Innate Immunity Flashcards
Innate immune system
The non-specific arm of the immune system
The first line of defence against pathogens & is ready from birth
Innate immune cells
There is some overlap between innate and adaptive immune cells
- Neutrophils
- Monocytes/ macrophages
- B-cells
- Mast cells
- Eosinophils
- Dendritic cells
- NK cells
- NKT cells
- Innate lymphoid cells
Anatomical barriers of the innate immune system
The innate immune system includes all physical barriers to infection
- Skin
- Mucosal surfaces
- Coughing
- Flow of urine
Physiological barriers of the innate immune system
The physiology of the human body can inhibit microbial growth
- Body temperature (fever)
- pH
- Chemical mediators
Innate lymphoid cells
Have no T-cell receptor and do not have PRRs
Are activated by local mediators (except NK cells)
Found mostly in the skin and mucosa
There are 3 groups of innate lymphoid cells
Innate lymphoid cells- group 1
Includes NK cells and ILC1 cells
Secrete pro-inflammatory cytokines IFNy and TNFa
NK cells = Immunity to intracellular pathogens
ILC1 cells = immunity to extracellular pathogens
Innate lymphoid cells- group 2
Includes ILC2 cells
Secrete cytokines that activate eosinophils
ILC2 cells = immunity to worms & promote wound healing
Innate lymphoid cells- group 3
Includes ILC3 cells
Secrete regulatory cytokines
ILC3 cells = play a role in lymphoid tissue development and intestinal health
immunity to extacellular bacteria and fungi
Natural killer T-cells
Have a T-cell receptor but do not recognise presented antigen
Recognise CD1 and lipid antigens during innate immunity
Secrete pro-inflammatory cytokines
y/d T-cells
Recognise bacterial antigens
Known to phagocytose
B1 cells
A sub-group of B-cells that express CD5
Produce low-affinity IgM antibodies against bacterial antigens
Important in neonate immunity
