Chimeric antigen receptor T (CAR T) cells targeting CD19 have achieved breakthroughs in the treatment of hematological malignancies, such as relapsed/refractory non-Hodgkin lymphoma (r/rNHL); however, high rates of treatment failure and recurrence after CAR T cell therapy are considerable obstacles to overcome. In this study, we designed a series of tandem CARs (TanCARs) and found that TanCAR7 T cells not only showed dual antigen targeting of both CD19 and CD20 but also formed superior and stable immunological synapse (IS) structures, which may be related to their robust antitumor activity. In an open-label, single-arm phase I/IIa trial (ClinicalTrials.gov number NCT03097770), we enrolled 33 patients with r/rNHL, and a total of 28 patients received an infusion after conditioning chemotherapy. The primary objective was to evaluate the safety and tolerability of TanCAR7 T cells. Efficacy, progression-free survival and overall survival were evaluated as secondary objectives. Cytokine release syndrome (CRS) occurred in 14 patients (50%), with 36% grade 1 or 2 and 14% grade 3. No cases of CAR T cell-related encephalopathy syndrome (CRES) of grade 3 or higher were confirmed in any patient. One patient died from a treatment-associated severe pulmonary infection. The overall response rate was 79% (95% confidence interval [CI], 60 to 92), and the complete response rate was 71%. The progression-free survival rate at 12 months was 64% (95% CI, 43 to 79). In this study, TanCAR7 T cells elicited a potent and durable antitumor response but not grade 3 or higher CRES in patients with r/rNHL.
B lymphocytes use B cell receptors (BCRs) to sense the chemical and physical features of antigens. The activation of isotype-switched IgG-BCR by mechanical force exhibits a distinct sensitivity and threshold in comparison with IgM-BCR. However, molecular mechanisms governing these differences remain to be identified. In this study, we report that the low threshold of IgG-BCR activation by mechanical force is highly dependent on tethering of the cytoplasmic tail of the IgG-BCR heavy chain (IgG-tail) to the plasma membrane. Mechanistically, we show that the positively charged residues in the IgG-tail play a crucial role by highly enriching phosphatidylinositol (4,5)-biphosphate (PI(4,5)P2) into the membrane microdomains of IgG-BCRs. Indeed, manipulating the amounts of PI(4,5)P2 within IgG-BCR membrane microdomains significantly altered the threshold and sensitivity of IgG-BCR activation. Our results reveal a lipid-dependent mechanism for determining the threshold of IgG-BCR activation by mechanical force.
The B7-family inducible costimulator (ICOS) activates phosphoinositide-3 kinase (PI3K) and augments calcium mobilization triggered by the T-cell receptor (TCR). We surprisingly found that the entire cytoplasmic domain of ICOS is dispensable for its costimulation of calcium mobilization. This costimulatory function relies on the unique transmembrane domain (TMD) of ICOS, which promotes association with the tyrosine kinase Lck. TMD-enabled Lck association is also required for p85 recruitment to ICOS and subsequent PI3K activation, and Lck underlies both the bystander and costimulatory signaling activity of ICOS. TMD-replaced ICOS, even with an intact cytoplasmic domain, fails to support T FH development or GC formation in vivo. When transplanted onto a chimeric antigen receptor (CAR), the ICOS TMD enhances interactions between T cells and antigen-presenting target cells. Therefore, by revealing an unexpected function of the ICOS TMD, our study offers a new perspective for the understanding and potential application of costimulation biology.
The RLRs play critical roles in sensing and fighting viral infections especially RNA virus infections. Despite the extensive studies on RLRs in humans and mice, there is a lack of systemic investigation of livestock animal RLRs. In this study, we characterized the porcine RLR members RIG-I, MDA5 and LGP2. Compared with their human counterparts, porcine RIG-I and MDA5 exhibited similar signaling activity to distinct dsRNA and viruses, via similar and cooperative recognitions. Porcine LGP2, without signaling activity, was found to positively regulate porcine RIG-I and MDA5 in transfected porcine alveolar macrophages (PAMs), gene knockout PAMs and PK-15 cells. Mechanistically, LGP2 interacts with RIG-I and MDA5 upon cell activation, and promotes the binding of dsRNA ligand by MDA5 as well as RIG-I. Accordingly, porcine LGP2 exerted broad antiviral functions. Intriguingly, we found that porcine LGP2 mutants with defects in ATPase and/or dsRNA binding present constitutive activity which are likely through RIG-I and MDA5. Our work provided significant insights into porcine innate immunity, species specificity and immune biology.
The RIG-I-like receptors (RLRs) RIG-I and MDA5 play critical roles in sensing and fighting viral infections. Although RIG-I and MDA5 have similar molecular structures, these two receptors have distinct features during activation. Further, the signaling domains of the N terminal CARD domains (CARDs) in RIG-I and MDA5 share poor similarity. Therefore, we wonder whether the CARDs of RIG-I and MDA5 play similar roles in signaling and antiviral function. Here we expressed porcine RIG-I and MDA5 CARDs in 293T cells and porcine alveolar macrophages and found that MDA5 CARDs exhibit higher expression and stronger signaling activity than RIG-I CARDs. Nevertheless, both RIG-I and MDA5 CARDs exert comparable antiviral function against several viruses. Transcriptome analysis showed that MDA5 CARDs are more effective in regulating downstream genes. However, in the presence of virus, both RIG-I and MDA5 CARDs exhibit similar effects on downstream gene transcriptions, reflecting their antiviral function.
This experiment was conducted to study the protective efficacy of recombinant plasmid pET32a(+)-ADF-3-1E in coccidian-infected breeding chickens. The 7-day-old chickens were randomly divided into five groups: a recombinant plasmid pET32a(+)-ADF-3-1E group, a pET32a(+)-ADF group, a pET32a(+)-3-1E group, a control group, and an infection control group. The chickens were immunized intramuscularly with recombinant plasmid DNA in a dose of 200 μg, respectively, and a booster vaccination was given at the same dosage 1 week later. The peripheral blood T lymphocyte proliferation, serum IgG antibody response, and levels of interleukin 2 (IL-2) and interferon gamma (IFN-γ) were detected, respectively. The chickens were inoculated with 4 × 10(6) Eimeria acervulina-sporulated oocysts (Baoding strain) on the seventh day after the last immunization to evaluate the protective efficiency of the recombinant plasmid DNA. The results showed that the lymphocyte proliferation, serum IgG antibody, and IL-2 and IFN-γ levels in recombinant plasmid DNA group were significantly higher than those in control group (P < 0.01). The lymphocyte proliferation, serum IgG antibody, and IL-2 and IFN-γ levels in pET32a(+)-ADF-3-1E group were significantly higher than those in pET32a(+)-3-1E group and pET32a(+)-ADF group, respectively (P < 0.05). It indicated that the pET32a(+)-ADF-3-1E could produce stronger immune responses. The relative body weight gain rate in pET32a(+)-ADF-3-1E group was 88.36 %, which was significantly higher than that in control group (P < 0.05) and infection control group (P < 0.01). The reductions of oocyst production and lesion scores in pET32a(+)-ADF-3-1E group were 67.88 and 67.13 %, respectively. The oocyst excretion and the lesion score of chickens in pET32a(+)-ADF-3-1E group were lower than those in infection control group, respectively. Anticoccidial index (ACI) value in group immunized with pET32a(+)-ADF-3-1E was 169.82. ACI value of 160-179 was considered as effective. These results demonstrated that the pET32a(+)-ADF-3-1E recombinant plasmid DNA could effectively improve the cellular responses and humoral immune responses of the chickens, and it might provide protection against coccidiosis in chickens.
Protein modification plays an essential role in biological and pharmaceutical research. Due to the ordinary selectivity and inevitable damage to proteins of chemical synthetic methods, increased efforts were focused on biocatalysts which exhibited high regioselectivity and mild reaction conditions. However, separation of the biocatalysts and modified proteins remained a problem, especially when scaling up. Here, we developed a simple method for site-specific protein modification with a recyclable biocatalyst. The immobilizing tyrosinase (BmTYR) on magnetic beads can oxidize C-terminal tyrosine residues of the target protein to o-quinone, followed by the spontaneous addition of different nucleophiles (e.g., aniline derivatives), resulting in a C-terminal modified protein. Compared to the homogeneous biocatalytic system reported before, this heterogeneous system leads to an easier separation. Furthermore, the solid-phase biocatalyst can be regenerated during separation, providing reusability and lower costs.
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