Production of monoclonal antibodies that recognize specific and cross-reactive antigens of Fusobacterium nucleatum

Limit dilution analysis of peripheral blood T lymphocytes specific to periodontopathic bacteria

Limit dilution analysis (LDA) was used to determine the presence and frequency of periodontopathic-bacteria-specific T cells in the peripheral blood of patients with chronic inflammatory periodontal disease. Twelve adult periodontitis (AP), 13 marginal gingivitis (MG) and 12 healthy control subjects took part in the study. Bacteroides gingivalis and Actinomyces viscosus were used as test organisms, while tetanus toxoid was used as the control antigen. The median PTL-p frequencies to B. gingivalis were 46.33 x 10(-6), 45.33 x 10(-6) and 58.83 x 10(-6) in the control, gingivitis and AP groups respectively, while the median PTL-p frequencies to A. viscosus were 13.8 x 10(-6), 17.33 x 10(-6) and 11.5 x 10(-6), again in the control, gingivitis and AP groups. There were no statistically significant differences between the groups. All subjects displayed 'single-hit' kinetics with the control tetanus toxoid antigen and, with three exceptions, 'single-hit' kinetics was also found with the two test organisms. One control subject displayed a 'saw-tooth' curve with A. viscosus and a 'suppressor' curve with B. gingivalis, while two MG subjects had a 'saw-tooth' curve with B. gingivalis. These complex curves suggest that, in some subjects, more than one limiting cell type may exist in the cultures. Nevertheless, the results of the present study illustrate that lymphocytes specific to periodontopathic bacteria exist in the peripheral blood of both diseased and non-diseased subjects.

Interleukin-1 and interleukin-1 inhibitor production by human adherent cells stimulated with periodontopathic bacteria

This study examined the effect of the putative periodontopathic bacteria Bacteroides gingivalis and Fusobacterium nucleatum on the production of interleukin-1 (IL-1) and IL-1 inhibitors by human plastic-adherent mononuclear cells from normal donors. Fusobacterium mortiferum was used as a non-oral, non-pathogenic control organism. Unstimulated adherent cells spontaneously secreted an IL-1 inhibitor, whereas stimulation with B. gingivalis induced the synthesis and secretion of IL-1. With both fusobacteria IL-1 was present in the intracellular environment, whereas the predominant secretory product was either IL-1 or an IL-1 inhibitor. These results suggest that bacteria are capable of modulating cytokine production by monocytes and may thereby alter the local immune response.

An immunohistopathological characterisation of mixed non-seminomatous germ cell tumors

Immunohistological techniques were used to characterise inflammatory cell infiltrates in mixed germ cell tumours. The distribution of these infiltrates was much more variable than in pure seminomas but could not be related accurately to any particular tumour type. There were approximately equal numbers of B and T cells in these areas and helper/inducer T cells were more common than suppressor/cytotoxic lymphocytes. Within these areas of inflammatory cells, the subtype composition was similar to that seen in pure seminomas.

Monoclonal antibodies against bacteria

Highlights are presented of most recent work in which monoclonal antibodies have been instrumental in the study of bacteria and their products. Topics summarized pertain to human and veterinary medicines, dentistry, phytopathology, ichthyology, and bacterial ecophysiology, differentiation, evolution and methanogenic biotechnology.

Immunohistological analysis of experimental gingivitis in humans

Immunohistological analysis of experimental gingivitis in humans was carried out to provide a baseline for the study of immunoregulatory mechanisms in chronic inflammatory periodontal disease. Using a panel of monoclonal antibodies in an avidin biotin immunoperoxidase technique, T cell subsets were identified and the pattern of Class II major histocompatibility complex (MHC) antigens determined. Twenty third-year dental students took part in the study. Following the cessation of oral hygiene procedures, gingival biopsies were taken from each of five students at days 0, 4, 8 and 21 during the development of the inflammatory lesion. Each student had one biopsy which healed uneventfully. The T4:T8 ratio showed only slight variation over the time course of the lesion varying from 2.18:1 at day 0 to 2.48:1 at day 4. At all stages the T cells displayed both HLA-DR and HLA-DQ antigens, but less than 10% had detectable IL-2 receptors. The predominant macrophage population was acid phosphatase + ve, adenosine triphosphatase -ve, HLA-DR+ and HLA-DQ+ antigens suggesting an activated phagocytic population. During the development of the lesion, the number of intraepithelial Langerhans cells (T6+) increased but there appeared to be a discrepancy between HLA-DR and HLA-DQ expression on these cells. Similarly, the keratinocytes expressed HLA-DR but failed to express HLA-DQ at any stage. These results suggest that the developing gingival lesion is a well controlled lesion and follows a similar pattern to a controlled delayed type hypersensitivity (DTH) response.