Personalized ex vivo multiple peptide enrichment and detection of T cells reactive to multiple tumor-associated antigens in prostate cancer patients

Abstract

Personalized peptide vaccination is a promising immunotherapeutic approach in prostate cancer (PCa). We therefore examined whether an approach, utilizing personalized multiple peptide-mediated ex vivo enrichment with effector T cells reactive to multiple tumor-associated antigens (TAAs), could be employed as a basis for the development of T cell immunotherapy of PCa. In this study, we used the non-adherent fraction (lymphocytes) of cryopreserved peripheral blood mononuclear cells from a leukapheretic product of biochemically recurrent (BR, n = 14) and metastatic hormone-refractory (HR, n = 12) PCa patients. The lymphocytes were primed with a pool of mixed overlapping peptides derived from 6 PCa TAAs-PSA, PAP, NY-ESO-1, MAGE-A1, MAGE-A3 and MAGE-A4. After 2 weeks of culture, the cells were stimulated with the peptides and T cell reactivity determined by externalization of CD107a. No TAAs-reactive effector T cells were detected in the patient's lymphocytes after their reconstitution. However, following their priming with the TAAs-derived peptides and 2-week culturing, the lymphocytes became enriched with polyclonal TAAs-reactive effector CD8 T cells in 8 out of 14 BR and 5 out of 12 HR patients. No such reactive CD8 T cells were detected in cultured lymphocytes without the peptide priming. Stimulation of the responding cultures with peptides derived from individual TAAs revealed a unique repertoire of the reactive CD8 T cells. Our strategy revealed that the personalized multiple peptide-mediated ex vivo enrichment with multiple TAAs-reactive T cells in the PCa patient's lymphocytes is a viable approach for development of T cell immunotherapy of PCa.

The WNT/β-catenin signaling inhibitor XAV939 enhances the elimination of LNCaP and PC-3 prostate cancer cells by prostate cancer patient lymphocytes in vitro

“…BRPCa patients’ lymphocytes were prepared as described previously 24 . Cryopreserved lymphocytes of 12 BRPCa patients after radical prostatectomy or salvage radiotherapy were available for this study.…”

“…Cryopreserved BRPCa lymphocytes were reconstituted in a human serum containing culture medium [LM; RPMI 1640 medium (Thermo Scientific) with 5% pooled human serum (One Lambda, Kittridge, CA), 100 U/ml penicillin-streptomycin, 2 mM Glutamax, 1 mM sodium pyruvate and a non-essential amino acid mix (Thermo Scientific)] as described previously 24 . The reconstituted cells were resuspended in LM at a concentration of 1.0 × 10 6 cells/ml, and 1 ml of the cell suspension was transferred to a flat-bottom 48-well plate well.…”

Functional and mechanistic studies reveal MAGEA3 as a pro-survival factor in pancreatic cancer cells

“…Further, we targeted MAGEA3 in PCCs and observed enhanced cytotoxic effect of various existing molecules upon MAGEA3 depletion but the cytotoxic effect is reduced when MAGEA3 is overexpressed in PCCs. Thus, it cautious the strategy to overexpress molecules like MAGEA3 in pancreatic cancer cells, which will make them more immunogenic like in other cancers [73–76] but may have a serious negative consequence. In the future, along with existing chemotherapy, MAGEA3-targeted therapy can be explored for a better therapeutic approach against PCA.…”

CD4 T cells of prostate cancer patients have decreased immune responses to antigens derived from SARS-CoV-2 spike glycoprotein

“…We rst investigated how SARS-CoV-2 and HCoV-229E spike glycoprotein-derived peptides (peptide pools) affected the proportions of CD4 + and CD8 + T cells during a 14-day culture. For this purpose, we used the culture protocol we previously used for culture enrichment with tumor-associated antigenreactive T cells [24]. As shown in HCoV-229E spike glycoprotein-derived peptides enriched the cultured cells with CD4 + T cells that crossreact with SARS-CoV-2 spike glycoprotein-derived peptides Previous studies have shown that T cells speci c to the Dengue virus can mediate cross-protection against the Zika virus [15].…”

“…The cryopreserved cells were reconstituted, and a 14-day enrichment with antigen-speci c T cells was performed as previously described [32]. For the enrichment of the reconstituted cells with antigen-speci c Cell stimulation, intracellular cytokine staining, and cytokine release The cells were processed as described previously [24,33]. Brie y, the cells were harvested, pelleted by centrifugation, and resuspended at a concentration of 1-4 × 10 6 cells/ml in fresh human plasma serumcontaining culture medium [LM medium; RPMI 1640 medium, 5% human plasma serum (One Lambda, Canoga Park, CA), 100 U/ml penicillin-streptomycin, 2 mM Glutamax, 1 mM sodium pyruvate and nonessential amino acid mix (Thermo Scienti c)].…”