Virus neutralization reveals antigenic variation among feline immunodeficiency virus isolates

Comparative study of the cell tropism of feline immunodeficiency virus isolates of subtypes A, B and D classified on the basis of the env gene V3-V5 sequence

“…Only the Sendai-1 isolate classified as subtype A replicated in CrFK cells in the same way as the Petaluma isolate does. Osborne et al (1994) have recently adapted three isolates, FIV/Glasgow-8, FIV/Amsterdam 4 and 6, which had (Phillips et al, 1990). However, the isolates of at least subtypes B and D did not replicate in CrFK cells in this study.…”

“…At present the reason why the viruses grown in CrFK cells showed strong cytopathogenicity for lymphoblastoid cell lines is not known. Osborne et al (1994), who compared the sequence of the env V5 region of the viruses grown in lymphoblastoid cell cultures and those adapted and grown in CrFK cells, reported the absence of change in either of the two types of virus. Some studies have shown the possibility that the env V3 region determines cell tropism in HIV and simian immunodeficiency virus (Cann et al, 1992;Hwang et al, 1991;Kirchhoff et al, 1994).…”

Neutralization sensitivity and accessibility of continuous B cell epitopes of the feline immunodeficiency virus envelope

“…The HO6T1/2 subline of CrFK was generously provided by R. Osborne (MRC Retrovirus Research Laboratory, University of Glasgow, UK) and corresponds to the CrFK/ID10/R clone (Osborne et aL, 1994). A chronically infected CrFK cell line (CrFK-Petaluma) was established after infection of HO6T1/2 cells with the Petaluma isolate of FIV (FIVp~tamm~).…”

“…CrFK by FIV was performed essentially as described by Osborne et al (1994). CrFK-HO6TI/2 fibroblasts were resnspended at I x l05 cells/mt in complete DMEM and 0'5 ml was placed in each well of 48-well tissue culture plates (5 × 104 cells per well).…”

“…Antibodies elicited during natural infection are frequently observed to neutralize infection of cultured cells Osborne et al, 1994;reviewed for HIV in Nara et al, 1991); however, where appropriate cellular systems exist to assess enhancing antibodies, these have also been found (Takeda et al, 1988;Robinson et al, 1988;Homsy et al, 1988). The measurement of neutralizing antibodies depends upon, The use of ex vivo models has shown that most if not all neutralizing activity in serum of humans infected with HIV is specific for the envelope glycoproteins and has permitted the localization of several B cell epitopes sensitive to neutralizing antibodies in both the surface (SU) and transmembrane (TM) components of the virus envelope (reviewed in Nara et aI., 1991).…”