Different antigens trigger different Th1/Th2 reactions in neonatal mononuclear cells (MNCs) relating to T-bet/GATA-3 expression

Neonates are known to have poor cellular immunity, especially poor Th1 response. We investigated how neonatal mononuclear cells raised different Th1/Th2 reactions in response to different antigens. Employing Dermatophagoides pteronyssinus (Der p) extract and varicella zoster virus (VZV) as antigens, we assessed Th1/Th2 reactions as demonstrated by IL-4/IFNγ production and mRNA expression, and transcriptional factors T-bet/GATA-3 mRNA expression in mononuclear cells from human umbilical cord blood (CBMC). Results showed that VZV induced a dramatic increase of IFNγ production by adult peripheral blood mononuclear cells (PBMC), whereas VZV did not drive CBMC to release significant IFNγ production (1614.7±362.0 vs. 49.0±29.3, p<0.005). However, Der p induced higher IFNγ production by CBMC than VZV (298.1±171.8 vs. 49.0±29.3, P=0.047). In contrast, VZV did not induce significant IL-4 production either by CBMC or by PBMC. Der p induced a comparative IL-4 production by CBMC and PBMC (2.58±0.84 vs. 2.04±0.37, p>0.05). A real-time RT-PCR analysis of IL-4 and IFNγ mRNA expression showed that VZV induced a significantly higher IFNγ, but not IL-4, mRNA expression in PBMC than CBMC. Der p did not induce significant difference of IFNγ or IL-4 mRNA expression in PBMC and CBMC. VZV enhanced Th1-related transcription factor T-bet mRNA expression, in association with later down-regulation of Th2-related GATA-3 mRNA expression in PBMC. However, VZV did not up-regulate T-bet or down-regulate GATA-3 expression significantly in CBMC. In contrast, Der p induced an early GATA-3 expression and later T-bet expression in CBMC. These results suggest that different antigens trigger various Th1/Th2 reactions in PBMC and CBMC resulting from kinetic changes of T-bet/GATA-3 expression.