Adult T cell leukemia associated cell strain

An adult T cell leukemia associated cell strain obtained from a mixed culture of leukocytes of a rabbit and adult T cell leukemia associated antigen producing cells, said cell strain being characterized by having cells which are derived from a rabbit and have a chromosome number of 44, are lymphoblasts which are negative to peroxidase reaction, have no surface immunoglobulin, no receptor for sheep red blood cells, no receptor for Fc part of IgG and no receptor for complement, do not react with monoclonal antibodies which bind to human T cell antigens Leu-1 or Leu-2 or Leu-3a or Ia antigen OKI 1 and have C-type virions outside the cells which have the same shape as that of adult T cell leukemia virus, said virions having a diameter of 100 to 150 nm and being composed of a nucleoid and an external membrane.