Immune

immunology

study of defenses the body uses to recognize itself from non self (foreign) substances or cells; immune system destroys or renders harmless foreign matter

innate immune response

• non specific

• defend against substances or cells without having to recognize their specific identities

adaptive immune response

• specific

• depend on recognition by lymphocytes of the substance or cell to be attacked

neutrophils

• phagocytosis

• release chemicals involved in inflammation

basophils

carry out functions in blood similar to those of mast cells

eosinophils

immediate hypersensitivity reactions

monocytes

transform into macrophages

lymphocytes

recognition cells

B cells

initiate antibody mediated immune response

• transformed into plasma cells which secrete antibodies

• present antigen to helper T cells

cytotoxic T cells

directly destroy cells

helper T cells

activate B cells, cytotoxic T cells, NK cells and macrophages

regulatory T cells

inhibitors on other immune cells

NK cells

bind to cancer cells and kill them

plasma cells

secrete antibodies

macrophages

• phagocytosis

• extracellular killing

• secrete cytokines

dendritic cells

phagocytosis, antigen presentation

mast cells

release histamine

interleukin 1

induce fever, systemic responses to inflammation

interleukin 2

stimulate proliferation, promote conversion to plasma cells

interferons type 1

stimulate cells to produce antiviral proteins

interferons type 2

stimulate proliferation and secretion of cytotoxic compounds

chemokines

facilitate accumulation of leukocytes at sites of injury and inflammation

chemotaxis

• neutrophils move out of capillaries & venules

  • move into interstitial space of inflamed area due to attraction by various chemicals

  • chemoattractants released by damaged cells

margination

loose attachment of neutrophils to endothelial cells by adhesion molecules, resulting in collection of neutrophils near infection site

diapedesis

squeezing of neutrophils b/t adjacent endothelial cells of capillaries to enter the infection site

complement

opsonizes or directly kills pathogens

histamine

increases vascular permeability

cytokines

chemoattraction for leukocytes

B cells

do not interact with MHC proteins

helper T

class II, found only on macrophages, dendritic cells, and B cells

cytotoxic T

class I, found on all nucleated cells of body

NK

interaction with MHC proteins not required for activation

clonal deletion

destruction by apoptosis of T cells in thymus with receptors capable of binding to self proteins

clonal inactivation

development of nonresponsiveness in potentially self reacting T cells in periphery of body

IgG

most abundant class of antibodies, gamma globulins

IgM

fairly abundant, provide most of specific immunity against bacteria and viruses in extracellular fluid

IgE

mediate allergic responses and participate in defenses against parasitic infections

IgA

found in linings of GI, respiratory and genitourinary tracts and in milk

immediate hypersensitivity

mediated by IgE antibodies, mast cells, eosinophils

cytotoxic hypersensitivity

antibodies that lead to damage or destruction of cells as in hemolytic disease of newborn

immune complex hypersensitivity

mediated by antigen antibody complexes deposited in tissue 

delayed hypersensitivity

helper T cells & macrophages, independent of antibodies