Innate Immunity Flashcards
(33 cards)
what are routes of entry for pathogens through mucosal surfaces?
- airway
- GI
tract - GU
what are routes of entry for pathogens through external epithelia?
- external surface (skin)
- wounds and abrasions
- insect bites
what pathogen causes meningococcal meningitis?
neisseria meningiditis
what pathogen causes syphilis?
treponoma pallidum
what pathogen causes athlete’s foot?
tinea pedis
what are the phases of innate immunity?
- infection
- recognition by preformed nonspecific effectors
- removal of infectious agent
- 0-4 hours
what are the phases of early induced response?
- infection
- recruitment of effector cells
- recognition and activation
- removal of infectious agent
- 4-96 hours
what are the phases of adaptive immune response?
- infection
- transport of antigen to lymphoid organs
- recognition by naive B and T cells
- clonal expansion of effector cells
- removal of infectious agents
- > 96 hours
what are some mechanical barriers to infection?
- tight junctions between cells
- air and fluid flow across epithelium
- movement of mucus by cilia
what are some chemical barriers to infection?
- fatty acids on skin
- enzymes: lysozyme in saliva, swear and tears
- low pH in stomach
- antibacterial peptides: defensins (skin and gut), cryptidins (gut)
what are some microbiological barriers to infection?
normal flora compete for nutrients and attachment (biofilms), and also produce antibacterial substances (colicins)
what are monocytes?
- 1 of 3 types of phagocytic cell of immune system
- circulate in bloodstream
- differentiate into macrophages in tissue
what is the role of a macrophage?
- phagocytosis and killing of microorganisms
- activation of T cells and initiation of immune response
what are examples of granulocytes?
- neutrophils
- eosinophils
- basophils
what is an alternate name for granulocytes?
polymorphonuclear (PMN) leucocytes - due to shape of nuclei
what is the role of a neutrophil?
- phagocytosis and killing of microorganisms
- most numerous and important cell of innate immunity
what does a deficiency of neutrophils lead to?
overwhelming bacterial infections
what is the role of an eosinophil?
- killing of antibody-coated parasites through release of granule contents
- important in parasite defence
what is the function of a mast cell?
- expulsion of parasites from body through release of granules containing histamine and other active agents
- well known due to IgE mediated triggering in allergies
- effect vascular systems
what is the role of a basophil?
function similar and complementary to eosinophils and mast cells
what are lymphocytes?
- B or T cells
- B cells produce antibody
- T cells becoming cytotoxic cells (CD8) or helper cells (CD4)
what are natural killer (NK) cells?
- large granular lymphocytes
- can recognise virally infected cells non-specifically
what are dendritic cells?
- potentially the most important immune cell
- bridges innate and adaptive immune responses
- specialised in antigen uptake and antigen presentation
what is the difference between NK cells and T cells?
- NK cells are not antigen specific
- don’t undergo length clonal expansion of T cells in lymph nodes when virus detected
