Immunological and histological disorders in cats experimentally infected with feline immunodeficiency virus subtype B (TM2 stain).

Three conventional cats were experimentally infected with subtype B (TM2 strain) of FIV, and two conventional cats served as controls. The infected cats were examined immunologically 99-176 weeks post FIV inoculation (wpi) and histologically at 130 wpi. Two of the three infected cats exhibited lower CD4/CD8 T cell ratios and hypergammaglobulinemia compared with two control cats. Further, all the infected cats showed morphological changes in popliteal lymph nodes such as lymphoid depletion, atrophy and plasma cell hyperplasia. In addition, apoptosis was induced in peripheral blood mononuclear cells (PBMC) from the FIV-infected cats after in vitro culture for one or two days, but not in PBMC from uninfected cats. These observations indicate that FIV subtype B has the potential to induce some immunological and histological disorders in cats.