title: The Discovery of Streptomycin-binding IgG and Its Distribution in the Population.
abstract: It was found by using several immunochemistry methods that a kind of immunoglobulin G (IgG) which accounted for 0.5%-1% of the total IgG in human, rabbit or mice with no history of taking any streptomycin could bind specifically with the antibiotic. Although the IgG-binding action has not relation with the specificity of the antibody, the streptomycin-binding area was found to be on the antigen-binding region of Fab fragment of the antibody. This kind of IgG was termed streptomycin-binding IgG (SMBIgG) which may be capable of catalyzing the metabolism of streptomycin. The average content of SMBIgG in human and rabbit sera is about 0.1 mg/ml, with no samples with a lower level than the mean value, but in a few cases levels two or three times higher than the mean were detected. Further study indicated that the ratio of SMBIgG to total IgG is nearly constant in the population. The discovery of SMBIgG in the normal body and its catalytic characteristic may be very helpful for understanding some of the special physiological functions of the antibody in the organism.
authors.affiliation: National Institute for the Control of Pharmaceutical and Biological Products, Beijing 100050, China.
authors.forename: Chang-Qin
authors.initials: CQ
authors.lastname: Hu
authors.forename: Xin
authors.initials: X
authors.lastname: Hu
authors.forename: Shao-Hong
authors.initials: SH
authors.lastname: Jin