Ex Vivo Expansion and Th1/Tc1 Maturation of Umbilical Cord Blood T Cells by CD3/CD28 Costimulation

Abstract

One of the major limitations of unrelated umbilical cord blood transplantation (UCBT) is the lack of donor cells available for post-transplant donor leukocyte infusions (DLI) to boost immunity or induce GVL. Starting from ~5% fraction of a UCB graft we report the feasibility and biological characteristics of ex vivo expansion of frozen/thawed cord blood T cells by anti-CD3 and anti-CD28 antibody-coated Dynal beads in the presence of IL-2. We postulated that while undergoing expansion, CB T cells may mature towards a Th1/Tc1 phenotype and acquire the potential for cytotoxicity. While an almost 2 log expansion also led to the acquisition of IL-12Rα and increase in Th1 characteristics, post-expansion lymphocytes produced less IFNγ, TNFα, Granzyme B, stored almost no perforin, and lacked cytotoxicity against allogeneic targets. Collectively, these suggest relative safety from acute/hyperacute GVHD. CD8+ T cells expanded preferentially while a higher rate of apoptosis among CD4+ T cells promoted an inverted CD4/CD8 ratio. Most expanded T cells retained expression of CD27, CD28, L-selectin, however, the majority down regulated CCR-7. In sum, CB T cell proliferation sustained by CD3/CD28 costimulatory beads and IL-2 can lead to clinically relevant doses of DLI from a very small fraction of the UCB graft, although future strategies to reduce apoptosis may enhance their clinical potential.

Umbilical Cord Blood T Cells Respond against the Melan-A/MART-1 Tumor Antigen and Exhibit Reduced Alloreactivity as Compared with Adult Blood-Derived T Cells

“…It was proposed that naive UCB T lymphocytes became biased toward Th2 in utero by placenta-derived factors (IL-4, IL-10, TGF-b, PGE 2 ) that are thought to be involved in the maintenance of pregnancy (36). The relative cytolytic inefficacy of UCB T cells was associated with reduced expression of granzymes and perforin (28,37). Costimulation mediated via NKG2D and TLRs was recently shown to be involved in the functional responsiveness of UCB-derived CD8 + T cells (38,39).…”

Interleukin-22 as a molecular adjuvant facilitates IL-17-producing CD8+T cell responses against a HBV DNA vaccine in mice

“…11 Tc1 is a classical cytotoxic CD8 + T cell, producing IFN-γ and TNF-α and cytolytic effects by secreting perforin and granzyme B when in contact with target cells. [44][45][46] However, Tc17 cells reportedly enhance anti-fungal responses via neutrophil recruitment, so may not exert their cytotoxic activity directly. 10,47 In addition, Tc17 could acquire cytotoxic potential in vivo without IFN-γ being present in a vaccinia virus (VV) model and this was associated with Fas-Fasl interaction.…”

Cord Blood Transplantation in Adults with Acute Leukemia

“…Ex vivo generation of T cells from CB naïve T cells has been achieved in several methods using CD3/CD28 costimulation, interleukin (IL)-2, and IL-7 (Mazur et al, 2008;Davis et al, 2010). Moreover, several researchers successfully have generated antigens-specific cytotoxic T lymphocytes (CTLs) from CB.…”