ABSTRACT
Little information is available regarding the role of natural killer T (NKT) cells during the early stage of Rickettsia conorii infection. Herein, C3H/HeN mice were infected with the Malish 7 strain of R. conorii. Splenocytes from these mice were analysed in the early stage of the infection by flow cytometry and compared with uninfected controls. Our results showed an increase in NKT cells in infected mice. Additionally, NKT interleukin (IL)-17(+) cells increased three days after infection, together with a concurrent decrease in the relative amount of NKT interferon (IFN)-γ(+) cells. We also confirmed a higher amount of NK IFN-γ(+) cells in infected mice. Taken together, our data showed that NKT cells producing Il-17 increased during the early stage of rickettsial infection. These results suggest a connection between IL-17(+) NKT cells and vasculitis, which is the main clinical symptom of rickettsiosis.
Subject(s)
Boutonneuse Fever/immunology , Immunity, Cellular , Mice, Inbred C3H/microbiology , Natural Killer T-Cells/pathology , Rickettsia conorii/immunology , Spleen/pathology , Animals , Boutonneuse Fever/microbiology , Boutonneuse Fever/veterinary , Cells, Cultured , Mice , Mice, Inbred C3H/immunology , Natural Killer T-Cells/microbiology , Spleen/immunology , Spleen/microbiologyABSTRACT
A method to assess the expansion of antigen-specific intracellular IFN-γ positive T cell subsets during the infection will be helpful for a better understanding of mycoplasmal infections physiopathology in the sheep. We analysed the percentage of antigen-specific lymphocytes positive for intracellular IFN-γ during the infection of sheep with Mycoplasma agalactiae by culturing peripheral blood mononuclear cells of infected or uninfected animals with irradiated M. agalactiae. The expansion of antigen-specific IFN-γ positive lymphocytes in infected sheep was initially sustained by CD4(+) T cells at day 15 after infection, when antigen specific IgG start to be detectable, followed by CD8/IFN-γ double positive cells. γδ T-cells were not expanded at any time point analysed. IFNγ(+) T cells disappear 60 days after infection, suggesting that antigen specific IFNγ(+) T cells, mainly detected in the early phase of the disease, could be useful to understand the role of cell-mediated immunity during M. agalactiae infection.
