L1: Overview of Immune Responses Flashcards
define immunity
set of cooperative defense mechanisms which provide protection from various infectious diseases
define immunopathology
an immune response against microbes can cause tissue injury
aka collateral damage
define antigens
non-infectious foreign substances that can elicit an immune response
can also be called immunogens
define antibodies
a protein produced by the immune system when it detects antigens
define epitope
also called antigenic determination
a portion of an ag molecule to which an antibody binds
list properties of adaptive immunity
specific diversity memory clonal expansion specialization contraction - homeostasis nonreactivity to self
T cell receptors recognize
linear amino acid sequences
all immunogens are Ags but not
all Ags are immunogens
some very small ags = haptens, can bind abs but don’t elicit an immune response
innate system overview
first line of defense against infection works rapidly gives rise to an acute inflammation has some specificity for Ag that is pre-existing has no memory
adaptive system overview
slower takes longer to develop highly specific shows memory -- remembers ags that have been encountered and works faster when it is a known ag
components of innate immunity
phagocytes, NK cells – cellular immunity
blood components – humoral immunity
cellular and chemical barriers (skin, mucous)
antimicrobial peptides
small peptides which target pathogenic microorganisms ranging from viruses to parasites
complement system
sys. of plasma proteins that enhance the ability of abs and phagocytic cells to clear pathogens from host
acute phase proteins
APPs
large group of blood proteins whose plasma conc. changes in response to tissue injury, acute infections, burns or inflammation
cytokines
cell signaling molecules that aid in cell to cell communication in immune response
chemokines
a subfamily of cytokines
secreted by immune cells to induce chemotaxis
mvt of nearby cells
phagocytes
immune cells that have the ability to ingest and digest microbes
includes neutrophils and macrophages
activated phagocytes secret cytokines to promote immune responses
components of adaptive immunity
cell/chemical barriers
blood proteins – abs, cytokines
cells – b and t lymphocytes
_____ immune system is the decision maker
innate
eval the invader and then provides instructions for the adaptive system
functions of cytokines
regulate growth and differentiation
activate the effector functions of lymphocytes and phagocytes
most innate cells are in _____ and ______ when ag is contacted. list the cells
in blood, deployed upon contact
neutrophil eosinophil basophil mast cell monocyte -- macrophage dendritic cells NK cells
steps in functional responses of phagocytes
- recruitment of cells to site
- recognition and activation by microbes
- ingestion by phagocytosis
- destruction of ingested microbes
polymorphonuclear leukocytes
neutrophils — poly lobed nucleus
most abundant wbc in blood
thus mediates earliest phases of inflammation
neutrophil production
produced in bone marrow arise via G-CSF factor produced every day circulate in blood few hours enter tissue for 1-2 days then die
M-theta
resident tissue macrophages
monocytes residing in tissue
monocyte production
arise in bone marrow
driven by M-CSF factor
resident macrophages
heterogeneous population of immune cells that fulfill tissue-specific and niche-specific functions
functions: homeostasis, immune surveillance of tissues, response to infection, resolution of inflammation
dendritic cells are of _____ immunity
innate
dendritic cell comprise a diverse group of professional ______ cells.
APCs
prof. antigen presenting cells
dendritic cells are potent stimulators of ? to induce ?
of T cells
induce adaptive immunity
dendritic cells are broadly divided into ?
myeloid - mDCs
plasmacytoid - pDCs
mDCs are derived from ? and differentiated from peripheral ?
monocytes
peripheral blood mononuclear cells
Langerhan’s cells are a subpopulation of what type of cell, residing where?
DCs
epidermis
these cells play roles in innate and adaptive immune responses
mast cells
mast cell function
protect against helminthes and reactions that cause allergic diseases
mast cells share what common feature with various inflammatory and antimicrobial mediators?
cytoplasmic granules
mast cell location
common at sites in the body that are exposed to external environments
such as skin
in these locations they are found in close proximity to BVs
what does mast cell location allow them to do ?
can regulate vascular permeability and effector cell recruitment
can modulate activity by releasing mediators
what are the two types of adaptive immunity
humoral and cellular immunity
interactions between what cells are critical to the development of specific immunity?
between T and B cells
and
between T cells and APCs
maturation of T cells
occurs in thymus
when a mature T cell is ag stimulated it gives rise to cellular immunity
maturation of B cells
occurs in bone marrow
gives rise to humoral immunity
what is humoral immunity
immunity that involves production of soluble molecules - immunoglobulins
what mediates humoral immunity
by abs in the blood and mucosal secretions
which are produced by B cells
function of Abs
recognize Ags
neutralize the infectivity of microbes
target microbes for elimination thus effectors
principal defense for extracell microbes
what controls cellular immunity
by responses of T cells
cellular immunity function
mediates host defense against intracellular microbes
such as viruses and bacteria - where they are inaccessible to abs
cmi functions to kill the infected host cells
T helper cells
help b cells to make effective abs
b cells secrete ?
abs
to prevent infections and eliminate extracell microbes
in cellular immunity T helper cells activate ? to do what ?
resident macrophages
to kill phagocytized microbes or cytotoxic t cells to directly destroy infected cells
adaptive - specificity
ensures that the immune response to a microbe is selective to that microbe
adaptive - diversity
enables the immune sys to respond to a large variety of ags
adaptive - memory
increases the ability to combat repeat infections by the same microbe
adaptive - clonal expansion
increases the number of ag specific lymphocytes to keep pace w/ microbes
adaptive - specialization
generates responses that are optimal for defense against different types of microbes
adaptive - contraction and homeostasis
allows the immune sys to recover from one response so that it can effectively respond to a newly encountered ag
adaptive - nonreactivity to self
prevents injury to the host during responses to foreign ags
clonal selection hypothesis
ag-specific clones of lymphocytes develop before and independent of exposure to ag
post elimination of microbe, a few activated lymphocytes will become ? for memory
become ag-specific memory cells
which can survive for years
memory cells are more effective in combat than naïve cells
memory cells are more _____ than naïve cells. and will respond ______ and more _______.
numerous
faster
effectively
define active immunity
conferred by a host in response to a microbe or microbial ag
define passive immunity
is conferred by adoptive transfer of abs or t cells specific for the microbe
only _____ immune responses generate immunologic memory
active
B lymphocytes
recognize soluble ags and develop into ab secreting cells
t helper lymphocytes
recognize ags on surfaces of APCs
secrete cytokines to stim dif. mechanisms of immunity and inflammation
cytotoxic t lymphocytes
recognize ags on infected cells and kill these cells
regulatory t cells
suppress and prevent immune response
ex. to self
