Berntman Emma, Rolf Julia, Johansson Cecilia, Anderson Per, Cardell Susanna L
Section for Infection and Immunology, Lund University, Lund, Sweden.
Eur J Immunol. 2005 Jul;35(7):2100-9. doi: 10.1002/eji.200425846.
CD1d-restricted natural killer T (NKT) cells belong to the innate-like lymphocytes which respond rapidly to stress and infectious challenge. We have studied murine CD1d-restricted NKT cells in the early immune response to virulent Salmonella enterica serovar Typhimurium after oral infection. In the liver and spleen, neutrophil and macrophage numbers had increased several-fold by day 5 post-infection, while the frequency of B and T lymphocytes decreased. These cellular changes occurred independently of CD1d-restricted NKT cells, and further, CD1d-restricted T cells did not influence the bacterial load. However, in CD1d(+) mice NK1.1(+) T cells and invariant CD1d-restricted T cells were activated by the infection, as demonstrated by an increase in size, up-regulation of CD69 and production of IFN-gamma. The NK1.1 antigen was down-modulated on these cells during the course of infection, while TCR levels were unaffected. While dendritic cells (DC) up-regulated CD1d-levels upon 24 h of in vitro exposure to the bacteria, increased CD1d expression was not evident on DC in vivo during infection. Furthermore, in vitro re-stimulation of CD1d-restricted T cells isolated from infected mice demonstrated a significant skewing of the cytokine profile, with suppressed IL-4 and increased IFN-gamma production.
CD1d限制性自然杀伤T（NKT）细胞属于对压力和感染性挑战能迅速做出反应的固有样淋巴细胞。我们研究了口服感染强毒鼠伤寒沙门氏菌后早期免疫反应中的小鼠CD1d限制性NKT细胞。在感染后第5天，肝脏和脾脏中的中性粒细胞和巨噬细胞数量增加了数倍，而B淋巴细胞和T淋巴细胞的频率降低。这些细胞变化独立于CD1d限制性NKT细胞发生，而且，CD1d限制性T细胞不影响细菌载量。然而，在CD1d(+)小鼠中，NK1.1(+) T细胞和不变的CD1d限制性T细胞被感染激活，表现为细胞大小增加、CD69上调和IFN-γ产生。在感染过程中，这些细胞上的NK1.1抗原被下调，而TCR水平未受影响。虽然树突状细胞（DC）在体外接触细菌24小时后上调了CD1d水平，但在感染期间体内DC上CD1d表达增加并不明显。此外，对从感染小鼠中分离出的CD1d限制性T细胞进行体外再刺激显示，细胞因子谱有明显偏差，IL-4受到抑制，IFN-γ产生增加。
