[Interaction of thyroid hormones with immunoglobulins isolated from human blood serum. I. Parameters of complex formation and the nature of the binding reaction].
The kinetic and equilibrium characteristics of the interaction of thyroxine (T4) with immunoglobulins (Ig) A, G and M as well as with Bence-Jones proteins purified from human blood serum have been investigated. The formation of complexes between T4 and human immunoglobulins has been found to be time-dependent, reversible, saturable and sensitive to specific inhibitors. The L-chain (ae or lambda) is a component of the immunoglobulin molecular structure which appears to be essential and sufficient for the T4 binding. The covalent attachment of the H-chain can increase dramatically the affinity for the thyroid hormone (the mu-chain in IgM) or alter the sensitivity of the binding region to chemical agents and pH (the mu-chain in IgM, the gamma-chain in IgG). The experimental data suggest that the T4-binding IgM does not belong to a pathological type of proteins- anti-T4 autoantibodies-because: (i) the dependence of the T4 binding reaction on the physico-chemical conditions of the environment is typical of normal transport proteins; (ii) the prevalence of the T4-binding IgM in random individual serum samples from healthy subjects is 100%; (iii) the IgM-T4 complex differs structurally from the antigen-antibody complex, being unable to interact with the first complement component. The specific T4-binding properties of normal human serum immunoglobulins could remain so far unrecognized due to the inability of the conventional analytical methods to detect the weak manifestations of the T4-binding activity of these proteins in physiological fluids containing the endogenous inhibitor (Cl-), and/or the exogenous inhibitor (8-anilino-1-naphthalene sulphonic acid).
Sviridov
O V
OV
Ermolenko
M N
MN
D001323:Autoantibodies; D001536:Bence Jones Protein / Q000378:metabolism*; D001665:Binding Sites; D006801:Humans; D007147:Immunoglobulin Light Chains / Q000097:blood / Q000378:metabolism*; D007700:Kinetics; D013974:Thyroxine / Q000276:immunology / Q000378:metabolism*
D001323:Autoantibodies; D007147:Immunoglobulin Light Chains; D001536:Bence Jones Protein; D013974:Thyroxine
Vzaideĭstvie tireoidnykh gormonov s immunoglobulinami, vydelennymi iz syvorotki krovi cheloveka. I. Parametry kompleksoobrazovaniia i priroda reaktsii sviazyvaniia.