Lecture 4: Innate Immunity Flashcards
what are the key cells of the innate immune response?
neutrophils, eosinophils, basophils, mast cells
what are the key cells involved in the early adaptive immune response?
NK, NKT, ILC, monocytes, macrophages, dendritic cells
what are the keys cells involved in the primary adaptive response?
T and B cells
what are the key cells in the secondary adaptive immune response?
T and B cells
the innate and early adaptive immune responses are considered together as the ____ response
innate
the primary and secondary adaptive immune responses are referred to as the ___ response
adaptive
what are the 2 main roles of the innate immunity?
- first line of defence to slow infection until adaptive response can take over
- mechanism for directing the adaptive immune response (introduce inflammation, activate dendritic cells, produce cytokines that shape the adaptive immune response)
what is the response time of the innate immune system?
minutes to hours
what is the response time of the adaptive immune response?
days
describe the level of specificty the innate immune response has
specific for molecules and molecular patterns that are typically found on pathogens and recognize the molecules typically produced by dead/damaged cells
describe the level of diversity of the innate immune response
a limited number of cnserved, germ-line-encoded receptors
describe the level of memory responses of the innate immune response
some (has been observed in invertebrate innate responses and mouse & human NK cells)
describe how well the innate immune response can differentiate between self and nonself
perfectly bc they only recognize conserved features of pathogens
what are the soluble compenents of blood from the innate immune response?
many antimicrobial peptides, proteins, and other mediators
what are the major cell types of the innate immune response?
phagocytes (monocytes, macrophages, neutrophils), NK cells, leukocytes, epithelial and endothelial cellls
describe the specificity of the adaptive immune response
highly specific, discriminates between tiny differences in molecular structure of microbial and non-microbial molecules
describe the level of diversity of the adaptive immune resposne
highly diverse; very large number of receptors arising from genetic recombination or receptors genes in each person
describe the memory responses of the adaptive immune responses
persistent memory with faster response of greater magnitude on subsequent exposure
describe the level of self vs nonself discrimination in the adaptive immune response
very good, but there are occaisional failures which result in auti-immune diseases
what are the soluble components of the blood of the adaptive immune response?
antibodies and cytokines
what are the major cell types of the adaptive immune response?
T cells, B cells, and antigen presenting cells
list 2 anatomic barriers to infection
- skin
2. mucus membranes
t/f the skin (epidermis and dermis) is a mechanical barrier impermeable to most infectious agents
t
what is the epidermis?
several layers of epithelial cells where the outermost layer contains dead cells filled with keratin (a waterproofing proetin)
what are mucus membranes?
epithelium lining the interior surfaces of the body that secrete mucus to trap foreign particles to prevent them from adhereing to epithelial cells
what happens to the foreign particles trapped in the mucus of mucus membranes?
expelled by the mechanical action of cilia or by sneezing, coughing, or swallowing
what is the function of commensal (good) gut bacteria?
inhibit the growth of pathogenic bacteria; produce protective peptides
what are the special feature of the mucus membranes in the GI tract that prevent infection?
enzymes and normal flora
what are the special features of the mucus membranes of the respiratory tract that help prevent infection?
mucus, mechanical action of cilia, macrophages in alveoli
what are the special features of the mucus membranes in the urogenital tract?
mucus, fluid flow, aggregation of urinary mucins, low pH, antimicrobial peptides, proteins in vaginal secretions
what are 3 physiologic and chemical barriers that the body’s points of entry have to prevent infection?
- acidic pH of lactic acid and fatty acids present in sweat and sebaceous secretions
- acidic pH of the stomach
- body temperatire and fever response
antimicrobial (host defence) peptides are short ____ (cationic or anionic) peptides that are usually ____ amino acids in length
cationic; 29-35
antimicrobial (host defence) peptides are ____ (hydrophillic or hydrophobic)
amphipathic (both hydrophillic and hydrophobic parts)
antimicrobial (host defence) peptides are ____ expressed
constitutively
antimicrobial host defence peptides are active against what types of pathogens?
bacteria, fungi, enveloped viruses
antimicrobial host defence peptides bind to ____ charged (positive or negative) microbial structures and membranes via what type of interactions?
negative; electrostatic
give an example of part of a pathogen that an antimicrobial host defence peptide might bind to
LPS
how do antimicrobial host defense peptides work to stop pathogens?
disrupt the microbial membrane integrity by introducing bulky hydrophobic amino acids & internalized peptides inhibit DNA/RNA/protein synthesis and activate antimicrobial enzymes
how long does it take antimicrobial host defence enzymes to kill pathogens?
rapidly (minutes to hours)
give an example of antimicrobial host defence peptides
defensins (alpha and beta)
defensins are secreted by ___ cells and other ___ cells and are stored in ___
intestinal epithelial Paneth cells and other epithelial cells; stored in netrophil granules
location of defensins can be found where?
skin, mucosal epithelia (mouth, intestine, nasal/respiratory tract, urogenital tract)
how do defensins have antimicrobial activity?
disrupt membranes of bacteria, fungi, protazoan parasite and viruses. Have additional toxic effects intracellularly
defensins are able to kill ___ and disable ___
bacteria; viruses
how does streptococcus pneumoniae get into the body?
airways
how does E.coli get into the body?
GI tract
how does HIV get into the body?
urogenital
how does staph. aureus get into teh body?
cuts in the skin
how does West Nile get into the body?
mosquito bites
after penetrating epithelial barriers, pathogens are detected by what 3 innate immune components?
- soluble innate immune recognition elements
- phagocytic and other cells
- pattern recognition receptors like toll-like receptors
what are soluble innate immune recognition elements that recognize pathogens?
mannose-binding lectin, C-reactive proteins, complement, interferons
what are phagocytes and other cells that act as innate immune resposnes against pathogens?
neutrophils, macrophages, dendritic cells, NK cells
pattern recognition receptors (PRRs) like toll-like receptors (TLRs) can be found on what innate immune cells?
macrophages, mast cells, dendritic cells that function as sentinel cells
what is the acute phase response?
systemic, generic response to infection for containment and mobilization of immune cells and effector proteins
acute phase response creates a ____ response to slow pathogen growth and help immune reactions
fever
in the acute phase response, the local acute inflammation sends what cytokines to the hypothalamus?
IL-1, TNF-alpha, IL-6
in the acute phase response, the local acute inflammation sends what cytokines to the liver?
IL-1, TNF-a, IL-6, LIF, OSM
in the acute phase response, the local acute inflammation sends what cytokines to the bone marrow?
IL-6, TNF-a
what is the effect of cytokines being sent to teh hypothalamus in the acute phase response?
produce prostaglandins to create the fever; also sends ACTH via the pituitary to teh adrenal cortex which will send corticosteroids to the liver to release acute phase proteins
what is the effect of cytokines being sent to the liver in the acute phase response?
acute phase proteins are made; C-reactive protein (CRP), serum amyloid A (SAA), fibronogen, manose-binding protein, complement compoenents
what is the effect of cytokines being sent to the bone marrow in the acute phase response?
causes increased CSF by stromal cells and macrophages and induced leukocytosis (making more WBCs)
what are the 3 major pro-inflammatory cytokines that cause vascular permeability, systemic and local effects?
IL-1, IL-6, TNF-alpha
what is the anti-inflammatory cytokine?
IL-10
what cells produce IL-1?
monocytes, macrophages, dendritic cells, keratinocytes, epithelial cells, vascular endothelial cells
what cells does IL-1 act on?
lymphocytes, bone marrow, vascular endothelium, liver, hypothalamus
what is the immune response fo IL-1?
enhances inflammatory reponse, promotes neutrophil production, activates and increases vascular permeability, induces acute pahse response, fever
what is the immune response of IL-6?
regulates activity, promotes hematopeiesis (neutrophils), activates and increases vascular permiability, induces acute phase response, fever
what is the immune response of TNF-a?
activates inflammatatory response, activates and increases vascular permeability, fluid loss, local blood clotting, induces acute phase response, fever, cytotoxic for many tumor cells
what cells produce IL-6?
monocytes, macrophages, dendritic cells, NK cells, epithelial cells, vascular endothelial cells