IL-15 drives neonatal T cells to acquire CD56 and become activated effector cells.
Expression of one or more natural killer (NK) receptors on T cells may correlate with effector function. This study investigated the frequency of neonatal NK receptor-positive (NKR+) T cells and their expansionary properties with interleukin-2 (IL-2), IL-7, or IL-15. While cord blood contains significantly decreased frequencies of NKR+ T cells compared with adult blood, newborn CD56+CD3+ cells could be expanded 200-fold during culture with IL-15. By depleting CD56+ cells, we were able to determine that this expansion was due to a subpopulation of T cells acquiring CD56 expression. Moreover, CD56 acquisition was associated with a distinct CD8+CD25+ interferon gamma-positive (IFN-gamma+) phenotype. This property could therefore be exploited during bone marrow reconstitution and may partially account for the resilience of the newborn to infection.
Cookson
Sharon
S
Children's Research Centre, Our Lady's Hospital for Sick Children, Dublin 12, Ireland. sharon.cookson@ucd.ie
Reen
Denis
D
D000328:Adult; D000367:Age Factors; D019002:CD56 Antigen / Q000378:metabolism*; D002478:Cells, Cultured; D005312:Fetal Blood / Q000166:cytology; D006801:Humans; D007107:Immune System / Q000166:cytology / Q000254:growth & development* / Q000276:immunology; D007231:Infant, Newborn; D019409:Interleukin-15 / Q000378:metabolism*; D007694:Killer Cells, Natural / Q000166:cytology / Q000276:immunology / Q000378:metabolism; D013601:T-Lymphocytes / Q000166:cytology / Q000276:immunology* / Q000378:metabolism*
D019002:CD56 Antigen; D019409:Interleukin-15