Abstract 93

Background: Natural killer cells (NK cells), defined as CD56+ CD3- cells, mediate unspecific immunity and may play an important role in the immunity of neonates. We investigated RNA cytokine expression of highly enriched neonatal and adult CD56+ cells.

Material and Measurements: CD56+ cells were highly enriched (purity >98%) by immunomagnetic isolation (MACS), cord blood (n=5), adult controls (n=5). RNA was isolated by density gradient centrifugation. Cytokine expression of 28 different cytokines was qualitatively determined by polymerase chain reaction.

Results: RT-PCR revealed a complex pattern of cytokine RNA expression. No expression of IL-2, IL-7, IL-9, SCF and TGFβ2 was found in any sample under investigation. A majority of neonatal and adult samples (4-5 of 5) showed expression of IFNα, IL-4, IL-5, LIF, PDGFα, TGFβ1 and TNFβ. Neonatal samples predominantly (4-5 of 5) expressed IL-1β, IFNγ, IL-6, IL-8, IL-12, IL-13, IL-15, MCSF, PDGFβ and TNFα, whereas in adult controls no expression of IL-13 and only low expression (1 of 5) of IL-1β IL-6, IL-8, IL-12, IL-15 and MCSF was found.

Conclusion: Neonatal and adult CD56+ cells, albeit showing some similarities in cytokine expression, differ with respect to the frequency of cytokine RNA expression. This may originate from a different immunologic and functional status of neonates and adults.

Supported by fortüne 328-1, University of Tübingen, Germany