11.10 immune system Flashcards
blood is a
connective tissue
albumin
important plasma protein that regulates osmotic pressure and transports stuff. MOST abundant in blood
innate immunity
nonspecific and first line of defense.
- skin with acid
- antimicrobial proteins like lysosomes
- cilia: in lungs
- gastric juice: stomach
- symbiotic bacteria: outcompetes orgs
2nd line of defense
also nonspecific all WBCs
leukocytes
all WBC’s originate from stem cell in bone marrow but some multiply + become non-naive in the lymph node
relative amounts of cells in blood
erythrocytes»_space;> platelets >
leukocytes.
neutrophils (macrophage)
non specific
- – fxn in destruction of pathogens in infected tissues; drawn to infected/injured
areas by chemicals via process of chemotaxis; slip between endothelial cells of capillary
(into tissue) via diapedesis. Neutral to acidic/basic dyes, and have a distinctive 4-5 lobed nucleus
monocytes (macrophage)
circulate in blood until they move into tissues (diapedesis) where they develop into macrophages (which phagocytize cell debris + pathogens, are a professional antigen- presenting cell). Alternatively, can give rise to dendritic cells
Eosinophils
– work collectively to surround and destroy multicellular parasites. Stain in acid dyes (not phagocytic)
Dendritic Cells
responsible for the ingestion of pathogens and stimulates acquired immunity (“main function as APCs that activates T-lymphocytes”). Can have myeloid (from monocyte) or lymphoid lineage.
Mast Cells
fxn in allergic response, inflammatory response (histamine release),
anaphylaxis. Reside in tissues.
basophiles
release histamines for inflammatory response. Stain in basic dyes. Found circulating in
blood; recruited into tissue when needed. Contain histamine, heparin [works as an anticoagulant],
and several cytokines.
phagocytes
leukocytes (WBC’s) engulf pathogens by phagocytosis (neutrophils and monocytes
[enlarge into macrophages]). Other WBCs called natural killer cells (NK cells) attack abnormal body cells-tumors or pathogen-infected.
pus
After neutrophils and macrophages engulf necrotic tissue + bacteria they die; these dead
leukocytes + necrotic tissue + tissue fluid = pus
- Complement system:
~30 complement proteins; circulate in inactive state activated by substance on microbe surfaces activation results in cascade help attract phagocytes to foreign cells and help destroy by promoting cell lysis.
Interferons:
secreted by cells invaded by viruses/pathogens that stimulate neighboring cells to produce
proteins defend against virus.
Inflammatory response:
- histamine released by mast cells causes vasodilation
- increase in blood supply to area, increase temp to stimulate WBS and kill pathogens
- phagocytes attracted to injury to complement eat bad stuff
- complement: helps phagocytes engulf cells, release more histamine through basophiles
causative agents of inflammatory response
prostaglandins and lymphokines, basophiles
how do pathogens evade
system. Some bacteria have an outer capsule
preventing molecular recognition & phagocytosis, others can resist breakdown within lysosomes
specific defense
develops after body has been attacked
Major histocompatibility complex:
self and non self differentiation. is a collection of glycoprotein that exists on membranes of all body cells.
Antigen presentation. Involved in transplant/graft rejection: foreign
MHC triggers T-cell attack
lymphocytes
specific immunity
- response, leukocytes that originate in bone marrow but
concentrate in lymphatic tissues such as lymph nodes, thymus gland, and spleen.
** these are B cells
B cells (produce antibodies):
originates and mature (?) in bone marrow (B cell for bone); response
to antigens (foreign particles). Plasma membrane of B cells contains antigen receptor-antibodies. The
soluble form of the receptor is a free antibody (immunoglobulins).
antibodies
are proteins; specific to each antigen, five classes (IgA, IgD, IgE, IgG, IgM. Y-shaped
protein w/ constant and variable regions). Note that disulfide bonds connect the heavy chains
to each other and to light chains.
IgG
antibody. most abundant in serum and can cross placenta to protect fetus
IgA
breast milk antibody. found in secretions
IgM
1st antibodies produced after initial exposure to antigen
IgE
allergy antibody
antibody remembering
G is gross so most, A is abundant in secretion, M is mono for first exposure, E is for sneeze, D is for Diminished (not many)
IgD
not many of this
fetus immunity
the protection of fetus by pregnant mother’s IgG antibodes is
considered passive immunity because the antibodies in the recipient are produced by
another individual
b cells mature in fetus where
liver
when an antigen binds to B cell
proliferation (2 copies) into daughter B cells (assisted by helper T)
plasma cells
B cells that release specific free antibodies that circulate in blood
Antibodies dispose of antigens upon binding
- Preventing virus from blocking to host cell
- Mark for macrophage/neutrophil/natural killer cell phagocytosis (opsonization)
- Lysis by complement proteins (pore formation)
- Agglutination of antigenic substance
- Chemical inactivation (if a toxin)
- Free antibodies may also attach their base to mast cells, if it encounters antigen
histamine release
Memory cells:
long-lived B cells that circulate the body, proliferate, and response quickly (via
antibody synthesis) to eliminate subsequent invasion by same antigen. FAST
T cells (foreign):
bone marrow but mature in thymus. DON”T make antibodies but check nonself cells.
how t cells figure out self
- MHC markers on plasma membrane of cells distinguish between self and nonself cells.
- When body cell is invaded by pathogen (non-self), it displays a combination of self and nonself
markers. T cells interpret this as non-self. - Cancer cells or tissues transplant cells are often recognized as nonself by T cells due to the
combination.
what happens when t cells encounter nonself
they divide and produce four kinds of cells:
a. Cytotoxic T cells: killer T cells recognize and destroy by releasing perforin protein to puncture
them (lysis). Can attack many cells because they do not phagocytize their victims.
b. Helper T cells: stimulate activation of B cells, cytotoxic T cells, and suppressor T cells. Target
for the virus that causes AIDS (HIV).
c. Suppressor T cells: play negative feedback roll in the immune system
d. Memory T cells: similar fxn to memory B cells
natural killer cells
attack virus-infected cells or abnormal body cells (tumors) [these are part of the
innate immunity, not specific]. Note that they attack infected body cells, not the microorganisms
directly.
Clonal Selection:
when antigen bind to B cell or when nonself binds to T cell
divide into daughter
cells, only B or T cells that bears effective antigen receptor is “selected” and reproduces to make clones.
two kinds of adaptive immunity response
cell mediated response and antibody mediated response
cell mediated response
T cells and responds to any non self cells.
- produce cytotoxic T cells and helper t cells
- helper T cells bind macrophages (engulf pathogens)
- helper T cells then produce interleukins to stimulate proliferation of T cell, B cell and macrophage
humoral or antibody mediated response
- responds to antigens or pathogens that circulate in lymph or blood (basically B cells)
- fluid is flushed into lymph system with lymphocytes
- macrophages process antigen to b lymph
- helper t helps b differentiate into plasma and memory cell
- plasma cells make antibodies to attack
what happens after B cells make memory cells immune
goes from mature to plasma to antibody
- a single B cell only makes one antibody type
negative selection of t and b cells
develop in thymus and bone marrow,
- if they bind self, they are destroyed, can also do positive selection so cells recognize self to SOME extent
vaccine mechanism
stimulate memory cell production from inactivated virus or weakened bacteria
inactivated vaccine
made of inactive pathogen that has been destroyed
attenuated vaccine
live pathogen that is disabled to prevent virulence
toxoid vaccine
inactivated toxic compounds that cause illness RATHER than the pathogen itself
passive immunity
transferred antibodies from mum
- nonspecific and short
- gamma globulin (blood with antibodies) and provide protection
primary response
first time antigen is seen in body. 20 days to reach potential
natural/ artificial immunity
how the response was induced
active or passive
whether antibody is yours
cytokines
signaling molecules (chemical) used in immune response for immune cells to communicate with one another.
interleukin 2
- kind of cytokine
Interleukin-2 primarily
triggers the immune system to produce T-cells and activates the clonal expansion of B-cells; they are
made by helper T-cells.
interleukin 1
- kind of cytokine
Interleukin-1 is involved with the acute-phase response that accompanies
inflammatory reaction – IL-1 causes neurons in the hypothalamus to raise the body temperature several
degrees above normal to impede growth of microorganisms; they are made by macrophages.
paracrine system
- local mediations that fun in the immediate area of release
- can be proteins AA Der, or fatty acids
prostaglandins
locally acting autocrine/paracrine lipid messenger molecule [specifically a
modified fatty acid] that has physiological effects (e.g. contract/relax smooth muscle, platelet aggregation, inflammation, fever, pain sensation etc.).
Aspirin
inhibits prostaglandin synthesis, thus
considered anti-inflammary, and decreases blood clotting
