phys review #3 Flashcards
virulence
ability to cause disease
5 total types of leukocytes
3 granulocytes and 2 non-granulocytes
granulocytes
1=neutrophils
2=eosinophils
3=basophils
non granulocytes
1=monocytes
2=lymphocytes
two types of lymphocytes
B cells
-transform into plasma cells that secrete antibodies
T cells
-responsible for cell mediated immunity
lymphoid tissues
-Bone marrow
* Lymph nodes
* Spleen
* Thymus
* Tonsils
* Adenoids
* Appendix
* Brochus-associated lymphoid Tissue
(BALT)
* Peyer’s patches (GALT)
- Gut Associated Lymphoid Tissue
innate immune system
Responses work
immediately upon
exposure
* Exogenous: pathogen-
associated molecular
patterns
* Endogenous: damage-
associated molecular
patterns
adaptive immune system
Customizes defenses for
specific pathogens
- T and B lymphocytes as
well as antibodies
molecules important in innate defense
neutrophils, macrophages, and several plasma proteins
defenses of innate immune system
- Inflammation
- Interferon
- Complement system
- Natural killer cells, Neutrophils,
Macrophages, Dendritic cells,
Eosinophils, and Mast cells
in INNATE IMMUNITY Phagocytes have pattern recognition
receptors (PRR’s) for detecting
threatening agents
Toll like receptors
retinoic acid inducible gene
Nucleotide-binding oligomerization
domain NOD) like receptors
ultimate goal of inflammation
Ultimate goal is to bring phagocytes and
plasma proteins to invaded or injured area
phagocytes with key role in inflammation
neutrophils and monocytes
sequence of innate immunity inflammation response
1= defense by resident tissue (macrophages)
2=Localized vasodilation and increased capillary permeability (histamine release by mast cells)
3=localized edema
4=walling off inflamed area (clotting cascade)
5= emigration of leukocytes
6= leukocyte proliferation
7=Marking of bacteria for destruction by Opsonins
- Opsonins: make bacteria more susceptible to
phagocytosis
8=leukocyte destruction of bacteria
emigration of leukocytes in innate immunity
-Neutrophils and Monocytes (that mature into macrophages)
- Margination – blood borne neutrophils and monocytes stick to
inner endothelial lining of capillaries in affected tissue.
- Diapedesis: Leukocytes start leaving vessels
- Leukocytes find injured area by chemotaxis by sensing things like
cytokines
cytokines
Protein signal molecules – help regulate immune
responses
*affect distant locations- do not interact directly with antigens
what are lost cells replaced by in nonregenrative tissuee?
scar tissue
chronic inflammation can lead to illness
Alzheimer’s Disease, atherosclerosis and coronary
artery disease, asthma, rheumatoid arthritis,
obesity, diabetes, and possibly cancer
interferon
Chemical (cytokine or cytokines) released
nonspecifically from any cell infected by a virus
*whistle blower
anti cancer effects of interferons
Enhances effects of NK cells and Tc-cells.
* Slows cell division and suppresses tumor growth
Natural killer (NK) cells
-Naturally occurring lymphocyte-like cells
- Nonspecifically destroy virus-infected cells and
cancer cells
- Antibodies enhance their activity, but they are
non-specific.
- Directly lyse cell membranes upon first
exposure to these cells.
complement system (innate immunity)
-Nonspecific response
- Forms membrane attack complexes that punch holes
in victim cells
- Composed of plasma proteins that are produced by
the liver and circulate in inactive form.
- Originally named “complement” because it
complements the actions of antibodies
complement system of innate immunity activated in 2 ways
1.Primary mechanism activated by antibodies to kill
foreign cells. Adaptive response – classic complement pathway
- Also activated by exposure to carbohydrate chains
present on surfaces of microorganisms but not on
human cells. – Alternate complement pathway.
membrane attack complex sequence of events
C1 is activated → activates C4 → activates C2
→ activates C3 → activates C5 through C9
two classes of antibody immunity
1- antibody mediated, or humoral immunity
2-cell mediated immunity
define anitbody
mmunoglobulin produced by B
lymphocyte against a specific antigen
antibody mediated or humoral immunity (part of adaptive immunity)
Involves production of antibodies by B lymphocyte derivatives known as plasma
cells
cell mediated immunity
-Involves production of activated T
lymphocytes
- Directly attack unwanted cells
origins of T cells vs B cells
-Whether they are a T cell or B cell depends on site of
final differentiation and maturation of the original cell in the lineage
- B cells differentiate and mature in the bone marrow.
- T cells are processed in the Thymus (hence their name)
thymosin
-hormone important in maintaining the T-cell lineage
* Enhances the proliferation of new T cells in
peripheral lymphoid tissue
antigen
-Large, foreign, unique molecule
- Induces an immune response against itself
- In general, the more complex a molecule is, the greater its antigenicity
T-dependent vs T-independent antigens
-T-independent: stimulate production of
antibodies from B cells without help of a T-cells
- T-dependent: typically protein antigens, require the help of a helper T-cell to
stimulate production of antibodies.
BCRs cause B cells to bind with antigens, once they do this what happens
-most b cells differentiate into active plasma cells
-other b cells become dormant
-1-2% become regulatory B cells
function of plasma cells
Produce antibodies that combine with a specific kind of antigen
gamma globulins or immunoglobulins
antibodies in the blood
immunoglobulin subclasses
IgM
-initial antibody produced by the adaptive immune
system in response to a foreign pathogen
* Secreted in early stages of plasma cell response
IgG
-Most abundant immunoglobulin in blood
* Produced in large amounts when body is exposed to
same antigen
IgE
-Helps protect against parasitic worms
* Antibody mediator for common allergic responses
IgA
-Found in secretions of digestive, respiratory, and
genitourinary systems;
also in milk and tears
IgD
Present on surface of many B cells, function is
uncertain
describe composition of antibody
Composed of four interlinked
polypeptide chains
- Two long, heavy chains and two
short, light chains
* Properties of tail portion
determine functional
properties of the antibody
* Identical antigen-binding
fragments (Fab) at tip of each
arm (unique for each different
antibody)
* Tail is the constant (Fc) region.
Within each subclass the tails
are identical.
how can antibodies physically hinder antigens?
By neutralization, they combine with toxins and prevent harmful chemicals from interacting with susceptible cells
- Can bind to foreign cells by agglutination
how do antibodies enhance activities of other defense systems?
- activating complement system
-enhancing phagocytosis
-stimulating killer NK cells
clonal selection theory
-diverse b cells are produced during fetal development
-When antigen arrives, the naïve
lymphocytes (clones) that have
the correct BCR (B-cell
receptors) are activated
(selected).
* First antibody produced is IgM,
which are inserted into the B
cells membrane.
- These bind to the antigen, &
specific Ab produced
active immunity
-“self-generated”
- Results from exposure to an antigen
passive immunity
-“borrowed immunity”
- Results from transfer of preformed antibodies
- Can provide immediate protection or bolster
resistance
- Example of passive immunity is transfer of IgG
antibodies from mother to fetus
natural vs artificial active immunity
Naturally acquired active immunity
* Natural exposure to antigen
- Artificially acquired active immunity
* Response to vaccination
