Introduction to Immunology Flashcards
What are some examples of some pathogens?
- Fungi
- Parasites
- Viruses
- Bacteria
What molecules, proteins and cells can be found in the blood?
- Leukocytes
- Neutrophils
- T & B cells
- Phagocytes
- Antibodies
- Monocytes
- Mast cells
- Dendritic cells
- Cytokines
- Macrophages
Leukocytes is an umbrella term for which 3 types of cells?
- Lymphocytes
- Phagocytes
- Auxiliary cells
What are some examples of lymphocytes, and what mediators do they release?
- B cells: antibodies
- T cells: cytokines
- Large granular lymphocytes: cytokines
What are some examples of phagocytes, and what mediators do they release?
- Mononuclear phagocytes: cytokines & complement
- Neutrophils
- Eosinophils
What are some examples of auxiliary cells, and what do they release?
- Basophils
- Mast cells
- Platelets
They all release inflammatory mediators
What is the difference between the innate and the adaptive immune system?
Innate: it is the body’s 1st line of defence.
Adaptive: it is where the immune system adapts as the pathogen adapts, e.g. a flu.
What is the difference between cellular adaptive immunity and humoral adaptive immunity?
Cellular: T cells attack infected body cells that display the antigen on its surface (protects against intracellular pathogens).
Humoral: B cells produce antibodies after being activated by antigens in the blood (protects against extracellular pathogens).
What are some examples of some exterior defences of the body?
- Skin
- Mucosal membranes
- Cilia secretions
- Tissue fluid with antimicrobial agents
Where do most cells of the immune system derive from?
Hematopoietic stem cells, in the bone marrow.
What do cells of the immune system have on their surface which helps in identifying them (like markers)?
They contain CD (cluster differentiation) markers.
CD4: T helper cells
CD8: cytotoxic T cells
What are phagocytes responsible for?
They engulf, internalise & destroy pathogens
Which type of cell is known for being short-lived?
Neutrophils
What do monocytes develop into, & where are they involved?
Monocytes develop into macrophages, & are involved in chronic inflammation.
Which type of cell is found in both the innate & the adaptive immune system?
Natural killer (NK) cells
What is the function of auxiliary cells?
They attract leukocytes & release mediators (cytokines) to the site of inflammation.
They create a cytokine storm where lots of cytokine is released
Which type of cells arise from allergies, and what do they release?
Mast cells & platelets. They release histamines.
How do cells of the immune system recognise pathogens?
- Through pathogen associated molecular patterns (PAMP), which is a sugar/lipid on the microbial surface & is important for the bacterial cell wall.
It is also a ligand to some receptors & if altered, it will kill the bacteria. - Opsonisation can also happen, in which the pathogen is ‘tagged’ with the binding of opsonin to allow phagocytes to attack it (make food ready for -)
What is the mechanism of phagocytosis?
- The microbe binds to the phagocyte receptor
- Phagocyte membrane engulfs it through endocytosis
- The microbe is ingested into a phagosome
- The Phagosome lyses with a lysosome to create a phagolysosome
- In the phagolysosome, degradative enzymes kill & digest the microbe
- The contents are released from the cell through exocytosis
What 3 receptors are present on phagocytes that can recognise PAMPs?
- Scavenger receptors
- Carbohydrate receptors, e.g. lectin
- Toll-like receptors
Where can neutrophils be contained in?
Pus.
What are the granules in neutrophils?
They are lysosomes.
Where are neutrophils found, internally?
They are found in tissues of bacterial invasions, where they engulf & destroy.
