title: Antiproliferative activity of Actinobacillus (Haemophilus) actinomycetemcomitans and Fusobacterium nucleatum in peripheral blood mononuclear cells.
abstract: Several studies indicate Actinobacillus (Haemophilus) actinomycetemcomitans and Fusobacterium nucleatum as etiologic agents of periodontal disease. Immunosuppressive factors produced by microorganisms probably contribute to the initiation and evolution of this disease. This study evaluated the antiproliferative activity of ammonium precipitate fractions of A. (H.) actinomycetemcomitans and F. nucleatum isolates from humans and marmosets both with and without periodontal disease. All A. (H.) actinomycetemcomitans and most F. nucleatum strains inhibited PBMC proliferation in a dose-dependent manner. The degree of cell proliferative inhibition of each bacterial species differed among the strains and was independent of host clinical status. The in vitro inhibition of stimulated lymphocyte proliferation induced by different A. (H.) actinomycetemcomitans and F. nucleatum isolates demonstrated the importance of this phenomenon in bacterial virulence, playing a possible suppressor role in host defense mechanisms in vivo. Moreover, our findings pointed out a marked difference between A. (H.) actinomycetemcomitans and F. nucleatum cytoplasmic extracts in their antiproliferative activity, regarding the antigen concentration required for maximum inhibition and their vulnerability to heating and proteolytic treatment.
authors.affiliation: Núcleo de Pesquisa em Imunologia, Faculdade de Ciências da Saúde-FACS, Universidade Vale do Rio Doce-UNIVALE, Gov. Valadares, MG, Brazil.
authors.forename: Carmen Helena Barbosa
authors.initials: CH
authors.lastname: do Vale
authors.forename: Lucia Alves
authors.initials: LA
authors.lastname: de Oliveira Fraga
authors.forename: Alexandre S
authors.initials: AS
authors.lastname: Costa
authors.forename: Carlos Alberto P
authors.initials: CA
authors.lastname: Tavares
authors.forename: Olindo Assis
authors.initials: OA
authors.lastname: Martins-Filho
authors.forename: Luiz
authors.initials: L
authors.lastname: de Macedo Farias
authors.forename: Maria Auxiliadora
authors.initials: MA
authors.lastname: Roque de Carvalho
mesh_terms: D000189:Actinobacillus Infections / Q000276:immunology / Q000382:microbiology; D000328:Adult; D016976:Aggregatibacter actinomycetemcomitans / Q000472:pathogenicity*; D000818:Animals; D002144:Callithrix; D002478:Cells, Cultured; D005260:Female; D005674:Fusobacterium Infections / Q000276:immunology / Q000382:microbiology; D016967:Fusobacterium nucleatum / Q000472:pathogenicity*; D006801:Humans; D007165:Immunosuppression Therapy; D007963:Leukocytes, Mononuclear / Q000276:immunology*; D008213:Lymphocyte Activation / Q000276:immunology* / Q000502:physiology; D008297:Male; D010510:Periodontal Diseases / Q000276:immunology* / Q000382:microbiology