Transdifferentiation of polymorphonuclear neutrophils: acquisition of CD83and other functional characteristics of dendritic cells

Polymorphonuclear neutrophils (PMN) are in the first line of defense agains t bacterial infections. They are considered to be end-differentiated cells undergoing constitutive apoptosis within hours after release from the bone marrow. During pathological events, however, their life span is extended in conjunction with morphological and functional alterations indicative of a transdifferentiation of mature PMN. To further characterize differentiated PMN, the alterations seen in vivo were reproduced by cultivating PMN of hea lthy donors with either gamma -interferon, granulocyte/macrophage colony st imulating factor, or a combination thereof. Thus cultivated cells escaped f rom apoptosis, and protein synthesis was induced, notably of the major hist ocompatibility complex (MHC) class II antigens, CD80 and CD86. Moreover, CD 83, thought to be specific for dendritic cells was synthesized, while typic al markers of PMN, including CD66b, CD11a/CD11b/CD11c, CD15, CD18 were pres erved. A profound alteration of both cellular morphology and of function wa s seen: the cultivated PMN lost their chemotactic activity but had acquired the ability to present to T-cells a peptide antigen in a MHC class H restr icted manner. The data lead to the conclusion that mature PMN can different iate further to cells with characteristics of DCs, thereby connecting PMN t o the specific T-cell response.