Characterization of a canine long-term T cell line (DLC 01) established from a dog with Sezary syndrome and producing retroviral particles

The canine DLC 01 cell line derives from a lymph node of a dog with Sezary syndrome. The DLC 01 cell phenotype is CD4(-), CD8(+), CD45(+), DQ(+), similar to that of original cells after treatment with dimethylsulfoxide or phorbol myristate. Canine cutaneous T cell lymphoma are usually CD4(-), CD8(+) in contrast to their human counterparts which are CD4(+), CD8(-). Therefore, the DLC 01 cell line appears to be a unique model to study the mechanism of all surface molecule expression in vitro. Viral particles with retrovirus type-C morphology were found in ultrathin sections of DLC 01 cell pellets. Retroviral particles are spontaneously produced after the 50th cell passage or after induction with 0.5% dimethylsulfoxide. This is the first description of a dog lymphoid cell line spontaneously growing and producing a retrovirus. It was found to share several features in common with feline and murine leukemia viruses.