Immunoglobulin E

INTRODUCTION:
  • Molecular weight 8 S molecule
  • Normal serum levels: few nanograms per ml
  • Only heat labile Ig (inactivated at 560C in 1 hour)
  • Shortest half-life
  • Maximum glucose concentration
  • Antibody with least serum concentration IgE
  • Does not fix complement
  • Has affinity for the surface of tissue cells (particularly mast cells) of the same species - hornocytotropism
  • Mostly extravascular
  • Responsible for anaphylactic type of hypersensitivity
  • Protection against pathogens by mast cell degranulation and release of inflammatory mediators
  • Elevated IgE levels seen in type I allergic conditions (asthma, hay fever, eczema, children living in insanitary conditions with high load of intestinal parasites Main defence against helminthic infestations
  • Cannot be demonstrated by conventional serological reactions like precipitation or complement fixation
STRUCTURE:
  • Monomer
  • Extra domain (CH4)
PROPERTIES:
  • Least common serum Ig
  • Binds to basophils and mast cells (Does not require Ag binding)
  • Allergic reactions
  • IgE shows homocytotropism
  • Binds to Fc receptor on eosinophils
  • Does not fix complement
Exam Question
  • The immunoglobulin involved in type I hypersensitivity reaction is IgE
  • IgE is inactive when the temperature is raised
  • Antibody with least serum concentration IgE
  • IgE is associated with allergic disorders
  • IgE shows homocytotropism
  • IgE is involved in anaphylaxis
  • IgE binds to basophils, Mast cells
Don't Forget to Solve all the previous Year Question asked on Immunoglobulin E