T cell receptor–targeted immunotherapeutics drive selective in vivo HIV- and CMV-specific T cell expansion in humanized mice
Mengyan Li, … , Steven C. Almo, Harris Goldstein
Mengyan Li, … , Steven C. Almo, Harris Goldstein
Published October 21, 2021
Citation Information: J Clin Invest. 2021;131(23):e141051. https://doi.org/10.1172/JCI141051.
View: Text | PDF
Research Article AIDS/HIV Immunology

T cell receptor–targeted immunotherapeutics drive selective in vivo HIV- and CMV-specific T cell expansion in humanized mice

Abstract

To delineate the in vivo role of different costimulatory signals in activating and expanding highly functional virus-specific cytotoxic CD8+ T cells, we designed synTacs, infusible biologics that recapitulate antigen-specific T cell activation signals delivered by antigen-presenting cells. We constructed synTacs consisting of dimeric Fc-domain scaffolds linking CD28- or 4-1BB–specific ligands to HLA-A2 MHC molecules covalently tethered to HIV- or CMV-derived peptides. Treatment of HIV-infected donor PBMCs with synTacs bearing HIV- or CMV-derived peptides induced vigorous and selective ex vivo expansion of highly functional HIV- and/or CMV-specific CD8+ T cells, respectively, with potent antiviral activities. Intravenous injection of HIV- or CMV-specific synTacs into immunodeficient mice intrasplenically engrafted with donor PBMCs markedly and selectively expanded HIV-specific (32-fold) or CMV-specific (46-fold) human CD8+ T cells populating their spleens. Notably, these expanded HIV- or CMV-specific CD8+ T cells directed potent in vivo suppression of HIV or CMV infections in the humanized mice, providing strong rationale for consideration of synTac-based approaches as a therapeutic strategy to cure HIV and treat CMV and other viral infections. The synTac platform flexibility supports facile delineation of in vivo effects of different costimulatory signals on patient-derived virus-specific CD8+ T cells, enabling optimization of individualized therapies, including HIV cure strategies.

Authors

Mengyan Li, Scott J. Garforth, Kaitlyn E. O’Connor, Hang Su, Danica M. Lee, Alev Celikgil, Rodolfo J. Chaparro, Ronald D. Seidel, R. Brad Jones, Ravit Arav-Boger, Steven C. Almo, Harris Goldstein

×

Figure 7

In vivo pp65- or SL9-synTac treatment stimulates expansion of pp65- and SL9-specific CD8+ T cells from HIV-seronegative and -seropositive donors in a humanized mouse model.

Options: View larger image (or click on image) Download as PowerPoint
In vivo pp65- or SL9-synTac treatment stimulates expansion of pp65- and ...
(A) pp65-4-1BBL-synTac serum levels at indicated time points after intravenous injection (n = 5 mice) measured by ELISA and presented as mean ± SD. (B) Experimental design. (C) NSG mice intrasplenically injected with HGLK055 PBMCs were untreated or intravenously injected with the indicated synTacs (4 mg/kg) and after 1 week, the spleens were analyzed by flow cytometry and gated for viability and expression of human CD45 and CD8. (D) pp65-specific CD8+ T cells in the spleens of mice that were untreated (n = 8) or treated with pp65-αCD28-synTac (n = 7), pp65-4-1BBL-synTac (n = 7), pp65-FLAG- synTac (n = 5), SL9-αCD28 synTac (n = 3), SL9-4-1BBL synTac (n = 3), or SL9-FLAG synTac (n = 3). Shown are pooled data from more than 3 independent experiments statistically analyzed using 1-way ANOVA followed by Tukey’s multiple comparisons test. (E) Fraction of pp65-specific CD8+ T cells in the spleens of humanized mice treated with the indicated synTac shown in C, which were effector memory (CD45RO+CCR7–) cells. (F–J) NSG mice were intrasplenically injected with PBMCs from HIV-seropositive donor 619 and untreated or intravenously injected with SL9-αCD28-synTac or pp65-αCD28-synTac. One week later, spleens were analyzed by flow cytometry. Dot plots represent SL9 (F) or pp65 (H) tetramer staining from a representative mouse from each group. (G) Summary of the percentage of SL9-specific CD8+ T cells in the spleens of mice that were untreated (n = 7) or treated with SL9-αCD28 synTac (n = 7) or pp65-αCD28-synTac (n = 3). (I) Summary of the percentage of pp65-specific CD8+ T cells in the spleens of mice that were untreated or treated with SL9-αCD28-synTac or pp65-αCD28-synTac (n = 3/group). Statistical significance was determined by ordinary 1-way ANOVA followed by Tukey’s multiple comparisons test. (J) Percentage of SL9-specific CD8+ T cells or pp65-specific CD8+ T cells, which were effector memory (CD45RO+CCR7–) cells in the spleens of mice treated with SL9-αCD28-synTac (n = 3 mice) or pp65-αCD28-synTac (n = 3 mice), respectively shown in G and I.