intro to immunology Flashcards
Immunity:
resistance to infectious disease
Immune system:
collection of cells, tissues, and molecules that mediate resistance to infections
Immune response:
coordinated reaction of the immune system to infectious microbes
Immunology:
study of the immune system, including its responses to microbial pathogens anddamaged tissues and its role in disease
roles in the IS
infection defense
tumor defense
injure cells/induce pathogenic inflamm
recognize/respond to introduced tissues and proteins
def. immunity and vaccines
immune response can cause what pathologies
immune repsones can be barriers to?
Innate Immune Response components
- Epithelial barriers
- Phagocytes and Sentinel cells.
..Neutrophils
..Monocytes / Macrophages
..Dendritic cells - Complement
- Natural Killer (NK) cells.
- IFN α/β (Type I interferons)
innate immunity response time frame
Acts immediately or within hours.
specificity of the innate IS, genetics?
Is not antigen specific- Instead, recognizes “Pathogen-associated molecular patterns” (PAMPs)that are shared by many different microbes, and Damage-associated molecular patterns (DAMPs).
Genes encoding receptors that recognize PAMPs are present in the germ line. They do not undergo somatic recombination or hyper mutation.
clonal expansion in the innate response
no
self reactive or memory function of the innate
neither
adaptive response components
- Humoral response ..Antibodies produced by B cells - Cell-mediated response ..Cytotoxic T cells (CTLs) ..Helper T cells
adaptive response time
days to weeks
adaptive response specificity, genetics?
Is highly antigen-specific- Recognizes specific epitopes on
specific proteins of specific pathogens.
Functional genes encoding antigen receptors are not present in the germ
line. Instead, functional antigen receptor genes are generated by somatic recombination and mutation of germ line genes during maturation of B cells and T cells (prior to exposure to any antigens).
clonal proliferation/selection
Clonal selection and proliferation of B and T lymphocytes specific for particular antigens following exposure to those antigens.
memory/self reactive of the adaptive response
possesses memory
not self reactive
types of adpative immunity
humoral and cellular
humoral immunity responds to? effector cell? secretes? effect?
responds to extracellualr microbes
b lymphocytes are the effectors
will secrete Ab
Ab bind the Ag and prevent infection/eliminate extracellualr microbes
cell-mediated immunity
responds to phago microbes of microbes that have infected cells
responders are Th/ Tc
Th will respond to phago microbes with Ag presentation cauing them to produce activate the immune response/ eliminate phago microbes
Tc will kill infected cells
Properties of adaptive immune responses
specifity diversity memory clonal expansion specialization contraction and homestasis non reactive to self
specify functional significance
diversity functional significance
memory functional significance
clonal expansion functional significance
specialization functional significance
contraction and homeostasis functional significance
non-reactivity to self functional significance
Clonal selection
naive lymphocytes with diverse receptors arise in lymph organs and encounter Ag and only those that react to it will expand
Ag specific response will then occur
Primary and secondary immune responses
enhanced response with additional exposure to same Ag/microbe, based on memory cells
primary: slower/less
seconday: fast and more
types of lymphocytes
b and t
b lymphocyte functions
mediate humoral immunity
t lymphocyte function
mediate cellular immunity
Ag presenting cells/ function
macrophages
dendritic cells
follicular dendritic cells
b cells
capture Ag for presentation to lymphocytes
dendritic cells function
initiate t cell response
macrophages active phase
effector phase of cell-mediated immunity
follicular dendritic cell function
display Ag to B lymphocytes for humoral immunity
effector cells/ functions
t lymphocytes
macrophages
granulocytes
eliminate Ag
t lymphocyes functions
activate phagocytes/ kill infected cells or supress immune response (Ts)
macrophages function
killing of microbes/ phagocytosis
granulocytes function
kill microbes
b lymphocyte Ag recognition/ response
surface Ab bind Ag
dif to plasma cell and produce Ab to be released which can neutralize microbe, induce phago and complement
Th cell action
Ag presented to Th by a presenting cell
produces cytokines that can activate phago, inflam, and prolif of b and t lymphocytes
Tc action
will recognize cell expressing Ag on it surface and kill it
regulatory t lymphocyte actions
suppress immune responses to prevent self damage
Maturation of lymphocytes
both begin in bone marrow but only B is completed here, T is completed at the thymus
both are naive and migrate to lymphoid tissue where they can survey the lymph for Ag, spleen to survey blood, or mucosal surfaces
naive t lymphocyte:
migration
frequency of cells responsive to particular Ag
effector responses
peripheral Ln
very low
none
activated t lymphocyte:
migration
frequency of cells responsive to particular Ag
effector responses
inflammed tissues
high
cytokine secertion/ cytotoxic
memory t lymphocyte:
migration
frequency of cells responsive to particular Ag
effector responses
some at LN others at the mucosa and inflamed tissues
low
none
naive b lymphocyte:
Ig type
affinty to produced Ig
effector functions
IgM and IgD
relatively low
none
active b lymphocyte:
Ig type
affinty to produced Ig
effector functions
IgG,IgA,IgE
increased
Ab secretion
memory b lymphocyte:
Ig type
affinty to produced Ig
effector functions
IgG, IgA, IgE
relatively high
none
lymphocytes at the LN
B and T here
B at the periphery in follicles and T in the cortex, both survey lymph for Ag
After lymphocytes activated by antigen, B & T cells migrate towards each other & meet at edge of follicle.
There, helper T cells interact with and help B cells differentiate into antibody producing cells.
Early innate immune response, if passed?
Innate defensive mechanisms to keep out microbes if defensive barriers are crossed: inflammation and antiviral mechanisms
Phases of adaptive immune response diagrammed
active immunity
microbial Ag present, infection occurs followed by recovery
possesses both specificity and memory
passive immunity
serum with Ab presented to uninfected indiviual, infection occurs followed by recovery
does have specifity, but no memory.
