Pub Date : 2023-09-22DOI: 10.3389/fviro.2023.1288953
Samuel Ken-En Gan, E. Kostaki
{"title":"Editorial: Methods in bioinformatic and predictive virology","authors":"Samuel Ken-En Gan, E. Kostaki","doi":"10.3389/fviro.2023.1288953","DOIUrl":"https://doi.org/10.3389/fviro.2023.1288953","url":null,"abstract":"","PeriodicalId":73114,"journal":{"name":"Frontiers in virology","volume":"2 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139337603","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Cotton blue disease from Africa and its de facto relationship with cotton leafroll dwarf virus: a misleading etiological discrepancy","authors":"Connor Ferguson, Akhtar Ali","doi":"10.3389/fviro.2023.1253174","DOIUrl":"https://doi.org/10.3389/fviro.2023.1253174","url":null,"abstract":"OPINION article Front. Virol., 20 September 2023Sec. Emerging and Reemerging Viruses Volume 3 - 2023 | https://doi.org/10.3389/fviro.2023.1253174","PeriodicalId":73114,"journal":{"name":"Frontiers in virology","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136314997","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-09-07DOI: 10.3389/fviro.2023.1225818
Dieke Boezen, Maritta Vermeulen, Marcelle L. Johnson, René A. A. van der Vlugt, Carolyn M. Malmstrom, M. Zwart
Many plant viruses have a multipartite organization, with multiple genome segments packaged into separate virus particles. The genome formula describes the relative frequencies of all viral genome segments, and previous work suggests rapid changes in these frequencies facilitate virus adaptation. Many studies have reported mixed viral infections in plants, often resulting in strong virus–virus interactions. Here, we tested whether mixed infections with tripartite alfalfa mosaic virus (AMV) and monopartite potato virus Y (PVY) affected the genome formula of the tripartite cucumber mosaic virus (CMV), our experimental model. We found that the CMV titer was reduced in mixed infections with its tripartite Bromoviridae relative AMV and in triple infections with both AMV and PVY, indicating notable virus–virus interactions. The variability of the CMV genome formula was significantly lower in mixed infections (CMV and AMV, CMV and PVY, and CMV and AMV and PVY) than in single infections (CMV only). These observations led to the surprising conclusion that mixed infections with two distinct viruses constrain the CMV genome formula. It remains unclear how common these effects are for different combinations of virus species and strains and what the underlying mechanisms are. We, therefore, extended a simulation model to consider three putative scenarios in which a second virus affected the genome formula. The simulation results also suggested that shifts in the genome formula occur, but may not be widespread due to the required conditions. One scenario modeled—co-infection exclusion through niche differentiation—was congruent with the experimental data, as this scenario led to reductions in genome formula variability and titer of the multipartite virus. Whereas previous studies highlighted host–species effects, our results indicate that the genome formula is also affected by mixed infections, suggesting that there is a broader set of environmental cues that affect the genome formula.
{"title":"Mixed viral infection constrains the genome formula of multipartite cucumber mosaic virus","authors":"Dieke Boezen, Maritta Vermeulen, Marcelle L. Johnson, René A. A. van der Vlugt, Carolyn M. Malmstrom, M. Zwart","doi":"10.3389/fviro.2023.1225818","DOIUrl":"https://doi.org/10.3389/fviro.2023.1225818","url":null,"abstract":"Many plant viruses have a multipartite organization, with multiple genome segments packaged into separate virus particles. The genome formula describes the relative frequencies of all viral genome segments, and previous work suggests rapid changes in these frequencies facilitate virus adaptation. Many studies have reported mixed viral infections in plants, often resulting in strong virus–virus interactions. Here, we tested whether mixed infections with tripartite alfalfa mosaic virus (AMV) and monopartite potato virus Y (PVY) affected the genome formula of the tripartite cucumber mosaic virus (CMV), our experimental model. We found that the CMV titer was reduced in mixed infections with its tripartite Bromoviridae relative AMV and in triple infections with both AMV and PVY, indicating notable virus–virus interactions. The variability of the CMV genome formula was significantly lower in mixed infections (CMV and AMV, CMV and PVY, and CMV and AMV and PVY) than in single infections (CMV only). These observations led to the surprising conclusion that mixed infections with two distinct viruses constrain the CMV genome formula. It remains unclear how common these effects are for different combinations of virus species and strains and what the underlying mechanisms are. We, therefore, extended a simulation model to consider three putative scenarios in which a second virus affected the genome formula. The simulation results also suggested that shifts in the genome formula occur, but may not be widespread due to the required conditions. One scenario modeled—co-infection exclusion through niche differentiation—was congruent with the experimental data, as this scenario led to reductions in genome formula variability and titer of the multipartite virus. Whereas previous studies highlighted host–species effects, our results indicate that the genome formula is also affected by mixed infections, suggesting that there is a broader set of environmental cues that affect the genome formula.","PeriodicalId":73114,"journal":{"name":"Frontiers in virology","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41615181","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-08-29DOI: 10.3389/fviro.2023.1163385
Neale J Harrison, L. Richardson, Chiara Pallini, I. Morano, Elizabeth Jinks, Jamie Cowley, Hujo Chan, Harriet J. Hill, A. Tuekprakhon, Zhi Li, Cristina Matas de las Heras, A. Teodósio, Andrea Lavado, Robert Moring, A. Ashraf, T. Dafforn, D. Grammatopoulos, J. Gordon, Catherine A. Brady, L. Young, N. Barnes, Z. Stamataki, O. Qureshi
The engagement of the SARS-CoV-2 spike protein with ACE2 is a critical step for viral entry to human cells, and, therefore, blocking this interaction is a major determinant of the efficacy of monoclonal antibody therapeutics and vaccine elicited serum antibodies. The emergence of SARS-CoV-2 variants has necessitated the development of adaptable assays that can be applied to assess the effectiveness of antibody-based therapeutics.Through the testing of a range of recombinant spike proteins, we have developed a cell-based, ACE2/spike protein interaction assay that characterises monoclonal anti-spike protein antibodies and neutralising antibodies in donor serum. The assay uses high-content imaging to quantify cell-bound spike protein fluorescence.Using spike proteins from the original “Wuhan” SARS-CoV-2 strain and the Delta and Omicron variants, we identified differential blocking activity of three monoclonal antibodies directed against the spike receptor-binding domain. Importantly, biological activity in the spike interaction assay translated to efficacy in a SARS-CoV-2 infection assay.The spike protein interaction assay can be used to monitor anti-spike antibodies against the major known SARS-CoV-2 variants and is readily adaptable for quantification of the impact of antibodies against new and emerging SARS-CoV-2 variants.
{"title":"A cell-based, SARS-CoV-2 spike protein interaction assay to inform the neutralising capacity of recombinant and patient sera antibodies","authors":"Neale J Harrison, L. Richardson, Chiara Pallini, I. Morano, Elizabeth Jinks, Jamie Cowley, Hujo Chan, Harriet J. Hill, A. Tuekprakhon, Zhi Li, Cristina Matas de las Heras, A. Teodósio, Andrea Lavado, Robert Moring, A. Ashraf, T. Dafforn, D. Grammatopoulos, J. Gordon, Catherine A. Brady, L. Young, N. Barnes, Z. Stamataki, O. Qureshi","doi":"10.3389/fviro.2023.1163385","DOIUrl":"https://doi.org/10.3389/fviro.2023.1163385","url":null,"abstract":"The engagement of the SARS-CoV-2 spike protein with ACE2 is a critical step for viral entry to human cells, and, therefore, blocking this interaction is a major determinant of the efficacy of monoclonal antibody therapeutics and vaccine elicited serum antibodies. The emergence of SARS-CoV-2 variants has necessitated the development of adaptable assays that can be applied to assess the effectiveness of antibody-based therapeutics.Through the testing of a range of recombinant spike proteins, we have developed a cell-based, ACE2/spike protein interaction assay that characterises monoclonal anti-spike protein antibodies and neutralising antibodies in donor serum. The assay uses high-content imaging to quantify cell-bound spike protein fluorescence.Using spike proteins from the original “Wuhan” SARS-CoV-2 strain and the Delta and Omicron variants, we identified differential blocking activity of three monoclonal antibodies directed against the spike receptor-binding domain. Importantly, biological activity in the spike interaction assay translated to efficacy in a SARS-CoV-2 infection assay.The spike protein interaction assay can be used to monitor anti-spike antibodies against the major known SARS-CoV-2 variants and is readily adaptable for quantification of the impact of antibodies against new and emerging SARS-CoV-2 variants.","PeriodicalId":73114,"journal":{"name":"Frontiers in virology","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45662914","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-08-17DOI: 10.3389/fviro.2023.1232906
Mikako Hirohama, S. Yamashita, Masamitsu N. Asaka, Takahiro Kuroki, Atsushi Kawaguchi
The influenza virus genome consists of single-stranded RNAs and forms viral ribonucleoprotein (RNP) complexes. After viral genome replication in the nucleus, the viral RNP interacts with viral protein M1. The M1-viral RNP complex is exported to the cytoplasm via the CRM1-dependent pathway using NS2/NEP as an export adaptor protein. NEP is a 14 kDa protein and diffusely localizes in the nucleus and cytoplasm. Upon binding to the NLS motif of M1, NEP inhibits the nuclear accumulation of M1 and promotes the nuclear export of M1-viral RNP complex. However, the detail mechanism by which NEP binds to M1 only in the nucleus remains unclear.To visualize the interaction of NEP with M1 in the formation of vRNP export complexes, we performed in situ proximity ligation assays. The close proximity of N-terminal and C-terminal domains of NEP was tested by split Renilla luciferase complementation assays in which the N-terminal and C-terminal fragments of Renilla luciferase were fused to the N-terminus and C-terminus of NEP, respectively.We found that the intramolecular interaction of NEP inhibits the interaction of NEP with M1. The intramolecular interaction of NEP was mediated through the interaction of the N-terminal NES motif with the M1-binding domain at the C-terminus. By adding leptomycin B, a potent inhibitor of CRM1, the interaction of NEP with M1 was impaired. These results suggest that CRM1 disrupts the intramolecular interaction of NEP by recognizing the NES motif at the N-terminus of NEP, thereby promoting the interaction of NEP with M1. We also found that NEP mutant deficient in the intramolecular interaction was co-localized with M1 at the plasma membrane and did not show nuclear localization with M1. Based on these results, we propose that the intramolecular interaction of NEP regulated by CRM1 ensures the unidirectional transport of M1.
{"title":"Intramolecular interaction of NEP regulated by CRM1 ensures the unidirectional transport of M1 for the nuclear export of influenza viral ribonucleoprotein","authors":"Mikako Hirohama, S. Yamashita, Masamitsu N. Asaka, Takahiro Kuroki, Atsushi Kawaguchi","doi":"10.3389/fviro.2023.1232906","DOIUrl":"https://doi.org/10.3389/fviro.2023.1232906","url":null,"abstract":"The influenza virus genome consists of single-stranded RNAs and forms viral ribonucleoprotein (RNP) complexes. After viral genome replication in the nucleus, the viral RNP interacts with viral protein M1. The M1-viral RNP complex is exported to the cytoplasm via the CRM1-dependent pathway using NS2/NEP as an export adaptor protein. NEP is a 14 kDa protein and diffusely localizes in the nucleus and cytoplasm. Upon binding to the NLS motif of M1, NEP inhibits the nuclear accumulation of M1 and promotes the nuclear export of M1-viral RNP complex. However, the detail mechanism by which NEP binds to M1 only in the nucleus remains unclear.To visualize the interaction of NEP with M1 in the formation of vRNP export complexes, we performed in situ proximity ligation assays. The close proximity of N-terminal and C-terminal domains of NEP was tested by split Renilla luciferase complementation assays in which the N-terminal and C-terminal fragments of Renilla luciferase were fused to the N-terminus and C-terminus of NEP, respectively.We found that the intramolecular interaction of NEP inhibits the interaction of NEP with M1. The intramolecular interaction of NEP was mediated through the interaction of the N-terminal NES motif with the M1-binding domain at the C-terminus. By adding leptomycin B, a potent inhibitor of CRM1, the interaction of NEP with M1 was impaired. These results suggest that CRM1 disrupts the intramolecular interaction of NEP by recognizing the NES motif at the N-terminus of NEP, thereby promoting the interaction of NEP with M1. We also found that NEP mutant deficient in the intramolecular interaction was co-localized with M1 at the plasma membrane and did not show nuclear localization with M1. Based on these results, we propose that the intramolecular interaction of NEP regulated by CRM1 ensures the unidirectional transport of M1.","PeriodicalId":73114,"journal":{"name":"Frontiers in virology","volume":"108 ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-08-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41277207","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-08-14DOI: 10.3389/fviro.2023.1270008
S. Zúñiga, Jennifer A. Corcoran
{"title":"Editorial: Post-transcriptional regulation of viral protein expression and function","authors":"S. Zúñiga, Jennifer A. Corcoran","doi":"10.3389/fviro.2023.1270008","DOIUrl":"https://doi.org/10.3389/fviro.2023.1270008","url":null,"abstract":"","PeriodicalId":73114,"journal":{"name":"Frontiers in virology","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42404855","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-08-02DOI: 10.3389/fviro.2023.1253524
A. Adachi, T. Koma, Masako Nomaguchi
{"title":"Editorial: HIV/SIV basic research update","authors":"A. Adachi, T. Koma, Masako Nomaguchi","doi":"10.3389/fviro.2023.1253524","DOIUrl":"https://doi.org/10.3389/fviro.2023.1253524","url":null,"abstract":"","PeriodicalId":73114,"journal":{"name":"Frontiers in virology","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-08-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45451692","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-07-25DOI: 10.3389/fviro.2023.1221156
Wendy G. Marchant, H. Mugerwa, Saurabh Gautam, H. Al-Aqeel, J. Polston, G. Rennberger, Hugh Smith, Bill Turechek, S. Adkins, Judith K. Brown, R. Srinivasan
Tomato yellow leaf curl virus (TYLCV) is a monopartite DNA virus with a genome size of ~ 2,800 base pairs. The virus belongs to the genus Begomovirus within the family Geminiviridae. Extant TYLCV strains are differentiated based on an established threshold of 94% genome-wide pairwise nucleotide identity. The phylogenetic relationships, diversification mechanisms, including recombination, and extent of spread within and from the center of origin for TYLCV have been reported in previous studies. However, the evolutionary relationships among strains, strains’ distribution and genomic diversification, and genetic mechanisms shaping TYLCV strains’ evolution have not been re-evaluated to consider globally representative genome sequences in publicly available sequence database, including herein newly sequenced genomes from the U.S. and Middle East, respectively. In this study, full-length genome sequences for the extant strains and isolates of TYLCV (n=818) were downloaded from the GenBank database. All previously published genome sequences, and newly sequenced TYLCV genomes of TYLCV isolates from Kuwait and USA, determined herein (n=834), were subjected to recombination analysis. To remove the ‘phylogenetic noise’ imparted by interspecific recombination, the recombinant genomes were removed from the data set, and the remaining non-recombinant genome sequences (n=423) were subjected to population genetics and Bayesian analyses. Results of the phylogeographical analysis indicated that the type strain, TYLCV-Israel, and TYLCV-Mild strain, were globally distributed, spanning Africa, America, Asia, Australia/Oceania, Europe, and New Caledonia, while the other TYLCV strains were prevalent only throughout the Middle East. The results of Bayesian evolutionary (ancestral) analysis predicted that TYLCV-Israel represents the oldest, most recent common ancestor (MRCA) (41,795 years), followed by TYLCV-Mild at 39,808 years. These were closely followed by two Iranian strains viz., TYLCV-Kerman and TYLCV-Iran at 37,529 and 36,420 years, respectively. In contrast, the most recently evolving strains were TYLCV-Kuwait and TYLCV-Kahnooj at 12,445 and 298 years, respectively. Results of the neutrality test indicated that TYLCV-Israel and TYLCV-Mild populations are undergoing purifying selection and/or population expansion, although statistically significant selection was documented for only TYLCV-Israel, based on positive selection acting on five codons.
{"title":"Phylogenomic and population genetics analyses of extant tomato yellow leaf curl virus strains on a global scale","authors":"Wendy G. Marchant, H. Mugerwa, Saurabh Gautam, H. Al-Aqeel, J. Polston, G. Rennberger, Hugh Smith, Bill Turechek, S. Adkins, Judith K. Brown, R. Srinivasan","doi":"10.3389/fviro.2023.1221156","DOIUrl":"https://doi.org/10.3389/fviro.2023.1221156","url":null,"abstract":"Tomato yellow leaf curl virus (TYLCV) is a monopartite DNA virus with a genome size of ~ 2,800 base pairs. The virus belongs to the genus Begomovirus within the family Geminiviridae. Extant TYLCV strains are differentiated based on an established threshold of 94% genome-wide pairwise nucleotide identity. The phylogenetic relationships, diversification mechanisms, including recombination, and extent of spread within and from the center of origin for TYLCV have been reported in previous studies. However, the evolutionary relationships among strains, strains’ distribution and genomic diversification, and genetic mechanisms shaping TYLCV strains’ evolution have not been re-evaluated to consider globally representative genome sequences in publicly available sequence database, including herein newly sequenced genomes from the U.S. and Middle East, respectively. In this study, full-length genome sequences for the extant strains and isolates of TYLCV (n=818) were downloaded from the GenBank database. All previously published genome sequences, and newly sequenced TYLCV genomes of TYLCV isolates from Kuwait and USA, determined herein (n=834), were subjected to recombination analysis. To remove the ‘phylogenetic noise’ imparted by interspecific recombination, the recombinant genomes were removed from the data set, and the remaining non-recombinant genome sequences (n=423) were subjected to population genetics and Bayesian analyses. Results of the phylogeographical analysis indicated that the type strain, TYLCV-Israel, and TYLCV-Mild strain, were globally distributed, spanning Africa, America, Asia, Australia/Oceania, Europe, and New Caledonia, while the other TYLCV strains were prevalent only throughout the Middle East. The results of Bayesian evolutionary (ancestral) analysis predicted that TYLCV-Israel represents the oldest, most recent common ancestor (MRCA) (41,795 years), followed by TYLCV-Mild at 39,808 years. These were closely followed by two Iranian strains viz., TYLCV-Kerman and TYLCV-Iran at 37,529 and 36,420 years, respectively. In contrast, the most recently evolving strains were TYLCV-Kuwait and TYLCV-Kahnooj at 12,445 and 298 years, respectively. Results of the neutrality test indicated that TYLCV-Israel and TYLCV-Mild populations are undergoing purifying selection and/or population expansion, although statistically significant selection was documented for only TYLCV-Israel, based on positive selection acting on five codons.","PeriodicalId":73114,"journal":{"name":"Frontiers in virology","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48807059","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-06-30DOI: 10.3389/fviro.2023.1192184
T. Koma, T. Odaka, Sung-il Lee, N. Doi, Tomoyuki Kondo, K. Okuma, J. Fujisawa, A. Adachi, Masako Nomaguchi
Animal models are essential for basic and clinical research on virus diseases. Humanized mice (mice reconstituted with human hematopoietic cells) have been effectively used for various virus studies as small animal models. Studies on human-tropic HIV-1 have also been performed using different humanized mouse models. Various humanized mice have been generated using distinct mouse strains and engraftment methods. These different techniques affect the reconstitution of human hematopoietic cells in individual mice, and in turn the HIV-1 replication in vivo. In this report, we describe the details of the generation method of humanized mice, i.e., severely immunodeficient mice (NSG mice) transplanted with human CD133-positive cells via intra-bone marrow injection (IBMI). It has been shown that the CD133-positive cells are highly capable to generate CD34-positive cells in vivo and IBMI is an excellent methodology for lymphoid and myeloid cell repopulation. In humanized mice transplanted with CD133-positive cells into the bone marrow, human lymphocytes were increased 3 months after the transplantation and a steady increase in CD4-positive cells was observed until 6–8 months after the transplantation. In order to test the utility of our system, CXCR4-tropic and CCR5-tropic HIV-1 clones were intraperitoneally inoculated into the resultant humanized mice 6–8 months after the transplantation. Upon inoculation at the same dose of viruses, the plasma viral load in CCR5-tropic HIV-1-inoculated mice peaked earlier than that in CXCR4-tropic HIV-1-inoculated mice (2–3 weeks vs 5–10 weeks post-inoculation). While a rapid decrease in CD4-positive cells was observed at the peak or prior to the peak of viremia for CXCR4-tropic HIV-1-inoculated mice, CD4-positive cells were gradually decreased in CCR5-tropic HIV-1-inoculated mice. Upon inoculation at the same dose of viruses, a Nef-deleted R5-tropic HIV-1 exhibited retarded growth kinetics in the inoculated mice compared to the parental virus (around 8 weeks vs 2–3 weeks post-inoculation), which appears to reflect the decrease in replication potential in primary cells. Taken all together, in addition to the humanized mice reported so far, our humanized mice generated by transplanting CD133-positive cells with the IBMI method would be an appropriate prototype model for understanding HIV-1 biology in vivo.
{"title":"Humanized mice generated by intra-bone marrow injection of CD133-positive hematopoietic stem cells: application to HIV-1 research","authors":"T. Koma, T. Odaka, Sung-il Lee, N. Doi, Tomoyuki Kondo, K. Okuma, J. Fujisawa, A. Adachi, Masako Nomaguchi","doi":"10.3389/fviro.2023.1192184","DOIUrl":"https://doi.org/10.3389/fviro.2023.1192184","url":null,"abstract":"Animal models are essential for basic and clinical research on virus diseases. Humanized mice (mice reconstituted with human hematopoietic cells) have been effectively used for various virus studies as small animal models. Studies on human-tropic HIV-1 have also been performed using different humanized mouse models. Various humanized mice have been generated using distinct mouse strains and engraftment methods. These different techniques affect the reconstitution of human hematopoietic cells in individual mice, and in turn the HIV-1 replication in vivo. In this report, we describe the details of the generation method of humanized mice, i.e., severely immunodeficient mice (NSG mice) transplanted with human CD133-positive cells via intra-bone marrow injection (IBMI). It has been shown that the CD133-positive cells are highly capable to generate CD34-positive cells in vivo and IBMI is an excellent methodology for lymphoid and myeloid cell repopulation. In humanized mice transplanted with CD133-positive cells into the bone marrow, human lymphocytes were increased 3 months after the transplantation and a steady increase in CD4-positive cells was observed until 6–8 months after the transplantation. In order to test the utility of our system, CXCR4-tropic and CCR5-tropic HIV-1 clones were intraperitoneally inoculated into the resultant humanized mice 6–8 months after the transplantation. Upon inoculation at the same dose of viruses, the plasma viral load in CCR5-tropic HIV-1-inoculated mice peaked earlier than that in CXCR4-tropic HIV-1-inoculated mice (2–3 weeks vs 5–10 weeks post-inoculation). While a rapid decrease in CD4-positive cells was observed at the peak or prior to the peak of viremia for CXCR4-tropic HIV-1-inoculated mice, CD4-positive cells were gradually decreased in CCR5-tropic HIV-1-inoculated mice. Upon inoculation at the same dose of viruses, a Nef-deleted R5-tropic HIV-1 exhibited retarded growth kinetics in the inoculated mice compared to the parental virus (around 8 weeks vs 2–3 weeks post-inoculation), which appears to reflect the decrease in replication potential in primary cells. Taken all together, in addition to the humanized mice reported so far, our humanized mice generated by transplanting CD133-positive cells with the IBMI method would be an appropriate prototype model for understanding HIV-1 biology in vivo.","PeriodicalId":73114,"journal":{"name":"Frontiers in virology","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44273561","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-06-29DOI: 10.3389/fviro.2023.1216285
L. Stewart, K. Willie, Wenshuang Xie, J. Todd, Hong Hanh Tran
Plant viruses classified in the genus Waikavirus, family Secoviridae, are positive sense single-stranded RNA viruses that include important pathogens of maize (maize chlorotic dwarf virus; MCDV) and rice (rice tungro spherical virus; RTSV). Many aspects of the molecular biology of waikaviruses remain unexplored because of experimental challenges and lack of infectious clones for low titer, phloem-limited, and obligately vector-transmitted waikaviruses. Here we report the first development of waikavirus infectious clones for two MCDV strains, MCDV-S and MCDV-M1, and insect-free launching of infections from these clones in maize by vascular puncture inoculation. We further developed a green fluorescent protein (GFP)-tagged MCDV clone by replacing the viral p27-encoding sequence with GFP-encoding sequence. GFP-tagged virus moved systemically in plants and caused symptomatic infection similar to wild type virus, with vascular expression of GFP. Development of waikavirus infectious clones is a major advance for this group of agriculturally significant viruses.
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