INTERACTION OF OLIGONUCLEOTIDES WITH BLOOD-SERUM PROTEINS

The interaction of alkylating derivatives of deoxyribonucleotides whos e 5'-terminal phosphate group contains 4-[(N-2-chloroethyl-N-methyl)am ino]benzylamine with blood serum proteins was studied Incubation of hu man whole serum with different concentrations of alkylating derivative of p(T)(16) induced affinity modification of several proteins, includ ing albumin and immunoglobulins M and G. The dependence of their modif ication on oligonucleotide concentration showed the higher affinity of the oligonucleotide for IgM in comparison with the two other proteins . Binding of activated oligonucleotides to proteins was inhibited by t he presence of various polyanions: other oligonucleotides, double-stra nded DNA, and heparin. The latter possesses the highest inhibiting eff ect for immunoglobulins, suggesting a relatively nonspecific ionic int eraction during formation of the IgG-oligonucleotide complex. The inte raction of oligonucleotide with GI subtype mouse monoclonal antibodies was inhibited by specific antigen. This suggests a possible interacti on of oligonucleotides with immunoglobulins either at or near the site of antigen recognition.