The effects of maternal competence and situational stress level on children's help-seeking expectations across 4 to 6 years of age.

Help-seeking is a crucial problem-solving strategy for young children. However, it is not yet clear how children weigh different cues to make help-seeking decisions across preschool years, especially in caregiver-child interactions. The current study used a social expectation task to examine the effects of maternal competence and situational stress level on 4- to 6-year-old children's help-seeking expectations from a third-party perspective. Children's expectations of whether to seek help were measured. A total fo 135 Han Chinese children aged 4 to 6 years from an eastern city of China participated in this study. We found that 4- to 6-year-olds expected to seek more help from a competent mother than from an incompetent mother in low-stress conditions. When the stress level was high, however, they expected to seek help regardless of maternal competence levels. These results suggest that the interaction between the situational stress level and maternal competence determines young children's help-seeking expectations across preschool years. They further suggest that young children seek help from mothers in an active and discriminatory way.

Alloantigen-specific T-cell hyporesponsiveness induced by dnIKK2 gene-transfected recipient immature dendritic cells.

Immature dendritic cells (iDCs) have been shown to be able to induce peripheral T-cell tolerance through distinct pathways. Here, we investigated the tolerogenic property of recipient iDCs whose maturation was arrested by a dominant negative mutant of inhibitor of nuclear factor kappa-B kinase 2 (dnIKK2) gene. We found that dnIKK2-iDCs presented a typical semi-mature morphology and expressed lower levels of CD80 and CD86, slightly higher MHC-II than untransfected iDCs. The expression of these molecules had no significant change even dnIKK2-iDCs were pulsed by donor antigen. In primary mixed leukocyte reaction (MLR), dnIKK2-iDCs exhibited impaired ability to stimulate allogeneic T-cells, but induced CD4(+)CD25(-) T-cell formation. In co-culture MLR, these CD4(+)CD25(-) T-cells suppressed T-cell alloreaction in an antigen-specific manner. Besides, CD4(+)CD25(-) T-cells inhibited IL-2 and IFN-γ release, whereas promoted IL-10 and TGF-ß secretion. These data suggested recipient dnIKK2-iDCs could maintain peripheral tolerance through down-regulating costimulatory molecule expressions and inducing CD4(+)CD25(-) T-cell formation.