Large-scale early in vitro response to actinobacillus actinomycetemcomitans suggests superantigenic activation of T-cells.
The mode of T-cell response to Actinobacillus actinomycetemcomitans is largely unknown. The present study sought to investigate the hypothesis that A. actinomycetemcomitans expresses superantigens, capable of antigen-non-specific T-cell activation. To that end, peripheral blood mononuclear cells were stimulated with A. actinomycetemcomitans, and T-cell expression of the early activation marker, CD69, was determined by flow cytometry. Results showed that A. actinomycetemcomitans activated a large number of T-cells with magnitude similar to that of staphylococcal enterotoxin superantigens. A. actinomycetemcomitans sonicate preferentially activated T-cells expressing Vbeta5.1 and Vbeta8, while the extracellular preparation activated Vbeta5.1+, Vbeta8+, and Vbeta12+ T-cells. T-cell response to A. actinomycetemcomitans was observed in the presence of autologous, as well as heterologous, antigen-presenting cells, suggesting a MHC-non-restricted response. Thus, the in vitro response to A. actinomycetemcomitans is characterized by large-scale T-cell activation in a Vbeta-specific and MHC-non-restricted manner, consistent with the involvement of superantigens.
Department of Periodontology, University of Southern California, School of Dentistry, Los Angeles 90098, USA. zadeh@hsc.usc.edu
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D016976:Aggregatibacter actinomycetemcomitans / Q000276:immunology*; D000911:Antibodies, Monoclonal; D000938:Antigen-Presenting Cells / Q000276:immunology; D000942:Antigens, Bacterial / Q000276:immunology*; D015703:Antigens, CD / Q000276:immunology; D000945:Antigens, Differentiation, T-Lymphocyte / Q000276:immunology; D017252:CD3 Complex / Q000276:immunology; D005434:Flow Cytometry; D019085:Fluorescent Antibody Technique, Direct; D006801:Humans; D037181:Lectins, C-Type; D008213:Lymphocyte Activation / Q000276:immunology*; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000276:immunology; D018089:Superantigens / Q000276:immunology*; D016176:T-Lymphocyte Subsets / Q000276:immunology*; D000099192:CD69 Antigens
D000911:Antibodies, Monoclonal; D000942:Antigens, Bacterial; D015703:Antigens, CD; D000945:Antigens, Differentiation, T-Lymphocyte; D017252:CD3 Complex; D037181:Lectins, C-Type; D016693:Receptors, Antigen, T-Cell, alpha-beta; D018089:Superantigens; D000099192:CD69 Antigens