FIV infection of IL-2-dependent and -independent feline lymphocyte lines: Host cells range distinctions and specific cytokine upregulation

Abstract

We have analyzed the ability of three molecular clones of feline immunodeficiency virus (FIV) and an ex vivo variant to infect nine distinct specific-pathogen-free feline cell lines in tissue culture. The purpose of these studies was to elucidate mechanisms by which host cells regulate the level of virus infection and expression and to assess host cell cytokine responses to virus infection. Cells used for the analyzes included four IL-2-dependent continuous T-cell lines (104-C1, 104-C7, MCH5-4 and DB FeTs) which arose from long-term passage, followed by limiting dilution cloning of peripheral blood mononuclear cells (PBMCs); two IL-2-independent T-cell lines (104-C1DL and MCH5-4DL) which originated from two of the IL-2-dependent lines, 104-C1 and MCH5-4; respectively; Crandell feline kidney cells (CrFK); G355-5 brain-derived glial cells; and the T-cell lymphoma line, 3201. Cells were infected with FIV-PPR, FIV-34TF10, FIV 34TF10orf2rep, and a variant arising from FIV-PPR during ex vivo passage on 104-C1DL cells, termed FIV-PPRglial. Infection of the IL-2-dependent T-cell line, 104-C1, by FIV-PPR resulted in the specific and distinct upregulation of cytokine expression. In particular, these cells doubled their expression of the pleiotropic cytokines, interleukin-4 and interleukin-12 after FIV infection. Interferon-gamma production also increased after infection with FIV whereas, TNFalpha expression remained constant. Also, a marked upregulation of MHC class II expression was noted post infection of MCH5-4 and 104-C1 cells with FIV-PPR. Similar results were obtained after infection with FIV-34TF10orf2rep, indicating that the upregulation of cytokine expression is not an isolate-specific phenomenon. Changes in cytokine and class II expression are similar to various reports for the in vivo cytokine alterations in FIV, SIV and HIV infections. The ex vivo infection of these cell lines offers amanipulable system to examine the mechanism(s) by which lentiviruses alter cytokine expression.

Expanded Host Cell Tropism and Cytopathic Properties of Feline Immunodeficiency Virus Strain PPR Subsequent to Passage through Interleukin-2-Independent T Cells

“…A previous study described the generation of an uncharacterized cytopathic pool of FIV-PPR, termed FIVPPRglial, possessing an altered cytotropism concomitant with a vigorous increase in viral kinetics and the ability to form syncytia upon adherent cell lines (33). To generate a molecular clone, CrFK cells were acutely infected with FIV-PPRglial.…”

“…6A and B). FIV-34TF10 was excluded from these studies, since it is unable to productively infect MCH5-4 cells due to an interruption of the orf2 gene (33). An 85% reduction in the FIVPPRchim42 infection of T cells was observed in the presence of SDF1␣, whereas the FIV-PPR infection was inhibited by only 55%.…”

“…Assessment of viral infection was determined by using virion-associated, pelletable RT as previously described (33). The only exception was that the supernatant volume was reduced to 500 l and pelleted at 60,000 rpm for 30 min in a TLA 120.1 rotor (Beckman).…”

Factors That Increase the Effective Concentration of CXCR4 Dictate Feline Immunodeficiency Virus Tropism and Kinetics of Replication

“…We have previously shown that 3201 cells were permissive to FIV-34TF10 infection and that productive infection with FIV-PPR occurred after 2 to 3 weeks of adaptation (23). Adapted viruses could then productively infect the 3201 cells with a peak in virus production usually observed 5 to 7 days after the initiation of infection.…”

Characterization of a Highly Pathogenic Molecular Clone of Feline Immunodeficiency Virus Clade C

“…Crandell feline kidney (CrFK) cells and primary activated peripheral blood mononuclear cells (PBMC) were maintained as previously reported (20). CrFK cells (2 ϫ 10 5 ) were plated in six-well plates and allowed to attach overnight.…”