[The dependence of the antigen-binding activity of immunoglobulin preparations on their molecular composition].

The antigen-binding activity of commercial preparations of immunoglobulin with different molecular composition was studied in the enzyme immunoassay with Escherichia coli lipopolysaccharide and serogroup B Neisseria meningitidis protein antigen. Immunoglobulin preparations for intramuscular injection were found to possess higher specific antigen-binding activity than immunoglobulin preparations for intravenous injection, which was determined by both the presence of the highly active polymer and dimer fractions and greater specific activity of the monomer fraction. A group of intramuscular immunoglobulin preparations with a considerable content of polymers were found to have significantly greater specific activity than a group of preparations containing small amounts of polymers.