Eosinophil adoptive transfer system to directly evaluate pulmonary eosinophil trafficking in vivo

Abstract

Most in vivo studies of granulocytes draw conclusions about their trafficking based on examination of their steady-state tissue/blood levels, which result from a combination of tissue homing, survival, and egress, rather than direct examination of cellular trafficking. Herein, we developed a unique cell transfer system involving the adoptive transfer of a genetically labeled, bone-marrow-derived unique granulocyte population (eosinophils) into an elicited inflammatory site, the allergic lung. A dual polychromatic FACS-based biomarker-labeling system based on the IL4-eGFP transgene (4get) or Cd45.1 allele was used to track i.v. transferred eosinophils into the airway following allergen or T H 2-associated stimuli in the lung in multiple mouse strains. The system was amenable to reverse tagging of recipients, thus allowing transfer of nonlabeled eosinophils and competitive tracking of multiple populations of eosinophils in vivo. The half-life of eosinophils in the blood was 3 h, and migration to the lung was dependent upon the dosage of transferred eosinophils, sensitive to pertussis toxin pretreatment, peaked at ∼24 h after adoptive transfer, and revealed a greater than 8-d eosinophil half-life in the lung. Eosinophil migration to the lung was dependent upon recipient IL-5 and IL-13 receptor α1 and donor eosinophil C-C chemokine receptor type 3 (CCR3) and interleukin 1 receptor-like 1 (ST2) in vivo. Taken together, this unique eosinophil transfer system provides an unprecedented opportunity to examine airway eosinophil migration without the need for extensive efforts to acquire donor source and timeconsuming genetic crossing and has already been used to identify a long eosinophil half-life in the allergic lung and a definite role for ST2 in regulating eosinophil trafficking.asthma | allergy | eosinophilia | chemoattraction

In Vivo Expansion of Activated Foxp3+ Regulatory T Cells and Establishment of a Type 2 Immune Response upon IL-33 Treatment Protect against Experimental Arthritis

“…First, IL-33 induced a 3-fold increase of eosinophil frequency, defined as SSC high CD45 + Siglec-F + CD11c 2 cells, among total blood leukocytes ( Fig. 2A, 2B) (29).…”

Eosinophils in mucosal immune responses

“…IL-33 potently activates murine eosinophils, including induction of marked gene expression and release of chemokines and cytokines such as IL-4 34 . IL-33 also increases the survival of human eosinophils 35 and, in a murine adoptive transfer model system, provides a survival advantage that allows for greater pulmonary trafficking 16 . This result highlights the importance of the direct effects of these innate cytokines on eosinophil function and justifies their use as potential targets to modify eosinophil function in disease states.…”

“…A strong driver of the expression of these eotaxins is IL-13 19 , which has increased expression in patients with atopic asthma 85–87 . A newly developed system for monitoring the trafficking of adoptively transferred murine eosinophils has demonstrated that eosinophil recruitment to the lungs in response to antigen challenge requires IL-5 and IL-13Rα1 expression by the recipient and CCR3 and ST2 expression by the eosinophil 16 , highlighting the importance of eotaxins and the cytokines IL-13 and IL-33 to pulmonary eosinophil recruitment.…”

“…Tissue eosinophils survive for a prolonged time relative to the time that they are in circulation. For instance, in a murine adoptive transfer model, eosinophil half-life in the allergic lungs after allergen challenge was 8 days 16 . Conversely, in vivo studies indicate that both human 17 and murine 18 eosinophils only spend approximately one day in the bloodstream.…”

Novel Therapies for Eosinophilic Disorders

“…115 Sorely needed are ways of detecting organ-specific disease activity, such as the “string test” in EoE 116 and nuclear medicine-based scans of eosinophil trafficking and accumulation. 117–119 Reliable biomarkers of disease activity, remission and drug responsiveness other than blood eosinophil counts would improve disease management, including confidence and safety during tapering of treatment. 120, 121 Examples of such biomarkers might include the presence of an activated eosinophil surface phenotype as detected by flow cytometry, 122, 123 , and a variety of measurements in biological fluids such as serum periostin in IL-13-driven asthma; 124, 125 serum CCL17 in HES and atopic dermatitits; 29, 126 serum levels of soluble receptors such as for IL-5, EMR1 and Siglec-8 in various forms of HES; 16, 121, 127 and detection of EPX in biological fluids.…”