Distribution of biotypes and leukotoxic activity of Aggregatibacter actinomycetemcomitans isolated from Brazilian patients with chronic periodontitis

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Occurrence of Aggregatibacter actinomycetemcomitans in Brazilian indians from Umutina Reservation, Mato Grosso, Brazil

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Role of inflammatory mediators in priming, activation, and deformability of bovine neutrophils

Objective-To determine the capacity of inflammatory mediators tumor necrosis factor-alpha (TNF-alpha), interleukin-8 (IL-8), platelet-activating factor (PAF), lipopolysaccharide (LPS), and leukotoxin to prime, activate, or alter deformability of adult bovine neutrophils.Sample Population-Blood collected from 5 healthy adult Holstein cows.Procedure-Isolated neutrophils or whole brood was incubated with TNF-alpha, IL-8, PAF, LPS, or leukotoxin, and neutrophil chemiluminescence, degranulation, deformability, shape change, CD11b expression, and size distribution was measured.Results-incubation with TNF-alpha, IL-8; PAF, and IFS primed neutrophils for oxygen radical release but caused minimal oxygen radical release by themselves. None of the inflammatory mediators induced degranulation. Incubation with TNF-alpha and PAF resulted in a decrease in neutrophil deformability and induced shape change in neutrophils. incubation with PAF consistently resulted in an increase in neutrophil size as measured by use of flow cytometry. Only IL-8 caused an increase in expression of CD11b by neutrophils.Conclusions and Clinical Relevance-Inflammatory mediators tested had minimal effects on neutrophil oxygen radical production or degranulation but did prime neutrophils for oxygen radical production. Incubation with PAF and TNF-alpha caused a decrease in neutrophil deformability and altered neutrophil shape and size. Results of our study indicate that PAF- and TNF-alpha-induced changes in neutrophil deformability and size may cause integrin- and setectin-independent trapping of neutrophils in the lungs of cattle with pneumonic pasteurellosis.

Leukotoxic activity of Actinobacillus actinomycetemcomitans isolated from Brazilian periodontal patients

The leukotoxic activity of 31 Actinobacillus actinomycetemcomitans isolates from Brazilian periodontal patients [nine from Localized Juvenile Periodontitis (LJP) patients, 22 from patients with AIDS-associated Necrotizing Ulcerative Periodontitis (AIDS/NUP)], and from the reference strain A. actinomycetemcomitans ATCC43718, were analyses for their cytotoxicity on human monocytes. A cytotoxicity inhibitory assay of the isolate P35 and the reference strain ATCC 43718 with sera from ten LJP patients and ten healthy subjects was also performed and leukotoxin reactivity was evaluated with serum from rabbits immune to leukotoxin from A. actinomycetemcomitans ATCC 43718. The cytotoxicity results were not statistically different among groups of A. actinomycetemcomitans isolates from LJP and AIDS/NUP patients, but the individual analysis of each isolate showed two isolates (P24 and P35) from LJP patients with high leukotoxic activity (P<0.05). Also, a high leucotoxic inhibitory effect with LJP patients' sera compared with healthy subjects with sonic extract from isolate P35 (P<0.05) and the reactivity of rabbit antiserum to leukotoxin were observed. Both leukotoxic and non-leukotoxic activity is more frequent in PJL than AIDS/NUP patients. Even though A. actinomycetemcomitans exhibits leukotoxic activity, there is an immune response to the leucotoxin in LJP patients. (C) 2000 Academic Press.

Leukotoxicity of Aggregatibacter actinomycetemcomitans in generalized aggressive periodontitis in Brazilians and their family members

Objective: The purpose of this study was to examine the leukotoxin promoter types of Aggregatibacter actinomycetemcomitans clones in subjects with generalized aggressive periodontitis (GAgP) and in their family members (FM). Material and Methods: Thirty-five patients with GAgP (33.9+/-7.1 years), 33 of their FM (22.8+/-11.4 years), and 41 patients with chronic periodontitis (CP) (44.1+/-9.4 years) were clinically analyzed using the plaque index, gingival index, probing depth (PD), and clinical attachment level (CAL). Subgingival biofilm samples were collected from four interproximal periodontal sites (>PD and >CAL) of each patient. The presence of A. actinomycetemcomitans and its leukotoxic clone was confirmed by polymerase chain reaction (PCR). Results: A. actinomycetemcomitans was observed in 23 (51.1%) GAgP patients and 16 (30.1%) CP patients. Thirty-seven (94.8%) patients showed minimally leukotoxic strains and 2 (5.1%) showed highly leukotoxic strains. In the FM group, 10 (30.3%) had aggressive periodontitis (AgP), 12 (36.3%) had CP, 11 (33.3%) were periodontally healthy or had gingivitis, and 12.2% were A. actinomycetemcomitans positive. Greater full mouth PD and CAL were observed in GAgP patients positive for the bacteria than those negative for it (p<0.05), and the presence of A. actinomycetemcomitans positively correlated with GAgP (Odds ratio, 3.1; confidence interval, 1.4-7.0; p=0.009). Conclusions: The presence of A. actinomycetemcomitans was associated with the clinical condition of GAgP, with most patients exhibiting a generalized form of the disease and minimally leukotoxic clones. Most of the relatives of GAgP patients presented either CP or AgP.