Induction of systemic murine B-cell responses by Fusobacterium nucleatum and Porphyromonas gingivalis.

The purpose of this study was to examine the antigenic abilities of Fusobacterium nucleatum strain ATCC 25586 and Porphyromonas gingivalis strain W50 black inbred BALB/cABom mice immunized subcutaneously. Furthermore, we aimed to analyze whether the outer membranes (OM) and whole cells (WC) of F. nucleatum or P. gingivalis had an effect on the levels of antibody response and whether a combination of both could either enhance or suppress the B-cell response. A single-cell assay, solid-phase enzyme-linked immunospot (ELISPOT), was used to analyze the splenic B-cell response (immunoglobulin A (IgA), IgG and IgM). Enzyme-linked immunosorbent assay (ELISA) and immunoblotting were used to verify the specific antibody response in the sera. A statistically significant lower level of spontaneous antibody production was observed in the group immunized with P. gingivalis OM compared with groups immunized with F. nucleatum and saline. The specific antibody titers measured by ELISA indicated that the bacterial preparations were able to induce IgG and IgM response. The preparations containing P. gingivalis OM induced higher humoral response than the preparations containing P. gingivalis WC, but for F. nucleatum such a difference was not observed. The prominent proteins revealed had apparent molecular masses of 40 kDa for F. nucleatum and 115, 55-56 and 43 kDa for P. gingivalis; whereas the immunoreactive proteins were 70, 65 and 40 kDa for mice immunized with F. nucleatum and 115, 55-56, 43 and 33-34 kDa for mice immunized with P. gingivalis. Quantitative analysis of B-cell response at the single cell level with ELISPOT revealed that some component(s) of P. gingivalis OM may have a suppressive ability on splenocytes incubated for a short time.

Spontaneous gingival antibody production to Fusobacterium nucleatum outer membrane in patients with adult periodontitis.

The local antibody response to Fusobacterium nucleatum outer membrane (FnOM) was analyzed in patients with adult periodontitis (AP) at the single cell level. Furthermore, we analyzed whether periodontal hygienic treatment could alter the antibody response. The number of IgG- and IgM-producing cells were investigated in gingival samples collected from 20 patients with AP. The patients were divided into 2 groups, before (BT, n = 9) and after (AT, n = 11) periodontal hygienic treatment. Four healthy gingival samples were used as controls. The results obtained showed that local antibody production against FnOM occurred in gingiva of patients with AP, but not in healthy gingiva. The IgG anti-FnOM was the predominant isotype observed. However, there was no statistically significant difference between the BT and AT groups. These results indicate that periodontal hygienic treatment was not sufficient to alter significantly the number of IgG- and IgM-secreting cells present in gingival tissue of AP patients, but it promoted a reduction of IgG anti-FnOM secreting cells. The presence of anti-FnOM antibodies in AP but not in control patients indicates that this bacteria may play a role in the pathogenesis of periodontal disease.

Epithelial expression of HLA class II antigens and Fc gamma receptors in patients with adult periodontitis.

The distribution of HLA class II (DR, DP, DQ) and Fc gamma R (I, II, III) was analyzed in the epithelia of patients with advanced marginal periodontitis using cryostat sections incubated with monoclonal antibodies (MoAb) against the Langerhans cell (LC) (CD1a) and various subtypes of HLA class II and Fc gamma R, and the indirect immunofluorescence technique. In the oral gingival epithelium (OGE), LC were concentrated subjacent to the connective tissue papillae, while in the pocket epithelium (PE), they were most abundant at the gingival margin. HLA-DP, DQ, and DR stained LC in both OGE and PE. HLA-DQ+ LC were significantly fewer than DP+ and DR+ LC. HLA-DR also stained keratinocytes (KC) in the whole extension of both OGE and PE. HLA-DP was also observed on KC, but not HLA-DQ. Fc gamma R II stained both LC and focal areas of KC. In PE FC gamma R II+ LC were concentrated near the bottom of the pocket, while in the OGE, they were concentrated at the gingival margin. Fc gamma R III was present only on KC, especially in the basal and suprabasal layer. The results indicate that the epithelial cells are actively involved in the development and maintenance of the inflammation of periodontal disease.