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

Dendritic cells are professional antigen presenting cells that play an important role as sentinels at the infection site by interacting directly with pathogens. Some pathogens hijack different parts of the immune pathways involving DCs to enhance their survival. In the present study, we demonstrate that SARS-CoV does not have significant effect on the expression of TLRs on adult or CB DCs (Figs. 1 &2) . However, there was significant upregulation of CCR-1 and CCR5 in SARS-CoV infected adult DCs and CCR-3 in SARS-CoV infected CB DCs which may be related to the autocrine regulation of DC migration (Fig. 3) . Moreover, we demonstrate a significant upregulation of TRAIL on both adult and CB DCs (Fig. 4) . We hypothesize that the upregulation of chemokine receptors may facilitate the autocrine mobilisation of DCs away from the infection sites and the upregulation of death receptor liganads may result in apoptosis of other immune cells, leading to immunosuppression and lymphopenia.