A primer set for the rapid isolation of scFv fragments against cell surface antigens from immunised rats

Antibody phage display is a powerful platform for discovery of clinically applicable high affinity monoclonal antibodies against a broad range of targets. Libraries generated from immunized animals offer the advantage of in vivo affinity-maturation of V regions prior to library generation. Despite advantages, few studies have described isolation of antibodies from rats using immune phage display. In our study, we describe a novel primer set, covering the full rat heavy chain variable and kappa light chain variable regions repertoire for the generation of an unbiased immune libraries. Since the immune repertoire of rats is poorly understood, we first performed a deep sequencing analysis of the V(D)J regions of VH and VLK genes, demonstrating the high abundance of IGVH2 and IGVH5 families for VH and IGVLK12 and IGVLK22 for VLK. The comparison of gene’s family usage in naïve rats have been used to validate the frequency’s distribution of the primer set, confirming the absence of PCR-based biases. The primers were used to generate and assemble a phage display library from human CD160-vaccinated rats. CD160 represents a valid therapeutic target as it has been shown to be expressed on chronic lymphocytic leukaemia cells and on the surface of newly formed vessels. We utilised a novel phage display panning strategy to isolate a high affinity pool (KD range: 0.399–233 nM) of CD160 targeting monoclonal antibodies. Subsequently, identified binders were tested for function as third generation Chimeric Antigen Receptors (CAR) T cells demonstrating specific cytolytic activity. Our novel primer set coupled with a streamlined strategy for phage display panning enable the rapid isolation and identification of high affinity antibodies from immunised rats. The therapeutic utility of these antibodies was demonstrated in CAR format

Epilepsia partialis continua complicated by disseminated tuberculosis and hemophagocytic lymphohistiocytosis: a case report.

BACKGROUND: We describe a patient copresenting with epilepsia partialis continua, tuberculosis, and hemophagocytic lymphohistiocytosis. To our knowledge, this is the first documented case of this triad. CASE PRESENTATION: A 54-year-old black South African woman presented to a hospital in Scotland with an acute history of right-sided facial twitching, breathlessness, and several months of episodic night sweats. Clinical examination revealed pyrexia and continuous, stereotyped, right-sided facial contractions. These worsened with speech and continued through sleep. A clinical diagnosis of epilepsia partialis continua was made, and we provide a video of her seizures. Computed tomographic imaging of the chest and serous fluid analyses were consistent with a diagnosis of disseminated Mycobacterium tuberculosis. An additional diagnosis of hemophagocytic lymphohistiocytosis was made following the identification of pancytopenia and hyperferritinemia in peripheral blood, with hemophagocytosis evident in bone marrow investigation. We provide images of her hematopathology. The patient was extremely unwell and was hospitalized for 6 months, including two admissions to the intensive care unit for ventilatory support. She was treated successfully with high doses of antiepileptic drugs (benzodiazepines, levetiracetam, and phenytoin) and 12 months of oral antituberculosis therapy, and she underwent chemotherapy with 8 weeks of etoposide and dexamethasone for hemophagocytic lymphohistiocytosis, followed by 12 months of cyclosporine and prednisolone. CONCLUSIONS: This combination of pathologies is unusual, and this case report helps educate clinicians on how such a patient may present and be managed. A lack of evidence surrounding the coexpression of this triad may represent absolute rarity, underdiagnosis, or incomplete case ascertainment due to early death caused by untreated tuberculosis or hemophagocytic lymphohistiocytosis. Further research is needed

Tunable control of CAR T cell activity through tetracycline mediated disruption of protein-protein interaction

Chimeric antigen receptor (CAR) T cells are a promising form of cancer immunotherapy, although they are often associated with severe toxicities. Here, we present a split-CAR design incorporating separate antigen recognition and intracellular signaling domains. These exploit the binding between the tetracycline repressor protein and a small peptide sequence (TIP) to spontaneously assemble as a functional CAR. Addition of the FDA-approved, small molecule antibiotic minocycline, acts as an "off-switch" by displacing the signaling domain and down-tuning CAR T activity. Here we describe the optimization of this split-CAR approach to generate a CAR in which cytotoxicity, cytokine secretion and proliferation can be inhibited in a dose-dependent and reversible manner. Inhibition is effective during on-going CAR T cell activation and inhibits activation and tumor control in vivo. This work shows how optimization of split-CAR structure affects function and adds a novel design allowing easy CAR inhibition through an FDA-approved small molecule

Brexucabtagene autoleucel for relapsed or refractory mantle cell lymphoma in the United Kingdom: A real‐world intention‐to‐treat analysis

Brexucabtagene autoleucel (brexu‐cel) is an autologous CD19 CAR T‐cell product, approved for relapsed/refractory (r/r) mantle cell lymphoma (MCL). In ZUMA‐2, brexu‐cel demonstrated impressive responses in patients failing ≥2 lines, including a bruton's tyrosine kinase inhibitor, with an overall and complete response rate of 93% and 67%, respectively. Here, we report our real‐world intention‐to‐treat (ITT) outcomes for brexu‐cel in consecutive, prospectively approved patients, from 12 institutions in the United Kingdom between February 2021 and June 2023, with a focus on feasibility, efficacy, and tolerability. Of 119 approved, 104 underwent leukapheresis and 83 received a brexu‐cel infusion. Progressive disease (PD) and/or manufacturing (MF) were the most common reasons for failure to reach harvest and/or infusion. For infused patients, best overall and complete response rates were 87% and 81%, respectively. At a median follow‐up of 13.3 months, median progression‐free survival (PFS) for infused patients was 21 months (10.1–NA) with a 6‐ and 12‐month PFS of 82% (95% confidence interval [CI], 71–89) and 62% (95% CI, 49–73), respectively. ≥Grade 3 cytokine release syndrome and neurotoxicity occurred in 12% and 22%, respectively. On multivariate analysis, inferior PFS was associated with male sex, bulky disease, ECOG PS > 1 and previous MF. Cumulative incidence of non‐relapse mortality (NRM) was 6%, 15%, and 25% at 6, 12, and 24 months, respectively, and mostly attributable to infection. Outcomes for infused patients in the UK are comparable to ZUMA‐2 and other real‐world reports. However, ITT analysis highlights a significant dropout due to PD and/or MF. NRM events warrant further attention

Results of a United Kingdom real-world study of polatuzumab vedotin, bendamustine, and rituximab for relapsed/refractory DLBCL

The addition of polatuzumab vedotin to bendamustine and rituximab (Pola-BR) has been shown to improve overall survival (OS) in stem cell transplant (SCT)-ineligible patients with relapsed/refractory (R/R) diffuse large B-cell lymphoma (DLBCL). It is also increasingly used as bridging to CAR T-cell therapy (CAR-T). We retrospectively analysed the efficacy of Pola-BR in 133 patients at 28 UK institutions. Treatment intent was bridging to CAR-T for N=40, re-induction with planned SCT for N=13 and stand-alone treatment for N=78. The overall response rate (ORR) was 57.0% (complete response (CR) 32.8%). After median 7.7 months follow-up, median PFS and OS were 4.8 months and 8.2 months respectively. For stand-alone treatment shortened PFS was associated with bulk disease (>7.5cm) (HR 2.32 (95% CI 1.23-4.38), p=0.009), >1 prior treatment (HR 2.17 (95% CI 1.19-3.95), p=0.01) and refractoriness to the last treatment (HR 3.48 (95% CI 1.79-6.76), p<0.001). For CAR-T bridging the ORR was 42.1% (CR 18.4%) and for treatment after CAR-T failure the ORR was 43.8% (CR 18.8%). These data demonstrate efficacy for Pola-BR as a treatment for SCT-ineligible patients with R/R DLBCL, help to delineate which patients may benefit most, and provide preliminary evidence of efficacy as bridging to CAR-T and after CAR-T failure