Figure 1

An increased number of monocytes characterized by low expression levels of MHC-II molecules is observed in chickens infected with Av. paragallinarum. Mononuclear cells isolated from blood samples were incubated with different antibody cocktails. A Gating strategy used to analyse mononuclear cells. We gated out debris, doublets, and dead cells (Sytox blue positive cells), and evaluated the percentages of CD3⁺TCRγδ⁺ cells, CD3⁺TCRγδ⁻ cells, and Bu-1⁺ cells (B cells). The percentages of CD4⁺ and CD8α⁺ cells were evaluated inside the CD3⁺TCRγδ⁻ gate. The percentage of CD8α⁺ cells was also evaluated inside the CD3⁺TCRγδ⁺ gate. The dashed arrow indicates the strategy used to evaluate the populations of monocytes (MRC1L-B⁺) and other APC (MHC-II⁺MRC1L-B⁻) using another antibody cocktail. B Quantitative data regarding the percentages of CD3⁺TCRγδ⁻ cells, CD3⁺CD4⁺TCRγδ⁻ cells, CD3⁺CD8α⁺TCRγδ⁻ cells, Bu-1⁺ cells, CD3⁺TCRγδ⁺ cells, CD3⁺TCRγδ⁺CD8α⁺ cells, monocytes and other APC in infected and uninfected animals. The data are presented as percentages of Sytox blue negative cells. Each dot represents an animal. Significant differences are indicated by *p = 0.0317. The results are expressed as the mean ± standard deviation values. A total of 30,000 events per sample were acquired using a Gallios flow cytometer. C The figure on the left shows the percentage of monocytes in whole blood. The figure on the right shows the absolute monocyte counts. D PBMC or whole blood were used to evaluate MHC-II expression in the monocyte population and MHC-II⁺MRC1L-B⁻ population. The gate used to identify this population is shown in A. Each dot represents an animal, and the mean values ± standard deviations are indicated by the bars. Significant differences are indicated by *p = 0.0286 and **p = 0.0023. A total of 30,000 events were acquired for analysis of PBMC, and 300,000 events per sample were acquired for analysis of whole blood samples using a FACSMelody flow cytometer.