Actinobacillus pleuropneumoniae-induced thymic lesions in mice and pigs.
AUTOR(ES)
Stine, D L
RESUMO
Actinobacillus pleuropneumoniae produces several hemolysins/cytotoxins that may be important in the pathogenesis of acute lesions. Little is known, however, about the role of these virulence factors in chronic disease or the carrier state. We investigated the effects of live bacterial infection and transthoracic injection of a sterile culture supernatant on primary lymphoid organs and lymphocyte populations. Transthoracic inoculation of mice or intranasal inoculation of pigs with virulent A. pleuropneumoniae serotypes 1 and 7 induced thymic cortical lymphoid necrosis. These lesions were reproduced in mice by transthoracic injection of a concentrated sterile culture supernatant. The cytotoxic effect of this culture supernatant was also demonstrated in vitro by using a tetrazolium dye reduction assay. Both porcine and murine thymic lymphocytes as well as splenic T lymphocytes were susceptible to the toxin. Porcine convalescent serum, but not preimmune serum, prevented thymic lesions and neutralized the in vitro cytotoxic effect of the culture supernatant on murine thymic lymphocytes. Thymic lesions also were reproduced in mice by using purified lipopolysaccharide (LPS) from Escherichia coli O111:B4; however, LPS had no in vitro cytotoxic effect on either porcine or murine thymic lymphocytes. These results suggest that secreted A. pleuropneumoniae toxin(s) is capable of affecting host T-lymphocyte populations and may affect host immune function.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=258109Documentos Relacionados
- Endobronchial inoculation with Apx toxins of Actinobacillus pleuropneumoniae leads to pleuropneumonia in pigs.
- Antibody- and cell-mediated immune responses of Actinobacillus pleuropneumoniae-infected and bacterin-vaccinated pigs.
- In vivo association of Actinobacillus pleuropneumoniae serotype 2 with the respiratory epithelium of pigs.
- Phagocytosis and killing of Actinobacillus pleuropneumoniae by alveolar macrophages and polymorphonuclear leukocytes isolated from pigs.
- Evaluation of counterimmunoelectrophoresis for serotyping Actinobacillus pleuropneumoniae isolates and detection of type-specific antigens in lungs of infected pigs.