IL-17 and γδ T-lymphocytes play a critical role in innate immunity against Nocardia asteroides GUH-2

• Published in: Microbes and infection 2012-11, Vol.14 (13), p.1133-1143
• Main Authors: Tam, Stanley, Maksaereekul, Saipiroon, Hyde, Dallas M., Godinez, Ivan, Beaman, Blaine L.
• Format: Article
• Language: English
• Subjects: Animals; Bacteriology; Biological and medical sciences; Female; Fundamental and applied biological sciences. Psychology; Immunity, Innate; Interleukin-17; Interleukin-17 - immunology; Interleukin-17 - metabolism; Lung - immunology; Lung - microbiology; Mice; Mice, Inbred C57BL; Microbiology; Miscellaneous; Neutrophil; Neutrophil Infiltration - immunology; Neutrophils - immunology; Neutrophils - metabolism; Nocardia asteroides - growth & development; Nocardia asteroides - immunology; Nocardia Infections - immunology; Nocardia Infections - microbiology; Nocardiosis; Receptors, Antigen, T-Cell, gamma-delta - immunology; Receptors, Antigen, T-Cell, gamma-delta - metabolism; T-Lymphocyte Subsets - immunology; T-Lymphocyte Subsets - metabolism; T-lymphocytes
• ISSN: 1286-4579; 1769-714X
• DOI: 10.1016/j.micinf.2012.05.008

The early host response during pulmonary nocardiosis is highly dependent on neutrophils and the successful clearance of bacteria in tissue. The data presented in this study showed that IL-17 mediated the neutrophil response following intranasal inoculation with Nocardia asteroides strain GUH-2. Flow cytometry revealed that neutrophil levels in C57BL/6 mice were increased by day 1 post inoculation and remained elevated until day 3, during which time the majority of bacterial clearance occurred. Intracellular cytokine staining for IL-17 showed a 3.5- to 5-fold increase in IL-17 producing T-lymphocytes that were predominately comprised by CD4−CD8− γδ T-lymphocytes. The importance of IL-17 and γδ T-cells was determined by the in vivo administration of antibody, capable of blocking IL-17 binding or TCR δ, respectively. Neutralization of either IL-17 or γδ T-cells in Nocardia treated mice resulted in attenuated neutrophil infiltration. Paralleling this impaired neutrophil recruitment, nearly a 10-fold increase in bacterial burden was observed in both anti-IL-17 and anti-TCR δ treated animals. Together, these data indicate a protective role for IL-17 and suggest that IL-17 producing γδ T-lymphocytes contribute to neutrophil infiltration during pulmonary nocardiosis.