Lecture 1: Overview of Immune Responses Flashcards
Cellular innate components
Phagocytes (macrophages, neutrophils), dendritic cells, NK cells, Monocytes, Mast Cells, Eosinophils, Basophils
PMN (neutrophil)
Mononuclear phagocytes (monocyte & macrophages)
Granulocytes: neutrophil, eosinophil, basophil, mast cells
Steps in functional response of phagocytes
chemokine: recruitment from blood to site of infection
receptor: recognition and activation by microbes
Form phagosome - ingest microbe via phagocytosis
Destruction of ingested microbes
Function of cytokines
Regulate growth and differentiation of all immune cells
Activate the effector functions of lymphocytes/phagocytes
Reactivity to self for innate and/or adaptive immunity?
None
Humoral innate components
Complements, APPs, cytokines, chemokines
T or F: Innate immune system exists before infection
True
Cells communicate through
Direct cell-cell contact and through interactions involving cytokines and chemokines
Macrophage maturation stages
Monocytes enter the blood circulation and migrate into tissues, where they further mature into macrophages, especially during inflammation
Each cytokine acts via
Specific signaling receptor expressed on target cell
Phagocytes include
Neutrophils and macrophages
Macrophages produced where and stimulated by
Produced in bone marrow, stimulated by M-CSF
Adaptive immunity
Longer to develop
Highly specific
Shows memory
How does innate immune system respond after repeated exposures to Ag
Same way every time
Phagocytes
Ability to ingest and digest microbes (innate)
Dendritic cell function
Potent stimulators of T cells to induce adaptive immunity
Can divide to myeloid DCs and plasmacytoid DCs
Also include langerhans cells
Mast cell location/function
Common at sites in the body exposed to external environment (skin)
Close proximity to blood vessels
Can release mediators to modulate behavior of nearby cells
Neutrophils are produced where and production is stimulated by what
In the bone marrow, stimulated by granulocyte colony stimulating factor (G-CSF)
Response to intracellular infections
Cytotoxic T cells
NK T cells
Macrophages/phagocytes
Innate immune cells include
Phagocytes
Natural killer cells
Blood components
Specificity of innate immunity is for
Ags shared by groups of related microbes and molecules produced by damaged host cells
Neutrophil life span
Circulate in blood for few hours to few days
What is an antibody
Protein produced by immune system when it detects antigens
Activated phagocytes secrete
Cytokines or promote or regulate immune responses
Diversity of innate immunity
Limited- germline encoded
Specificity of adaptive immunity is for
Microbial and non-microbial antigens
Response to extracellular infections
Polymorphonuclear cells PMNs (Neutrophils/phagocytes)
Antibodies
Complement
Cytokines
Cell signaling molecules that aid cell to cell communication in immune response
Innate immune system recognizes
Common Ags belonging to groups of related microbes.
Do not distinguish fine differences between microbes
T cell receptors recognize
Linear amino acid sequence
What mediates the earliest phases of inflammatory reactions
Neutrophils (polymorphonuclear leukocytes)
Dendritic cells do what and function in what type of immunity
Comprise a diverse group of antigen presenting cells.
Function in innate immunity
Macrophages function in what type of immunity
Both innate and adaptive immunity. They can assume specialized phenotypes depending on the tissue in which they reside
Acute phase proteins APP
Group of blood proteins whose plasma concentraions change in response to tissue injury, acute infections, burns or inflammation (Part of Innate immune system)
What is an epitope
A portion of an antigen to which the antibody binds
Can be multiple on one antigen
Mast cell, basophils and eosinophils type of immunity
Innate and adaptive immune responses
Protect against helminthes and reactions causing allergic disease
Have cytoplasmic granules filled with various inflammatory and antimicrobial mediators
Innate immunite
Rapid
Causes acute inflammation
Some specificity for Ag
No memory
Immunogens are
Antigens that can stimulate an immune response
Haptens are
Small antigens that can bind Abs but do not initiate immune response
Antimicrobial peptides are
Small peptides which target pathogenic organsims
What are antigens
Substances that induce an immune response
i.e. proteins, carbs, lipids and nucleic acids
Diversity of adaptive immunity
Very diverse- receptors produced by somatic recombination of gene elements
Complement system
A system of plasma proteins that enhances the ability of Abs and phagocytic cells to clear pathogens (innate immune system)
Chemokines
Subfamily of cytokines secreted by immune cells to induce chemotaxis (movement) in nearby cells
