In this study the extraction and the immunochemical features of a lipopolysaccharide-like (LPSL) macromolecule of T denticola strains 35405,35404,33521 and 11 were investigated. The yield of LPSL molecule ranged between 0.5-0.9% of the cell dry weight, it possessed Limulus amebocyte lysate clotting activity, and it contained glucosamine, phosphate, heptose, glucose, small amounts of KDO, myristic and beta hydroxy myristic acid. Sera obtained from healthy individuals (ADA type I) periodontitis, from 3-8 month old infants, or the mouse monoclonal antibody, diluted 1 : 2, against T pallidum did not react with the LPSL antigens of i ? denticola strains 35405,35404,33521, and 11. Sera from patients with ADA type 111-IV periodontitis were reactive with two 8-14 kDa bands even at serum dilutions of 1 : 2000. Sera from patients with ADA type I1 periodontitis showed good antibody response to the 8-14 kDa band at a dilution of 1 : 50, but were weekly reactive, or nonreactive at serum dilutions of 1 : 200. This study indicates that extraction of a lipopolysaccharide-like macromolecule is feasible from the assay spirochetes, and this macromolecule may be used as an antigen for the diagnosis of ADAtypes 11-IV periodontitis.
An important factor in periodontal disease is the bacterial plaque. The microflora associated with periodontitis is heterogenous (LISTGARTEN and HELLDEN 1978, SLOTS 1982, MOORE 1987), but among the bacteria that are invariably present are spirochetes (LOESCHE 1988). Intermediate size oral spirochetes, including Treponema denticola, have been associated with acute necrotizing ulcerative gingivitis (OHTA et al. 1986). Four serovars a, b, c, d of 7: denticola have been described (CHENG et al. 1985, SIMONSON et al. 1988). 7: denticola produces immunosuppressive substances (BOEHRINGER et al. 1984), tissue damaging enzymes (OHTA et al. 1986), metabolic products (LOESCHE 1988), and cellular components (YOTIS et al. 1991, GOPALSAMI et al. 1991) which may be harmful. The host uses antibody prqduction to suppress the unwanted microorganism and to prevent future attacks by the same organism. Elevated levels of antibody of 7: denticola in sera of patients with advanced periodontitis have been reported using an enzyme-linked immunosorbent assay. Ten of I1 periodontitis patients had elevated levels of antibody to at least one of the three serovars a, b, c, of 7: denticola represented by ATCC strains 34505,33521 and 35404 respectively (JACOB et al. 1982). This study was conducted to search for major patterns of human immunological responses to T denticola using the immunoblotting assay. This sensitive assay provided some interesting information about the human antibody response to 7: denticola antigens that provoke this antibody response.
Methods
Microorganisms: T. denticola ATCC 35405, 33521, 35404 and a fresh isolate strain 11, representing serovars a, b, c and d were used in this investigation. All strains were isolated from periodontal patients. The spirochetes were cultured in prereduced GM-1 broth (BLAKEMORE and CANALE-PAROLA 1976), which was supplemented with 0.3 % (vol/vol) heat inactivated rabbit serum, and 2 pg/ml rifampin. The organisms