Background Using reverse genetics we generated a recombinant low-pathogenic LaSota strain Newcastle disease virus (NDV) expressing the glycoprotein (GP) of Ebola virus (EBOV) designated rLa-EBOVGP and evaluated its biological characteristic in vivo and in vitro. trypsin. rLa-EBOVGP is usually more resistant to NDV antiserum than the vector NDV and is moderately sensitive to EBOV GP antiserum. More importantly contamination with rLa-EBOVGP was markedly inhibited by IPA3 indicating that rLa-EBOVGP uses macropinocytosis as the major internalization pathway for cell entry. Conclusions The results demonstrate that EBOV GP in recombinant NDV particles functions independently to mediate the viral contamination of the VX-702 host cells and alters the cell-entry pathway. of the family gene between the and genes in the genomic cDNA of the NDV LaSota strain (rLa) (Physique?1A). Expression of the gene was confirmed by indirect confocal immunofluorescent staining of rLa-EBOVGP-infected BHK-21 cells. rLa-EBOVGP-infected BHK-21 cells were stained with mouse anti-EBOV GP antiserum whereas rLa-infected BHK-21 cells were not stained with the antiserum (Physique?1B). NDV antigens and EBOV GP protein colocalized around the surfaces of the BHK-21 cells confirming the surface expression VX-702 of the EBOV GP protein in the rLa-EBOVGP-infected BHK-21 cells (Physique?1B). Physique 1 Generation of recombinant NDV expressing the EBOV and genes and the EBOV gene inserted into the gene did Rabbit Polyclonal to PARP4. not increase the virulence of the NDV vector in poultry or mice which is usually consistent with the results of a previous study in monkeys . EBOV GP was incorporated into the viral particles of rL-EBOVGP and allowed the NDV vector to infect mammalian cells independently of exogenous trypsin. The restriction of NDV replication in mammalian host cells is one of the most attractive properties of lentogenic NDV in terms of its safety when used as a live vaccine vector in animals and humans as is also the case for fowlpox virus [54 55 and a modified vaccinia virus Ankara [56 57 The V protein encoded by the NDV gene functions as an interferon antagonist and is usually less efficient in mammalian cells [58-60]; NDV is usually a strong inducer of VX-702 the interferon response in mammalian cells and is highly sensitive to the interferon induced in these cells [61 62 The limited replication in mammalian cells of low-pathogenic NDV like the LaSota strain is also determined by its trypsin-dependent infectivity. The trypsin-independent infectivity acquired by rLa-EBOVGP means that this virus behaves like a velogenic NDV in mammalian host cells. Its restricted replication may have to depend around the only defense line in host the native immunity. The ability of foreign envelope proteins to function as new cell-entry proteins has also been exhibited in VX-702 other enveloped negative-strand RNA viruses . The function of EBOV GP in mediating the cell entry of VSV when the gene had been deleted from the VSV genome could be compensated by several foreign envelope glycoproteins from different viruses in trans or with recombinant expression including Ebola virus Marburg VX-702 virus Lassa fever virus Hantaan virus and Nipah virus [4 6 7 64 Therefore it is affordable to infer that this incorporation of EBOV GP into the viral particle may cause the trypsin-independent infectivity of rL-EBOVGP. So far very few studies have examined the biological functions of native and foreign envelope glycoproteins when they are incorporated into the same viral particle. Our previous study showed that this G proteins of the rabies virus were incorporated on the surface of a recombinant NDV LaSota particle. An anti-rabies virus antiserum did not reduce the infectivity of the recombinant NDV . The G proteins around the virion surface of the rabies virus did not mediate the infection of cells by the recombinant NDV particle . The reasons for these phenomena are unclear. Another study showed that EBOV GP was incorporated into the viral particle of recombinant human parainfluenza virus 3 (hPIV3) and that the recombinant hPIV3 became more sensitive to neutralizing antibody directed against EBOV than to neutralizing antibody directed against hPIV3 . Because the biological functions of the hPIV3 envelope glycoproteins could not be abolished it was difficult to clarify whether EBOV GP around the virion surface functioned independently to mediate the infection of cells by the recombinant hPIV3 particle. In the present study the recombinant NDV.