Alphavirus vaccine vectors for lentiviruses targeted to dendritic cells in vivo.
Int Conf AIDS 2000 Jul 9-14; 13:(abstract no. WeOrA477)
Johnston R, MacDonald G, Richmond E, Aronson J, Johnson P, Davis N R. Johnston, University of North Carolina, Chapel Hill, NC 27599 7290, United States, Tel.: +1 919 966 35 07, Fax: +1 919 962 81 03, E-mail: rjohnst@med.unc.edu
The efficacy of a vaccine vector system is influenced by the anatomical site and particular cell type in which expression occurs. Vaccine vectors based on the alphavirus Venezuelan equine encephalitis virus (VEE) have been employed successfully in a number of animal models of disease, including simian immunodeficiency virus (Pushko et al., 1997. Virol. 239: 389-401; Davis et al., 1999. J. Virol. 74: 371-378). The VEE replicon RNA contains the gene of an immunogen in place of the structural protein genes. The replicon RNA is packaged into VEE replicon particles (VRP) by supplying the capsid and glycoprotein genes on helper RNAs in trans. VRP expressing GFP (gfp-VRP) and packaged in wild-type glycoproteins targeted efficiently to dendritic/Langerhans cells expressing DEC205 and MHCII surface markers. These cells were found in the subcapsular region of the draining lymph node within 1 hr after subcutaneous inoculation. Single amino acid substitutions in the E2 glycoprotein dramatically altered these targeting characteristics. VRP packaged in the V3010 coat was inefficient in transit to the draining lymph node and was in small, round cells in the medulla of the node. Targeting to dendritic cells was restored in a second site revertant of V3010 (V3533), although V3533 targeted a broader range of dendritic cell types than wild-type. For reasons of safety, the VRP used in the successful VEE vector vaccine experiments to date were packaged in the glycoproteins of V3014, a VEE mutant carrying two attenuating point mutations. While low doses (10e3 IU) of V3014-packaged VRP targeted to lymph nodes, expression was in small, round cells in the medulla. At the higher doses used in the vaccination experiments (10e5-10e7 IU), targeting to dendritic cells was observed. The efficiency of the VRP in inducing an immune response was enhanced when the immunizing VRP were packaged in glycoproteins that targeted them to dendritic cells in vivo.
Keywords: AEGIS, Alphavirus, Lentivirus, Encephalitis Virus, Venezuelan Equine, Encephalomyelitis, Venezuelan Equine, Dendritic Cells, Vaccines, Replicon, Vaccines, Synthetic, Vaccination, Vaccines, Attenuated, Viral Vaccines, Langerhans Cells, Luminescent Proteins, Capsid, AIDS Vaccines, Glycoproteins, RNA, green fluorescent protein, genetics, immunology
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