Innate Immunity Flashcards
(24 cards)
What is innate immunity?
A non-specific, fast-acting arm of the immune system that responds to pathogens immediately.
What are the two main arms of the immune system?
Innate (non-specific) and Adaptive (specific).
Which cells are phagocytes?
Neutrophils, monocytes, macrophages, dendritic cells.
What are granulocytes?
Cells with cytoplasmic granules that release toxins to kill pathogens; includes neutrophils, eosinophils, basophils, and mast cells.
What do neutrophils do?
First responders that phagocytose and kill pathogens using reactive oxygen species.
What is the function of eosinophils?
Defend against parasitic worms using toxic proteins and contribute to allergy.
What is the role of mast cells?
Important in inflammation and allergy; release histamine and cytokines.
What is the role of natural killer (NK) cells?
Kill virus-infected and tumour cells via perforin and granzymes or ADCC.
What are PAMPs?
Pathogen-associated molecular patterns, microbe-specific components essential for survival.
What are PRRs?
Pattern recognition receptors that detect PAMPs; includes Toll-like receptors (TLRs).
Which TLR recognises LPS?
TLR4.
Which TLRs recognise viral nucleic acids?
TLR3 (dsRNA), TLR7 (ssRNA), TLR9 (CpG DNA).
What is respiratory burst?
Rapid uptake of oxygen by neutrophils to generate toxic oxygen species for killing microbes.
Name toxic molecules used by phagocytes.
Hydrogen peroxide, superoxide, nitric oxide, myeloperoxidase.
Where does oxidative killing occur?
Inside the phagolysosome.
What are the signs of inflammation?
Redness, swelling, heat, and pain.
Which cytokines trigger acute phase response?
IL-1, TNF-alpha, IL-6.
What is the role of IL-8?
Chemokine that attracts neutrophils to the infection site.
What are the three complement activation pathways?
Classical (antibody-dependent), Lectin (MBL), and Alternative (direct pathogen recognition).
What are the three main functions of complement?
Opsonisation, inflammation, direct lysis of pathogens.
What is C3 convertase?
An enzyme complex central to complement activation, cleaves C3 into C3a and C3b.
What are MHC class I and II molecules?
MHC I presents endogenous antigens to CD8+ T cells; MHC II presents exogenous antigens to CD4+ T cells.
What are the primary antigen presenting cells (APCs)?
Dendritic cells, macrophages, and B cells.
Where do APCs encounter T cells?
In peripheral lymphoid organs like lymph nodes and spleen.
