Development of a cytotoxic T-cell assay in rabbits to evaluate early immune response to human T-lymphotropic virus type 1 infection

Viral Immunol. 2009 Dec;22(6):397-405. doi: 10.1089/vim.2009.0059.

Abstract

Human T-lymphotropic virus type 1 (HTLV-1) infection causes adult T-cell lymphoma/leukemia (ATL) following a prolonged clinical incubation period, despite a robust adaptive immune response against the virus. Early immune responses that allow establishment of the infection are difficult to study without effective animal models. We have developed a cytotoxic T-lymphocyte (CTL) assay to monitor the early events of HTLV-1 infection in rabbits. Rabbit skin fibroblast cell lines were established by transformation with a plasmid expressing simian virus 40 (SV40) large T antigen and used as autochthonous targets (derived from same individual animal) to measure CTL activity against HTLV-1 infection in rabbits. Recombinant vaccinia virus (rVV) constructs expressing either HTLV-1 envelope surface unit (SU) glycoprotein 46 or Tax proteins were used to infect fibroblast targets in a (51)Cr-release CTL assay. Rabbits inoculated with Jurkat T cells or ACH.2 cells (expressing ACH HTLV-1 molecule clone) were monitored at 0, 2, 4, 6, 8, 13, 21, and 34 wk post-infection. ACH.2-inoculated rabbits were monitored serologically and for viral infected cells following ex vivo culture. Proviral load analysis indicated that rabbits with higher proviral loads had significant CTL activity against HTLV-1 SU as early as 2 wk post-infection, while both low- and high-proviral-load groups had minimal Tax-specific CTL activity throughout the study. This first development of a stringent assay to measure HTLV-1 SU and Tax-specific CTL assay in the rabbit model will enhance immunopathogenesis studies of HTLV-1 infection. Our data suggest that during the early weeks following infection, HTLV-1-specific CTL responses are primarily targeted against Env-SU.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Animals
  • Cell Line, Transformed
  • Cytotoxicity Tests, Immunologic / methods*
  • Female
  • Fibroblasts / virology
  • Gene Products, env / genetics
  • Gene Products, env / immunology
  • Gene Products, tax / immunology
  • Genes, pX
  • HTLV-I Infections / immunology*
  • Human T-lymphotropic virus 1 / immunology*
  • Human T-lymphotropic virus 1 / physiology
  • Humans
  • Jurkat Cells / immunology
  • Major Histocompatibility Complex / immunology
  • Proviruses / isolation & purification
  • Rabbits
  • Recombinant Fusion Proteins / immunology
  • Retroviridae Proteins, Oncogenic / genetics
  • Retroviridae Proteins, Oncogenic / immunology
  • T-Lymphocytes, Cytotoxic / immunology*
  • Time Factors
  • Virus Replication

Substances

  • Gene Products, env
  • Gene Products, tax
  • Recombinant Fusion Proteins
  • Retroviridae Proteins, Oncogenic
  • gp46 protein, Human T-cell leukemia virus type I
  • tax protein, Human T-lymphotrophic virus 1