Adoptive transfer of gene-engineered CD4+ helper T cells induces potent primary and secondary tumor rejection

Abstract

Because CD4 ؉ T cells play a key role in aiding cellular immune responses, we wanted to assess whether increasing numbers of gene-engineered antigenrestricted CD4 ؉ T cells could enhance an antitumor response mediated by similarly gene-engineered CD8 ؉ T cells. In this study, we have used retroviral transduction to generate erbB2-reactive mouse T-cell populations composed of various proportions of CD4 ؉ and CD8 ؉ cells and then determined the antitumor reactivity of these mixtures. Gene-modified CD4 ؉ and CD8 ؉ T cells were shown to specifically secrete Tc1 (T cytotoxic-1) or Tc2 cytokines, proliferate, and lyse erbB2 ؉ tumor targets following antigen ligation in vitro. In adoptive transfer experiments using severe combined immunodeficient (scid) mice, we demonstrated that injection of equivalent numbers of antigenspecific engineered CD8 ؉ and CD4 ؉ T cells led to significant improvement in survival of mice bearing established lung metastases compared with transfer of unfractionated (largely CD8 ؉ ) engineered T cells. Transferred CD4 ؉ T cells had to be antigen-specific (not just activated) and secrete interferon ␥ (IFN-␥) to potentiate the antitumor effect. Importantly, antitumor responses in these mice correlated with localization and persistence of geneengineered T cells at the tumor site. Strikingly, mice that survived primary tumor challenge could reject a subsequent rechallenge. Overall, this study has highlighted the therapeutic potential of using combined transfer of antigen-specific gene-modified CD8 ؉ and CD4 ؉ T cells to significantly enhance T-cell adoptive transfer strategies for cancer therapy. IntroductionMuch attention has been directed at the genetic modification of T cells and their therapeutic potential in the adoptive immunotherapy of cancer. T cells engineered to express chimeric surface receptors that incorporate an extracellular single-chain antibody domain (scFv) and a transmembrane and cytoplasmic signaling domain can specifically direct antitumor immune responses in a major histocompatibility complex (MHC)-independent manner at targets normally capable of evading immune recognition. These targets also often lack important costimulatory ligands for maximal T-cell activation. The therapeutic potential of engineered T cells extends from studies demonstrating specific antigen binding and target-cell lysis in vitro 1-3 and in a range of different mouse tumor models 4-8 to their successful transfer into patients with minimal side effects in phase 1 clinical trials. 9 A number of studies have demonstrated the importance of CD4 ϩ T-cell help in elimination of infectious disease and for antitumor immunity. 10,11 CD4 ϩ T cells have been demonstrated to be critical for maintenance of CD8 ϩ T-cell numbers, their recruitment to the tumor site, 12-14 and induction of a memory response. 15,16 In patients infected with HIV, the coinfusion of genetically modified CD4 ϩ and CD8 ϩ T cells has been demonstrated to overcome the lack of T-cell persistence observed with transfusion of engineered CD8 ϩ T cel...

Adoptive immunotherapy using human peripheral blood lymphocytes transferred with RNA encoding Her-2/neu-specific chimeric immune receptor in ovarian cancer xenograft model

“…ScFv-based CIR approaches is advantageous for adoptive immunotherapy that T cells can recognize target cells based on the surface expression of antigen and are able to kill in an MHCunrestricted fashion rather than processed antigens. [7][8][9] Most of the reports on scFv-engineered T cells are dependent on retro-or lentivirus for genetic modification. [7][8][9] Despite of its efficiency in generating stable transfectants through drug selection, the time and labor required for establishing transduced clones limits clinical applicability.…”

“…[7][8][9] Most of the reports on scFv-engineered T cells are dependent on retro-or lentivirus for genetic modification. [7][8][9] Despite of its efficiency in generating stable transfectants through drug selection, the time and labor required for establishing transduced clones limits clinical applicability. By the time therapeutic numbers of transfectants are obtained, cells will be exhausted due to the long-term selection, which results in shortening of telomere, expressing low levels of activation markers, poor proliferation and short-term persistency in vivo.…”

“…However, adoptive transfer of CD8 þ T cells alone is largely ineffective against more established disease. 8,9 It was demonstrated both in viral infection and tumor models that CD4 þ T cells support CD8 þ T cells for full activation by providing costimulatory signals and necessary cytokines. [32][33][34][35] Nonetheless, a concern on the use of PBLs may arise because a portion of CD4 þ T cells exerts Th2 response.…”

“…Since the first generation of CIR using only extracellular antigen-binding domain and CD3z signaling portion, studies have focused on the use of costimulatory domains including intracellular-signaling chains of CD28 and 4-1BB so that maximal T-cell activation can be efficiently optimized and the antitumor responses can be maintained upon antigen-receptor ligation. [7][8][9] Poor expression of major histocompatibility complex (MHC) and costimulatory molecules by tumors may be one of limitation of adoptive cell transfer therapy using TCR. 10 The approach with scFv-CIR can avoid MHC limitations imposed by the use of TCR, thus stable transfectants expressing CIR has shown its therapeutic potentials against several surface tumor antigens.…”

Combination of Vaccination and Chimeric Receptor Expressing T Cells Provides Improved Active Therapy of Tumors

“…There are several aspects of CR design, manipulation, and transduction methodology, which may improve the action of CR T cells. Thus, murine CR T cell populations with a low proportion (ϳ10%) of the CD4 ϩ subset perform less effectively against established tumor in vivo than mixtures of CR T cells given with a 1:1 CD4:CD8 ratio (47). The inference is that ensuring a high prevalence of CD4 ϩ T cells in the CR population (in these studies, CD4 ϩ comprised ϳ20% of the total CR population) may improve overall antitumor responses.…”