosis by?
By acting as opsonins (C3b) and chemoattractants (C3a, C5a) to recruit immune cells and ultimately lead to pathogen lysis via generation of MAC
3 mediators of influx of neutrophils and monocytes toward inflammation site
All released by activated endothelial cells and immune cells at inflam site:
- IL-8 and CXCL 8 (chemoattractant cytokines/chemokines)
- MCP-1, CCL-2
- MIP-1a, CCL-3
Mediates egress of immune cells from BV into the inflammatory site
Adhesive interactions between cell surface receptors (L-selectin, integrin) on immune cells and ligands (sialyl-Lewis x, ICAM-1)
These include TLRs, NLRs., scavenger receptors, mannose receptors and LPS-binding CHON that recognize PAMPs
Pattern Recognition Receptors
These stimulate the release of proinflammatory cytokines, chemokines, and interferons upon recognition of PAMPS
PRRs
3 cells that secrete IFN-y and IL-17
NK cells
NKT cells
gamma-delta T cells
Activates resident tissue macrophages and dendritic cells
IFN-y
Recruits neutrophils
IL-17
Cells that are able to recognize and destroy virus infected
normal cells as well as tumor cells without prior stimulation.
NK cells
Receptors that deliver inhibitory signals to NK cells to prevent them from killing normal cells
Killer Cell Ig-like Receptors on NK cells surface (specific for MHC 1 molecules)
How do NK cells kill target cells?
By releasing cytotoxic granules (perforins, granzymes)
Cells that recognize microbial lipid
antigens presented by a CD1 and have been implicated in host defense against
microbial agents, autoimmune diseases, and tumors.
NKT cells
Unique characteristics of Adaptive Immune System
- Respond to a variety of antigens in a specific manner
- Can discriminate between self and non self
- Responds to a previously encountered antigen
Effectors of humoral immunity
Antibodies
Effectors of cell-mediated immunity
T lymphocytes
What are the APCs that induce adaptive immunity?
Dendritic cells
Macrophages
B lymphocytes
Explain how APCs function.
APCs phagocytose/endocytose pathogens or protein antigens > generate peptides after enzymatic digestion > loaded to class 1 or 2 MHC > presented to cell surface TCR
MHC recognized by CD8 T cells
MHC Class I
MHC recognized by CD4 T cells
MHC Class II
2 signals for T cell activation
- TCR + peptide-bound MHC molecules
2. Ligation (binding) of costimulatory molecules on APC to their respective ligands
Regulates activation of T cells
CTLA-4 (T-lymphocyte associated antigen)
CTLA-4 is mobilized to the cells surface after CD28 is engaged to CD80 or CD86. CTLA-4 displaces CD28 resulting in suppression of T-cell activation and proliferation
A recombinant
humanized antibody that binds CTLA-4 and prevents
its association with CD80/CD86.
ipilimumab, anti-CTLA-4 antibody
AE associated with ipilimumab
autoimmune toxicity
lymphocytes develop and learn to recognize self and non-self
antigens in the?
Thymus
A process by which T cells bind with high affinity
to self antigens in the thymus undergo apoptosis.
Negative selection
Strengthen activation signals between APCs and T lymphocyte
CD40/CD40L and ICAM-1/LFA-1 interactions
A process by which T lymphocytes recognize foreign antigens in the
presence of self MHC molecules and are retained and expanded for export to the periphery
Positive selection
Produced by TH1 cells
IFN-y
IL-2
IL-12
How do TH1 cells induce cell-mediated
immunity?
by activation of macrophages, cytotoxic T cells (CTLs),
and NK cells
Produced by TH2 cells
IL-4 IL-5 IL-6 IL-10 IL-13
How do TH2 cells induce cell-mediated
immunity?
by inducing B-cell proliferation
and differentiation into antibody-secreting plasma cells
Produced by TH2 cells to inhibit cytokine production by TH1 cells
via the down-regulation of MHC expression by APCs
IL-10
Produced by TH1 cells inhibits the proliferation of TH2 cells.
IFN-y
Causes the elaboration of TH2 cytokines for the production of neutralizing and opsonic antibodies
extracellular bacteria
Elicit the production of TH1 cytokines
Intracellullar bacteria
Subsets of helper T cells
TH1 and TH2
Produces transforming growth factor-β (TGF-β),
whose numerous functions include down-regulation of proliferation
and differentiation of T lymphocytes
TH3
A population of CD4 T cells that is essential for preventing
autoimmunity and allergy as well as maintaining homeostasis and
tolerance to self antigens.
regulatory T cell (Treg) T cell
Involves retro-translocation of antigens from
the endosome to the cytosol for peptide generation in the proteosome
and is thought to be useful in generating effective immune
responses against infected host cells that are incapable of priming
T lymphocytes
Cross-presentation
Ways by which CD8 induce target cell death
- Granzymes
- Perforins
- Fas-FasL apoptosis pathway
The repertoire of antigen specificities by T cells is
genetically determined and arises from?
T-cell receptor gene rearrangement
The specificities of B cells arise from ?
immunoglobulin
gene rearrangement
A matrure B cell binds the antigen, internalizes and processes it, and presents its peptide—bound to class II MHC—to?
CD4 helper cells
CD4 helper cells secrete ___ to stimulate B-cell differentiation into memory B cells and antibody-secreting plasma cells
IL-4
IL-5
How do antiodies mediate their functions?
Antibodies mediate their functions by acting as opsonins to
enhance phagocytosis and cellular cytotoxicity and by activating
complement to elicit an inflammatory response and induce bacterial
lysis.
A purified adenosine deaminase from a bovine source used in the management of Severe Combined Immunodeficiency Syndrome
Pegademase
first hormonal agents
recognized as having lympholytic properties
Glucocorticoids (corticosteroids)
Contact
hypersensitivity mediated by T DTH cells is usually
abrogated by?
glucocorticoid therapy
ID Immunosuppressive Agent used: Acquired factor XIII antibodies
Cyclophosphamide plus factor XIII
ID Immunosuppressive Agent used: Acute glomerulonephritis
Prednisone, mercaptopurine, cyclophosphamide
ID Immunosuppressive Agent used: Liver Organ transplantation
Cyclosporine, prednisone, azathioprine, tacrolimus, sirolimus
ID Immunosuppressive Agent used: Bone Marrow Organ transplantation
Cyclosporine, cyclophosphamide, prednisone, methotrexate, ALG
ID Immunosuppressive Agent used: Prevention of cell proliferation
Coronary stents
Sirolimus (impregnated stent)
ID Immunosuppressive Agent used: Prevention of cell proliferation Neovascular macular degeneration
Ranibizumab (labeled), bevacizumab (off-label)
first-line immunosuppressive therapy for both solid
organ and hematopoietic stem cell transplant recipients
Glucocorticoids (corticosteroids)
Peptide antibiotic that appears to act
at an early stage in the antigen receptor-induced differentiation of
T cells and blocks their activation
Cyclosporine (cyclosporin A, CSA)
MOA of Cyclosporine (cyclosporin A, CSA)
Cyclosporine binds to cyclophilin , a member of a class of intracellular proteins called immunophilins.
Cyclosporine and cyclophilin form a complex that
inhibits the cytoplasmic phosphatase, calcineurin, which is necessary
for the activation of a T-cell-specific transcription factor. This
transcription factor, NF-AT, is involved in the synthesis of interleukins
(eg, IL-2) by activated T cells.
ophthalmic
solution of this drug is now available for severe dry eye syndrome and ocular graft-versus-host disease
Cyclosporine (cyclosporin A, CSA)
Inhaled form of this drug is being
investigated for use in lung transplantation.
Cyclosporine (cyclosporin A, CSA)
This immunosuppressive agent causes nephrotoxicity, hypertension,
hyperglycemia, liver dysfunction, hyperkalemia, altered
mental status, seizures, and hirsutism.
Cyclosporine (cyclosporin A, CSA)
This immunosuppressive agent causes increased incidence
of lymphoma and other cancers (Kaposi’s sarcoma, skin
cancer)
Cyclosporine (cyclosporin A, CSA)
This immunosuppressive agent induces
TGF-β, which promotes tumor invasion and metastasis.
Cyclosporine (cyclosporin A, CSA)
sole immunosuppressant for cadaveric transplantation
of the kidney, pancreas, and liver, and it has proved extremely
useful in cardiac transplantation as well
Cyclosporine (cyclosporin A, CSA)
A standard prophylactic regimen to
prevent graft-versus-host disease after allogeneic stem cell transplantation
Cyclosporine (cyclosporin A, CSA) + methotrexate
an immunosuppressant macrolide antibiotic
produced by Streptomyces tsukubaensis
Tacrolimus (FK 506)
Cyclosporine (cyclosporin A, CSA) and Tacrolimus (FK 506) bind to which enzymes?
cytoplasmic peptidylprolyl isomerases
Calcineurin Inhibitors
Cyclosporine (cyclosporin A, CSA) and Tacrolimus (FK 506)
While cyclosporine binds to cyclophilin,
tacrolimus binds to the?
immunophilin FK-binding protein
FKBP
now considered a standard prophylactic agent
(usually in combination with methotrexate or mycophenolate
mofetil) for graft-versus-host disease
Tacrolimus (FK 506)
Cyclosporine and Tacrolimus are primarily metabolized by the ____ enzyme system in the
liver with resultant multiple drug interactions
P450 3A
Its
toxic effects include nephrotoxicity,
neurotoxicity, hyperglycemia, hypertension, hyperkalemia,
and gastrointestinal complaints.
Tacrolimus (FK 506)