Figure 5

Natural killer cells are predominant IFN-γ secretors in response to Mycoplasmopsis bovis. PBMCs from 8 individual animals were either for 18 h unstimulated or stimulated with M. bovis (live or heat-inactivated). Stimulations were run at 37 °C. A Cytokine/chemokine secretion in supernatants of PBMC cultures, using Multiplex immunoassay. A single measurement was done per samples tested, and each symbol represents an individual cow. Heat map shows log₂-fold changes in concentration of 15 Cytokines/chemokines. For a given cytokine/chemokine, normalization was as follow: [concentration for a given animal] / [average concentration of reference points for 8 animals]. B Correlation coefficient (r) obtained with percentage of IFN-γ⁺ cells for different immune cell subsets (measured by FCM) calculated as a function of IFN-γ concentration (pg/mL) in culture supernatant (measured by multiplex immunoassay). Significance was reached for all immune cell subsets, excepting γδ T cells. Each symbol represents an individual animal. Stars indicate significance levels. ***, p < 0.001; ****, p < 0.0001; ns: not significant. C FCM contour plots from a representative animal, gated on γδ T cells, CD21^low B cells or NK cells. Numbers indicate the percentage of IFN-γ⁺ cells for this specific animal. Notably, a clear activation (intracellular IFN-γ detection) of NK cells is found, with almost 40% of positive cells in optimal cell culture conditions.