intro to immune system Flashcards
what is the difference between innate and adaptive immunity
innate: natural immunity that exists prior to sensitization and exposure (non specific)
ex: phagocytosis
adaptive: aquired immunity that occurs after sesnitization with antigen ( specific and generates immunologival memory)
define antigen and antibody
antigen: protein molecule recognised as foreign from the body
antibody: antigen specific proteins produced by b lymphocytes in response to antigen exposure
what are types of lymphocytes (lymphoid progenitor)
- b cells/plasma cells
- T cells
- natural killer cells
define inflammation hypersensitivity and allergy
inflammation: physiological response to injury which includes heat pain redness and swelling due to blood vessels becoming more leaky
hypersensitivity: an excessive immune reaction that leads to reproducible symptoms in individuals.
allergy: hypersensitivity reactions that are initiated by the immune system to harmless substances
what is the function of the spleen
filters blood borne pathogens and antigen (looks for potential danger when blood flows through)
contains b and t cells
distinguish between the 5 classes of immunoglobulins (antibodies)
igG:
most common
neutralizes toxins
crosses placenta for neonatal immunity
provides long term immunity (memory)
used for opsonization (tagging) for phagocytosis
igM:
made first in response to antigen
pentameric (made of 5 igG)
is the receptor found on naive B cells
igA:
receptor found on B cells
found in secretions like milk bile and saliva.
allows mucosal immunity
dimer
igE:
bound to mast cells via Fc epselon receptors
leads to activation of allergic response via mast cell degranulation
atopic individuals produce more IgE. (correlated with increased sucseptibility to allergies)
igD: antigen receptor of naive B cells
differentiate between primary and secondary response
primary: first encounter with pathogen where weak and short response occurs and memory T and B lymphocytes are produced
secondary: another encounter with same pathogen where memory cells rapidly divide and reproduce. faster and stronger protection
what does adaptive immunity consist of
- humoral immunity:
immune response mediated by antibodies and complement - cell-mediated immunity
immune response mediated by immune cells like T lymphocytes (independent of antibodies)
list the antigen presenting cells
- B cells
produced by the bone marrow and matured in the spleen
generate antibodies for antigens
some develop inti memory cells for secondary response - macrophages
engulf and digest pathogens
present the antigen on the surface of the cell to activate other immune cells like t cells.
other names for specialized body parts: kupffer cells, microglial cells - dendritic cells
activate T cells and promote their clonal expansion (proliferation and differentiation into a large population of effector cells)
also ingest pathogens
differentiate between types of T cells
Helper:
have T cell receptors and CD4 receptors that bind to antigen presenting cells
once bound to antigens t helper cells release cytokines
cytotoxic:
have T cell receptors and CD8 receptors that recognise virally infected cells and kills them
list the granulocyte cell types
neutrophils
mainly phagocytic role (like macrophages but macrophages in tissue neutrophils in blood)
basophils
release histamine
eosinophils
release leukotrienes and cytokines
ex: interleukins and TNF alpha
they are all formed in bone marrow and circulate bloodstream while waiting for signals that recruit them into sites of infections
describe the effects of mast cell degranulation
mast cells release inflammatory mediators such as histamine chemotactic factors and cytokines
activated through IgE signalling.
histamine causes blood vessel dilatation which enables more blood to reach the site of inflammation
give information on immune mediators
cytokines:
-Interlukins 1-25
IL-1: pro inflammation, stimulates T cells
IL-8: chemokine of neutrophils (attracts them)
-cysteinyl leukotrienes
contract SM, increases; vascular permeability, mucus; and attracts leukocytes.
-TNF alpha
pro inflammation, chemotactic (attracts other cells to inflammation)
increases SM proliferation
chemokines:
consists of chemotactic cytokines
guides the migration of cells to inflammation areas.
bind to chemokine receptors
describe and give examples of autoimmune diseases
immune system attacks itself with autoantibodies
ex: type 1 diabetes
arthritis
describe and give examples of immune deficiencies
ex:
AIDS caused by HIV virus which inactivate T cells
common variable immunodeficiency (Low B cell count)
severe combined immunodeficiency (absent T cells and no antibodies)
chemotherapy and irradiation for cancer
immunosuppressive medications
