title: Preliminary Assessment of Various Additives on the Specific Reactivity of Anti- rHBsAg Monoclonal Antibodies.
abstract: BACKGROUND
  Antibodies have a wide application in diagnosis and treatment. In order to maintain optimal stability of various functional parts of antibodies such as antigen binding sites, several approaches have been suggested. Using additives such as polysaccharides and polyols is one of the main methods in protecting antibodies against aggregation or degradation in the formulation. The aim of this study was to evaluate the protective effect of various additives on the specific reactivity of monoclonal antibodies (mAbs) against recombinant HBsAg (rHBsAg) epitopes.
  
  
  METHODS
  To estimate the protective effect of different additives on the stability of antibody against conformational epitopes (S3 antibody) and linear epitopes (S7 and S11 antibodies) of rHBsAg, heat shock at 37°C was performed in liquid and solid phases. Environmental factors were considered to be constant. The specific reactivity of antibodies was evaluated using ELISA method. The data were analyzed using SPSS software by Mann-Whitney nonparametric test with the confidence interval of 95%.
  
  
  RESULTS
  Our results showed that 0.25 M sucrose, 0.04 M trehalose and 0.5% BSA had the most protective effect on maintaining the reactivity of mAbs (S3) against conformational epitopes of rHBsAg. Results obtained from S7 and S11 mAbs against linear characteristics showed minor differences. The most efficient protective additives were 0.04 M trehalose and 1 M sucrose.
  
  
  CONCLUSIONS
  Nowadays, application of appropriate additives is important for increasing the stability of antibodies. It was concluded that sucrose, trehalose and BSA have considerable effects on the specific reactivity of anti rHBsAg mAbs during long storage.
authors.affiliation: Infectious Diseases Research Center, Golestan University of Medical Sciences, Gorgan, Iran ; Department of Molecular Medicine, Faculty of Advanced Medical Technologies, Golestan University of Medical Sciences, Gorgan, Iran.
authors.forename: Yaghoub
authors.initials: Y
authors.lastname: Yazdani
authors.affiliation: Department of Molecular Medicine, Faculty of Advanced Medical Technologies, Golestan University of Medical Sciences, Gorgan, Iran.
authors.forename: Saeed
authors.initials: S
authors.lastname: Mohammadi
authors.affiliation: Department of Immunology, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran.
authors.forename: Mehdi
authors.initials: M
authors.lastname: Yousefi
authors.affiliation: Department of Immunology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran ; Monoclonal Antibody Research Center, Avicenna Research Institute, ACECR, Tehran, Iran.
authors.forename: Fazel
authors.initials: F
authors.lastname: Shokri
keywords: Epitopes; Monoclonal antibodies (mAbs); Polysaccharides