X - Immune System and Lymphoid Organs Flashcards
Immediate, nonspecific actions that prevent infections or penetration of the host body
Innate Immunity
Immunity: skin, mucous membranes, neutrophils, leukocytes, NK cells
Innate Immunity
Immunity: HCl, organic acids, defensins, lysozyme, complement, interferons
Innate Immunity
Immunity: acquired gradually by exposure to microorganisms, more specific, slower, B and T cells, antigen presenting cells, memory lymphocytes
Adaptive Immunity
Immunity: involved in both innate and adaptive, coordinate cell activities in the immune response
cytokines
Cytokines: growth and differentiation factors for leukocyte progenitor cells in bone marrow
GM-CSF, M-CSF
Cytokines: stimulation of inflammation and fever
TNF-α, TGF-β, IL-1
Cytokines: stimulation of growth in T lymphocytes and NK cells
IL-12
Cytokines: growth factors for T helper cells and B lymphocytes
IL-2, IL-4
Cytokines: eosinophil proliferation, differentiation and activation
IL-5
Cytokines: activation of macrophages
Interferon-γ, IL-4
Cytokines: inhibition of macrophages and specific adaptive immune responses
IL-10
Cytokines: antiviral activity
Interferon-α, Interferon-β
Cytokines: chemokine for neutrophils and T lymphocytes
IL-8
Large Y-shaped protein produced by B-cells that is used by the immune system to identify and neutralize foreign objects such as bacteria and viruses
antibodies
Recognizes a unique part of the foreign target called an antigen
antibodies
Each tip of the “Y” of the antibody contains a _____ (lock) that is specific for an _____ (key).
paratope, epitope
Antibodies are produced by
plasma cells
Immunoglobulins by Amount
G (75-85%), A (10-15%), M (5-10%), E (0.002%), D (0.001%)
Immunoglobulins: secretory IG, mucosal areas, gut, respiratory tract, prevents colonization by pathogens, saliva, tears, milk
IgA
Immunoglobulins: antigen receptor on B-cells that have not been exposed to antigens, activate basophils and mast cells to produce antimicrobial factors
IgD
Immunoglobulins: binds to allergens and triggers histamine release from mast cells and basophils, protects against parasitic worms
IgE
Immunoglobulins: provides the majority of antibody-based immunity against invading pathogens, only antibody capable of crossing the placenta to give passive immunity to fetus
IgG
Immunoglobulins: expressed on the surface of B-cells (monomer) and in a secreted form (pentamer) with very high avidity, first antibody produced in initial immune response, activates complement
IgM
Hypersensitivity: immediate
type I
Hypersensitivity: anaphylaxis
type I
Hypersensitivity: atopy
type I
Hypersensitivity: IgE
type I
Hypersensitivity: cytotoxic (antibody-dependent)
type II
Hypersensitivity: Goodpasture’s Syndrome
type II
Hypersensitivity: Erythroblastosis Fetalis
type II
Hypersensitivity: IgM, IgG
type II
Hypersensitivity: Immune Complex
type III
Hypersensitivity: SLE
type III
Hypersensitivity: RA
type III
Hypersensitivity: Serum Sickness
type III
Hypersensitivity: IgG, complement
type III
Hypersensitivity: delayed
type IV
Hypersensitivity: chronic transplant rejection
type IV
Hypersensitivity: Multiple Sclerosis
type IV
Hypersensitivity: Mantoux Test
type IV
Hypersensitivity: T-cells
type IV
T lymphocytes: Thymus
100%
T lymphocytes: Bone Marrow
10%
T lymphocytes: Spleen
45%
T lymphocytes: Lymph Nodes
60%
T lymphocytes: Blood
70%
B lymphocytes: Thymus
0%
B lymphocytes: Bone Marrow
90%
B lymphocytes: Spleen
55%
B lymphocytes: Lymph Nodes
40%
B lymphocytes: Blood
30%
Lymphoid Organs: induction of central tolerance preventing autoimmunity
thymus
Lymphoid Organs: one of the largest lymphoid organs (70% of all immune cells), tonsils (palatine, lingual, pharyngeal), Peyer’s patches, appendix
MALT - Mucosa-Associated Lymphoid Tissue
Lymphoid Organs: completely encapsulated, 400-450 in the body, in-line filters of lymph that defend against the spread of microorganisms and tumor cells, facilitate production of plasma cells secreting non-IgA antibodies
lymph nodes
Lymphoid Organs: largest single accumulation of lymphoid tissue, only one involved in the filtration of blood, main site of erythrocyte destruction
spleen
Thymus: cortex/medulla
present (distinct)
Thymus: lymphoid nodules
absent
Thymus: lymhatic vessels
(-) afferents, few efferents
Thymus: unique features
Hassall corpuscles in the medulla, epithelial-reticular cells in cortex and medulla
MALT: cortex/medulla
absent
MALT: lymphoid nodules
present
MALT: lymphatic vessels
(-) afferents, (+) efferents
MALT: unique features
crypts lined by surface mucosa in tonsils, epithelial M cells in mucosa over Peyer patches
Lymph Nodes: cortex/medulla
present
Lymph Nodes: lymphoid nodules
in cortex only
Lymph Nodes: lymphatic vessels
afferents at capsule, efferent at hilum
Lymph Nodes: unique features
thin paracortical region between cortex and medulla, high endothelial venules (HEV)
Spleen: cortex-medulla
absent
Spleen: lymphoid nodules
in white pulp only
Spleen: lymphatic vessels
(-) afferents, efferents in trabeculae
Spleen: unique features
minor white pulp component with central arterioles, major red pulp component (splenic cords of Billroth) with sinusoids (RBC removal)