Effect of succinylation of antibodies on their conformation and interaction with the antigen

Abstract

Using succinic anhydride, a succinylated derivative of anti-urease IgG having 49 +/- 6% modification was prepared and its physicochemical and immunological properties were studied. IgG undergoes substantial changes in its native conformation on succinylation, which was mainly attributed to electrostatic destabilization of the native protein conformation. The modified IgG exhibited a decrease in its cross-reactivity with urease. This decrease is attributed to the conformational change in IgG upon succinylation and/or is due to the disruption of the lysine residues in the antigen-binding site of IgG upon succinylation, which may be involved in binding the antigen. IgG was able to bind to the specific antigen although its conformation was partially modified. Therefore, partial modification of the conformation of the antigen-binding site of IgG is permissible in order to bind to the antigen.

Effects of Charge on Antibody Tissue Distribution and Pharmacokinetics

“…While it may seem counterintuitive that both cationization and anionization increase plasma clearance, different underlying mechanisms are involved: tissue sequestration in the former case, and more rapid whole body clearance in the latter. Various anionic groups may be exploited for this type of modification, including DTPA , 1,4,8,11-tetraazacyclododecane- N , N ′, N′′ , N′′′ -tetraacetic acid (DOTA) , , and succinic acid (Figure c). Similar induction of negative charge is imparted by protein conjugation to 1,4,8,11-tetraazacyclotetradecane- N , N ′, N′′ , N′′′ -tetraacetic acid (TETA) , and other polyaminopolycarboxylate chelates that are routinely used in radiopharmaceutical applications , .…”

“…In contrast, modified antibodies having more acidic pI values (Table , Anionized/Neutralized Antibodies) displayed decreased tissue uptake and increased whole-body (including blood) clearance. Nevertheless, cautious interpretation of data must be exercised due to additional consequences of charge modification beyond electrostatic interactions, such as conformational changes in overall antibody structure and steric effects . It is also plausible that chemical modification of antibodies may, in some cases, deleteriously impact an antibody’s binding affinity to FcRn which, in turn, could trigger a reduction in serum half-life − .…”

Effect of lysine modification on the stability and cellular binding of human amyloidogenic light chains

“…16 significantly impair antigen recognition, presumably as a result of altered conformation [32]. Further, reduced immune function in patients with diabetes has been attributed to lack of antigen recognition induced by adduction of glucose to lysine residues on IgG variable regions [33].…”