Immunology 1 Flashcards
What is innate immunity?
present continuously, it is a defense mechanism that is present from birth and is generally non-specific (i.e. the same generic response occurs towards many different types of material)
What is acquired immunity?
induced by the presence of ‘foreign’ or ‘non-self’ material (including infectious micro-organisms). The response that occurs is (usually) unique to the specific substance or pathogen that induced the response.
What are the 4 types of entry for a pathogen?
Digestive, respiratory, urogenital systems and skin damage
What are the 2 main routes of attack for a pathogen?
Circulatory and / or lymphatic systems
What 4 things do sebaceous glands secrete?
Hydrophobic oils, lysozyme, ammonia and antimicrobial peptides
What are 2 physiological factors about the skin?
Low ph of 5.5 and low oxygen tension
What enzymes does mucous contain as a physical barrier?
Lysozyme, defensins and antimicrobial peptides directly kill invading pathogens. Lactoferrin acts to starve bacteria of iron
What is the function of secretoy igA in mucous?
Prevents pathogens attaching to and penetrating epithelial cells
What is the function of cilia?
Directly trap pathogens and contribute to the removal of mucous.
What do commensal bacteria do?
Compete with pathogenic microorganisms for scarce resources’ also produce fatty acids and bactericidins that inhibit the growth of many pathogens.
What are 2 tissue-resident innate immune cells?
Macrophage and mast cells.
What are 2 phagocytic cells?
Macrophages and dendritic cells.
What is special about extracellular bacterial cells?
They do not invade cells and proliferate instead in the extracellular environment which is enriched with body fluids.
What are the modes of ingestion of pathogens by macrophages?
Pinocytosis, receptor mediated endocytosis and phagocytosis.
What is pinocytosis?
Ingestion of fluid surrounding cells
What is receptor mediated endocytosis?
When molecules bound to membrane receptors are internalized.
What is phagocytosis?
A specific form of endocytosis by which cells internalise solid matter, including apoptotic cells and microbial pathogens.
What speeds up the rate of phagocytosis?
Opsonisation
What do pathogens express on their surface?
PRRSs
Why are pro-inflammatory mediators released during phagocytosis?
To promote acute inflammation and pathogen-derived proteins are expressed on the cell surface receptors.
What are MHC-11 molecules?
Pathogen derived peptides which are expressed on cell surface receptors.
Where is the debris of phagocytosis released to?
The extracellular fluid.
What is opsonisation?
The coating of pathogens by soluble factors to enhance phagocytosis
What are some examples of opsonins?
C3B, IgM, IgG and CRP (c reactive protein)
