title: Central role of interleukin-15 in postovulatory recruitment of peripheral blood CD16(-) natural killer cells into human endometrium.
abstract: A large number of CD16(-) natural killer (NK) cells appear in the human endometrium after ovulation. One possible explanation for this phenomenon is recruitment from peripheral blood (PB) CD16(-) NK cells. In this study, we examined whether IL-15 is involved in postovulatory recruitment from PB CD16(-) NK cells. The IL-15 receptor alpha chain was expressed on PB CD16(-) NK cells but not on CD16(+) NK cells. In an in vitro migration assay, recombinant human IL-15 enriched PB CD16(-) NK cells. Endometrial soluble protein fraction in the secretory phase, but not in the proliferative phase, also enriched these NK cells. Neutralization of IL-15 in the secretory phase endometrium with anti-IL-15 monoclonal antibody significantly lowered the enrichment of PB CD16(-) NK cells. In contrast, neutralization of other potential chemokines, including stromal cell-derived factor-1 or macrophage inflammatory protein-1alpha, had no significant effect. The IL-15 concentration in the endometrial soluble protein fraction was higher in the secretory phase than in the proliferative phase, with a peak in the midsecretory phase. These results support the idea that endogenous IL-15 in secretory phase endometrium plays a central role in postovulatory recruitment of PB CD16(-) NK cells into the human endometrium.
authors.affiliation: Department of Obstetrics and Gynecology, Kyoto Prefectural University of Medicine, 465 Kajii-cho, Kamigyo-Ku, Kyoto 602-8566, Japan. kitaya@koto.kpu-m.ac.jp
authors.forename: Kotaro
authors.initials: K
authors.lastname: Kitaya
authors.forename: Takeshi
authors.initials: T
authors.lastname: Yamaguchi
authors.forename: Hideo
authors.initials: H
authors.lastname: Honjo
mesh_terms: D000328:Adult; D002465:Cell Movement; D004717:Endometrium / Q000276:immunology*; D005260:Female; D006801:Humans; D019409:Interleukin-15 / Q000502:physiology*; D007694:Killer Cells, Natural / Q000502:physiology*; D008183:Luteal Phase / Q000276:immunology; D008597:Menstrual Cycle / Q000276:immunology; D017452:Receptors, IgG / Q000032:analysis*; D053647:Receptors, Interleukin-15; D015375:Receptors, Interleukin-2 / Q000032:analysis
chemical_list: C508024:IL15RA protein, human; D019409:Interleukin-15; D017452:Receptors, IgG; D053647:Receptors, Interleukin-15; D015375:Receptors, Interleukin-2