Abstract: Objective To study the influence of different immune adjuvants on the switch of antibody classes against pemphigus vulgaris antigen ECI-2 epitope(PVA ECI-2).Methods PVA ECI-2 fusion protein,combined with complete Freund's adjuvant(CFA)or aluminum hydroxide hydrate[Al(OH)₃],was used to immunize C57BL/6 mice.After immunization,the titers and subclasses of specific antibody as well as related cytokines were measured.The affinity of antibody subclasses with antigen and pathogenicity of antibody subclasses were studied by indiret immune-fluorescence(IIF)and in vitro culture of skin graft from neonatal mice,respectively.Results After immunization,the level of IFN-γa Thl type cytokine,was elevated in CFA group,while the level of IL-4,a Th2 type cytokine,was increased in Al(OH)₃ group.Specific antibodies were detected in both groups of mice.IgG2a subclass predominated in CFA group,but only IgG1 subclass was detected in the A1(OH)₃ group.IIF showed a weak fluorescence between the squamous epithelial cells with the addition of antisera from CFA group,but a relatively bright fluorescence with the addition of antisera from the AI(OH)₃ group.Furthermore,the in vitro culture of skin graft with the antisera from the AI(OH)₃ group showed intraepithelial blister,but that from the CFA group only showed mild acantholysis.Conclusion Different immune adjuvants may have direct influence on the antibody subclasses against PVA ECl-2.

Key words: Immunodominant epitopes, Adjuvants, immunologic, Pemphigus, Immunoglobulin G