title: Apoptotic eosinophils express IL-2R chains alpha and beta and co-stimulatory molecules CD28 and CD86.
abstract: BACKGROUND
  IL-2 and the IL-2 receptor are most commonly connected to lymphocytes and the proliferation of T-cells. In addition, the co-stimulatory molecules CD28, CD86 and CD40 are associated to lymphocytes and antigen processing. Under certain conditions, eosinophils are also able to express these antigens on their surface.
  
  
  OBJECTIVE
  In this study we explored the apoptotic mechanisms by looking for a surface expression on eosinophils exclusive to apoptosis.
  
  
  METHODS
  Flow cytometry analysis was performed on fresh and cultured isolated eosinophils from healthy blood donors and allergic patients. The cells were cultured up to 72 h and then incubated with monoclonal antibodies toward cell surface antigens.
  
  
  RESULTS
  After culture, the apoptotic eosinophils, but not the viable cells, expressed CD25, CD122, CD28 (B7-ligand) and CD86 (B7-2). The expression of CD9, a common eosinophil marker, was maintained on viable cells, but absent on the apoptotic eosinophils. Addition of IL-2 to the culture did not influence the viability of the cells.
  
  
  CONCLUSIONS
  Our data suggest that apoptotic eosinophils have a unique signalling system and might function in ways different from the role of the living eosinophil. The apoptotic eosinophil expresses markers that indicate communication with lymphocytes and antigen-presenting cells.
authors.affiliation: Department of Medical Sciences, Unit of Clinical Chemistry, University Hospital, Uppsala University, Uppsala 5-751 85, Sweden. kristina.seton@medsci.uu.se
authors.forename: Kristina
authors.initials: K
authors.lastname: Seton
authors.forename: Lena
authors.initials: L
authors.lastname: Håkansson
authors.forename: Marie
authors.initials: M
authors.lastname: Carlson
authors.forename: Gunnemar
authors.initials: G
authors.lastname: Stålenheim
authors.forename: Per
authors.initials: P
authors.lastname: Venge
mesh_terms: D000328:Adult; D015703:Antigens, CD / Q000378:metabolism*; D051940:B7-2 Antigen; D018106:CD28 Antigens / Q000378:metabolism*; D002470:Cell Survival; D002478:Cells, Cultured; D004804:Eosinophils / Q000166:cytology / Q000378:metabolism*; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D008297:Male; D008562:Membrane Glycoproteins / Q000378:metabolism*; D008875:Middle Aged; D015375:Receptors, Interleukin-2 / Q000378:metabolism*; D060245:Tetraspanin 29
chemical_list: D015703:Antigens, CD; D051940:B7-2 Antigen; D018106:CD28 Antigens; C497964:CD86 protein, human; C554869:CD9 protein, human; D008562:Membrane Glycoproteins; D015375:Receptors, Interleukin-2; D060245:Tetraspanin 29