Exam 4 Flashcards
innate immunity
fights the same every time it is exposed to a pathogen
adaptive immunity
changes and becomes better every time it fights an infection
immunological memory
ex: chicken pox/small pox
exterior defenses
- skin (thick)
- secretions (lysosomes, mucus)
- mechanical effects (respiratory elevator)
- normal flora (attack bacteria)
lysosyme
enzyme, most produced, that breaks sugar and peptidoglycan bond
respiratory elevator
mucus coats the walls of the bronchial tubes
- cilia are synchronized, beat in time with one another
- particles are moved 1-3 cm/hr out of the lower resp. tract
inside defenses
phagocytic cells
splenic macrophage
recycles old blood
phagocyctic
take it in and break it down
monocyte/macrophage
get rid of big old cells
- circulating and resident
polymorphonuclear cell (neutrophil)
- first response (primary circulating phagocyte)
- non-dividing
- short lived
- no mitochondria
what do PMNs do
float around in blood stream and eat things when they touch it
monocyte
when it is circulating/before it decides to eat
macrophage
when it decides to do the eating
blood
monocyte
liver
kupffer cells
kidney
intraglomerular mesangial cells
lung
alveolar macrophage
connective tissue
histiocyte
brain
microglia
spleen
sinus macrophage
lymph node
sinus macrophage
PAMPs
pathogen activated molecular pattern
toll-like receptor
surface proteins recognize macromolecules and trigger phagocytic response when attaches to target (responds to PAMP and triggers pathway signals)
oxidative burst
- reactive compounds
- anti-microbial
(lysozyme)
(lactoferrin) - myeloperoxidase
(halogen compounds)
opsonin
binds to cells and makes them susceptible to phagocytosis
C3b
an opsonin
complement
part of blood that works with the immune system to remove dead cells
pro-inflammatory molecules
C3a and C5a
formation of the membrane attack complex (MAC)
C5b, C6-C9
three C3 pathways
- inflammation
- opsonization (makes a thing easy to phagocytose)
- cytolysis (membrane attack)
what releases pro-inflammatory compounds
mast cells
classical complement pathway
antibodies bind to microbe
- C1 binds to antibody
- cleavage of C2, C4 produces C2a and C4b, leads to activation of C3
- cleavage of C3
(the three C3 pathways)
alternative complement pathway
- factors B, D, P are complement proteins
- interact with lipid carbohydrate complex on microbial surface
- act directly on C3
lectin complement pathway
- mannose binding lectin (MBL)
- mannose found in many bacterial cell surface structures
- activates C2 and C4, C2a and C4b activate C3
- MBP takes place of C1 antibody complex
membrane attack complex
- amphipathic structure
- 1 hydrophobic face
- 1 hydrophilic face
acute inflammation chemical mediators
mast cells
acute inflammation
- phagocyte chemotaxis
- permeabilization of the vascular wall
- fluid flow into tissue
- diapedesis
recruitment by MO
- pro inflammatory cytokines
- neutrophil chemotaxis
- vascular permeabilization
acute phase proteins
- high levels in blood during inflammation
- opsonin
- pro inflammatory signal
anti-viral activity of IFN
- infection with virus stimulates IFN alpha/beta
- IFN receptor on adjacent cells
- make surrounding cells less susceptible to infection
- paracrine response (localized)
NK cells
find cells in body without surface antigens and kill them
- release chemicals causing cell to kill itself or induce apoptosis
apoptosis
- programmed cell death
doesn’t induce inflammation
eosinophils
- anti-helminthic
- C3b receptor
- IgE receptor
- triggers release of granule content
Process of inflammation in tissue
microbe -> mast cell -> mediators -> acute inflammatory response
evasion
some bacteria are resistant to MAC formation
- gram - pathogens with elongated LPS molecules and other liposaccharides on surface
- Streptococci have a peptidase that cleaves C5a (inhibits histamine release) and M protein that inhibits opsonization
- Nematode cuticle resistant to chemical damage
immunity
specific immune response to antigens
antibodies
the proteins in blood that bind specifically to antigens
- proteins consisting of constant and variable regions
- basic shape of a Y
- two heavy chains and two light chains
active immunity
body makes antibodies to a given antigen
antigen
thing on the microbe that is recognized by the immune system
- thing antibody binds to
- foreign substances bound by antibodies
passive immunity
antibodies are passed from mother to child, confer immunity
acquired immunity
- specific response of body to particular pathogen
- only occurs naturally on exposure to the particular invader
- may be artificially induced by immunization
- contrast with innate immunity, which is general response to invasive organisms
two arms of the immune system
- humoral
- cellular
humoral arm
- antibody mediated
- makes antibodies
- antigens stimulate production of antibodies by B cells
- antibodies bind to antigens, inactivate toxins, opsonize bacteria
cellular arm
- cell-mediated
- activates cells
- cytolytic T-lymphocytes are activated
-helper T-cells activate macrophages - active against helminths, protozoa, viral infections
- rejection of tissue transplant
- driven by cytokine production
epitope
parts of antigens that are recognized on the surface
constant region
- what the type is
determine antibody type - IgG, IgA, IgM, IgE, IgD
Ig = immunoglobulin
variable region
- where does it stick and what does it do
- adapted to bind to specific antigens (form antigen binding site)
hypervariable regions (CDRs)
complementary determining regions in heavy and light chains
- more variability in heavy chains
IgM
pentameric on B-cell surface, first secreted
IgG
monomeric primary circulating antibody, produced by most plasma cells after class (isotype) switch
IgA (sIgA)
dimer secreted into mucosal surfaces
IgE
monomer binds to mast cells, histamine release (allergy)
IgD
on B-cell surface and circulates, function unknown
agglutination
blood cells or bacteria clump together
neutralization
blocking the entry of a pathogen into a cell
antigen-antibody binding
- agglutination
- opsonization
- neutralization
- antibody dependent cell-mediated cytotoxicity (ADCC)
- complement activation (inflammation)
inflammation and antibody
- IgE mediated
- mast cell Fc receptor
- mediates specificity of mast cell response
- allergy
ADCC
- bound antibodies recognized by activated macrophages and eosinophils
- respond by producing perforin and lytic enzymes
- mechanism to attack larger parasites
B-cells
derived from bone marrow
- matured b cells are in lymphoid tissues
- have IgM and IgD on surface
activated b-cells become ___
plasma cells
plasma cells produce ____
antibodies
antibody genes are produced by…
somatic cell genetic recombination
V(D)J recombination (Tonegawa)
joins segments in a single b-cell to form an antibody
(each b-cell makes one antibody)
result: 100 million unique antibody-antigen interactions
what results in clonal selection?
Ab-Ag interactions
- the b-cell that has IgM, IgD on the surface that binds Ag divides, differentiates
- result: lots of antibodies to specific Ab
different Igs arise by ___
isotype switching
mature b-cells produce mainly ___
IgG
Memory cells are produced by ___
activation
secondary response is …
faster, larger, mainly IgG
T-Cells
effectors of the cellular arm of the immune system
- interact with, direct function of other effector cells
CSF
colony stimulating factors
TNF
tumor necrosis factors
pre t-cells
produced from hematopoietic stem cells in bone marrow
- migrate to the thymus, where they mature into t-cells
where do t-cells end up?
end up in lymphatic tissue and blood
CD4
helper T-cells
CD8
cytotoxic T cells
Ag binding sends signals to…
T-cell (activation)
MHC class 1
on every cell
- CD8 TCD on CTL
- endogenous
MHC class 2
on professional APC
- CD4 TCR on Th cell
- exogenous
T-cells can only “see” Ag presented by…
antigen presenting cell (APC)
APC presents Aga after…
intracellular processing on MHC
- professional uses class 2
- active T helper
- other cells use class 1
- activate CTL
helper t-cells
central role in progression of immune response
Th1
Th1 cells activate cell-mediated immunity (IL-2, IFN-y)
Th2
Th2 cells activate humoral immunity (IL-2, IL-4)
IL-2
autocrine growth factor
CTL
cytotoxic T-cell
cytotoxic T-cell
- can be activated by class 1 MHC
- dont require stimulation by “professional” antigen presenting cells
cytolytic enzymes
- perforin
- similar to macrophage
helper t-cells cannot recognize…
Ag presented in class 1 MHC
what might be required for production of Ab
t-cell activation
