Studies on the therapeutic effects of anti-dengue virus nonstructural protein 1 polyclonal and monoclonal antibodies both in vitro and in vivo

摘要

Dengue virus (DENV) is a mosquito-transmitted flavivirus with four serotypes and is endemic in tropical and subtropical regions of the world Infection with DENV causes diseases ranging from mild dengue fever to severe dengue hemorrhagic fever and dengue shock syndrome Currently there is no approved vaccine to prevent dengue infection Our previous studies showed that the cross-reactive epitopes reside in the C-terminal region of DENV nonstructural protein 1 (NS1) and cause anti-DENV NS1 antibodies (Abs)-mediated endothelial cell apoptosis and platelet dysfunction Therefore we deleted the C-terminal region of DENV NS1 protein or replaced the C-terminal region with JEV NS1 protein to generate ΔC NS1 and DJ NS1 respectively Our previous studies also suggested that passive immunization with anti-ΔC or anti-DJ NS1 Abs twice can provide some therapeutic effects in DENV-infected mice In this study we attempted to determine the effective single dose of anti-modified NS1 Abs against DENV infection in a therapeutic mouse model Results showed that the DENV-induced prolonged bleeding time was significantly reduced by treatment with anti-DJ NS1 Abs with a single dosage Besides polyclonal Abs we also investigated the therapeutic effects of anti-NS1 monoclonal Abs (mAbs) The mAb 2E8 can recognize NS1 of all four DENV serotypes but does not recognize epitopes of DENV NS1 which cross-react with host proteins Further analysis showed that the epitope recognized by mAb 2E8 is on the solvent accessible area of NS1 We found that mAb 2E8 causes complement-mediated cytolysis in vitro after DENV infection Chimeric mAb 2E8 and another therapeutic candidate mAb 31B2 also induce complement-mediated cytolysis of DENV-infected cells In the mouse model studies treatment with mAb 2E8 reduced mouse tail prolonged bleeding time viral antigen expression and macrophage infiltration to local infection sites We further found that administering anti-DJ NS1 or mAb 2E8 at day 1 3 or 4 post-inoculation reduced prolonged bleeding time and hemorrhage even at day 5 post-infection In summary administration of a single dose of anti-DJ NS1 Abs or mAb 2E8 protected mice against DENV infection suggesting that anti-modified DENV NS1 Abs may be a therapeutic option against dengue disease

獎項日期	2014 8月 25
原文	English
監督員	Yee-Shin Lin (Supervisor)