Description: IgG is the major immunoglobulin in blood, lymph fluid, cerebrospinal fluid, and peritoneal fluid and a key player in the humoral immune response. The Fc portion of IgG, but not F(ab')2 or Fab fragments, can cross the placenta of a mother to enter the fetal circulation providing the fetus with postpartum protection.
IgG molecules are able to react with Fc-gamma receptors that are present on the surfaces of macrophages, neutrophils, natural killer cells, and can activate the complement system.
The binding of the Fc portion of IgG to the receptor present on a phagocyte is a critical step in the opsonizing property IgG provides to the immune response. Phagocytosis of particles coated with IgG antibodies is a vital mechanism to cope with microorganisms.
Recently it became evident that certain inbred strains of mice such as C57Bl/6, C57Bl/10, SJL, and NOD with the Igh1-b allele do not have the gene for IgG2a but instead express IgG2c. Since commercially available Mouse IgG2a ELISA only inadequately cross react with Mouse IgG2c, eBioscience has developed an ELISA specifically for the detection of murine IgG2c isotype.