T Cells and B Cells
Terms in this set (48)
Monocytes --> Macrophages
B cells --> Plasma cells
Natural Killer Cells
Innate defense cells vs. acquired "immune cell" defense
Innate Defense cells: Polymorphonuclear WBCs & Mononuclear WBCs
Acquired Defense cells: Mononuclear WBCs & Lymphocytes
-stay in tissue (mostly)
Dendritic cell locations
"border tissue" visitors
-Skin (langerhans), gut, airways, etc. - border between environment and inside body
-Will migrate to lymph tissue once activated
T cell locations
lymph tissue residents
-Attack abnormal cells directly (host microbe)
-Direct B cells to target invaders
B cell locations
lymph tissue residents
-Mark specific invaders for destruction
How do cytotoxic T cells function? (check ID's)
Check IDs via class 1 MHC on host cells
-Will NOT attack a 'healthy self' cell
-WILL attack an 'unhealthy self' cell: infected, damaged, old, etc.
-WILL attack a "non-self" cell: most any cell from someone else - common transplants/grafts: kidney, liver, heart, lung, skin
How do Cytotoxic T cells recognize 'healthy self cell'?
It recognizes normal 'self' peptide on cell surface.
'Self' peptides held out via Class I MHC proteins
-MHC=Major Histocompatibility Complex AKA HLA: Human Leukocyte Antigen
Explain organ/tissue/transplant graft Rejection (problem, pre- & post- prevention)
-Problem: The greater Class I MHC difference - greater rejection
-PRE-transplant/graft rejection prevention: "MHC tissue typing" used to identify difference - Lymphocytes collected and analyzed; the closer the relative the closer the match
-POST-transplant/graft rejection prevention: Suppress immune system - Azathioprine, Prednisone, Cyclosporin A or Tacrolimus
How is Azathioprine used to suppress the immune system in post-transplant/graft rejection prevention?
Reduces replication (DNA synthesis) of ALL CELLS
How is Prednisone used to suppress the immune system in post-transplant/graft rejection prevention?
Reduces number and activity of ALL WBCs
How is Cyclosporin A or Tacrolimus used to suppress the immune system in post-transplant/graft rejection prevention?
-Reduces activity of Cytotoxic T cells
-Does not effect regulatory T cells
How do cytotoxic cells become activated?
when they recognize a foreign MHC on cell surface
When cytotoxic cells become activated, how do they attack?
Attack by releasing:
-Cytokines: apoptosis, chemoattractant
-Perforins: create pores in membrane
-Enzymes: attack inside of cell
What is the role of Regulatory T cells (AKA Suppressor T cells)
-Also activated by cell displaying non-self peptides or abnormal peptides via Class I MHC proteins
-But activated much more sloooowly
-Work to suppress the cytotoxic T cells
What happens when a microbe is recognized by your mononuclear cells (phagocytes, antigen-presenting cells) aka macrophages and dendritic cells
-Dendritic cells (border tissue visitors) engulf and degrade the microbe.
-Expresses microbial peptide (AKA antigen) on cell surface and held there via CLASS II MHC PROTEINS
-This process mostly mediated by dendritic cell (border) also macrophages (omni-tissue residents)
What happens after the Class II MHC is expressed on the macrophage/dendritic cell surface?
-Regulatory T cells are activated sloooowly
-Helper T cells are activated - quickly: Accelerate Cytotoxic T cell maturation, Put helper T cells in reserve (memory helper T cells), Activate B cells for antibody production
In the process of Antibody production, what happens before T helper cells arrive?
-Naive B cells interact with antigen within lymph node closest to injury site.
-Antigen interacts with naive B cells to result in Sensitized B Cells.
(B cell is displaying antigen on MHC II protein)
What happens after Naive B cells become Sensitized B cells and T helper cells have arrived
Activated T helper cells stimulate Sensitized B cells to proliferate into Plasma cells (and some Memory B cells)
(B cell doesn't really know what to do until helper T cell comes along)
What happens after Sensitized B cells have proliferated into plasma cells (with the help of T helper cells)?
Plasma cells produce antibodies specific to antigen at a rate of 10,000/sec for several days
-These antibodies have the same target as the antibodies on the surface of the sensitized B cell.
-Plasma cells die off after a few days
What is the role of Memory B cells in antibody production?
When B cells become sensitized, they proliferate into plasma cells, and some early plasma cells are saved as memory B cells.
-They are saved and can be stored dormany for 20+ years unless reactivated directly by antigen
-This is the key to immunization. Doesn't need to go through long cascade of helper T cells, body remembers the antigen and can react quickly to it.
What area of the antibody binds the antigen?
F-ab portion: "Fragment-antigen binding"
"Variable region": over 1,000,000 possibilities recognizes specific antigens
What area of the antibody binds to the macrophage?
F-c portion: "Fragment-constant"
"Constant region": 1 basic sequence recognized by macs
Coating of microbe with antibodies
What is the function of opsonization?
-Opsonization against invasion: coating inhibits invasion of individual invaders; Coating can also bind together microbes (agglutination) - (the antibodies are binding to those docking points so now the microbe cannot attach to your host cell)
-Opsonization for attack by complement: coating activates complement binding and attack
-Opsonization for attack by cells: targeted by granulocytes, phagocytes
-Opsonization for phagocytosis: targeted by phagocytes
Major antibody isotypes
Immunoglobulin making up 7% of antibodies in your body whose specialty is agglutination and is the first type of antibody secreted by plasma cells. Pentamer shape
Immunoglobulin that is 75% of antibodies in your body making it the major type of antibody secreted by plasma cells whose specialty is opsonization and complement activation. It can cross placenta from mother to fetus (passive immunity)
Immunoglobulin that is 15% of antibodies in your body, whose specialty is agglutination. Because its locations are are at the body's borders, it is the first antibody defense because it immobilizes pathogens
-First antibody defense
Invaginations: gut, lungs, urethra, vaginal canal
Secretions: mucus, tears, saliva
-immobilizes pathogens so can't penetrate from border
Immunoglobulin making up <0.1% of antibodies in your body. Found on surface of basophils or mast cells. Bind to allergens. Initiate release of histamine and more in allergic response
What is the primary response to a microbe?
Sick: 1 to 2 weeks
-Naive B cells (slow response): plasma cells and memory cells
-Non-specific response: inflammation
What is the secondary response?
-Memory cells (fast response): plasma cells, Memory cells
What is the primary response of vaccination?
1 to 2 weeks: not sick
-Naive B cells (slow response): plasma cells and memory cells
-No strong defense response: isolated antigens, dead microbes, attenuated live microbes
What is the secondary response to microbe after vaccination?
-Memory cells (fast response): Plasma cells and memory cells
What vaccines should be administered in age group 0-6mos.
-DTaP (diptheria, tetanus, acellular pertussis)
-Hib (Haemophilus influenzae type b)
-PCV (pneumococcal conjugate)
-IPV (inactivated poliovirus)
Annual Flu (IIV)
What vaccines should be administered in age group 9mos.- 6 y.o.?
-MMR (measles, mumps, rubella)
-HepA (hepatitis A)
-Annual Flu (IIV)
What vaccines should be administered in age group 7-18y.o.?
-Tdap (tetanus, diptheria, acellular pertussis if >/= 7years old)
-HPV4 (males and females)
What is the recommended schedule for Tetanus, diptheria, and pertussis immunizations for 18+?
Get a Tdap vaccine once, then a Td booster every 10 years
When should HPV vaccine be administered in women?
in 3 doses between ages 19-26
When should HPV vaccine be administered in men?
-in 3 doses between ages 19-21
-for high risk persons Age 22-26 (3 doses)
When should Zoster shingles vaccine be administered?
1 dose > 60 years old
When should MMR vaccine be administered in adults?
in 1 or 2 doses between ages 19-55 who have not been previously vaccinated.
When should Pneumococcal vaccine be administered in adults?
1 dose if 65+
if high risk: 1-3 doses between ages 19-64
What vaccines are recommended for all HIGH RISK persons age 19-65?
What vaccines are recommended for all adults 19-65 who have not been previously vaccinated?
-Tdap (get a Tdap once, then a Td booster every 10 years)
-Varicella (chickenpox)-2 doses