Introduction Flashcards
introduction
Which cells link the innate and adaptive immune systems by presenting antigens to T cells?
Dendritic cells
What are the professional antigen presenting cells?
macrophages, dendritic cells and b cells (all present antigen to T cells to initiate immune response)
What is immunity?
Defense of the host against foreign pathogens (antigens)
What are the 3 categories of host defense?
Physical & chemical barriers
Cells of innate immune system
Cells of adaptive immune system
What are the chemical barriers against infection?
- Tears
- Sweat
- Mucus
- Stomach acid
- Antibodies
- Antimicrobial peptides
What are physical barriers against infection?
Skin
Mucosal surfaces- upper and lower respiratory tract, intestinal epithelium, vaginal epithelium
What cells are considered granulocytes?
neutrophils, basophils, eosinophils and mast cells (although mast cells are not involved in granulocytosis)
What are the key cells of the innate immune system?
macrophages- monocytes
dendritic cells
granulocytes
natural killer cells
What are the tissue-specific macrophages?
- Alveolar and Peritoneal macrophages
- Kuppfer cells
- Osteoclast
- Microglial in brain
- Histiocytes
What are monocytes?
a monocyte is a circulating precursor of
macrophages in blood
they leave bloodstream and become more specialised and mature into macrophages
Describe macrophages
Phagocytosis and killing of microorganisms
Activation of T cells and initiation of the immune
response (they are a professional antigen presenting cell meaning they present antigen to T cell to activate them and induce immune response (adaptive))
What are the functions of neutrophils?
phagocytosis
degranulation- granules can be expelled to kill other cells when invaded
involved in neutrophil extracellular traps (NETs)
Discuss neutrophils structure etc.
they are polymorphonuclear
they are a granulocyte
Short life span (hours)
Very important at “clearing” bacterial infections
What links the innate and adaptive immune systems?
the immune system acts in synergy to fight infections
T cells and apc interactions link innate and adaptive immune response
There is close synergy between the two systems with the adaptive response greatly improving the efficiency of
the innate response and the innate response setting the scene for activation of the adaptive response
Discuss granulocytes other than neutrophils
eosinophils and mast cells - found in tissues
basophil - found in circulation
all play a role in allergic inflammation and destruction of parasites via degranulation
eosinophils- produce antihistamines and have a double-lobed nucleus