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

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  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.