1
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Beilinson HA, Erickson SA, Golovkina T. The endogenous Mtv8 locus and the immunoglobulin repertoire. Front Immunol 2024; 15:1345467. [PMID: 38504980 PMCID: PMC10948529 DOI: 10.3389/fimmu.2024.1345467] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Accepted: 02/16/2024] [Indexed: 03/21/2024] Open
Abstract
The vast diversity of mammalian adaptive antigen receptors allows for robust and efficient immune responses against a wide number of pathogens. The antigen receptor repertoire is built during the recombination of B and T cell receptor (BCR, TCR) loci and hypermutation of BCR loci. V(D)J recombination rearranges these antigen receptor loci, which are organized as an array of separate V, (D), and J gene segments. Transcription activation at the recombining locus leads to changes in the local three-dimensional architecture, which subsequently contributes to which gene segments are utilized for recombination. The endogenous retrovirus (ERV) mouse mammary tumor provirus 8 (Mtv8) resides on mouse chromosome 6 interposed within the large array of light chain kappa V gene segments. As ERVs contribute to changes in genomic architecture by driving high levels of transcription of neighboring genes, it was suggested that Mtv8 could influence the BCR repertoire. We generated Mtv8-deficient mice to determine if the ERV influences V(D)J recombination to test this possibility. We find that Mtv8 does not influence the BCR repertoire.
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Affiliation(s)
- Helen A Beilinson
- Department of Microbiology, University of Chicago, Chicago, IL, United States
| | - Steven A Erickson
- Department of Immunobiology, Yale University, New Haven, CT, United States
| | - Tatyana Golovkina
- Department of Microbiology, University of Chicago, Chicago, IL, United States
- Committee on Microbiology, University of Chicago, Chicago, IL, United States
- Committee on Immunology, University of Chicago, Chicago, IL, United States
- Committee on Genetics, Genomics and System Biology, University of Chicago, Chicago, IL, United States
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2
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Akhlaq S, Panicker NG, Philip PS, Ali LM, Dudley JP, Rizvi TA, Mustafa F. A cis-Acting Element Downstream of the Mouse Mammary Tumor Virus Major Splice Donor Critical for RNA Elongation and Stability. J Mol Biol 2018; 430:4307-4324. [PMID: 30179605 DOI: 10.1016/j.jmb.2018.08.025] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2018] [Revised: 08/28/2018] [Accepted: 08/28/2018] [Indexed: 12/11/2022]
Abstract
BACKGROUND The mouse mammary tumor virus (MMTV) encodes a functional signal peptide, a cleavage product of envelope and Rem proteins. Signal peptide interacts with a 3' cis-acting RNA element, the Rem-responsive element (RmRE), to facilitate expression of both unspliced genomic (gRNA) and spliced mRNAs. An additional RmRE has been proposed at the 5' end of the genome, facilitating nuclear export of the unspliced gRNA, whereas the 3' RmRE could facilitate translation of all other mRNAs, including gRNA. RESULTS To address this hypothesis, a series of mutations were introduced into a 24-nt region found exclusively in the unspliced gRNA. Mutant clones using MMTV or human cytomegalovirus promoters were tested in both transient and stable transfections to determine their effect on gRNA nuclear export, stability, and translation. Nuclear export of the gRNA was affected only in a small mutant subset in stably transfected Jurkat T cells. Quantitative real-time RT-PCR of actinomycin D-treated cells expressing MMTV revealed that multiple mutants were severely compromised for RNA expression and stability. Both genomic and spliced nuclear RNAs were reduced, leading to abrogation of Gag and Env protein expressed from unspliced and spliced mRNAs, respectively. RT-PCRs with multiple primer pairs indicated failure to elongate genomic MMTV transcripts beyond ~500 nt compared to the wild type in a cell line-dependent manner. CONCLUSIONS MMTV contains a novel cis-acting element downstream of the major splice donor critical for facilitating MMTV gRNA elongation and stability. Presence of a mirror repeat within the element may represent important viral/host factor binding site(s) within MMTV gRNA.
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Affiliation(s)
- Shaima Akhlaq
- Department of Biochemistry, College of Medicine and Health Sciences, UAE University, Tawam Hospital Complex, P.O. Box 17666, Al Ain, United Arab Emirates.
| | - Neena G Panicker
- Department of Biochemistry, College of Medicine and Health Sciences, UAE University, Tawam Hospital Complex, P.O. Box 17666, Al Ain, United Arab Emirates.
| | - Pretty S Philip
- Department of Microbiology & Immunology, College of Medicine and Health Sciences, UAE University, Tawam Hospital Complex, P.O. Box 17666, Al Ain, United Arab Emirates.
| | - Lizna M Ali
- Department of Microbiology & Immunology, College of Medicine and Health Sciences, UAE University, Tawam Hospital Complex, P.O. Box 17666, Al Ain, United Arab Emirates.
| | - Jaquelin P Dudley
- LaMontagne Center for Infectious Diseases, The University of Texas at Austin, 100 East 24th Street, NHB 2.616, Austin, TX 78712, USA.
| | - Tahir A Rizvi
- Department of Microbiology & Immunology, College of Medicine and Health Sciences, UAE University, Tawam Hospital Complex, P.O. Box 17666, Al Ain, United Arab Emirates.
| | - Farah Mustafa
- Department of Biochemistry, College of Medicine and Health Sciences, UAE University, Tawam Hospital Complex, P.O. Box 17666, Al Ain, United Arab Emirates.
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3
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Bann DV, Beyer AR, Parent LJ. A murine retrovirus co-Opts YB-1, a translational regulator and stress granule-associated protein, to facilitate virus assembly. J Virol 2014; 88:4434-50. [PMID: 24501406 PMCID: PMC3993753 DOI: 10.1128/jvi.02607-13] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2013] [Accepted: 01/28/2014] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED The Gag protein of the murine retrovirus mouse mammary tumor virus (MMTV) orchestrates the assembly of immature virus particles in the cytoplasm which are subsequently transported to the plasma membrane for release from the cell. The morphogenetic pathway of MMTV assembly is similar to that of Saccharomyces cerevisiae retrotransposons Ty1 and Ty3, which assemble virus-like particles (VLPs) in intracytoplasmic ribonucleoprotein (RNP) complexes. Assembly of Ty1 and Ty3 VLPs depends upon cellular mRNA processing factors, prompting us to examine whether MMTV utilizes a similar set of host proteins to facilitate viral capsid assembly. Our data revealed that MMTV Gag colocalized with YB-1, a translational regulator found in stress granules and P bodies, in intracytoplasmic foci. The association of MMTV Gag and YB-1 in cytoplasmic granules was not disrupted by cycloheximide treatment, suggesting that these sites were not typical stress granules. However, the association of MMTV Gag and YB-1 was RNA dependent, and an MMTV RNA reporter construct colocalized with Gag and YB-1 in cytoplasmic RNP complexes. Knockdown of YB-1 resulted in a significant decrease in MMTV particle production, indicating that YB-1 plays a role in MMTV capsid formation. Analysis by live-cell imaging with fluorescence recovery after photobleaching (FRAP) revealed that the population of Gag proteins localized within YB-1 complexes was relatively immobile, suggesting that Gag forms stable complexes in association with YB-1. Together, our data imply that the formation of intracytoplasmic Gag-RNA complexes is facilitated by YB-1, which promotes MMTV virus assembly. IMPORTANCE Cellular mRNA processing factors regulate the posttranscriptional fates of mRNAs, affecting localization and utilization of mRNAs under normal conditions and in response to stress. RNA viruses such as retroviruses interact with cellular mRNA processing factors that accumulate in ribonucleoprotein complexes known as P bodies and stress granules. This report shows for the first time that mouse mammary tumor virus (MMTV), a mammalian retrovirus that assembles intracytoplasmic virus particles, commandeers the cellular factor YB-1, a key regulator of translation involved in the cellular stress response. YB-1 is essential for the efficient production of MMTV particles, a process directed by the viral Gag protein. We found that Gag and YB-1 localize together in cytoplasmic granules. Functional studies of Gag/YB-1 granules suggest that they may be sites where virus particles assemble. These studies provide significant insights into the interplay between mRNA processing factors and retroviruses.
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Affiliation(s)
- Darrin V. Bann
- Department of Medicine, Penn State College of Medicine, Hershey, Pennsylvania, USA
| | - Andrea R. Beyer
- Department of Microbiology and Immunology, Penn State College of Medicine, Hershey, Pennsylvania, USA
| | - Leslie J. Parent
- Department of Medicine, Penn State College of Medicine, Hershey, Pennsylvania, USA
- Department of Microbiology and Immunology, Penn State College of Medicine, Hershey, Pennsylvania, USA
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4
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Kane M, Case LK, Kopaskie K, Kozlova A, MacDearmid C, Chervonsky AV, Golovkina TV. Successful transmission of a retrovirus depends on the commensal microbiota. Science 2011; 334:245-9. [PMID: 21998394 DOI: 10.1126/science.1210718] [Citation(s) in RCA: 282] [Impact Index Per Article: 21.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
To establish chronic infections, viruses must develop strategies to evade the host's immune responses. Many retroviruses, including mouse mammary tumor virus (MMTV), are transmitted most efficiently through mucosal surfaces rich in microbiota. We found that MMTV, when ingested by newborn mice, stimulates a state of unresponsiveness toward viral antigens. This process required the intestinal microbiota, as antibiotic-treated mice or germ-free mice did not transmit infectious virus to their offspring. MMTV-bound bacterial lipopolysaccharide triggered Toll-like receptor 4 and subsequent interleukin-6 (IL-6)-dependent induction of the inhibitory cytokine IL-10. Thus, MMTV has evolved to rely on the interaction with the microbiota to induce an immune evasion pathway. Together, these findings reveal the fundamental importance of commensal microbiota in viral infections.
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Affiliation(s)
- Melissa Kane
- Department of Microbiology, The University of Chicago, Chicago, IL 60637, USA
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5
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Kane M, Case LK, Wang C, Yurkovetskiy L, Dikiy S, Golovkina TV. Innate immune sensing of retroviral infection via Toll-like receptor 7 occurs upon viral entry. Immunity 2011; 35:135-45. [PMID: 21723157 PMCID: PMC3519935 DOI: 10.1016/j.immuni.2011.05.011] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2010] [Revised: 03/02/2011] [Accepted: 03/30/2011] [Indexed: 12/21/2022]
Abstract
Innate immune sensors are required for induction of pathogen-specific immune responses. Retroviruses are notorious for their ability to evade immune defenses and establish long-term persistence in susceptible hosts. However, some infected animals are able to develop efficient virus-specific immune responses, and thus can be employed for identification of critical innate virus-sensing mechanisms. With mice from two inbred strains that control retroviruses via adaptive immune mechanisms, we found that of all steps in viral replication, the ability to enter the host cell was sufficient to induce antivirus humoral immune responses. Virus sensing occurred in endosomes via a MyD88-Toll-like receptor 7-dependent mechanism and stimulated virus-neutralizing immunity independently of type I interferons. Thus, efficient adaptive immunity to retroviruses is induced in vivo by innate sensing of the early stages of retroviral infection.
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Affiliation(s)
- Melissa Kane
- Department of Microbiology, University of Chicago, 920 E. 58 Street, Chicago, IL 60637, USA
| | - Laure K. Case
- Department of Microbiology, University of Chicago, 920 E. 58 Street, Chicago, IL 60637, USA
| | - Christine Wang
- Department of Microbiology, University of Chicago, 920 E. 58 Street, Chicago, IL 60637, USA
| | - Leonid Yurkovetskiy
- Department of Microbiology, University of Chicago, 920 E. 58 Street, Chicago, IL 60637, USA
| | - Stanislav Dikiy
- Department of Microbiology, University of Chicago, 920 E. 58 Street, Chicago, IL 60637, USA
| | - Tatyana V. Golovkina
- Department of Microbiology, University of Chicago, 920 E. 58 Street, Chicago, IL 60637, USA
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6
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Abstract
Primary biliary cirrhosis (PBC) is characterized by unknown etiologies, anti-mitochondrial antibodies, injury of the biliary duct and the lack of a definite remedy. The etiologies of PBC have been well-discussed, including microorganisms and xenobiotics as the triggers for initiating the disease, and an abnormality of immune-tolerance. Recently, several animal models of PBC have been developed that may lead to the development of new therapies. Here, we reviewed the articles that address the etiology of PBC and the therapy for this disease for the confirmation of our current positions and future directions.
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Affiliation(s)
- Koji Fukushima
- Division of Gastroenterology, Tohoku University Graduate School of Medicine, Seiryo, Aobaku, Sendai, Japan
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7
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A novel block to mouse mammary tumor virus infection of lymphocytes in B10.BR mice. J Virol 2007; 82:1314-22. [PMID: 18003725 DOI: 10.1128/jvi.01848-07] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Classic studies on C57BL-derived mouse strains showed that they were resistant to mouse mammary tumor virus (MMTV) infection. Although one form of resistance mapped to the major histocompatibility complex (MHC) locus, at least one other, unknown gene was implicated in this resistance. We show here that B10.BR mice, which are derived from C57BL mice but have the same MHC locus (H-2(k)) as susceptible C3H/HeN mice, are resistant to MMTV, and show a lack of virus spread in their lymphoid compartments but not their mammary epithelial cells. Although in vivo virus superantigen (Sag)-mediated activation of T cells was similar in C3H/HeN and B10.BR mice, T cell-dependent B-cell and dendritic cell activation was diminished in the latter. Ex vivo, B10.BR T cells showed a diminished capacity to proliferate in response to the MMTV Sag. The genetic segregation of the resistance phenotype indicated that it maps to a single allele. These data highlight the role of Sag-dependent T-cell responses in MMTV infection and point to a novel mechanism for the resistance of mice to retroviral infection that could lead to a better understanding of the interplay between hosts and pathogens.
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8
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Huber BT, Beutner U, Subramanyam M. The role of superantigens in the immunobiology of retroviruses. CIBA FOUNDATION SYMPOSIUM 2007; 187:132-40; discussion 140-3. [PMID: 7796668 DOI: 10.1002/9780470514672.ch9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Murine mammary tumour viruses (MMTVs) are retroviruses that encode superantigens capable of stimulating T cells via superantigen-reactive T cell receptor V beta chains. MMTVs are transmitted to the suckling offspring via the milk. We have established that class II and B cell-deficient mice that were foster nursed by virus-secreting mice do not transfer infectious MMTVs to their offspring. No MMTV proviruses could be detected in the spleen and mammary tissue of these mice and there was no deletion of MMTV superantigen-reactive T cells. These results confirm that superantigen expression in the context of MHC class II molecules is required for MMTV transmission. We conclude that B cells are essential for the completion of the viral life cycle in vivo. This indicates that B cells are infected first and that viral amplification takes place only if infected B cells present the MMTV superantigen on their surface which, in turn, results in activation of T cells expressing the appropriate T cell receptor V beta chains. These activated T cells stimulate B cells which enables viral replication. Human T cells carry all the structural features required for an efficient response to murine retrovirally encoded superantigens. Superantigen-like stimulation of human T cells has been demonstrated in both infectious and autoimmune diseases. Human immunodeficiency virus may encode a superantigen but this has not been proven.
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Affiliation(s)
- B T Huber
- Department of Pathology, Tufts University School of Medicine, Boston, MA 02111, USA
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9
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Courreges MC, Burzyn D, Nepomnaschy I, Piazzon I, Ross SR. Critical role of dendritic cells in mouse mammary tumor virus in vivo infection. J Virol 2007; 81:3769-77. [PMID: 17267484 PMCID: PMC1866091 DOI: 10.1128/jvi.02728-06] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Mouse mammary tumor virus (MMTV) is a milk-transmitted betaretrovirus that causes mammary tumors in mice. Although mammary epithelial cells are the ultimate targets of MMTV, the virus utilizes components of the host immune system to establish infection. Previous studies indicated that dendritic cells play a role in MMTV infection. Here we show that dendritic cells are the first cells to be infected by MMTV in vivo and that they are capable of producing infectious virus that can be transmitted to other cell types. Moreover, upon contact with the virus, dendritic cells became more mature and migrated in response to the chemokine macrophage inflammatory protein 3beta. Finally, we demonstrate that targeted ablation of dendritic cells in vivo dramatically attenuated MMTV infection. These data indicate that MMTV infection of dendritic cells is critical to initial propagation of the virus in vivo.
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Affiliation(s)
- Maria Cecilia Courreges
- Department of Microbiology and Abramson Family Cancer Center, University of Pennsylvania, 313 BRBII/III, 421 Curie Blvd., Philadelphia, PA 19104-6142, USA
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10
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Ross SR, Schmidt JW, Katz E, Cappelli L, Hultine S, Gimotty P, Monroe JG. An immunoreceptor tyrosine activation motif in the mouse mammary tumor virus envelope protein plays a role in virus-induced mammary tumors. J Virol 2006; 80:9000-8. [PMID: 16940512 PMCID: PMC1563925 DOI: 10.1128/jvi.00788-06] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Mouse mammary tumor virus (MMTV) induces breast cancer with almost 100% efficiency in susceptible strains through insertional activation of protooncogenes, such as members of the wnt and fibroblast growth factor (fgf) families. We previously showed that expression of the MMTV envelope protein (Env) in normal immortalized mammary epithelial cells grown in three-dimensional cultures caused their morphological transformation, and that this phenotype depended on an immunoreceptor tyrosine-based activation motif (ITAM) present in Env and signaling through the Syk tyrosine kinase (E. Katz, M. H. Lareef, J. C. Rassa, S. M. Grande, L. B. King, J. Russo, S. R. Ross, and J. G. Monroe, J. Exp. Med. 201:431-439, 2005). Here, we examined the role of the Env protein in virus-induced mammary tumorigenesis in vivo. Similar to the effect seen in vitro, Env expression in the mammary glands of transgenic mice bearing either full-length wild-type provirus or only Env transgenes showed increased lobuloalveolar budding. Introduction of the ITAM mutation into the env of an infectious, replication-competent MMTV or into MMTV/murine leukemia virus pseudotypes had no effect on incorporation of Env into virus particles or on in vitro infectivity. Moreover, replication-competent MMTV bearing the ITAM mutation in Env infected lymphoid and mammary tissue at the same level as wild-type MMTV and was transmitted through milk. However, mammary tumor induction was greatly attenuated, and the pattern of oncogene activation was altered. Taken together, these studies indicate that the MMTV Env protein participates in mammary epithelial cell transformation in vivo and that this requires a functional ITAM in the envelope protein.
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Affiliation(s)
- Susan R Ross
- University of Pennsylvania, 313BRBII/III, 421 Curie Blvd., Philadelphia, PA 19104, USA.
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11
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Swanson I, Jude BA, Zhang AR, Pucker A, Smith ZE, Golovkina TV. Sequences within the gag gene of mouse mammary tumor virus needed for mammary gland cell transformation. J Virol 2006; 80:3215-24. [PMID: 16537589 PMCID: PMC1440402 DOI: 10.1128/jvi.80.7.3215-3224.2006] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Previously, we identified a group of replication-competent exogenous mouse mammary tumor viruses that failed to induce mammary tumors in susceptible mice. Sequence comparison of tumorigenic and tumor-attenuated virus variants has linked the ability of virus to cause high-frequency mammary tumors to the gag gene. To determine the specific sequences within the gag gene that contribute to tumor induction, we constructed five distinct chimeric viruses that have various amino acid coding sequences of gag derived from a tumor-attenuated virus replaced by those of highly tumorigenic virus and tested these viruses for tumorigenic capacities in virus-susceptible C3H/HeN mice. Comparing the tumorigenic potentials of these viruses has allowed us to map the region responsible for tumorigenesis to a 253-amino-acid region within the CA and NC regions of the Gag protein. Unlike C3H/HeN mice, BALB/cJ mice develop tumors when infected with all viral variants, irrespective of the gag gene sequences. Using genetic crosses between BALB/cJ and C3H/HeN mice, we were able to determine that the mechanism that confers susceptibility to Gag-independent mammary tumors in BALB/cJ mice is inherited as a dominant trait and is controlled by a single gene, called mammary tumor susceptibility (mts), that maps to chromosome 14.
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MESH Headings
- Amino Acid Sequence
- Animals
- Blotting, Western
- Cell Transformation, Neoplastic
- Chromosome Mapping
- Chromosomes
- Cloning, Molecular
- Conserved Sequence
- Crosses, Genetic
- Female
- Gene Expression Regulation, Neoplastic
- Gene Expression Regulation, Viral
- Genes, gag
- Genetic Engineering
- Haplotypes
- Mammary Neoplasms, Experimental/etiology
- Mammary Neoplasms, Experimental/virology
- Mammary Tumor Virus, Mouse/genetics
- Mammary Tumor Virus, Mouse/pathogenicity
- Mice
- Mice, Inbred BALB C
- Mice, Inbred C3H
- Mice, Transgenic
- Models, Genetic
- Molecular Sequence Data
- Mutagenesis
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12
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Abstract
Mouse mammary tumor virus (MMTV), a well-characterized retrovirus that causes mammary tumors in susceptible mice, is commonly used to investigate virus-host interactions. We have shown that YBR/Ei mice demonstrate a novel, dominant mechanism of resistance to MMTV infection and MMTV-induced mammary tumors. MMTV can both establish infection in YBR/Ei mice and be transmitted by YBR/Ei mice as an infectious virus. However, virus production is severely attenuated, resulting in gradual clearance of infection in successive generations. Our transfer experiments showed that T cells generated in MMTV-infected resistant mice were required to restrict MMTV replication in susceptible mice. These results emphasize the importance of inducing T-cell responses for effective protection against retroviral infections.
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13
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Pobezinskaya Y, Chervonsky AV, Golovkina TV. Initial stages of mammary tumor virus infection are superantigen independent. THE JOURNAL OF IMMUNOLOGY 2004; 172:5582-7. [PMID: 15100301 DOI: 10.4049/jimmunol.172.9.5582] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Exogenous mouse mammary tumor virus (MMTV) is transmitted via the milk from infected mothers to newborn pups. Efficient MMTV transmission is dependent on proliferation of T cells with particular TCR beta-chains, which occurs upon recognition of virally encoded superantigen (SAg) bound to MHC class II molecules. It is assumed that infection of these dividing cells favors MMTV amplification. SAg is important for MMTV infection, as mice that lack SAg-cognate T cells due to expression of endogenous Mtv loci or mice that express inappropriate MHC haplotypes unable to present viral SAg efficiently were shown to be resistant to MMTV infection. However, this resistance was not absolute, as these mice developed late onset MMTV-induced mammary tumors. In this study, we show that the success of initial MMTV infection in neonates is independent of SAg function but depends on the developmentally regulated proliferation of target cells. However, SAg was absolutely required for virus spread following completion of this proliferative stage.
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MESH Headings
- Animals
- Animals, Newborn
- Antigen Presentation/genetics
- Antigen Presentation/immunology
- Genetic Predisposition to Disease
- Immunity, Innate/genetics
- Mammary Tumor Virus, Mouse/immunology
- Mammary Tumor Virus, Mouse/physiology
- Mice
- Mice, Inbred BALB C
- Mice, Inbred C3H
- Mice, Inbred C57BL
- Mice, Inbred CBA
- Mice, Inbred DBA
- Mice, Transgenic
- Phenotype
- Postpartum Period/genetics
- Postpartum Period/immunology
- Retroviridae Infections/genetics
- Retroviridae Infections/immunology
- Retroviridae Infections/virology
- Superantigens/immunology
- Superantigens/metabolism
- Superantigens/physiology
- Tumor Virus Infections/genetics
- Tumor Virus Infections/immunology
- Tumor Virus Infections/virology
- Virus Replication/immunology
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14
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Selmi C, Ross SR, Ansari AA, Invernizzi P, Podda M, Coppel RL, Gershwin ME. Lack of immunological or molecular evidence for a role of mouse mammary tumor retrovirus in primary biliary cirrhosis. Gastroenterology 2004; 127:493-501. [PMID: 15300582 DOI: 10.1053/j.gastro.2004.05.033] [Citation(s) in RCA: 87] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
BACKGROUND & AIMS Recent observations, including a pilot clinical trial, have suggested that a human mouse mammary tumor virus (MMTV) causes primary biliary cirrhosis (PBC). We attempted to confirm such data. METHODS We obtained sera from 101 patients (53 with PBC and 48 controls), fixed liver sections from 10 patients (8 PBC and 2 controls), fresh liver specimens (6 PBC and 6 controls), and fresh peripheral blood lymphocytes (PBLs) (10 PBC and 10 controls). We studied sera for reactivities against 3 different strains of MMTV virions, MMTV(C3H), MMTV(FM), and MMTV(LA), including goat polyclonal antibodies against MMTV virions, gp52, and p27 as positive controls. We stained liver specimens using polyclonal antibodies against MMTV and gp52 and further examined tissue samples and PBLs for specific MMTV genome sequences. RESULTS By Western blot analysis, no detectable reactivity in any of the PBC sera against any of the 3 MMTV strains or MMTV gp52 or p27 was observed. However, viral proteins were recognized by our control positive polyclonal antibodies. We note that 13%-60% of PBC sera presented low reactivity against 2 proteins of approximately 57 and 74 kilodaltons. Such reactivity is related to the trace amounts of mitochondrial antigens in the virus preparations derived from murine mammary tumor tissue. No detectable immunohistochemical or molecular evidence for MMTV was found in the liver specimens or PBLs. CONCLUSIONS We were unable to recapitulate the data on this specific retroviral etiology of PBC and suggest that such data could be the result of contamination.
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Affiliation(s)
- Carlo Selmi
- Division of Rheumatology, Allergy, and Clinical Immunology, University of California at Davis, 95616, USA
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15
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Mpandi M, Otten LA, Lavanchy C, Acha-Orbea H, Finke D. Passive immunization with neutralizing antibodies interrupts the mouse mammary tumor virus life cycle. J Virol 2003; 77:9369-77. [PMID: 12915552 PMCID: PMC187390 DOI: 10.1128/jvi.77.17.9369-9377.2003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Mouse mammary tumor virus (MMTV) infects the host via mucosal surfaces and exploits the host immune system for systemic spread and chronic infection. We have tested a neutralizing rat monoclonal antibody specific for the retroviral envelope glycoprotein gp52 for its efficiency in preventing acute and chronic mucosal and systemic infection. The antibody completely inhibits the superantigen response and chronic viral infection following systemic or nasal infection. Surprisingly however, the antibody only partially inhibits the early infection of antigen-presenting cells in the draining lymph node. Despite this initially inefficient protection from infection, superantigen-specific B- and T-cell responses and systemic viral spread are abolished, leading to complete clearance of the retroviral infection and hence interruption of the viral life cycle. In conclusion, systemic neutralizing monoclonal antibodies can provide an efficient protection against chronic retroviral amplification and persistence.
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MESH Headings
- Animals
- Antibodies, Monoclonal/administration & dosage
- Antibodies, Viral/administration & dosage
- Antigens, Viral, Tumor/genetics
- Antigens, Viral, Tumor/immunology
- B-Lymphocytes/immunology
- B-Lymphocytes/pathology
- Base Sequence
- Cell Differentiation
- DNA, Viral/genetics
- Female
- Immunity, Mucosal
- Immunization, Passive
- Mammary Neoplasms, Experimental/immunology
- Mammary Neoplasms, Experimental/prevention & control
- Mammary Tumor Virus, Mouse/genetics
- Mammary Tumor Virus, Mouse/growth & development
- Mammary Tumor Virus, Mouse/immunology
- Mice
- Mice, Inbred BALB C
- Neutralization Tests
- Rats
- Rats, Inbred Lew
- Retroviridae Infections/immunology
- Retroviridae Infections/prevention & control
- Tumor Virus Infections/immunology
- Tumor Virus Infections/prevention & control
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Affiliation(s)
- M Mpandi
- Swiss Institute for Experimental Cancer Research. Institute of Biochemistry, University of Lausanne, Switzerland
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16
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Purdy A, Case L, Duvall M, Overstrom-Coleman M, Monnier N, Chervonsky A, Golovkina T. Unique resistance of I/LnJ mice to a retrovirus is due to sustained interferon gamma-dependent production of virus-neutralizing antibodies. J Exp Med 2003; 197:233-43. [PMID: 12538662 PMCID: PMC2193815 DOI: 10.1084/jem.20021499] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2002] [Revised: 12/11/2002] [Accepted: 12/11/2002] [Indexed: 11/16/2022] Open
Abstract
Selection of immune escape variants impairs the ability of the immune system to sustain an efficient antiviral response and to control retroviral infections. Like other retroviruses, mouse mammary tumor virus (MMTV) is not efficiently eliminated by the immune system of susceptible mice. In contrast, MMTV-infected I/LnJ mice are capable of producing IgG2a virus-neutralizing antibodies, sustain this response throughout their life, and secrete antibody-coated virions into the milk, thereby preventing infection of their progeny. Antibodies were produced in response to several MMTV variants and were cross-reactive to them. Resistance to MMTV infection was recessive and was dependent on interferon (IFN)-gamma production, because I/LnJ mice with targeted deletion of the INF-gamma gene failed to produce any virus-neutralizing antibodies. These findings reveal a novel mechanism of resistance to retroviral infection that is based on a robust and sustained IFN-gamma-dependent humoral immune response.
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MESH Headings
- Animals
- Animals, Newborn
- Antibodies, Viral/biosynthesis
- Cross Reactions
- Female
- Genetic Variation
- Immunoglobulin G/biosynthesis
- Interferon-gamma/biosynthesis
- Interferon-gamma/deficiency
- Interferon-gamma/genetics
- Mammary Glands, Animal/immunology
- Mammary Glands, Animal/virology
- Mammary Tumor Virus, Mouse/genetics
- Mammary Tumor Virus, Mouse/immunology
- Mammary Tumor Virus, Mouse/pathogenicity
- Mice
- Mice, Inbred BALB C
- Mice, Inbred C3H
- Mice, Knockout
- Milk/virology
- Neutralization Tests
- Retroviridae Infections/genetics
- Retroviridae Infections/immunology
- Retroviridae Infections/virology
- Superantigens/genetics
- Tumor Virus Infections/genetics
- Tumor Virus Infections/immunology
- Tumor Virus Infections/virology
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Affiliation(s)
- Alexandra Purdy
- The Jackson Laboratory, 600 Main Street, Bar Harbor, ME 04609, USA
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17
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Yamazaki K, Boyse EA, Bard J, Curran M, Kim D, Ross SR, Beauchamp GK. Presence of mouse mammary tumor virus specifically alters the body odor of mice. Proc Natl Acad Sci U S A 2002; 99:5612-5. [PMID: 11929982 PMCID: PMC122818 DOI: 10.1073/pnas.082093099] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
It has long been recognized that various genetic and metabolic human disorders alter body odor, which is not surprising because they may alter body chemistry. Thus, it has been suggested that some human diseases may be diagnosed by odor alone. In that regard, the mouse mammary tumor virus (MMTV) and its tumors of mice, which may have human counterparts, are of special interest because of the need for basic research possible only in inbred and genetically defined animals. Accordingly, we now show that the mouse MMTV, whether obtained environmentally or genetically transmitted, alters the body odor of mice in both males and females, and regardless of the presence or absence of tumors. These observations, together with the prospect of artificial human odor discrimination, may aid in the search for early human diagnostics.
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Affiliation(s)
- Kunio Yamazaki
- Monell Chemical Senses Center, 3500 Market Street, Philadelphia, PA 19104, USA
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18
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Czarneski J, Berguer P, Bekinschtein P, Kim DC, Hakimpour P, Wagner N, Nepomnaschy I, Piazzon I, Ross SR. Neonatal infection with a milk-borne virus is independent of beta7 integrin- and L-selectin-expressing lymphocytes. Eur J Immunol 2002; 32:945-56. [PMID: 11920560 DOI: 10.1002/1521-4141(200204)32:4<945::aid-immu945>3.0.co;2-m] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Mouse mammary tumor virus (MMTV) is acquired by neonates through milk and first infects lymphocytes in Peyer's patches. We show here that newborn mice lacking beta7 integrin or L-selectin were infected with MMTV at wild-type levels in both their lymphoid and mammary tissues. Superantigen-mediated activation and cognate T cell deletion were also unimpaired in both types of null mice. A large proportion of neonatal Peyer's patch lymphocytes in wild-type mice were beta7 and beta1 integrin low and both populations increased in response to MMTV infection. These results suggest that adhesion molecules other than beta7 integrin or L-selectin play a role in lymphocyte homing in the gut, peripheral lymph nodes and mammary gland in response to MMTV infection.
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Affiliation(s)
- Jennifer Czarneski
- Department of Microbiology, University of Pennsylvania, Philadelphia, USA
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19
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Golovkina T, Agafonova Y, Kazansky D, Chervonsky A. Diverse repertoire of the MHC class II-peptide complexes is required for presentation of viral superantigens. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2001; 166:2244-50. [PMID: 11160278 DOI: 10.4049/jimmunol.166.4.2244] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Among other features, peptides affect MHC class II molecules, causing changes in the binding of bacterial superantigens (b-Sag). Whether peptides can alter binding of viral superantigens (v-Sag) to MHC class II was not known. Here we addressed the question of whether mutations limiting the diversity of peptides bound by the MHC class II molecules influenced the presentation of v-Sag and, subsequently, the life cycle of the mouse mammary tumor virus (MMTV). T cells reactive to v-Sag were found in mice lacking DM molecules as well as in A(b)Ep-transgenic mice in which MHC class II binding grooves were predominantly occupied by an invariant chain fragment or Ealpha(52-68) peptide, respectively. APCs from the mutant mice failed to present v-Sag, as determined by the lack of Sag-specific T cell activation, Sag-induced T cell deletion, and by the aborted MMTV infection. In contrast, mice that express I-A(b) with a variety of bound peptides presented v-Sag and were susceptible to MMTV infection. Comparison of v-Sag and b-Sag presentation by the same mutant cells suggested that presentation of v-Sag had requirements similar to that for presentation of toxic shock syndrome toxin-1. Thus, MHC class II peptide repertoire is critical for recognition of v-Sag by the T cells and affects the outcome of infection with a retrovirus.
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MESH Headings
- Animals
- Antigen Presentation/genetics
- Antigen-Presenting Cells/immunology
- Antigen-Presenting Cells/metabolism
- Antigen-Presenting Cells/microbiology
- Antigen-Presenting Cells/virology
- Antigens, Viral/immunology
- Antigens, Viral/metabolism
- Enterotoxins/immunology
- Enterotoxins/metabolism
- Female
- Histocompatibility Antigens Class II/biosynthesis
- Histocompatibility Antigens Class II/genetics
- Histocompatibility Antigens Class II/physiology
- Male
- Mammary Neoplasms, Experimental/genetics
- Mammary Neoplasms, Experimental/immunology
- Mammary Tumor Virus, Mouse/immunology
- Mice
- Mice, Inbred BALB C
- Mice, Inbred C57BL
- Mice, Inbred CBA
- Mice, Knockout
- Mice, Transgenic
- Peptides/immunology
- Peptides/metabolism
- Retroviridae Infections/genetics
- Retroviridae Infections/immunology
- Staphylococcus aureus/immunology
- Superantigens/immunology
- Superantigens/metabolism
- T-Lymphocytes/immunology
- T-Lymphocytes/metabolism
- T-Lymphocytes/virology
- Tumor Virus Infections/genetics
- Tumor Virus Infections/immunology
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Affiliation(s)
- T Golovkina
- The Jackson Laboratory, Bar Harbor, ME 04609, USA.
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20
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Hook LM, Agafonova Y, Ross SR, Turner SJ, Golovkina TV. Genetics of mouse mammary tumor virus-induced mammary tumors: linkage of tumor induction to the gag gene. J Virol 2000; 74:8876-83. [PMID: 10982330 PMCID: PMC102082 DOI: 10.1128/jvi.74.19.8876-8883.2000] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Retroviruses are believed to induce tumors by acting as insertional mutagens that activate expression of cellular protooncogenes. Indeed, almost 90% of mouse mammary tumor virus (MMTV)-induced mammary tumors in C3H/He mice show upregulation of Int protooncogenes. We have analyzed three different MMTV variants [MMTV(C3H), MMTV(HeJ), and a genetically engineered MMTV hybrid provirus (HP)] for tumorigenicity in mice from two distinct genetic backgrounds. All three viruses were tumor causing in BALB/cJ mice. However, only MMTV(C3H), but not MMTV(HeJ) or HP, induced mammary tumors in C3H/He mice. All of the viruses were infectious on either background and up-regulated expression of Int genes in tumors they induced. Like HP, MMTV(HeJ) was found to be a genetic recombinant between endogenous Mtv1 provirus and exogenous MMTV(C3H). Sequence comparison of MMTV variants linked the tumorigenicity of MMTV(C3H) to the gag region of the retrovirus.
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Affiliation(s)
- L M Hook
- The Jackson Laboratory, Bar Harbor, Maine 04609, USA
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21
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Umemura M, Wajjwalku W, Upragarin N, Liu T, Nishimura H, Matsuguchi T, Nishiyama Y, Wilson GM, Yoshikai Y. Expression of mouse mammary tumor virus superantigen accelerates tumorigenicity of myeloma cells. J Virol 2000; 74:8226-33. [PMID: 10954519 PMCID: PMC116330 DOI: 10.1128/jvi.74.18.8226-8233.2000] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
To investigate whether superantigen (SAG) from endogenous mouse mammary tumor virus functions as an immunogenic or a tumorigenic factor in tumor development, the BALB/c myeloma cell line FO was transfected with the SAG gene from the 3' Mtv-50 long terminal repeat (LTR) open reading frame (ORF), the product of which was specific for Vbeta6. All five transfectants expressing Mtv-50 LTR ORF mRNA showed stimulatory activity for Vbeta6 T-cell hybridomas in vitro; this activity was inhibited by the addition of anti-Mtv-7 monoclonal antibody (MAb) or anti-major histocompatibility complex class II I-A(d) and I-E(d) MAb. All transfectants with the SAG gene grew more rapidly than did mock transfectants in BALB/c mice after subcutaneous inoculation, whereas all clones, including mock transfectants, grew equally well in athymic nude mice. A significant fraction of Vbeta6 T cells selectively expressed activation markers, including CD44(high), CD62L(low), and CD69(high), and produced large amounts of interleukin 5 (IL-5) and IL-6 in BALB/c mice inoculated with transfectants. These results suggested that the expression of viral SAG enhances the tumorigenicity of a myeloma cell line through the stimulation of SAG-reactive T cells.
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MESH Headings
- Animals
- Biomarkers, Tumor/biosynthesis
- CD4 Lymphocyte Count
- Flow Cytometry
- Interleukin-5/biosynthesis
- Interleukin-5/metabolism
- Interleukin-6/biosynthesis
- Interleukin-6/metabolism
- Leukemia, Myeloid
- Male
- Mammary Tumor Virus, Mouse/genetics
- Mice
- Mice, Inbred BALB C
- Mice, Nude
- Neoplasm Transplantation
- Receptors, Antigen, T-Cell, alpha-beta/immunology
- Receptors, Antigen, T-Cell, alpha-beta/metabolism
- Reverse Transcriptase Polymerase Chain Reaction
- Superantigens/genetics
- Superantigens/metabolism
- Superantigens/physiology
- Terminal Repeat Sequences
- Transfection
- Tumor Cells, Cultured
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Affiliation(s)
- M Umemura
- Laboratory of Host Defense, Research Institute for Disease Mechanism and Control, Nagoya University School of Medicine, Nagoya 466-8550, Japan
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22
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Abstract
Exogenous mouse mammary tumor virus (MMTV) is carried from the gut of suckling pups to the mammary glands by lymphocytes and induces mammary gland tumors. MMTV-induced tumor incidence in inbred mice of different strains ranges from 0 to as high as 100%. For example, mice of the C3H/HeN strain are highly susceptible, whereas mice of the I/LnJ strain are highly resistant. Of the different factors that together determine the susceptibility of mice to development of MMTV-induced mammary tumors, genetic elements play a major role, although very few genes that determine a susceptibility-resistance phenotype have been identified so far. Our data indicate that MMTV fails to infect mammary glands in I/LnJ mice foster nursed on viremic C3H/HeN females, even though the I/LnJ mammary tissue is not refractory to MMTV infection. Lymphocytes from fostered I/LnJ mice contained integrated MMTV proviruses and shed virus but failed to establish infection in the mammary glands of susceptible syngeneic (I x C3H.JK)F(1) females. Based on the susceptible-resistant phenotype distribution in N(2) females, both MMTV mammary gland infection and mammary gland tumor development in I/LnJ mice are controlled by a single locus.
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MESH Headings
- Animals
- Animals, Newborn
- B-Lymphocytes/cytology
- B-Lymphocytes/immunology
- B-Lymphocytes/virology
- CD4-Positive T-Lymphocytes/cytology
- CD4-Positive T-Lymphocytes/immunology
- CD4-Positive T-Lymphocytes/virology
- Cells, Cultured
- Chromosome Mapping
- DNA, Viral/analysis
- Female
- Genes, Recessive
- Immunity, Innate/genetics
- Immunity, Innate/immunology
- Male
- Mammary Glands, Animal/immunology
- Mammary Glands, Animal/virology
- Mammary Neoplasms, Experimental/genetics
- Mammary Neoplasms, Experimental/immunology
- Mammary Neoplasms, Experimental/virology
- Mammary Tumor Virus, Mouse/genetics
- Mammary Tumor Virus, Mouse/immunology
- Mammary Tumor Virus, Mouse/isolation & purification
- Mice
- Mice, Inbred C3H
- Mice, Neurologic Mutants/genetics
- Mice, Neurologic Mutants/immunology
- Retroviridae Infections/genetics
- Retroviridae Infections/immunology
- Retroviridae Infections/virology
- Tumor Virus Infections/genetics
- Tumor Virus Infections/immunology
- Tumor Virus Infections/virology
- Virus Shedding
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Affiliation(s)
- T V Golovkina
- The Jackson Laboratory, Bar Harbor, Maine 04609, USA.
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23
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Dzuris JL, Zhu W, Kapkov D, Golovkina TV, Ross SR. Expression of mouse mammary tumor virus envelope protein does not prevent superinfection in vivo or in vitro. Virology 1999; 263:418-26. [PMID: 10544114 DOI: 10.1006/viro.1999.9967] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Inbred mice expressing endogenous mouse mammary tumor virus envelope proteins can be infected with exogenous virus, and the mammary tumors that develop in these mice usually have many proviruses integrated in their genomes, indicating that this virus is not subject to receptor interference. We show here that transgenic mice expressing an exogenous mouse mammary tumor virus (C3H) envelope protein can still be infected with this virus. Moreover, cultured mammary gland cells expressing the mouse mammary tumor virus (C3H) envelope protein can be superinfected with pseudotyped viruses bearing that same protein. Thus cellular expression of the mouse mammary tumor virus envelope protein does not block superinfection in vivo or in vitro.
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MESH Headings
- Animals
- Blotting, Western
- Cell Line
- DNA, Viral/analysis
- DNA, Viral/genetics
- Female
- Mammary Glands, Animal/cytology
- Mammary Glands, Animal/metabolism
- Mammary Glands, Animal/pathology
- Mammary Neoplasms, Experimental/metabolism
- Mammary Neoplasms, Experimental/virology
- Mammary Tumor Virus, Mouse/genetics
- Mammary Tumor Virus, Mouse/metabolism
- Mice
- Mice, Inbred C3H
- Mice, Transgenic
- Proviruses/genetics
- Recombinant Proteins/genetics
- Recombinant Proteins/metabolism
- Retroviridae Infections/metabolism
- Retroviridae Infections/virology
- Superinfection/metabolism
- Superinfection/virology
- Transfection
- Transgenes/genetics
- Transgenes/physiology
- Tumor Virus Infections/metabolism
- Tumor Virus Infections/virology
- Viral Envelope Proteins/genetics
- Viral Envelope Proteins/metabolism
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Affiliation(s)
- J L Dzuris
- Department of Microbiology, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6148, USA
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24
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Golovkina TV, Dudley JP, Ross SR. B and T Cells Are Required for Mouse Mammary Tumor Virus Spread Within the Mammary Gland. THE JOURNAL OF IMMUNOLOGY 1998. [DOI: 10.4049/jimmunol.161.5.2375] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Abstract
Mouse mammary tumor virus (MMTV) is an infectious retrovirus transmitted through milk from mother to newborns. MMTV encodes a superantigen (SAg) whose activity is indispensable for the virus life cycle, since a genetically engineered virus with a mutation in the sag gene neither amplified in cells of the immune system of suckling pups nor infected their mammary glands. When wild-type MMTV was injected directly into the mammary glands of uninfected pubescent mice, their lymphoid as well as mammary gland cells became virus infected. To test whether this infection of lymphoid cells was dependent on SAg activity and required for virus spread within the mammary gland, we performed mammary gland injections of wild-type MMTV(C3H) into two strains of transgenic mice that lacked SAg-cognate, Vβ14+ T cells. Neither the MTV-ORF or LEL strains showed infection of their mammary glands. Moreover, no MMTV infection of their peripheral lymphocytes was detected. Similar experiments with mice lacking B cells (μ-chain knockouts) showed no detectable virus spread in the mammary glands or lymphoid tissues. These data suggest that SAg activity and MMTV-infected lymphocytes are required, not only for initial steps of viral infection, but also for virus spread within the mammary gland. Virus spread at late times in infection determines whether MMTV induces mammary tumors.
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Affiliation(s)
- Tatyana V. Golovkina
- *Department of Microbiology/Cancer Center, University of Pennsylvania School of Medicine, Philadelphia, PA 19104; and
| | | | - Susan R. Ross
- *Department of Microbiology/Cancer Center, University of Pennsylvania School of Medicine, Philadelphia, PA 19104; and
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25
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McMahon CW, Traxler B, Grigg ME, Pullen AM. Transposon-mediated random insertions and site-directed mutagenesis prevent the trafficking of a mouse mammary tumor virus superantigen. Virology 1998; 243:354-65. [PMID: 9568034 DOI: 10.1006/viro.1998.9071] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Mouse mammary tumor viruses (MMTVs) encode superantigens (Sags) which are critical to the life cycle of infectious virus and can mediate extensive deletion of T lymphocytes when expressed by endogenous proviruses. Little is known about the structure, intracellular trafficking, or nature of Sag association with major histocompatibility (MHC) class II products. In order to gain a better understanding of Sag structure-function relationships, we extensively mutagenized this type II glycoprotein using two different approaches: transposon-mediated random in-frame insertion mutagenesis and site-directed mutagenesis targeting clusters of charged residues. We find that 31 codon insertions are infrequently tolerated in Mtv-7 Sag, with just 1 of 14 insertion mutants functionally presented on the surface of B cells. Surprisingly, similar effects were observed with Sag mutants with substitutions at pairs of charged residues; only 2 of 6 mutants trafficked to the plasma membrane and stimulated T cells, 1 with a temperature-sensitive phenotype. The data suggest that the nonfunctional Mtv-7 Sag mutants are stringently retained in the endoplasmic reticulum due to conformational defects rather than disrupted interactions with MHC class II, thus identifying charged amino acids critical to the structural stability of viral superantigens.
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MESH Headings
- Amino Acid Sequence
- Animals
- Antigens, Viral/genetics
- Antigens, Viral/immunology
- Antigens, Viral/metabolism
- Blotting, Western
- Cell Line
- Cell Membrane/metabolism
- DNA Transposable Elements
- Histocompatibility Antigens Class II/immunology
- Intracellular Fluid
- Mammary Tumor Virus, Mouse/genetics
- Mammary Tumor Virus, Mouse/immunology
- Mammary Tumor Virus, Mouse/metabolism
- Membrane Glycoproteins/genetics
- Membrane Glycoproteins/immunology
- Membrane Glycoproteins/metabolism
- Mice
- Molecular Sequence Data
- Mutagenesis, Insertional
- Mutagenesis, Site-Directed
- Superantigens/genetics
- Superantigens/immunology
- Superantigens/metabolism
- Temperature
- Tumor Cells, Cultured
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Affiliation(s)
- C W McMahon
- Department of Immunology, University of Washington, Seattle 98195, USA
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26
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Golovkina TV, Dzuris J, van den Hoogen B, Jaffe AB, Wright PC, Cofer SM, Ross SR. A novel membrane protein is a mouse mammary tumor virus receptor. J Virol 1998; 72:3066-71. [PMID: 9525630 PMCID: PMC109755 DOI: 10.1128/jvi.72.4.3066-3071.1998] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/1997] [Accepted: 12/23/1997] [Indexed: 02/06/2023] Open
Abstract
Mouse mammary tumor virus (MMTV) infects a number of different cell types, including mammary gland and lymphoid cells, in vivo. To identify the cellular receptor for this virus, a mouse cDNA expression library was transfected into Cos-7 monkey kidney cells, and those transfected cells able to bind virus were selected by using antibody against the virus's cell surface envelope protein, gp52. One clone isolated from a library prepared from newborn thymus RNA, called MTVR, was able to confer virus binding to both monkey and human cells; this binding was blocked by anti-MTVR antibody. Moreover, transfection of MTVR into CV1 cells rendered them susceptible to infection by a murine leukemia virus-based retrovirus vector pseudotyped with the MMTV envelope protein. An epitope-tagged MTVR cofractionated with cellular membranes. Coimmunoprecipitation of the MMTV envelope protein and a MTVR-rabbit Fc fusion protein showed that these two proteins bound to each other. The MTVR sequence clone is unique, shows no homology to known membrane proteins, and is transcribed in many tissues.
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MESH Headings
- Amino Acid Sequence
- Animals
- Antigens, Viral, Tumor/metabolism
- Base Sequence
- COS Cells
- Cell Line
- Chlorocebus aethiops
- Chromosome Mapping
- Cloning, Molecular
- DNA, Complementary
- Female
- Humans
- Male
- Mammary Tumor Virus, Mouse/metabolism
- Membrane Proteins/genetics
- Membrane Proteins/metabolism
- Mice
- Mice, Inbred C57BL
- Molecular Sequence Data
- Receptors, Virus/genetics
- Receptors, Virus/metabolism
- Transcription, Genetic
- Tumor Cells, Cultured
- Viral Envelope Proteins/metabolism
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Affiliation(s)
- T V Golovkina
- Department of Microbiology/Cancer Center, University of Pennsylvania, Philadelphia 19104-6142, USA
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27
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Abstract
Mouse mammary tumor virus (MMTV) is a retrovirus that is transmitted through milk to offspring. Gut-associated B cells are the first cells to be infected during virus transmission, and these cells present a virus-encoded superantigen to cognate T cells. This allows MMTV to replicate and amplify in activated lymphocytes and ultimately results in virus transmission to the mammary epithelial cells. Because the superantigen has profound effects on the T cell repertoire and because MMTV replicates in lymphoid cells, loss of immune response to the virus may also play a role in its ability to persist within its host. Transcriptional control of MMTV expression also plays an important part in this pathway and DNA recognition sequences for transcription factors that allow its expression in lymphoid organs and mammary epithelia are encoded within the virus. Thus, this virus has evolved to take maximum advantage of its host's biology.
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Affiliation(s)
- S R Ross
- Department of Microbiology, University of Pennsylvania, Philadelphia 19104-6142, USA.
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28
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Vacheron S, Renno T, Acha-Orbea H. A highly sensitive in vitro infection assay to explore early stages of mouse mammary tumor virus infection. J Virol 1997; 71:7289-94. [PMID: 9311804 PMCID: PMC192071 DOI: 10.1128/jvi.71.10.7289-7294.1997] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Mouse mammary tumor virus (MMTV) infection of adult mice induces a strong response to superantigen (Sag) in their draining lymph nodes, which results from the presentation of Sag by MMTV-infected B cells to Sag-reactive T cells. To date, infection with physiologically relevant doses of MMTV can be detected in vivo only after several days of Sag-mediated T-cell-dependent amplification of infected B cells. Furthermore, no efficient in vitro system of detecting MMTV infection is available. Such a model would allow the dissection of the early phase of infection, the assessment of the contributions of different cell types, and the screening of large panels of molecules for their potential roles in infection and Sag response. For these reasons, we have established an in vitro model for detecting infection which is as sensitive and reproducible as the in vivo model. We found that the viral envelope (Env) protein is crucial for target cell infection but not for presentation of Sag. Furthermore, we show that infection of purified B cells with MMTV induces entry of Sag-responsive T cells into the cell cycle, while other professional antigen-presenting cells, such as dendritic cells, are much less efficient in inducing a response.
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Affiliation(s)
- S Vacheron
- Ludwig Institute for Cancer Research, Lausanne Branch, University of Lausanne, Epalinges, Switzerland
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29
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Xu L, Wrona TJ, Dudley JP. Strain-specific expression of spliced MMTV RNAs containing the superantigen gene. Virology 1997; 236:54-65. [PMID: 9299617 DOI: 10.1006/viro.1997.8717] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The transmission of milk-borne or exogenous mouse mammary tumor virus (MMTV) requires infection of B cells in the gut-associated lymphoid tissue and expression of the superantigen (Sag) protein at the B-cell surface. Presentation of Sag at the B-cell surface is required for the transmission of MMTV to T cells and subsequent infection of the target mammary gland tissue. Because several different promoters have been reported for MMTV sag mRNA expression, we investigated whether the detection of spliced sag RNAs was dependent upon the cell type infected or the particular MMTV strain examined. In this study, we detected expression of spliced sag RNA from the standard promoter and from an internal U3 promoter in B-cell lines expressing endogenous Mtv-6 by RT-PCR, although expression from the standard promoter appeared to be at least 10-fold higher than that observed from the internal U3 promoter. Sag RNA originating from exogenous C3H MMTV was not observed from either of the U3 promoters in any cell type examined. However, spliced mRNAs containing the exogenous C3H MMTV, endogenous Mtv-8, or endogenous Mtv-17 sag genes could be detected from a previously described promoter in the envelope coding region regardless of the cell type infected. Because sag-specific RNAs can be initiated independently of the LTR promoters, there may be selection for independent control of MMTV sag and structural gene expression.
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MESH Headings
- Amino Acid Sequence
- Animals
- Antigens, Viral/biosynthesis
- Antigens, Viral/genetics
- B-Lymphocytes/immunology
- B-Lymphocytes/virology
- Base Sequence
- Consensus Sequence
- Exons
- Genes, Viral
- Genes, env
- Genes, pol
- Introns
- Lymphoma, B-Cell
- Mammary Tumor Virus, Mouse/genetics
- Mice
- Mice, Inbred BALB C
- Mice, Inbred C3H
- Mice, Inbred Strains
- Molecular Sequence Data
- Polymerase Chain Reaction
- Promoter Regions, Genetic
- Proviruses/genetics
- Proviruses/physiology
- RNA Splicing
- RNA, Viral/biosynthesis
- Sequence Alignment
- Superantigens/biosynthesis
- Superantigens/genetics
- T-Lymphocytes/immunology
- T-Lymphocytes/virology
- Transcription, Genetic
- Tumor Cells, Cultured
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Affiliation(s)
- L Xu
- Department of Microbiology, The University of Texas at Austin, Austin, Texas 78712, USA
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30
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Abstract
Mouse mammary tumor virus (MMTV) infected both B and T tissue culture cells and primary B and T cells in vivo after milk-borne transmission of the virus. The infected tissue culture cells processed viral proteins, and both these and primary B and T cells shed virus when cultured in vitro. Moreover, the infected B and T tissue culture cells transmitted virus to uninfected mammary gland cells in vitro. The level of infection of these different cell types in vivo was dependent on the strain of mouse, with C3H/HeN mice showing greater B-cell infection and BALB/c mice greater T-cell infection after nursing on MMTV-infected C3H/HeN mothers. Although their B cells were less infected, BALB/c mice developed tumors more rapidly than C3H/HeN mice. These results indicate that both infected T and B cells are potential carriers of MMTV in vivo.
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Affiliation(s)
- J L Dzuris
- Department of Microbiology/Cancer Center, University of Pennsylvania School of Medicine, Philadelphia 19103-6142, USA
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31
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Tripp RA, Hamilton-Easton AM, Cardin RD, Nguyen P, Behm FG, Woodland DL, Doherty PC, Blackman MA. Pathogenesis of an infectious mononucleosis-like disease induced by a murine gamma-herpesvirus: role for a viral superantigen? J Exp Med 1997; 185:1641-50. [PMID: 9151901 PMCID: PMC2196306 DOI: 10.1084/jem.185.9.1641] [Citation(s) in RCA: 136] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/1996] [Revised: 02/25/1997] [Indexed: 02/04/2023] Open
Abstract
The murine gamma-herpesvirus 68 has many similarities to EBV, and induces a syndrome comparable to infectious mononucleosis (IM). The frequency of activated CD8+ T cells (CD62L(lo)) in the peripheral blood increased greater than fourfold by 21 d after infection of C57BL/6J (H-2(b)) mice, and remained high for at least a further month. The spectrum of T cell receptor usage was greatly skewed, with as many as 75% of the CD8+ T cells in the blood expressing a Vbeta4+ phenotype. Interestingly, the Vbeta4 dominance was also seen, to varying extents, in H-2(k), H-2(d), H-2(u), and H-2(q) strains of mice. In addition, although CD4 depletion from day 11 had no effect on the Vbeta4 bias of the T cells, the Vbeta4+CD8+ expansion was absent in H-2IA(b)-deficient congenic mice. However, the numbers of cycling cells in the CD4 antibody-depleted mice and mice that are CD4 deficient as a consequence of the deletion of MHC class II, were generally lower. The findings suggest that the IM-like disease is driven both by cytokines provided by CD4+ T cells and by a viral superantigen presented by MHC class II glycoproteins to Vbeta4+CD8+ T cells.
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Affiliation(s)
- R A Tripp
- Department of Immunology, St. Jude Children's Research Hospital, Memphis, Tennessee 38105, USA
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32
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Golovkina TV, Piazzon I, Nepomnaschy I, Buggiano V, de Olano Vela M, Ross SR. Generation of a tumorigenic milk-borne mouse mammary tumor virus by recombination between endogenous and exogenous viruses. J Virol 1997; 71:3895-903. [PMID: 9094666 PMCID: PMC191541 DOI: 10.1128/jvi.71.5.3895-3903.1997] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Two novel exogenous mouse mammary tumor viruses (MMTV), BALB2 and BALB14, that encode superantigens (Sags) with Vbeta2+ and Vbeta14+ specificities, respectively, were found in the BALB/cT mouse strain. BALB/cT females were crossed with AKR/J males to generate F1 females. Foster nursing of BALB/cT mice on (BALB/cT x AKR/J)F1 mothers resulted in the generation of a new mouse strain, BALB/cLA, that had acquired a new exogenous MMTV (hereafter called LA) with a Vbeta6+/Vbeta8.1+-T-cell-specific Sag. Sequence analysis of the long terminal repeats of the BALB2, BALB14, and LA viruses indicated that LA virus resulted from recombination between BALB14 and the endogenous Mtv-7 provirus. Mtv-7 is expressed only in lymphoid tissues but not the mammary glands of Mtv-7-containing mouse strains such as AKR. In contrast, LA virus was highly expressed in the mammary gland, although it had the sag-specific region from Mtv-7. The LA virus, as well as different recombinant viruses expressed in the mammary glands of (BALB/cT x AKR/J)F1 mice, acquired a specific DNA sequence from BALB14 virus that is required for the mammary-gland-specific expression of MMTV. Since the Sag encoded by LA virus strongly stimulated cognate T cells in vivo, selection for recombinant virus with the Mtv-7 sag most likely occurred because the increased T-cell proliferation resulted in greater lymphoid and mammary gland cell infection. As a result of the higher virus titer, 80% of BALB/cLA females developed mammary gland tumors, although the incidence was only 40% in BALB/cT mice.
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MESH Headings
- Amino Acid Sequence
- Animals
- Base Sequence
- Female
- Male
- Mammary Neoplasms, Experimental/etiology
- Mammary Tumor Virus, Mouse/genetics
- Mice
- Mice, Inbred AKR
- Mice, Inbred C57BL
- Mice, Inbred DBA
- Milk/virology
- Molecular Sequence Data
- Receptors, Antigen, T-Cell, alpha-beta/analysis
- Recombination, Genetic
- Repetitive Sequences, Nucleic Acid
- Superantigens/chemistry
- Superantigens/genetics
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Affiliation(s)
- T V Golovkina
- Department of Microbiology/Cancer Center, University of Pennsylvania, Philadelphia 19104-6142, USA
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33
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Mouse Mammary Tumor Virus: Immunological Interplays between Virus and Host **This article was accepted for publication on 1 October 1996. Adv Immunol 1997. [DOI: 10.1016/s0065-2776(08)60743-9] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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34
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Nakamura N, Wajjwalku W, Nishimura H, Okubo H, Niimi N, Ando Y, Yoshikai Y. Nucleotide sequences of env and 3'LTROrf genes of endogenous mouse mammary tumor viruses encoding superantigen specific for TcrVbeta2. Immunogenetics 1996; 44:319-20. [PMID: 8753866 DOI: 10.1007/bf02602565] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
- N Nakamura
- Laboratory of Host Defense and Germfree Life, Research Institute for Disease Mechanism and Control, Nagoya University School of Medicine, Nagoya 466, Japan
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35
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Westby M, Manca F, Dalgleish AG. The role of host immune responses in determining the outcome of HIV infection. IMMUNOLOGY TODAY 1996; 17:120-6. [PMID: 8820269 DOI: 10.1016/0167-5699(96)80603-7] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The progression of disease following infection with human immunodeficiency virus (HIV) correlates with an activated immune system and would appear to depend to some degree on the immunogenetics of the host. Here, Michael Westby, Fabrizio Manca and Angus Dalgleish discuss the evidence for HLA determination of clinical outcome and the potential implications of a restricted T-cell receptor repertoire for pathogenesis.
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Affiliation(s)
- M Westby
- Division of Oncology, Cellular and Molecular Sciences, St George's Hospital Medical School, Tooting, UK.
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36
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Kryukova IN, Malivanova TF, Kondrashova OM, Polevaya EB, Evtushenko VV. Possible pathways of circulation of human endogenous retrovirus similar to mouse mammary tumor virus. Bull Exp Biol Med 1995. [DOI: 10.1007/bf02445496] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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37
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Chervonsky AV, Xu J, Barlow AK, Khery M, Flavell RA, Janeway CA. Direct physical interaction involving CD40 ligand on T cells and CD40 on B cells is required to propagate MMTV. Immunity 1995; 3:139-46. [PMID: 7542547 DOI: 10.1016/1074-7613(95)90166-3] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The propagation of mouse mammary tumor virus (MMTV) has been analyzed in mice defective for expression of CD40 ligand (CD40L). Mice with endogenous viral superantigen (SAG) delete T cells with cognate V beta independent of CD40L expression. Nevertheless, CD40L-mice do not show deletion of cognate T cells after being exposed to infectious MMTV and have greatly diminished viral replication. The response of CD40L- T cells to SAG in vitro is also impaired, but can be reconstituted by adding B cells activated by recombinant CD40L to express costimulatory molecules. Thus, direct CD40L-dependent B cell activation appears to be a critical step in the life cycle of MMTV. The initial step in SAG-dependent T cell activation, and hence the MMTV life cycle, may be mediated by non-B cells, because splenocytes from B cell-deficient SAG-transgenic mice are able to activate cognate T cells.
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Affiliation(s)
- A V Chervonsky
- Section of Immunobiology, Yale University School of Medicine, Howard Hughes Medical Institute, New Haven, Connecticut 06510, USA
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38
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Golovkina TV, Dudley JP, Jaffe AB, Ross SR. Mouse mammary tumor viruses with functional superantigen genes are selected during in vivo infection. Proc Natl Acad Sci U S A 1995; 92:4828-32. [PMID: 7761408 PMCID: PMC41800 DOI: 10.1073/pnas.92.11.4828] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Mouse mammary tumor virus (MMTV) encodes a superantigen that is important for viral infectivity in vivo. To determine whether superantigen function was required for infection by milk-borne MMTV, we created HYB PRO/Cla transgenic mice. These mice produced a full-length, packaged viral RNA with a frameshift mutation that caused premature termination of the superantigen protein. Young HYB PRO/Cla mice showed no deletion of their cognate V beta 14+ T cells, although they shed virus in their milk. The nontransgenic offspring of the HYB PRO/Cla mice were infected with this virus, since transgene-specific viral transcripts were detected in their mammary glands. Surprisingly, these offspring demonstrated the progressive deletion of V beta 14+ T cells characteristic of exogenous MMTV (C3H) infection. Sequence analysis demonstrated that these newly acquired viruses had reconstituted superantigen open reading frames resulting from recombination between the HYB PRO/Cla and endogenous Mtv-1 proviral RNAs. Thus, there is selection during the infection process for MMTVs with functional superantigen genes.
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MESH Headings
- Amino Acid Sequence
- Animals
- Antigens, Viral/biosynthesis
- Antigens, Viral/genetics
- Base Sequence
- DNA Primers
- Female
- Flow Cytometry
- Gene Library
- Male
- Mammary Tumor Virus, Mouse/genetics
- Mammary Tumor Virus, Mouse/immunology
- Mammary Tumor Virus, Mouse/isolation & purification
- Mice
- Mice, Inbred C3H
- Mice, Inbred Strains
- Mice, Transgenic
- Molecular Sequence Data
- Pedigree
- Polymerase Chain Reaction
- Recombination, Genetic
- Repetitive Sequences, Nucleic Acid
- Superantigens/biosynthesis
- Superantigens/genetics
- T-Lymphocytes/immunology
- T-Lymphocytes/virology
- Transcription, Genetic
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Affiliation(s)
- T V Golovkina
- Department of Microbiology/Cancer Center, University of Pennsylvania, Philadelphia 19104-6142, USA
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39
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Niimi N, Wajjwalku W, Ando Y, Tomida S, Ueda M, Yoshikai Y. A new gene encoding the ligand for deletion of T cells bearing Tcrb-V6 and V8.1 (Mtv-50). Immunogenetics 1994; 40:312. [PMID: 8082898 DOI: 10.1007/bf00189982] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- N Niimi
- Department of Oral Surgery, Nagoya University School of Medicine, Japan
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40
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Golovkina TV, Jaffe AB, Ross SR. Coexpression of exogenous and endogenous mouse mammary tumor virus RNA in vivo results in viral recombination and broadens the virus host range. J Virol 1994; 68:5019-26. [PMID: 8035502 PMCID: PMC236444 DOI: 10.1128/jvi.68.8.5019-5026.1994] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Mouse mammary tumor virus is a replication-competent B-type murine retrovirus responsible for mammary gland tumorigenesis in some strains of laboratory mice. Mouse mammary tumor virus is transmitted horizontally through the milk (exogenous or milk-borne virus) to susceptible offspring or vertically through the germ line (endogenous provirus). Exogenously acquired and some endogenous mouse mammary tumor viruses are expressed at high levels in lactating mammary glands. We show here that there is packaging of the endogenous Mtv-1 virus, which is expressed at high levels in the lactating mammary glands of C3H/HeN mice, by the virions of exogenous C3H mouse mammary tumor virus [MMTV(C3H)]. The mammary tumors induced in C3H/HeN mice infected with exogenous MMTV (C3H) virus contained integrated copies of recombinant virus containing a region of the env gene from an endogenous virus. This finding indicates that there was copackaging of the Mtv-1 and MMTV(C3H) RNAs in the same virions. Moreover, because Mtv-1 encodes a superantigen protein with a V beta specificity different from that encoded by the exogenous virus, the packaging of Mtv-1 results in an infectious virus with a broader host range than MMTV(C3H).
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Affiliation(s)
- T V Golovkina
- Department of Biochemistry, University of Illinois School of Medicine, Chicago 60612
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41
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Abstract
Superantigens stimulate powerful T-cell responses that can have marked effects in vivo, sometimes leading to shock or even death. The demonstration that strong T-cell responses to superantigens in vivo can be followed by tolerance, reflecting either clonal elimination or anergy, has provided important insights into how mature T cells can be regulated. Further progress in understanding the factors that control these responses relies heavily on defining the specific interactions between T-cell receptors, superantigens and major histocompatibility complex molecules which lead to T-cell activation as well as on the characterization of the specific signal transduction events and molecules involved in this activation. Significant progress has been made, during the past year, in the first area and these findings are summarized below; though less information is available in the latter area, recent observations relevant to this issue are discussed.
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Affiliation(s)
- S R Webb
- Department of Immunology, Scripps Research Institute, La Jolla, California 92037
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