IMMUNOLOGY 1 Flashcards
study of immune system and its responses to invading pathogens
immunology
collection of cells, tissues, and molecules that mediate resistance to infection
immune system
coordinated reaction of the immune system to infectious microbes
immune response
state of relative resistance to disease
immunity
proteins that the body makes when stimulated by an antigen
secreted by plasma cells (immunoglobins)
antibody
white blood cells
formed in the bone marrow and lymph tissues
mobile units of body’s protective system
leukocytes
leukopoiesis is the process where leukocytes are formed and hormonally stimulated by ________
cytokines
formed in the red bone marrow
granulocytes and monocytes
formed in lymphatic tissue found in lymph nodes, tonsils, Peyer’s patches, spleen and thymus
lymphocytes and plasma cells
granulocytes
basophils eosinophils neutrophils
agranulocytes
monocytes lymphocytes plasma cells
polymorphonuclear, PMN 50-70%
4-6 hours in vessels, diapedesis, chemotaxis and act by phagocytosis (using its hydrolyzed enzyme)
plays a very important role in nonspecific cellular immunity system such as pathogenic organisms such as bacteria, virus, and parasites
neutrophils
older neutrophils
segments
younger neutrophils
bands
similar to mast cells
liberate heparin, histamine, bradykinin and serotonin
functions in allergic reactions (IgE)
basophils
immune reaction against parasitic infection
IgE mediated allergic reactions (modulates effects of basophils and mast cells)
eosinophils
10-20 hours in blood
once in tissues they swell and become macrophages
main function is phagocytosis
as many as 100 bacteria engulf in much larger particles
(antigen presenting cells) and cytokine production
monocytes
first line of defense
macrophages already present in the tissues occurs within minutes
tissue macrophages
caused by inflammatory cytokines and other biochemical products from inflamed tissues (INF and IL-1)
margination, diapedesis, chemotaxis
neutrophil invasion
metamorphoses WBCs pass through vessel wall getting into interstitial fluid
diapedesis
process that WBCs shift to some chemical material (metabolic production, antigen-antibody complex, bacteria, toxin, etc)
chemotaxis
process that WBCs enclose and engulf exotic or extraneous material and use intracellular enzyme digesting them
phagocytosis
third line of defense
monocytes from the blood enter the inflamed tissue and enlarge
slower build up for macrophages in tissues than neutrophils (several days to weeks)
low number of monocytes in blood and bone marrow
second macrophage invasion
stimulation of granulocytic and monocytic progenitor cells
takes 3-4 days to reach the stage of leaving the bone marrow
increased production of granulocytes and monocytes by the bone marrow
feed back control
tumor necrosis factor
interleukin 1
granulocyte-monocyte colony stimulating factor
granulocyte colony stimulating factor
monocyte colony stimulating factor
neutrophils and macrophages die after engulfing large number of bacteria and dead tissue
a cavity is excavated in inflamed tissues
necrotic tissue + dead neutrophils and macrophages + tissue fluid
pus
located most extensively in the lymph nodes
can also be found in the spleen, submucosal areas of GIT, thymus and bone marrow
lymphocytes
forms activated lymphocytes (cell mediated immunity)
T-lymphocytes
forms antibodies (humoral immunity)
B lymphocytes
preprocesses T lymphocytes
from the bone marrow rapidly divides at the thymus and develops extreme diversity for reacting against different specific antigens
makes sure that T lymphocytes will not react to antigens that are present in the body’s own tissues
thymus gland
during mid fetal life preprocesses B-lymphocytes
liver
late fetal and after birth preprocesses B lymphocytes
bone marrow
few lymphoblasts do not become plasma cells after action but form moderate numbers of new B lymphocytes
circulate throughout the body to populate the lymphoid tissues
immunologically remain dormant until activated once again by new quantity of the same antigen
memory cells
proteins that recognize and bind to a particular antigen with very high specificity
gamma globulins called IMMUNOGLOBULINS
composed of combination of light and heavy polypeptide chains
antibodies
5 general classes of antibodies
IgG A M D E
Large intravascular pentamer
complement fixation: yes
placental transfer: no
predominant early antibody in immune response to antigenically complex organisms
agglutinates particles
IgM
major antibody of the secondary immune response
found in secretions, blood, lymph, intestine
half life 23 days
complement fixation yes
placental transfer yes (passive immunity)
enhances phagocytosis, neutralizes toxins and viruses, protects fetus and newborn
IgG
predominant Ig in seromucous secretions (tears, saliva, intestine, milk), blood and lymph
half life in serum 6 days
no complement fixation and placental transfer: none
localized protection of mucosal surfaces, provides immunity to infant digestive tract
IgA
3 days half life in serum
no complemental fixation and placental transfer
in serum, function is unknown, on B cell surface, initiates immune response
IgD
scarce monomer
2 days half life in serum
known functions in allergic reactions
sensitizes cells on mucosal surfaces, has a role in immunity to helminths, asthma and hay fever
IgE
direct action on invading agents
agglutination
precipitation
neutralization
lysis
Ag-Ab bound together in clump
agglutination
Ag-Ab complex is so large, becomes insoluble and precipitates
precipitation
Ab cover toxic sites of antigenic agent
neutralizations
some potent Ab Attack cell membranes causing rupture
lysis
collective term describing a system of 20 proteins many of which are enzyme precursors
all these are present normally among the plasma proteins in the blood
enzyme precursors are normally inactive but the way the can be activated by the so called classical pathway
complement system
phagocytosis of bacteria to which the Ag-Ab is attached
C3b activates phagocytosis by neutrophils and macrophages
opsonization
direct effect of rupturing cell membranes of bacteria
C5b6789
Lysis
complement of products change the surfaces of invading organisms making them adhere to one another
agglutination
attack structures of some viruses making them nonvirulent
neutralization of viruses
migration of phagocytes into area adjacent to antigen
C5a
chemotaxis
release of histamine, heparin, into local fluid, increased blood flow, leakage of fluid and plasma protein into tissue that helps inactivate or immobilize antigen
C3a C4a C5a
activation of mast cells and basophils
further increase of blood flow
increase capillary leakage
coagulation of interstitial fluid proteins in tissue spaces
inflammatory effects
upon exposure to proper antigen T lymphocytes clone proliferatively and release large numbers of ________
activated t cells
_____________ are formed in the same way as B memory cells
t-lymphocyte memory cells
T lymphocytes respond only to antigens when they are bound to _____________ on the surface of __________ in the lymphoid tissue
MHC Proteins
Antigen presenting cells
3 major types of antigen presenting cells
(MBD)
macrophages
B-lymphocytes
dendritic cells
proteins that bind peptide fragments of degraded antigen protein and transports them to the cell membrane
major histocomplatibility complex
MHC protein that presents antigen to cytotoxic t cells
MHC 1 protein
presents antigen to T helper cells
MHC II protein
types of T cells
T-helper cells
Cytotoxic T cells
Suppressor T cells
most numerous more than 75%
serve as major regulator of virtually all immune functions
forms a series of protein mediators, lymphokines
IL2, IL3, IL4, IL5, IL6
GM CSF
interferon y
t-helper cells
stimulation of growth and proliferation of cytotoxic T cells and supressor cells
b cell growth and differentiation to form plasma cells and antibodies
regulatory functions of lymphokines
killer cells; direct attack cells
secretes hole-forming proteins called perforins
secretes cytotoxic substances into the attacked cell
cytotoxic t cells
capable of suppressing the functions of both cytotoxic and t helper cells
prevent cytotoxic cells from causing excessive immune reactions that might damage body’s own tissues
suppressor t cells
