We report on the design of a phase I, non-randomized, open-label study of idiotypic DNA vaccination in patients with B-cell non-Hodgkin's lymphoma (ISRCTN31090206). The study uses DNA fusion gene vaccination encoding patient-specific single chain variable fragment, or idiotype, linked to an immunostimulatory sequence. Two types of immunostimulatory sequence are being explored: potato virus X coat protein and human chemokine MIP3a. Linear polyethylenimine with low molecular weight (8 kDa) is used as a synthetic vehicle for vaccine delivery. Humoral and T-cellular immune responses to vaccination will be measured by ELISA and ELISPOT, respectively. The primary study endpoints are safety, tolerability and immunogenicity of DNA-PEI vaccination.

We report, in brief, the results of a phase I, non-randomized study of idiotypic DNA vaccination in patients with B-cell non-Hodgkin’s lymphoma (ISRCTN31090206). The DNA sequence of lymphoma-derived immunoglobulin variable regions was used as a tumor-specific antigen fused to the potato virus X coat protein. A conjugate of plasmid DNA with polyethylenimine was used for the intramuscular injections, followed by a boost with an oral live-attenuated Salmonella vaccine carrying the same plasmid. The patients with a complete or partial response to previous chemotherapy received one or two courses of vaccination, including four injections at monthly intervals. The vaccine was well tolerated, with low-grade adverse events. The T-cell immune responses were assessed by ELISpot, at last vaccine, one week and one month post-vaccination, and were detected in 11/14 (78.6%) of the patients. In cases of progression requiring chemotherapy, or the presence of a positive MRD after the first course of vaccination, the patients underwent a second course of vaccination. At the end point, 6/19 vaccinated patients had disease stabilization, while 13/19 were in complete remission. The overall survival was 100% at follow-up, of a median of 2.3 years.

We characterise the expansion, phenotype and functional activity of natural killer (NK) cells obtained for a clinical trial. Nineteen expansion procedures were performed to obtain NK cell products for 16 patients. NK cells were ex vivo expanded from haploidentical donor peripheral blood mononuclear cells in the presence of the locally generated feeder cell line K-562 with ectopic expression of 4-1BBL and mbIL-21.The median duration of expansion was 18 days (range 14-25). The median number of live cells yielded was 2.26 × 109 (range 0.89-5.5 × 109) with an NK content of 96.6% (range 89.0%-98.8%). The median NK cell fold expansion was 224.7 (range 42-647). The majority of expanded NK cells had the phenotype of immature activated cells (NKG2A+, double bright CD56++CD16++, CD57-) expressing NKp30, NKp44, NKp46, NKG2D, CD69, HLA-DR and CD96. Despite the expression of exhaustion markers, expanded NK cells exhibited high cytolytic activity against leukaemia cell lines, high degranulation activity and production of cytokines. There was noted decreased functional activity of NK cells in tests against the patient's blasts. NK cells obtained by ex vivo expansion with locally generated K562-41BBL-mbIL21 cells have both a relatively undifferentiated phenotype and enhanced cytolytic activity against cancer cell lines. Expansion of NK cells with the feeder cells allows obtaining a su cient quantity of the NK cell product to reach high cell doses or increase the frequency of cell infusions for adoptive immunotherapy. Registered at clinicaltrials.gov as NCT04327037.

Аннотация. Нейробластома -самая распространенная детская солидная опухоль с плохим прогнозом на IV стадии заболевания. Характерным маркером нейробластомы является высокая экспрессия тирозингидроксилазы (ТГ).ДНК-вакцинация является сопутствующим методом терапии онкологических заболеваний, которые характеризуются высокой вероятностью достижения ремиссии и риском последующего рецидива.Нами проведена ДНК-вакцинация мышей линии A/J с использованием конструкции ТГ в качестве опухолевого антигена. Для доставки вакцины применяли синтетический носитель полиэтиленимин (ПЭИ). Показано, что конъюгирование ДНК-вакцины с ПЭИ увеличивает эффективность разработанной вакцины, что проявляется в замедлении опухолевой прогрессии и активации клеточного ответа, включающего цитотоксический Т-клеточный ответ и продукцию гамма-интерферона.ключевые слова: ДНК-вакцины, нейробластома, тирозингидроксилаза, иммуногенность, полиэтиленимин для цитирования: Полиэтиленимин усиливает иммуногенность ДНК-вакцины на основе гена тирозингидроксилазы в мышиной модели нейробластомы / М. В. Стёганцева [и др.] // Вес. Нац. aкад. навук Беларусі.

We characterise the expansion, phenotype and functional activity of natural killer (NK) cells obtained for a linical trial. Nineteen expansion procedures were performed to obtain NK cell products for 16 patients. NK cells were ex vivo expanded from haploidentical donor peripheral blood mononuclear cells in the presence of the locally generated feeder cell line K-562 with ectopic expression of 4-1BBL and mbIL-21.The median duration of expansion was 18 days (range 14–25). The median number of live cells yielded was 2.26 × 109 (range 0.89–5.5 × 109) with an NK content of 96.6% (range 89.0%–98.8%). The median NK cell fold expansion was 224.7 (range 42–647). The majority of expanded NK cells had the phenotype of immature activated cells (NKG2A+, double bright CD56++CD16++, CD57-) expressing NKp30, NKp44, NKp46, NKG2D, CD69, HLA-DR and CD96. Despite the expression of exhaustion markers, expanded NK cells exhibited high cytolytic activity against leukaemia cell lines, high degranulation activity and production of cytokines. There was noted decreased functional activity of NK cells in tests against the patient’s blasts.NK cells obtained by ex vivo expansion with locally generated K562-41BBL-mbIL21 cells have both a relatively undifferentiated phenotype and enhanced cytolytic activity against cancer cell lines. Expansion of NK cells with the feeder cells allows obtaining a sufficient quantity of the NK cell product to reach high cell doses or increase the frequency of cell infusions for adoptive immunotherapy. Registered at clinicaltrials.gov as NCT04327037.