Ex Vivo Expansion of Human CD8.sup.+ T Cells Using Autologous CD4.sup.+ T Cell Help

• Published in: PloS one Vol. 7; no. 1; p. e30229
• Main Authors: Butler, Marcus O, Imataki, Osamu, Yamashita, Yoshihiro, Tanaka, Makito, Ansén, Sascha, Berezovskaya, Alla, Metzler, Genita, Milstein, Matthew I, Mooney, Mary M, Murray, Andrew P, Mano, Hiroyuki, Nadler, Lee M, Hirano, Naoto
• Format: Journal Article
• Language: English
• Published: Public Library of Science 12.01.2012
• Subjects: Analysis; Biological response modifiers; Cells (Biology); Genetic engineering; Genetically modified organisms; Interferon; Monoclonal antibodies; T cells
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0030229

Using in vivo mouse models, the mechanisms of CD4.sup.+ T cell help have been intensively investigated. However, a mechanistic analysis of human CD4.sup.+ T cell help is largely lacking. Our goal was to elucidate the mechanisms of human CD4.sup.+ T cell help of CD8.sup.+ T cell proliferation using a novel in vitro model. We developed a genetically engineered novel human cell-based artificial APC, aAPC/mOKT3, which expresses a membranous form of the anti-CD3 monoclonal antibody OKT3 as well as other immune accessory molecules. Without requiring the addition of allogeneic feeder cells, aAPC/mOKT3 enabled the expansion of both peripheral and tumor-infiltrating T cells, regardless of HLA-restriction. Stimulation with aAPC/mOKT3 did not expand Foxp3.sup.+ regulatory T cells, and expanded tumor infiltrating lymphocytes predominantly secreted Th1-type cytokines, interferon-[gamma] and IL-2. In this aAPC-based system, the presence of autologous CD4.sup.+ T cells was associated with significantly improved CD8.sup.+ T cell expansion in vitro. The CD4.sup.+ T cell derived cytokines IL-2 and IL-21 were necessary but not sufficient for this effect. However, CD4.sup.+ T cell help of CD8.sup.+ T cell proliferation was partially recapitulated by both adding IL-2/IL-21 and by upregulation of IL-21 receptor on CD8.sup.+ T cells. We have developed an in vitro model that advances our understanding of the immunobiology of human CD4.sup.+ T cell help of CD8.sup.+ T cells. Our data suggests that human CD4.sup.+ T cell help can be leveraged to expand CD8.sup.+ T cells in vitro.