Frontline Science: Cytokine-mediated developmental phenotype of mouse eosinophils: IL-5-associated expression of the Ly6G/Gr1 surface Ag. Issue 3 (1st November 2019)

• Record Type: Journal Article
• Authors: Limkar, Ajinkya R.; Mai, Eric; Sek, Albert C.; Percopo, Caroline M.; Rosenberg, Helene F.
• Is Part Of: Journal of leukocyte biology. Volume 107:Issue 3(2020)
• Page Start: 367
• Page End: 377
• Publication Date: 2019-11-01
• Subjects: cytokine -- interleukin-5 -- eotaxin-1 -- hematopoiesis -- chemotaxis; Leucocytes -- Periodicals; Reticulo-endothelial system -- Periodicals; 571.96
• DOI: 10.1002/JLB.1HI1019-116RR
• Languages: English
• ISSNs: 0741-5400

Abstract

Abstract: Eosinophils have broad and extensive immunomodulatory capacity; recent studies have focused on the roles of distinct eosinophil subsets in specific tissue microenvironments. Ly6G is a GPI-linked leukocyte surface Ag understood primarily as a marker of mouse neutrophils, although its full function is not known. Here, we show that Ly6G/Gr1, detected by mAbs 1A8 (anti-Ly6G) and RB6-8C5 (anti-Gr1), is detected prominently on a significant fraction of eosinophils from mouse bone marrow and bone marrow-derived culture, with fractions expressing this Ag increasing in IL-5-enriched microenvironments. Among our findings, we identified SiglecF + Gr1 + eosinophils in bone marrow from naïve, allergen-challenged and IL-5 transgenic mice; SiglecF + Gr1 + eosinophils were also prominent ex vivo in bone marrow-derived eosinophils (bmEos) in IL-5-enriched culture. Reducing the IL-5 concentration 20-fold had no impact on the rate of generation of SiglecF + bmEos but did result in a marked increase in the Gr1 − fraction (from 17.4 ± 2% to 30 ± 2.3%, *** P < 0.005). Reducing the IL-5 concentration also enhanced chemotaxis; SiglecF + Gr1 − bmEos were considerably more responsive to eotaxin-1 than were their SiglecF + Gr1 + counterparts. These results suggest that (i) IL-5 regulates the expression of Ly6G/Gr1, either directly or indirectly, in cells of the eosinophil lineage, (ii) eosinophils generated in response to high concentrations of IL-5 can be distinguished from those generated under homeostatic conditions by expression of the Ly6G/Gr1 cell surface Ag, and (iii) expression of Ly6G/Gr1 may have an impact on function, directly or indirectly, including the potential to undergo chemotaxis in response to eotaxin-1.