Toll-like receptors, chemokine receptors and death receptor ligands responses in SARS coronavirus infected human monocyte derived dendritic cells

Law, Helen KW; Cheung, Chung Yan; Sia, Sin Fun; Chan, Yuk On; Peiris, JS Malik; Lau, Yu Lung

Interestingly, we detected significantly higher levels of chemokines and CCRs genes in CB DCs than in adults DCs. Based on the function of chemokines on cell trafficking, more severe infiltration of cells to the lungs would be expected in children. On the contrary, SARS was less severe in children than adults [3, 4] . The age-dependency of disease severity in SARS merits further studies to elucidate the underlying mechanisms. The development of animal models for SARS has been difficult because relevant signs of clinical illness and death cannot be reproducible in most animal models [40] . Recently, aged BALB/ c mice have shown to develop more severe disease after SARS infection [41] and have lower vaccine efficacy than young mice [42] . The comparison of SARS-CoV infected senescent mice with adult mice can be extended to younger mice and knock out models for the study of agedependency in the pathogenesis of SARS. A recent study has shown that mice deficient in either CCR1, CCR2 or CCR5 exhibited more prominent airway epithelial cell apoptosis and more severe lung pathology. This suggests that CCRs may be playing different roles at the site of infection and in the trafficking of immune cells [27] .