Simian-human immunodeficiency virus (SHIV) was generated as a model for acquired immunodeficiency syndrome (AIDS) in order to overcome the narrow host range of human immunodeficiency virus (HIV-1). The first-generation SHIVs were nonpathogenic but evolved to become highly pathogenic viruses. Highly pathogenic SHIVs induce a distinct disease phenotype: a massive, systemic, and irreversible depletion of CD4+ T cells occurs within weeks of infection, followed by AIDS-like clinical manifestations. During the acute phase of infection, the virus predominantly infects and destroys CD4+ T cells. As a result, macrophages become the major virus-producing cell type.

Virus isolated during the macrophage phase of infection exhibits macrophage tropism, a property not possessed by the inoculum SHIV. The V1/V2 region of the env gene was found to be responsible for the expanded cell tropism observed in the macrophage-tropic virus. The viral entry coreceptor, CXCR4, was maintained during the evolution of the virus.

from Lentiviruses and Macrophages: Molecular and Cellular Interactions

Further reading:

• Lentiviruses and Macrophages
• Retroviruses: Molecular Biology, Genomics and Pathogenesis
• Virology publications

Labels: aids, CXCR4, HIV-1, Macrophage tropism, SHIV

For many years, retroviruses were known to be the cause of many kinds of animal leukemias and hematopoietic tumors. In spite of the high expectation that this would also be true for humans, very little evidence for retroviral involvement in any human diseases was forthcoming.

In the late 1970s, however, due to the development of sensitive and specific molecular methods to identify retroviruses and to produce large scale cultures of T lymphocytes, HTLV-I was discovered and implicated as the cause of adult T cell leukemia, a particular and relatively infrequent leukemia prevalent in southern Japan and parts of the Caribbean, and tropical spastic paraparesis, a demyelinating neuropathy similar to multiple sclerosis. The discovery that HTLV-I can be transmitted by breast milk has led to a significant decline in HTLV-I infections in Japan.

Although no retroviruses have been identified to date in other human leukemias or related diseases, the efforts that resulted in the discovery of HTLV-I were critical in isolating HIV-1 and identifying it as the cause of AIDS. The ability to grow the HIV-1 in quantity allowed the development of a blood test that has saved countless lives. The development of effective anti-retroviral drugs has made HIV-1 infection a somewhat manageable chronic condition rather than a certain death sentence. Although vaccine trials thus far have been rather disappointing, an effective vaccine is one of our most important needs.

Further reading: Retroviruses: Molecular Biology, Genomics and Pathogenesis

Labels: aids, Anti-retroviral drugs, HIV-1, HIV-2, HTLV-I, Paraparesis, Vaccine trials

Lentiviruses and Macrophages: Molecular and Cellular Interactions
Edited by: Moira Desport
Published: 2010 ISBN: 978-1-904455-60-8
In this timely book, top lentivirus and macrophage specialists comprehensively review cutting-edge topics in the molecular and cellular biology of the lentivirus-macrophage interaction. Topics include lentivirus tropism and disease, macrophage biology, macrophage in HIV-1 infection and disease progression, post-entry restrictions to lentiviral replication, HIV-2 tropism and disease, SHIV model of disease, the felid immunodeficiency viruses, EIAV, small ruminant lentiviruses, bovine lentiviruses, coinfections and superinfections.

Further reading: Lentiviruses and Macrophages: Molecular and Cellular Interactions

Labels: aids, books, dengue virus, hiv, lentivirus, lentiviruses, new book, virology books, virus books