VARIABLE SERUM IMMUNOGLOBULIN-G IMMUNE-RESPONSE TO GENETICALLY DISTINCT EIKENELLA-CORRODENS STRAINS COEXISTING IN THE HUMAN ORAL CAVITY

This study examined the variable serum immunoglobulin G (IgG) levels t o genetically distinct autologous Eikenella corrodens strains by enzym e-linked immunosorbent assay (ELISA). Twenty subjects, including 10 ad ult periodontitis patients, 5 juvenile periodontitis patients and 5 pe riodontally healthy subjects were examined. Each subject was colonized by 2-8 genetically distinct E. corrodens strains. The serum IgG level s to autologous E. corrodens within individuals were significantly dif ferent in 7 adult periodontitis patients, 4 juvenile periodontitis pat ients and a periodontally healthy subject. Poor correlation was found in diseased subjects between serum IgG levels to autologous strains an d to reference strains ATCC 23834 or FDC 373. Four adult periodontitis patients and two juvenile periodontitis patients exhibited significan t serum IgG levels to autologous E. corrodens strains (two standard de viations above the mean for periodontally healthy subjects); two of th ese six diseased subjects exhibited low serum IgG levels to reference strains and would have been classified as low immune responders if onl y reference strains had been used in ELISA. This study showed the impo rtance of using autologous E. corrodens strains in the assessment of s erum IgG immune responses to this organism.