NoteA flow-cytometric method to evaluate eosinophil-mediated uptake of probiotic Lactobacillus reuteri

•A method for evaluating uptake of L. reuteri by mouse eosinophils is presented.•Cells that have incorporated fluorescent L. reuteri are detected by flow cytometry.•Kanamycin destroys exogenous L. reuteri but has no impact on eosinophil viability.•This quantitative assay may be used to evaluate eosinophils from gene-deleted mice.

Eosinophils are resident leukocytes of gut mucosa. Here we present a combined flow cytometric-antibiotic protection assay to identify mouse eosinophils capable of bacterial uptake, specifically, Gram-positive Lactobacillus reuteri, in studies performed ex vivo. The assay may be adapted for use in vivo.