ABSTRACT
@#Abstract： Thimerosal is commonly used as a preservative in biological products，especially in vaccines. Although it has been removed from single ⁃ dose vaccines in most countries，thimerosal is still widely used in multi ⁃ dose vaccines at present. Thimerosal，as a component in vaccine preparation，should be compatible with other components，especially should not damage the activity of antigen. However，in recent years，many studies have reported that thiomersal can reduce the antigenicity and immunogenicity of vaccine antigens，especially protein antigens containing or rich in cysteine（Cys）， suggesting that the effect of thimerosal on vaccine antigen activity should be fully evaluated when it is used as a vaccine preservative. In this paper，the effects of thimerosal on antigenicity and immunogenicity of two inactivated vaccines and three recombinant protein vaccines and the possible mechanisms were reviewed，in order to provide reference for rational selection of vaccine preservatives.
ABSTRACT
Thimerosal has been widely used as a preservative in drug and vaccine products for decades.Due to the strong propensity to modify thiols in proteins,conformational changes could occur due to covalent bond formation between ethylmercury(a degradant of thimerosal)and thiols.Such a conformational change could lead to partial or even complete loss of desirable protein function.This study aims to investigate the effects of thimerosal on the capsid stability and antigenicity of recombinant human papillomavirus(HPV)18 virus-like particles(VLPs).Dramatic destabilization of the recombinant viral capsid upon thimerosal treatment was observed.Such a negative effect on the thermal stability of VLPs preserved with thimerosal was shown to be dependent on the thimerosal concentration.Two highly neutralizing antibodies,13H12 and 3C3,were found to be the most sensitive to thimerosal treatment.The kinetics of antigenicity loss,when monitored with 13H12 or 3C3 as probes,yielded two distinctly different sets of kinetic parameters,while the data from both monoclonal antibodies(mAbs)followed a biphasic expo-nential decay model.The potential effect of thimerosal on protein function,particularly for thiol-containing proteinaceous active components,needs to be comprehensively characterized during formulation development when a preservative is necessary.