LPS-induced inflammation in chickens decreased MHCII expression in splenic MRC1hiMHCIIlocells. Chickens were administered PBS or LPS (500 μL of 1 mg/kg body weight) i.p. for 4 h. Then, the spleen was collected and analysed to determine the A-C phenotype and D-F mRNA levels of potential mediators through flow cytometry and RT-qPCR, respectively. Representative histograms show the changes in A MRC1, B SSC, and C MHCII expression in the two subsets at 4 h after LPS injection. Solid histograms represent the PBS group, and dashed histograms show the LPS group. Dashed histograms without colour (left) and with colour (right) represent the isotype control. The bar graph represents the MFI of the expression (n = 10) **P < 0.01, ***P < 0.001. Transcriptional levels of D IL-10, E TGF-β, and F COX-2 in splenocytes were examined by RT-qPCR. The expression was normalized to the β-actin mRNA level (n = 10). Data are represented as the mean values ± SD. **P < 0.01.