FELINE IMMUNODEFICIENCY VIRUS (FIV)-ASSOCIATED LYMPHOMA - A POTENTIALROLE FOR IMMUNE DYSFUNCTION IN TUMORIGENESIS

To determine the potential role of immune dysfunction in feline immuno deficiency virus (FIV)-associated lymphomagenesis, we present the resu lts of immunological monitoring during the chronic phase of experiment al FIV infection in two cats which subsequently developed lymphoma. In one cat, C1, cell-mediated immunity was depressed throughout the moni toring period but particularly from 125-200 weeks post-infection (pi), when this cat demonstrated profoundly impaired lymphocyte blastogenes is and markedly increased interleukin-1 (IL-1) production compared to age-matched, uninfected control cats. Lymphocyte function in the other cat, C2, was preserved to a greater degree. Alterations in the levels of immunoglobulin isotypes M, A and G in CD4(+)-, CD8(+)- and CD21(+) -lymphocyte sub-sets were demonstrated in both cats. Southern blot ana lysis revealed the presence of integrated FIV-provirus in tumour DNA f rom C2 but not C1 indicating a possible direct role for the virus in t he former case only. In this study we have characterised, for the firs t time, the FIV-induced immune dysfunction in cats which developed lym phoma, demonstrating potential indirect mechanisms of tumourigenesis. (C) 1998 Elsevier Science B.V. All rights reserved.