Welcome to Dr. Kate Brilakis' Learning Portal
Diabetes
now we'll explore acquired
immunity
apoptotic bodies were once considered "garbage bags" left over from apoptotic cells but we know now that they are involved in cellular communication and macrophage stimulation
review question:
describe the inflammatory response.
Innate Immunity
review question:
describe the 3 physical and 3 chemical barriers of our external innate defense system
review question:
what is apoptosis? How do Cytotoxic T cells t trigger this process?
Growth Hormone
review question:
what is the function of a cytokine?
T cells are lymphocytes
2 types of T cells:
Cytotoxic (killer) T cells
Helper T cells
3. B cells are activated by helper T cells and are then
converted to
plasma B cells and memory B cells
review question:
Explain the process of Cell Mediated Immunity.
natural killer cells (NK cells) are white blood cells that destroy infected cells and cancer cells in your body.
3. interferons...
a type of cytokine
review question:
describe the two types of immunity.
immune response cells
naturally acquired passive immunity =
antibodies are acquired via breast milk
apoptotic bodies
are vesicles released during programmed cell death (apoptosis).
they contain cell debris.
players:
btw...
TNF-alpha = Tumor Necrosis Factor alpha = a cytokine
review question:
explain the humoral immune response.
1. cell mediated immunity:
cytotoxic T cells destroy pathogen
if the same pathogen/antigen infects the body again, memory B cells will be triggered by that antigen and converted into Plasma B cells which will then produce antibodies to the antigen.
4. complement
proteins
review question:
how do natural killer cells destroy infected/cancerous cells?
1.
cytokines are produced by macrophages, B lymphocytes,
T lymphocytes and mast cells
review question:
what are 3
functions of the Lymphatic System?
MHC class I MHC class II
6. fever
3. cytotoxic T cell secretes perforin and granzyme.
4. cell is degraded and triggers apoptosis
competitive gut bacteria
we just explored
innate immunity
Your spleen is responsible for filtering your blood by removing old or damaged RBCs, storing iron from recycled RBCS, and triggering immune responses by B/T cells circulating in your blood.
Interleukin released by monocytes is a cytokine
that can reset the
thermostat in the hypothalamus causing fever
review question:
how does a lymph node participate in the immune response?
autoimmunity
review question:
what is the purpose of memory B cells? How do they differ from plasma B cells?
Thymus Gland
T cells that the body's own tissues, leading to autoimmune diseases.
Autoimmune T cells target various self-antigens, leading to organ-specific or systemic autoimmune diseases.
The immune system normally recognizes and tolerates self-antigens, but in autoimmune diseases, this tolerance breaks down, allowing T cells to attack the body's own tissues.
the spleen has white pulp where the lymphocytes hang out to identify pathogens and red pulp where macrophages stand by the ready for phagocytosis.
examples of T cell-mediated
autoimmune diseases:
Multiple sclerosis:
T cells attack the myelin sheath of nerve cells in the brain and spinal cord disrupting the transmission of a nerve impulse
Type 1 diabetes:
T cells attack and destroy the insulin-producing cells in the pancreas
Rheumatoid arthritis:
T cells contribute to inflammation and damage to joints
review question:
What is the MHC?
How do Cytotoxic T cells and Helper T cells differ in the MHC they recognize? Why is this difference important?
review question:
list the immune response cells and provide a function for each
chemical barriers:
1. lysozyme in tears/saliva/mucus
2. stomach acid kills pathogens in digestive system
3. sweat is acidic - inhibits bacterial growth on the skin
Diabetes: Type 1
lymphatic vessels rely on lymphatic valves to assist in movement of lymph back into circulation
here's the process all together...
internal innate defenses
artificially acquired passive immunity =
antibodies are acquired via antibody injection
Acquired Immunity
compared to type 2
macrophages are professional antigen-presenting cells (APCs)
review question:
how do complement proteins fight an infection?
1. macrophages engulf pathogen
and present pathogen's antigen on cell surface using MHC II
exogenous pyrogens (from pathogens)
trigger the release of endogenous pyrogens which cause fever.
ex: lipopolysaccharide
(LPS of Gram-negative bacteria)
is an endotoxin and an exogenous pyrogen
how do antibodies fight off the pathogen?
helper T cells are a past of the antibody response
7. memory B cells
provide long-lasting immunity against previously encountered pathogens by producing antibodies if the same antigen is present
lymph drains back into circulation via the thoracic duct and lymphatic duct
physical barriers:
1. cilia in respiratory tract
2. skin
3. mucous membranes line respiratory, digestive, reproductive tracts
T cell maturation is a process where immature T cells, originating from hematopoietic stem cells in the bone marrow, travel to the thymus and mature into functional T cells capable of recognizing specific antigens.
T cell maturation involves positive and negative selection within the thymus to ensure T
cells recognize both the MHC molecule and
"self".
2. cytotoxic (killer) T cell binds to this combo and is activated.
2.
Lymph nodes screen/filter lymph.
lymph is exposed to B cells , T cells and macrophages. As lymph travels the node,
(think a strainer), 99% of antigens are removed.
nodes can swell in response to infection.
leucocytes = all white blood cells.
lymphocytes (B cells, T cells, NK cells) are a specific type of leukocyte.
1. infected cell present the antigen of the pathogen on its MHC I
2. natural killer cells
NKs
helper T cells (CD4+) recognize antigen presented on
MHC class II.
with subsequent infections to the same pathogen, antibodies are produced much more quickly
Thyroid
Hormone
immune response cells
1. lymphocytes: 30% of WBCs:
Helper and Killer T cells
B cells produce antibodies
Natural Killer cells (NKs)
2. neutrophils: 65% of WBCs. fight bacterial and fungal infections.
3. monocytes: large, phagocytic cells
4. macrophage: phagocytic cells that engulf pathogens/debris.
derived from monocytes migrating from the bloodstream into tissues.
5. eosinophils: allergic reactions and fight parasitic infections.
6. basophils: circulating cells release histamine and heparin
7. mast cells: tissue resident cells release histamine and heparin
8. dendritic cells: phagocytic APC (antigen presenting cell)
external innate defenses
1
2
3
4
5
6
thoracic duct returns lymph from the majority of your body to the left subclavian vein and left internal jugular vein...
the right lymphatic duct drains the right head and upper arm/torso into the right subclavian vein.
review question:
what is the role of macrophages in the humoral response?
inflammation:
1. damaged cells and immune cells release chemicals like histamine and cytokines.
2. these chemicals cause blood vessels to dilate (vasodilation), leading to increased blood flow to the area and increased permeability of the vessels, allowing fluids and white blood cells to leak into the tissues.
3. this increased blood flow, fluid leakage, and the activity of immune cells results in the the signs of inflammation we know: redness, swelling, heat and pain
4. immune cells try to eliminate the
pathogens/damaged cells and start repairing the tissue.
5. acute inflammation: tissue is repaired.
chronic inflammation: tissue damage and long-term health issues.
more on this later...
T cells differ by the type of MHC
(Major Histocompatability Complex) they recognize.
Lymphatic Organs
lymph nodes/nodules
artificially acquired active immunity =
antibodies produced when body is exposed to antigen in vaccine
Immunity
and the Lymphatic System
interferons are a type of cytokine
that "interferes" with viruses' ability to infect and multiply. .
your immune response
T cell maturation/selection
Lymph nodules are areas along the lymphatic vessels
where there are loads of lymphocytes. Nodes can form clusters...for example: your tonsils (pharyngeal, palatine, lingual) are lymph nodules located in your pharynx.
Another example is MALT = mucosa associated lymphoid tissue, lymphoid tissue that protects the epithelial lining of your gut, respiratory tract, urinary system and reproductive systems.
1. phagocytes
naturally acquired active immunity =
antibodies produced when body is exposed to antigen on pathogen
review question:
describe 3 ways antibodies prevent infection by pathogens.
5. plasma B cells
produce antibodies against the
specific antigen
review question:
Describe four reasons your immune system induces fever.
2. humoral/antibody immunity:
Helper T cells stimulate B cells
B cells produce antibodies
Memory B cells remember pathogen
thymus gland shrinks after puberty as the spleen and lymph nodes take over
when an infection is detected, the immune system triggers the release of chemicals (pyrogens) which signal the hypothalamus (the body's thermostat) to raise the body temperature trying to create an environment that is less friendly to the pathogen:
1. inhibits bacterial growth
2. stimulates phagocytosis
3. speeds up tissue repair
4.liver stores more iron so bacteria cant replicate
spleen
5. inflammation
T cells are screened in the Thymus Gland to make sure they do not recognize "self" as foreign
Major Histocompatibility Complex (MHC) = proteins on the surface of cells that help the immune system recognize foreign antigens
complement proteins are released when the complement system is activated.
this occurs in response to infection or tissue damage. inactive proteins are activated via through a cascade of enzymatic reactions which trigger a chain reaction where one protein activates the next.,
innate vs adaptive
immunity
review question:
what is the function of a phagocyte?
what is phagocytosis?
cytotoxic T cells
(CD8+) primarily recognize antigens presented on
MHC class I
2. helper T cells (CD4+) recognize antigen presented on
MHC class II.
immune response
participants
save for later
review question:
Explain how a fever is triggered. Include cytokines as part of the process.
6. antibodies are
Y-shaped proteins that bind to specific antigens
phagocytes may be monocytes, macrophages and neutrophils - white blood cells that engulf pathogens,
foreign material, and dead cells.