Lentiviruses are widespread pathogens of primates, ungulates and felids. While the ungulate lentiviruses induce a disease state typical of a chronic inflammatory condition, the felid and primate lentiviruses induce an immunodeficiency characterised by a progressive depletion of CD4+ T helper cells. FIV infection of the domestic cat may lead to a spectrum of diseases, ranging from a rapid, acute-onset immunodeficiency to a chronic wasting disease with concomitant neuropathology and persistent recurring opportunistic infections. Here, we examine the host and viral determinants of FIV cell tropism and pathogenicity. The virus targets activated CD4+ T cells selectively by interactions with its primary receptor, CD134 and co-receptor, CXCR4.

from Lentiviruses and Macrophages: Molecular and Cellular Interactions

Further reading:

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

Labels: CD134, CD4 T helper cells, CXCR4, FIV

Simians include diverse species of monkeys which are globally distributed predominantly in the southern hemisphere, and ape species that are restricted to the rainforests of central Africa and Southeast Asia. Types of simian retroviruses have been detected in almost all species of non-human primates which have been studied. As early identification and classification of primate retroviruses was largely possible due to the efforts to establish cell lines from various primate species, there were limitations.

Firstly, the search for simian retroviruses was frequently restricted to only a few species cell lines. Secondly, not all retroviruses were permissive to the available cell lines due to species specific restriction or cell-type specific factors. The earliest discoveries of simian retroviruses were often based on a specific observations which arose from diagnostic workups of cases of then undefined illness or unusual cancers. This chapter focuses on the four main groups of exogenous simian retroviruses; type D simian retroviruses (SRV), simian foamy viruses (SFV) commonly known as spumaviruses, the simian T-cell lymphotropic viruses (STLV), and the expanding group of simian immunodeficiency viruses (SIV).

Initially viruses in these subgroups of simian retroviruses were identified based on the diseases from which they were associated with. Retroperitoneal firbrosarcomas and chronic wasting disease led to the early identification of the SRVs, found to be associated with a spectrum of diseases in different species of macaques. Other simian retroviruses are frequently asymptomatic in their natural hosts and in some cases simply cause cytopathic effect (CPE) in cell culture (SFV).

In the last two decades molecular techniques have provided us with much more insight into the phylogeny of the wide variety of diverse retroviruses, knowledge which has enriched the seroprevalence evidence of widespread retroviral infections in many different primate species.


Further reading: Retroviruses: Molecular Biology, Genomics and Pathogenesis

Labels: BIV, BLV, CAEV, EIAV, FeLV, FIV, Simian Retroviruses, SIV, VMV