A soluble activator that favors the ex vivo expansion of CD8+CD27+ T cells
Esther I. Matus, Amanda Sparkes, Jean Gariépy
Esther I. Matus, Amanda Sparkes, Jean Gariépy
View: Text | PDF
Resource and Technical Advance Therapeutics

A soluble activator that favors the ex vivo expansion of CD8+CD27+ T cells

Abstract

Adoptive cell therapy involves the infusion of tumor-reactive T cells into patients with cancer to provide antitumor immunity. The ex vivo expansion and differentiation of such T cells are key parameters that affect their therapeutic potential. Human T cells are presently expanded in culture through the use of anti-CD3 and anti-CD28 mAbs immobilized on beads, expressed on cells, or assembled in the context of soluble antibody complexes. Here we report the design of a small, bispecific single-chain variable fragment construct agonizing both CD3 and CD28 pathways. This soluble T cell expansion protein, termed T-CEP, activates, expands, and differentiates human T cells ex vivo at concentrations in the femtomolar range. Importantly, T-CEP promotes the preferential growth of human CD8+ T cells over the course of 12 days in comparison with methods involving immobilized anti-CD3 mAb/soluble anti-CD28 mAb or soluble anti-CD3/CD28 mAb complexes. The differentiation profile of the resulting human T cell population is also singularly affected by T-CEP, favoring the expansion of a preferred CD8+CD27+ T cell phenotype. The activity profile of T-CEP on human T cells ex vivo suggests its use in generating human T cell populations that are more suited for adoptive cell therapy.

Authors

Esther I. Matus, Amanda Sparkes, Jean Gariépy

×

Figure 4

Monitoring the ex vivo expansion of activated human T cells over 12 days.

Options: View larger image (or click on image) Download as PowerPoint
Monitoring the ex vivo expansion of activated human T cells over 12 days...
(A) 12-Day expansion of purified human T cells from 5 PBMC donors, with representative expansion profiles of 3 donors. For each of the 5 donors, the number of viable cells was counted in duplicate samples using a hemocytometer following the staining of dead cells with trypan blue for each expansion method tested (right side, scatter plot). The average levels of T cell expansion were statistically greatest when T cells were treated with T-CEP, as compared with i αCD3, i αCD3 + s αCD28, and TACs. (n = 5, 1-way repeated measures ANOVA, with a Tukey’s multiple-comparison test.) (B) 12-Day expansion of CD4+ and CD8+ T cell subsets from purified T cells of 5 PBMC donors, along with individual expansion profiles of 3 representative donors. Scatter plots (right side) illustrate the effect of each treatment on the observed fold changes in the expansion of CD4+ or CD8+ T cells for each of 5 donors. The fold expansion was calculated based on the starting number of CD4+ or CD8+ T cells. T-CEP treatment resulted in the highest fold expansion of CD8+ T cells (n = 5, 1-way repeated measures ANOVA with a Tukey’s multiple-comparison test). (C) The percentage of activated human CD4+ and CD8+ T cell populations relative to the total number of viable lymphocytes as defined by flow cytometry following 12 days of culture. T-CEP or the combination of immobilized i αCD3 and soluble s αCD28 mAbs favored the expansion of CD8+ human T cells significantly more than TACs. (n = 5, 1-way repeated measures ANOVA with a Tukey’s multiple-comparison test.) TACs, tetrameric antibody complexes; i αCD3, immobilized anti-CD3; s αCD28, Soluble anti-CD28. *P < 0.05; **P < 0.01; ***P < 0.001; ☐, T-CEP; ○, TACs; ◇, i αCD3 + s αCD28; △, i αCD3; x, unstimulated.