Mononuclear cell subsets in bronchoalveolar lavage fluid during Dictyocaulus viviparus infection of calves: a potential role for γ/δ TCR‐expressing cells in airway immune responses?

• Published in: Parasite immunology 2005-05, Vol.27 (5), p.151-161
• Main Authors: Hagberg, M., Wattrang, E., Niskanen, R., Tråvén, M., Höglund, J., Lundén, A.
• Format: Article
• Language: English
• Subjects: Animals; Antibodies, Helminth - blood; bronchoalveolar lavage; Bronchoalveolar Lavage Fluid - cytology; Bronchoalveolar Lavage Fluid - immunology; Cattle; cellular immunity; Dictyocaulus; Dictyocaulus - immunology; Dictyocaulus - pathogenicity; Dictyocaulus Infections - immunology; Dictyocaulus Infections - parasitology; Dictyocaulus viviparus; eosinophils; Female; Leukocyte Count; Lung - immunology; Lung - parasitology; Lung Diseases, Parasitic - immunology; Lung Diseases, Parasitic - parasitology; Male; mononuclear cells; parasitic bronchitis; Receptors, Antigen, T-Cell, gamma-delta - metabolism; ruminant; T-Lymphocyte Subsets - immunology; γ/δTCR
• ISSN: 0141-9838; 1365-3024
• DOI: 10.1111/j.1365-3024.2005.00757.x

SUMMARY Mononuclear cell populations in the lungs of calves infected with Dictyocaulus viviparus were studied during primary infection and reinfection in order to identify cells involved in development of protective immunity to parasitic bronchitis. Three groups of calves were either inoculated with 500 third‐stage larvae at both weeks 0 and 10 (n = 6), inoculated only at week 10 (n = 6), or remained uninfected (n = 3). The animals were monitored weekly by collection of bronchoalveolar lavage fluid (BALF), blood and faeces. Among mononuclear BALF‐cell populations, the γ/δ TCR‐expressing cells showed a pronounced transient increase in proportion as well as in relative cell size 2 weeks post primary infection, whereas CD4‐, CD8‐, Ig‐ and CD14‐expressing cells showed no significant differences related to the infection. The increase in γ/δ TCR‐expressing cells coincided with significantly increased proportions of eosinophils and recovery of adult worms in BALF. After reinfection, γ/δ TCR‐expressing cells increased again, but not until week 3 post inoculation, whereas eosinophils were increased by week 2 and reached higher levels than after primary infection. After reinfection, establishment of D. viviparus was less successful than after primary infection. In conclusion, these results indicate a role for γ/δ TCR‐expressing lymphocytes in the pathogenesis of D. viviparus infection.