Abstract
Background IgE and IgG4 are implicated in atopic development and clinically utilized as major biomarkers. Atopic responses following certain pathogens, such as Porphyromonas gingivalis (Pg), are currently an area of interest for further research. The aim of this study is to measure the level of IgE, IgG4, and IgG4/IgE ratio periodically after exposure of periodontal pathogen Pg lipopolysaccharide (LPS). Methods We used 16 Wistar rats (Rattus norvegicus) randomly subdivided into four groups: Group 1, injected with placebo; Group 2, injected with 0.3 µg/mL of Pg LPS; Group 3, injected with 1 µg/mL of Pg LPS; and Group 4, injected with 3 µg/mL of Pg LPS. Sera from all groups were taken from retro-orbital plexus before and after exposure. Results Levels of IgE and IgG4 increased significantly following exposure of Pg LPS at day-4 and day-11. Greater increase of IgE rather than IgG4 contributed to rapid decline of IgG4/IgE ratio, detected in the peripheral blood at day-4 and day-11. Conclusion Modulation of atopic responses following exposure to Pg is reflected by a decrease in IgG4/IgE ratio that accompanies an increase of IgE. Therefore, Pg, a keystone pathogen during periodontal disease, may have a tendency to disrupt atopic biomarkers.