Apoptotic eosinophils express IL-2R chains alpha and beta and co-stimulatory molecules CD28 and CD86.
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.
Seton
Kristina
K
Department of Medical Sciences, Unit of Clinical Chemistry, University Hospital, Uppsala University, Uppsala 5-751 85, Sweden. kristina.seton@medsci.uu.se
Håkansson
Lena
L
Carlson
Marie
M
Stålenheim
Gunnemar
G
Venge
Per
P
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
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