Intro to Immunity Flashcards
(21 cards)
Characteristics of innate immunity
Responds rapidly to the presence of microorganisms
Not antigen specific, limited diversity
NO MEMORY
Stimulates the adaptive immune system
Hematopoiesis
Differentiation and Cytokines for Monocytes, Neutrophils, Eosinophils and Basophils
Pluripotent SC —> Myeloid SC —> CFU-GM —> (GM-CSF, IL-3) —> Monoblast —> (GM-CSF, M-CSF) —> Monocyte
CFU-GM —> (GM-CSF, IL-3) —> Myeloblast —> (GM-CSF, G-CSF) —> Neutrophil
Myeloid SC —> CFU-GM —> (GM- CSF, IL-3) —> Eosinophilc myeloblast —> (GM-CSF, IL-5) —> Eosinophil
Myeloid SC —> (IL-3) —> basophils myeloblast —> (IL-3, IL-4) —> basophil
Phagocytes (3 cells)
- Neutrophils
Short loves, rapid response - Monocytes/macrophages
Monocytes circulate, become macrophages in tissue, prolonged defense
A. MI classical macrophages induced by innate immune, play role in inflammation
B. M2 alternative macrophages indices by IL-4 and IL-13 play a role in tissue repair and control inflammation “shut it down” - Dendritic Cells
In all cells, Ag processing and presenting
Initiate inflammatory response, initiate adaptive immune response
Neutrophils
Release from BM into blood, migrate for 7-10 hrs, then go to tissue for 3d lifespan
First at site of infection
Highly phagocytic
Pyogenic
Cell surface marker/defined: CD15+ CD16b+
Monocyte/Macrophages
Phagocytes present in bloodstream as monocytes, tissue as macrophage
Respond to sites of inflammation 1-2 days, but survive longer than Neutrophils
Functions:
Garbage collectors (resting)
Ag presenting cells (activated, primed)
Vicious killers (angry)
Cell surface marker: CD14 aka TLR4
Recognizes and binds to LPS
Eosinophils
Differentiate in response to IL-5
Persist in circulation for about 8-12hrs, in tissue 8-12 days
1-6% of WBC
Responsible for combating multi-cellular parasites
Play major role in allergies (atopic disease)
Basophils
Circulatory cell
Non-phagocytic
Releases histamines (along with mast cells)
Atopic disease.
Mast Cells
Tissue resident
A. Tissue
B. Mucosal
Stimulated by direct injury, chemical, alcohols, certain antibiotics, cross linking of IgE receptors, or by activated C’ proteins
Play a key role in inflammatory process
Atopic responses
High affinity for FceR’:CD23
Dendritic Cells
Professional antigen presenting cell (APC) (also with macrophages and B cells)
Constitutively express high levels of class II HLA/MHC and B7 (CD80) (why better than macrophages and B cells)
After capturing Ag, migrate to blood/lymph and circulate to various lymphoid organs where they present Ag to T cells (mature, naive) (in blood born Ag present to spleen)
BRIDGE BETWEEN INNATE AND ADAPTIVE IMMUNITY
Characteristics of Adaptive Immunity
Specificity Diversity Memory Colonial Expansion- increases number of Ag-specific lymphocytes from a small number of naive lymphocytes Specialization Contraction and Homeostasis Non reactivity to self
Hematopoiesis
Differentiation and Cytokines for NK cells, T and B lymphocyte (and Plasma cell)
*Note- this is in adaptive immunity
Multipotent hematopietic SC —> (IL-7) —> Common lymphoid progenitor —> NK cell
Common lymphoid progenitor —> small lymphocyte —> T lymphocyte and B lymphocyte —> plasma cell
Lymphocyte Development
Come from BM, mature in thymus
Mature, naive lymphocyte- not yet activated by Ag
Effector lymphocyte- lymphocyte that have been activated by Ag and can now perform effector function
Memory lymphocyte- immunity
Adaptive Immunity: cel mediated and humoral
Humoral Immunity- Ab neutralize and eradicate EXOgenous Ag
Cell-mediated immunity- eradication of ENDOgenous Ag (i.e. virus, malignant); activate macrophages to kill phagocytosis microbes, kill infected cells and eliminate reservoirs of infection
Effector Cells of Adaptive Immunity
B lymphocyte- neutralization of microbe, phagocytosis, complement activation
Helper T lymphocyte- activation of macrophages, inflammation, activation (proliferation and differentiation of T and B lymphocytes) (helper B cells be fully activated)
Cytotoxic T lymphocyte- killing infected cell (part of tumor surveillance)
Regulatory T lymphocyte- Suppression of immune response (defect can lead to widespread autoimmunity)
Adaptive Cells Identification
B cells: CD19+ CD21+
T cells: CD3+ A. Th cells: CD3+ CD4+ Identified by cytokines secretion profile Th1: IL-2, IFN-y Th2: IL-4, IL-5, IL-13 Th17: IL-17, IL-22
Treg: CD3+, CD4+, CD25+, IL-10, TGF-B
CTL: CD3+ CD8+
Lymphocyte trafficking, migration and recirculation
Highest amount are where surfaces are exposed to the outside world
Highest: Lymph Nodes, Intestines, Lungs
Lymphocytes enter lymphoid tissues from circulation, they follow lymphocyte specific chemokines to different regions of tissue, if not activated by an APC they leave by the efferent Lymphatics and go to next lymphoid tissue, if not activated eventually end up in thoracic duct and back into circulation and start all over again
NK Cells
Innate Immunity (though lymph derived)
Recognize infected, stressed, or malignant cells and kill them
- release granzymes ten performing activating enzymes tat lead to apoptosis of target cell
Activated by IL-12 (macrophages), IL-15, type I IFNs
Activated NKs IFNy: activated macrophages —> IL-12 —> NK —> IFNy —-> macrophage —> IL-12
Adaptive immunity of ADCC: activating receptor of IgG Fc
Cell surface: CD16+, CD56+
Immunologic Memory
Primary immune response
First time Ag is encountered
Generation of memory cells
Takes 1-2 weeks
Secondary immune response Second time Ag encountered Activation of memory cells Stronger, faster, effector response Within a week
Mucosal Immunity
Largest surface area as barrier against the outside world
Has more bacterial DNA than human
Microbiome are part of the innate immune system
Contains very specialized cells and responses for protection
Cutaneous Immunity
Skin is the second largest barrier against the outside world
Has both specialized innate and adaptive cells and responses
Active vs. Passive Immunity
Active immunity- you are exposed to Ag
Have specificity and memory
Passive- given serum (Ab) from immune individual
ONLY has specificity, no memory
