Analysis of FeLV-FAIDS provirus burden and productive infection in lymphocyte subsets in vivo

Virology. 1996 Sep 1;223(1):1-9. doi: 10.1006/viro.1996.0449.


To help elucidate the immunopathogenesis of feline leukemia virus (FeLV)-induced immunodeficiency we studied the tropism of viruses derived from the FeLV-FAIDS isolate for lymphocyte subpopulations in cats. FeLV-FAIDS is composed of a replication-competent virus typical of subgroup A FeLV (prototype, clone 61E) and a family of replication-defective but immunopathogenic variant viruses (prototype, clone 61C). We sorted CD4+, CD8+, and IgG+ lymphocytes to > or = 97% purity and analyzed viral load in each cell population via genome-specific semiquantitative PCR. Both the 61E and 61C viruses were tropic for CD4+ and CD8+ T cells as well as IgG+ B lymphocytes in blood and lymph node. High provirus burden were established for both virus genomes-ranging from 0.3 to > 2 copies/cell. To identify the fraction of circulating cells which expressed viral antigen in vivo, we developed a flow cytometric method to simultaneously label blood leukocytes for surface immunophenotype and intracytoplasmic FeLV CA (p27 Gag). These experiments established that 20 to 60% of CD4+, CD8+, and IgG+ lymphocytes and > 85% of monocytes and granulocytes expressed FeLV p27 intracellularly. Thus the in vivo target cells for FeLV-FAIDS infection are manifold and include CD4+ and CD8+ T cells, B cells, and myeloid cells.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • B-Lymphocyte Subsets / immunology
  • B-Lymphocyte Subsets / virology*
  • CD4-Positive T-Lymphocytes / immunology
  • CD4-Positive T-Lymphocytes / virology
  • CD8-Positive T-Lymphocytes / immunology
  • CD8-Positive T-Lymphocytes / virology
  • Cats
  • Cell Line
  • DNA, Viral / analysis
  • Feline Acquired Immunodeficiency Syndrome / blood
  • Feline Acquired Immunodeficiency Syndrome / virology*
  • Gene Products, gag / immunology
  • Leukemia Virus, Feline / genetics
  • Leukemia Virus, Feline / immunology
  • Leukemia Virus, Feline / isolation & purification*
  • Proviruses / isolation & purification
  • T-Lymphocyte Subsets / virology*


  • DNA, Viral
  • Gene Products, gag