title: EFFECT OF LIPOSOMAL CLODRONATE-DEPENDENT DEPLETION OF PROFESSIONAL ANTIGEN PRESENTING CELLS ON NUMBERS AND PHENOTYPE OF CANINE CD4+CD25+FOXP3+ REGULATORY T CELLS.
abstract: Regulatory T cells (Tregs) are known to control autoreactivity during and subsequent to the development of the peripheral immune system. Professional antigen presenting cells (APCs), dendritic cells (DCs) and monocytes, have an important role in inducing Tregs. For the first time, this study evaluated proportions and phenotypes of Tregs in canine peripheral blood depleted of professional APCs, utilizing liposomal clodronate (LC) and multicolor flow cytometry analysis. Our results demonstrate that LC exposure promoted short term decreases followed by significant increases in the proportions or absolute numbers of CD4+CD25+FOXP3+Tregs in dogs. In general, the LC-dependent Treg fluctuations were similar to the changes in the levels of CD14+monocytes in Walker hounds. However, the proportions of monocytes showed more dramatic changes compared to the proportions of Tregs that were visually unchanged after LC treatment over the study period. At the same time, absolute Treg numbers showed, similarly to the levels of CD14+monocytes, significant compensatory gains as well as the recovery during the normalization period. We confirm the previous data that CD4+T cells with the highest CD25 expression were highly enriched for FOXP3. Furthermore, for the first time, we report that CD4+CD25lowFOXP3+is the major regulatory T cell subset affected by LC exposure. The increases within the lowest CD25 expressers of CD4+FOXP3+cells together with compensatory gains in the proportion of CD14+monocytes during compensatory and normalization periods suggest the possible direct or indirect roles of monocytes in active recruitment and generation of Tregs from naïve CD4+T cells.
authors.affiliation: Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, 240 Wise Center Drive, Mississippi State, MS 39762, USA.
authors.forename: Kriston F
authors.initials: KF
authors.lastname: Weaver
authors.affiliation: Department of Clinical Sciences, College of Veterinary Medicine, Mississippi State University, 240 Wise Center Drive, Mississippi State, MS 39762, USA.
authors.forename: John V
authors.initials: JV
authors.lastname: Stokes
authors.forename: Sagen A
authors.initials: SA
authors.lastname: Gunnoe
authors.forename: Joyce S
authors.initials: JS
authors.lastname: Follows
authors.forename: Lydia
authors.initials: L
authors.lastname: Shafer
authors.forename: Mais G
authors.initials: MG
authors.lastname: Ammari
authors.forename: Todd M
authors.initials: TM
authors.lastname: Archer
authors.forename: John M
authors.initials: JM
authors.lastname: Thomason
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Mackin
authors.forename: Lesya M
authors.initials: LM
authors.lastname: Pinchuk
keywords: Antigen Presenting Cells; Liposomal Clodronate; Monocytes; Regulatory T cells