Innate and Adaptive Immunity 1 Flashcards
immune system
the tissues, cells, and molecules involved in adaptive immunity, or sometimes the totality of host defense mechanisms
innate immune system
the component of the immune system in animals that is genetically determined and is nonspecific, as distinguished from the adaptive immune system
elements of the innate immune system include (6)
mucous secretions complement proteins
certain white blood cells (neutrophils, macrophages, and dendritic cells)
Adaptive immune system
the component of the vertebrate immune system involving lymphocytes (B cells and T cells) containing a small number of genetically encoded proteins that combine to produce an enormous variety of proteins capable of recognizing and deactivating specific antigens
categories of disease causing microorganisms (4)
viruses
bacteria
pathogenic fungi
parasites
The early phases of the host response to infection depend on — —
innate immunity
The early phases of the host response to infection depend on innate immunity in which a variety of innate resistance mechanisms (2)
recognize and respond to the presence of a pathogen
innate immunity utilizes invariant receptors that recognize
common features of pathogens
Innate immunity is present in all individuals at all times, does not increase with repeated
exposure to a given pathogen
innate immunity discriminates between
a group of related pathogens
The adaptive immune response or adaptive immunity is the response of
antigen-specific lymphocytes to antigen, including the development of immunological memory
Adaptive immune responses are generated by
clonal selection of lymphocytes
Adaptive immune responses are distinct from innate and nonadaptive phases of immunity, which are not mediated by
clonal selection of antigen-specific lymphocytes
Adaptive immune responses are also known as
acquired immune responses
In many cases adaptive immune responses lead to immunologic memory which confers
lifelong protective immunity to reinfection by the same pathogen
innate immunity (immediate, 0-4 hours) (3)
infection
recognition by preformed, non specific and beadily specific effectors
removal of infectious agent
early induced innate response (early, 4-96 hours) (4)
infection
recognition of microbial-associated molecular patterns
inflammation recruitment and activation of effector cells
removal of infectious agent
adaptive immune response (late: >96 hours) (5)
infection transport of antigen to lymphoid organs recognition by naive B and T cells clonal expansion and differentiation of effector cells removal of infectious agent
major cells of the innate immunity include (5)
macrophages granulocytes mast cells dendritic cells natural killer (NK) cells
activated function of macrophages (2)
phagocytosis and activation of bactericidal mechanisms
antigen presentation
where are macrophages present?
all tissues
macrophages are the mature form of
monocytes
macrophages orchestrate immune responses and help induce
inflammation
what do macrophages secrete
signaling proteins that activate other immune cells
macrophages are the general — cells in the body
scavenger
what receptors for microbial constituents are present on macrophages? (6)
mannose recept LPS receptor TLR2 TLR4 gluten receptor scavenger receptor
activated function of neutrophils
phagocytosis and activation of bactericidal mechanisms
most numerous immune cell
neutrophils
neutrophils. are most important in
innate immune responses
eosinophil active function
killing of antibody coated parasites
activated function of basophils
unknown
basophils and eosinophils release granules when activated that contain a
variety of enzymes and toxic proteins
basophils are thought to be chiefly involved in
defense against parasites
activated function of mast cells
release of granules containing histamine and active agents
activated function of dendritic cells (2)
antigen uptake in peripheral sites
antigen presentation
dendritic cells degrade pathogens they take up, but their main role is not clearance, but rather to
present antigens to the T lymphocytes
natural killer cell is part of — immunity, it is not specific for —
innate, antigen
what do nk cells release?
lytic granules that kill some virus infected cells
how does infection trigger an immune response? (3)
bacteria trigger macrophages to release cytokines and chemokines
vasodilation and increased vascular permeability cause redness, heat and swelling
inflammatory cells migrate into tissue, releasing inflammatory mediators that cause pain
how do dendritic cells initiate adaptive immune responses (3)
immature dendritic cells reside in peripheral tissues
dendritic cells migrate via lymphatic vessels to regional lymph nodes
mature dendritic cells active naive T cells in lymphoid organs such as lymph nodes
Infectious agents must overcome — host defenses in order to establish an infection
innate
infectious disease is generally quite
infrequent
the epithelial (mucosal) surfaces form the first barrier against most microorganisms and have — — mechanisms if injured
rapid repair
MALT
mucosal-associated lymphoid tissue
MALT can be classified beside (4)
Gut-associated (GALT)
Bronchus-associated (BALT)
Nasal-associated (NALT)
Tear-duct-associated lymphoid tissue (TALT)
how else can MALT be classified?
organized (O-MALT) if it forms an identifiable mass (tonsil)
diffuse (D-MALT)
MALT can be further divided into (2)
inductive sites
effector sites
Inductive Sites:
Organized MALT structures and the mucosa-draining lymph nodes
Effector Sites:
Mucosal epithelia and underlying lamina propia containing stromal cells and associated connective tissue stroma
Mucosal epithelial cells provide (2)
a physical barrier and innate immunity
Goblet cells secrete mucus that forms a
dense, protective covering for the entire epithelium
Peristalsis in the GI tract moves food and potential pathogens, while ciliated epithelial cells in the upper respiratory tract capture inhaled potential pathogenic particles and expel them through their
beating motion
Paneth cells produce
anti-microbial peptides
intraepithelial lymphocytes contain various
T-cells
which mucosal immune system are the best studied?
gut-associated lymphatic tissue (GALT)
Mucosal tissues are constantly exposed to microbes and are frequently
infected
Mucosal immunity is —, rather than reactive, constantly making — immune responses against microbes
proactive
adaptive
Mucosal immune system generally does not activate inflammation. In the gut, inflammation likely would — the infection rather than clear it out
exacerbate
Mucosal immune responses do little damage to the tissue involved and are part of the normal process and contribute to the frequency with which
gut epithelial cells are turned over and replaced
length of skin
2 m^2
25-30 m^2 if calculation includes invaginations due to hair follicles
length of lungs
140 m^2
length of GI tract
200 m^2
types of mucosal surfaces (2)
type 1
type 2
Type I mucosal surfaces are covered by
simple epithelium
type 1 mucosal surfaces express a
simple polymeric Ig receptor (pIgR) that allows dimeric IgA to access the lumen
examples of type 1 (3)
intestine
lungs
uterus
type 2 mucosal surface is covered by a
stratified squamous epithelium
stratified squamous epithelium of type 2 mucosa provides a
physical protective barrier activities that are important for the host
examples of type 2 (2)
oral cavity
vaginal cavity
mode of transmission of the airway (2)
inhaled droplet
spores
mode of transmission of the GI tract
contaminated food or water
mode of transmission of the reproductive tract
physical contact
COVID 19 spike protein
ligand that binds to human ACE2 protein, expressed in human epithelial airways. results in membrane fusion and entry into the host
Ab to the spike protein prevents
interaction between the virus and receptor
infection and stages of response (4)
adherence to epithelium
local infection, penetration of epithelium local infection of tissues
adaptive immunity
bactericidal agents produced and released by phagocytes (6)
acidification toxic oxygen derived products toxic nitrogen oxides antimicrobial peptides enzymes competitors
three types of mucosal epithelial cells in host defense
villus type (GI tract) ciliated epithelium (nose, URT) exocrine glands (ductal cells)
outer gut mucous layer (3)
non-sterile
degrading mucous
microbes utilize mucin carbohydrates for energy
inner mucus layer (3)
relatively sterile
rich in antimicrobial molecules
outer mucus layer vs inner mucus layer
outer is thinner, where the bacteria reside
inner is thicker and free of bacteria
