Patient-tailored adoptive immunotherapy with EBV-specific T cells from related and unrelated donors

BACKGROUND: Adoptive transfer of EBV-specific T cells can restore specific immunity in immunocompromised patients with EBV-associated complications. METHODS: We provide results of a personalized T-cell manufacturing program evaluating donor, patient, T-cell product and outcome data. Patient-tailored clinical-grade EBV-specific cytotoxic T-lymphocyte (EBV-CTL) products from stem cell donors (SCD), related third party donors (TPD) or unrelated TPD from the allogeneic T-cell donor registry (alloCELL) established at Hannover Medical School were manufactured by immunomagnetic selection using CliniMACS Plus or Prodigy device and EBV PepTivators EBNA-1 and Select. Consecutive manufacturing processes were evaluated and patient outcome and side effects were retrieved by retrospective chart analysis. RESULTS: Forty clinical-grade EBV-CTL products from SCDs, related or unrelated TPDs were generated for 37 patients with and without transplantation (Tx) history within 5 days (median) after donor identification. 34 patients received 1-14 EBV-CTL products (fresh and cryopreserved). EBV-CTL transfer led to complete response in 20 of 29 patients who were evaluated for clinical response. No infusion-related toxicity was reported. EBV-specific T cells in patients' blood were detectable in 16/18 monitored patients (89 %) after transfer and correlated with clinical response. CONCLUSION: In conclusion, personalized clinical-grade manufacturing of EBV-CTL products via immunomagnetic selection from SCD, related or unrelated TPD is feasible in a timely manner. Overall, EBV-CTL were clinically effective and well-tolerated. Our data suggest EBV-CTL as promising therapeutic approach for immunocompromised patients with refractory EBV-associated diseases beyond HSCT as well as patients with pre-existing organ dysfunction

Coreplication of the Major Genotype Group Members of Porcine Circovirus Type 2 as a Prerequisite to Coevolution May Explain the Variable Disease Manifestations ▿

A member of the family Circoviridae, porcine circovirus type 2 (PCV2), is associated with postweaning multisystemic wasting syndrome (PMWS), a recent emerging disease worldwide. PCV2 is also found in clinically asymptomatic animals. This paradoxical finding makes the syndrome etiology challenging. We developed new assays to study PCV2 with links to syndrome etiology. For analysis, we used PCV2-infected tissues from subclinically infected and diseased piglets. We compared antigen- and PCV2 DNA-derived signals for tissue localization and intensity. Oligonucleotides were designed to the signature motif of the PCV2 capsid open reading frame to discriminate experimentally between PCV2 genotype groups by PCR, in situ hybridization (ISH), and fluorescence in situ hybridization (FISH). Unexpectedly, all PCV2-infected animals carried both PCV2a and PCV2b genotype group members. Using confocal microscopy, genotype single-cell infections and cell superinfections were visible. Additionally, we discriminated replicative DNA from total PCV2 DNA isoforms with FISH. This aided in our inquiry into cellular genotype-specific replication. Importantly, single-genotype-group replication was not observed. In infected cells with replicating virus, both genotype groups were equally present. These findings suggest PCV2 genotype group members relaxed replication regulation requirements and may even point to PCV2 replication cooperativity in vivo. These observations explain the readily seen PCV2 DNA recombinations and the high overall PCV2 genome plasticity. Hence, we suggest a novel mechanism of syndrome etiology that consists of a continuously changing PCV2 genome pool in hosts and pig herds, posing a constant challenge to the individual maturing immune system