Differential cellular immune response of Galleria mellonella to Actinobacillus pleuropneumoniae

• Published in: Cell and tissue research Vol. 370; no. 1; pp. 153 - 168
• Main Authors: Arteaga Blanco, Luis Andrés, Crispim, Josicelli Souza, Fernandes, Kenner Morais, de Oliveira, Leandro Licursi, Pereira, Monalessa Fábia, Bazzolli, Denise Mara Soares, Martins, Gustavo Ferreira
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.10.2017; Springer; Springer Nature B.V
• Subjects: Actinobacillus Infections - immunology; Actinobacillus Infections - veterinary; Actinobacillus pleuropneumoniae - immunology; Animals; Apoptosis; Autophagy; Bacteria; Biomedical and Life Sciences; Biomedicine; Butterflies & moths; Caspase; Caspase-3; Cell activation; Cell Count; Cell death; Gram-negative bacteria; Hemocytes; Hemocytes - cytology; Hemocytes - immunology; Hemocytes - microbiology; Human Genetics; Immune response; Immune response (cell-mediated); Immunity, Cellular; Larva - cytology; Larva - immunology; Larva - microbiology; Larvae; Leukocytes (granulocytic); Molecular Medicine; Moths - cytology; Moths - growth & development; Moths - immunology; Moths - microbiology; Pathogens; Plasmatocytes; Proteomics; Regular Article; Strains (organisms); Virulence; Virulence (Microbiology); Autophagy; Immune response; Apoptosis; Galleria mellonella; Actinobacillus pleuropneumoniae
• ISSN: 0302-766X; 1432-0878
• DOI: 10.1007/s00441-017-2653-5

In the present work, we have investigate the cellular immune response of Galleria mellonella larvae against three strains of the gram-negative bacterium Actinobacillus pleuropneumoniae : low-virulence (780), high-virulence (1022) and the serotype 8 reference strain (R8). Prohemocytes, plasmatocytes, granulocytes, oenocytoids and spherulocytes were distinguished according to their size and morphology, their molecular markers and dye-staining properties and their role in the immune response. Total hemocyte count, differential hemocyte count, lysosome activity, autophagic response, cell viability and caspase-3 activation were determined in circulating hemocytes of naive and infected larvae. The presence of the autophagosome protein LC3 A/B within the circulating hemocytes of G. mellonella was dependent on and related to the infecting A. pleuropneumoniae strain and duration of infection. Hemocytes treated with the high-virulence strain expressed higher levels of LC3 A/B, whereas treatment with the low-virulence strain induced lower expression levels of this protein in the cells. Moreover, our results showed that apoptosis in circulating hemocytes of G. mellonella larvae after exposure to virulent bacterial strains occurred simultaneously with excessive cell death response induced by stress and subsequent caspase-3 activation.