Eosinophils express significant GPR65 promoter activity. GPR65^+/+ and GPR65^−/− (GFP knockin) peripheral blood was assessed for median GFP expression in the FL1 channel using flow cytometry. Cell types were defined as follows: T cells (CD3⁺), B cells (CD19⁺), neutrophils (CCR3⁻Gr-1^hi), and eosinophils (CCR3⁺Gr-1^lo). Quantification of a representative experiment is shown in panel A (n = 3 mice per genotype). (B) Histograms demonstrating GFP expression in different cell populations are shown. Results show the median FL1 ± SD. *P < .05. Representative experiment (of 4) is shown. (C) PCR analysis of GPR65 expression in cDNA made from human eosinophils and PBMC from 2 individual donors. −RT indicates negative control without reverse transcriptase.