Lymphoid cell responses to bacterial cell wall components: murine B-cell responses to a purified cell wall moiety of Actinomyces

Lack of effects on lymphocyte function from chronic topical ocular cyclosporine medication: a prospective study

AIM

Topical cyclosporine has been widely used in the treatment of canine keratoconjunctivitis sicca without apparent documented clinical side effects. Thus the finding of reduced lymphocyte proliferation in animals treated with the drug at a concentration of 2% was both surprising and concerning. This study aimed to repeat the previous study and to compare the systemic effects of 2% cyclosporine in corn oil and 0.2% topical cyclosporine ointment (Optimmune, Intervet-Schering Plough, Welwyn, UK).

METHODS

Twenty dogs treated with Optimmune or with topical 2% cyclosporine in corn oil where previous treatment with Optimmune had failed were included in this study. Blood samples were taken at the time of first evaluation and at 1, 3 and 6 months of treatment to provide a biochemical and hematological health evaluation of the dogs and at each examination to measure circulating levels of cyclosporine and to obtain a lymphocyte population with which to determine a mitogen stimulation index (MSI) on treatment with phytohaemagglutinin-P (PHA) and conconavlin A (con-A). Levels of circulating cyclosporine were measured with an enzyme-multiplied immunoassay method and also the more sensitive quantification technique of mass spectroscopy (MS).

RESULTS

No blood samples contained over 15 ng/ml cyclosporine, the lower limit of detection using the radioimmunoassay or the enzyme-multiplied immunoassay technique. Positive control samples taken from dogs treated with oral cyclosporine for anal furunculosis showed measurable levels in blood, demonstrating that the technique worked. Mean MSI values at 0, 1, 3 and 6 months of treatment were 10.2, 11.4, 11.6, and 10.5 for dogs treated with 0.2% cyclosporine and 10.4, 11.9, 11.7, and 12.9 for dogs treated with 2% cyclosporine. Mitogen stimulation index values were not statistically different between the first examination and any subsequent examination time-point.

CONCLUSIONS

The findings of the study contradict those of the previous studies. No change in lymphocyte stimulation index was noted, neither were significant blood levels of cyclosporine documented after topical administration of either 0.2% or 2% cyclosporine. This study shows that topical cyclosporine is safe to use in the canine eye in line with the drug's safety record in this therapeutic regime over the past 20 years since its first use.

Characterization and immunobiologic activities of lipopolysaccharides from periodontal bacteria

Bacterial surface structures play a critical role in the initiation of infectious diseases. Various surface components of pathogenic bacteria have been reported to be involved in host injury. There is a great deal of evidence incriminating certain Gram-negative, anaerobic bacteria present in the gingival crevice as etiologic agents of human periodontal diseases. We have isolated endotoxic cellular components from suspected periodontopathic bacteria and examined their immunobiological activities. Lipopolysaccharides (LPS) and lipid-associated proteoglycans (LPG) were prepared from whole cells by the phenol-water and butanol-water procedures, respectively. LPS from Bacteroides gingivalis, B. intermedius, B. oralis, and B. loescheii, Fusobacterium nucleatum and F. necrophorum, and Actinobacillus (Haemophilus) actinomycetemcomitans were found to possess biological activities comparable with those of LPS from E. coli K235 in terms of activation of Limulus lysate, B-cell mitogenicity, polyclonal B-cell activation, induction of bone resorption, and IL-1 production by macrophages. These LPS contained mainly sugars, amino sugars, and fatty acids. No heptose or 2-keto-3-deoxyoctonate (KDO) was detected in the Bacteroides LPS, while LPS from Actinobacillus and Fusobacterium species contained significant amounts of heptose as well as small quantities of KDO. Bacteroides LPS were clearly mitogenic for spleen cells of C3H/HeJ mice, which are non-responsive to LPS from E. coli, A. actinomycetemcomitans, and Fusobacterium species. Furthermore, polymyxin B was found to abrogate the mitogenic activity of LPS from E. coli, Actinobacillus, and Fusobacterium species, but not those from Bacteroides species. Spleen cells from both C3H/HeN and C3H/HeJ mice responded to all butanol-water-extracted LPG preparations, including those from E. coli, A. actinomycetemcomitans, and Fusobacterium species. It may be concluded that LPS and LPG isolated from suspected periodontopathic bacteria possess marked immunobiological potencies on lymphoreticular and bone cells.