Chimeric Antigen Research Articles

Antitumor activities of anti‑CD44 monoclonal antibodies in mouse xenograft models of esophageal cancer.

CD44 is a type I transmembrane glycoprotein associated with poor prognosis in various solid tumors. Since CD44 plays a critical role in tumor development by regulating cell adhesion, survival, proliferation and stemness, it has been considered a target for tumor therapy. Anti‑CD44 monoclonal antibodies (mAbs) have been developed and applied to antibody‑drug conjugates and chimeric antigen receptor‑T cell therapy. Anti-pan‑CD44 mAbs, C44Mab‑5 and C44Mab‑46, which recognize both CD44 standard (CD44s) and variant isoforms were previously developed. The present study generated a mouse IgG2a version of the anti‑pan‑CD44 mAbs (5‑mG2a and C44Mab‑46‑mG2a) to evaluate the antitumor activities against CD44‑positive cells. Both 5‑mG2a and C44Mab‑46‑mG2a recognized CD44s‑overexpressed CHO‑K1 (CHO/CD44s) cells and esophageal tumor cell line (KYSE770) in flow cytometry. Furthermore, both 5‑mG2a and C44Mab‑46‑mG2a could activate effector cells in the presence of CHO/CD44s cells and exhibited complement-dependent cytotoxicity against both CHO/CD44s and KYSE770 cells. Furthermore, the administration of 5‑mG2a and C44Mab‑46‑mG2a significantly suppressed CHO/CD44s and KYSE770 xenograft tumor development compared with the control mouse IgG2a. These results indicate that 5‑mG2a and C44Mab‑46‑mG2a could exert antitumor activities against CD44‑positive cancers and be a promising therapeutic regimen for tumors.

Intranasal and intraperitoneal immunization against Brucella infection using niosome and mannosylated niosomes containing Brucella recombinant trigger factor/Bp26/Omp31 chimeric protein in a mouse model.

Brucellosis, a zoonotic infectious disease, is a worldwide health issue affecting animals and humans. No effective human vaccine and the complications caused by the use of animal vaccines are among the factors that have prevented the eradication of the disease worldwide. However, bio-engineering technologies have paved the way for designing new targeted and highly efficacious vaccines. In this regard, the study aimed to evaluate immunity induced by mannosylated niosome containing Brucella recombinant trigger factor/Bp26/Omp31 (rTBO) chimeric protein in a mouse model. rTBO as chimeric antigen (Ag) was expressed in Escherichia coli BL21 (DE3) and, after purification, loaded on niosome and mannosylated niosome. The characteristics of the nanoparticles were assessed. The mice were immunized using rTBO, niosome, and mannosylated niosome-rTBO in intranasal and intraperitoneal routes. Serum antibodies (immunoglobulin [Ig]A, IgG, IgG1, and IgG2a) and splenocyte cytokines (interferon-gamma, interleukin [IL]-4, and IL-12) were evaluated in immunized mice. Finally, immunized mice were challenged by B. melitensis and B. abortus. A high antibody level was produced by niosomal antigen (Nio-Ag) and mannosylated noisomal antigen (Nio-Man-Ag) compared to the control after 10, 24, and 38 days of immunization. The IgG2a/IgG1 titer ratio for Nio-Man-Ag was 1.2 and 1.1 in intraperitoneal and intranasal methods and lower than one in free Ag and Nio-Ag. Cytokine production was significantly higher in the immunized animal with Ag-loaded nanoparticles than in the negative control group (p<0.05). Moreover, cytokine and antibody levels were significantly higher in the injection than in the inhalation method (p<0.05). The combination of mannosylated noisome and rTBO chimeric proteins stimulate the cellular and humoral immune response and produce cytokines, playing a role in developing the protective acquired immune response in the Brucella infectious model. Also, the intraperitoneal route resulted in a successful enhancement of cytokines production more than intranasal administration. Designing an effective vaccine candidate against Brucella that selectively induces cellular and humoral immune response can be done by selecting a suitable nanoniosome formulation as an immunoadjuvant and recombinant protein as an immune response-stimulating Ag.

Semiautomated design and soluble expression of a chimeric antigen TbpAB01 from Glaesserella parasuis.

Pathogenic bacterial membrane proteins (MPs) are a class of vaccine and antibiotic development targets with widespread clinical application. However, the inherent hydrophobicity of MPs poses a challenge to fold correctly in living cells. Herein, we present a comprehensive method to improve the soluble form of MP antigen by rationally designing multi-epitope chimeric antigen (ChA) and screening two classes of protein-assisting folding element. The study uses a homologous protein antigen as a functional scaffold to generate a ChA possessing four epitopes from transferrin-binding protein A of Glaesserella parasuis. Our engineered strain, which co-expresses P17 tagged-ChA and endogenous chaperones groEL-ES, yields a 0.346 g/L highly soluble ChA with the property of HPS-positive serum reaction. Moreover, the protein titer of ChA reaches 4.27 g/L with >90% soluble proportion in 5-L bioreactor, which is the highest titer reported so far. The results highlight a timely approach to design and improve the soluble expression of MP antigen in industrially viable applications.

CAR-T Therapy can be a Useful Treatment Modality for more than Just Hematologic Malignancies.

Chimeric antigen receptor-T-cell (CAR-T) therapy for hematologic malignancies has made significant advancements over the years, and it is now incorporated as a treatment algorithm. Early phase clinical trials are underway for various solid tumors, and the effectiveness of CAR-T cell therapy has been demonstrated for specific types of glioma and several solid tumors. However, its efficacy does not match that observed in hematological malignancies. Recently, a case series reported CAR-T therapy targeting CD19 for autoimmune diseases such as systemic lupus erythematosus, leading to a dramatic improvement in the clinical symptoms and the possibility of discontinuing immunosuppressive agents. Furthermore, CAR-T cell therapy is expected to be effective against various viruses and Aspergillus spp. Finally, attempts have been made to introduce CAR constructs into regulatory T cells to target their immunosuppressive effects. This article introduces the current progress in CAR-T cell therapy beyond the treatment of only hematologic malignancies and discusses future directions, considering the current medical situation in Japan.

Hepatitis B Virus Infection Status and Reactivation Analysis in Multiple Myeloma in China

Background: China is a highly endemic area for Hepatitis B virus (HBV) infection and HBV reactivation is an event of concern in treating patients with hematologic malignancy. However, there were very few reports regarding HBV reactivation in patients with multiple myeloma (MM) in China. Since the approval of novel agents, especially immunotherapy such as monoclonal antibody and chimeric antigen T cell immunotherapy, the risk of HBV reactivation has increased. Therefore, the study aimed to evaluate the HBV infection status in MM and explore the incidence and risk factors of HBV reactivation in MM patients in China. Methods: Newly diagnosed MM patients with available serologic assays for HBV infection were retrospectively enrolled between June 30, 2008 and December 30, 2022 in West China Hospital, Sichuan University. Demographic and clinical data were obtained from the “HemaTank” Chinese Multiple Myeloma Database (HCMMD). Meanwhile, patients diagnosed with Waldenstrom Macroglobulinemia (WM) at the same time were enrolled as the control group. HBV reactivation was defined as the occurrence of one of the following: ≥ 2 log increase in HBV-DNA levels from baseline level, detection of HBV-DNA with level &amp;gt; 100 IU/ml in a person with undetectable HBV DNA at baseline or HBsAg-negative becoming positive. The penalized maximum likelihood logistic regression for rare events was applied to identify independent risk factors related to HBV reactivation. Results: The study recruited 3040 MM patients with a median age of 62 (range 14~98) and 240 WM patients with a median age of 63 (range 25~92). The HBsAg-positive rates were similar between MM and WM (9.4% vs 10.8%, P=0.49), but both the HBcAb-positive rates and HBeAb-positive rates in WM were significantly higher than MM (76.3% vs 60.7%, P&amp;lt;0.001; 37.5% vs 25.1%, P&amp;lt;0.001). The analysis of co-expression of HBV markers shows that the prevalence of HBsAg-/Anti-HBs+/anti-HBC- in MM was significantly higher than WM (16.7% vs 8.3%, P&amp;lt;0.001) and HBsAg-/Anti-HBs-/anti-HBC+ in MM was significantly lower than WM (18.3% vs 27.1%, P&amp;lt;0.001). However, he prevalence of HBsAg+/ HBeAg+/anti-HBC+ and HBsAg+/ anti-HBeAb+/anti-HBC+ were similar between MM and WM (0.5% vs 1.3%, P=0.158; 8.6% vs 8.8%, P=0.503). The baseline characteristics of HBsAg-positive MM and HBsAg-negative MM were summarized in Table 1. The rates of HBsAg-positive MM were significantly increased in young male patients (P&amp;lt;0.05). The level of ALT and AST, and the incidence of HBV reactivation, liver cirrhosis and pulmonary disease were significantly higher in HBsAg-positive MM than in HBsAg-negative MM (P&amp;lt;0.05). Of the 2147 MM patients who have received at least one line of chemotherapy (Table 1), 924 (43%) MM patients received bortezomib-containing or lenalidomide-containing regimens as the frontline therapy, while only 21 (1.0%) received a daratumumab-containing regimen as the frontline therapy. During hospital-documented follow-up visits, 26 (1.21%) MM patients have experienced HBV reactivation. According to the multivariate analysis of risk factors for HBV reactivation in MM, liver cirrhosis (OR 8.63, 95%CI 2.95-25.24, P&amp;lt;0.001), autologous stem cell transplantation (OR 6.03, 95%CI 2.47-14.72, P&amp;lt;0.001) and HBsAg-positive (OR 14.45, 95%CI 6.50-32.14, P&amp;lt;0.001) were independent risk factors associated with high prevalence of HBV reactivation. The ROC curve of the model integrating the three factors is shown in Figure 1, and the AUC was 0.8584. Conclusions: Among Chinese MM patients with multiple myeloma, a high proportion of MM patients presented with resolved hepatitis B virus infection, whereas HBV reactivation was pretty rare. However, long-term HBV DNA levels monitoring is still needed for MM patients at high risk for HBV reactivation.

Abstract 13851: CAR-T Cells: A Potential Novel Strategy for Mitigating Fibrosis in Duchenne Muscular Dystrophy

Introduction: Chimeric Antigen T (CAR)-T cells have proven effective preclinically for mitigating cardiac fibrosis in hypertensive cardiomyopathy. Hypothesis: We assessed whether this approach could be applied to Duchenne Muscular Dystrophy (DMD) by targeting Fibroblast Activating Protein (FAP)-expressing activated fibroblasts in cardiac and skeletal muscle fibrosis. Methods: A protocol for the lymphodepletion conditioning of mice was developed to optimize the dosing of cyclophosphamide. Next, immune-magnetically selected T cells were retrovirally transduced to target FAP (FAP-CAR) and quality-controlled by co-culture killing assays using FAP-expressing HEK target cells. Finally, lymphodepleted D2. mdx mice were intravenously injected with 10 7 FAP-CAR T cells (n=9) or 10 7 GFP-T cells (n=9) or Bovine Serum Albumin (BSA, n=8). Cardiac and skeletal muscle end points were assessed 2 and 5 weeks after treatment. Results: In vitro , the engineered CAR-T cells expressed activation markers (CD69, PD-1) and released large amounts of granzyme, perforin and interferon γ upon exposure to FAP-expressing target cells. One IP injection of cyclophosphamide (3mg) 4 days before treatment was safe and induced a lymphodepletion which enabled robust in vivo expansion of FAP-CAR T cell assessed by flow cytometry in lymphoid organs and blood: 10 5 , 2.10 6 and 10 7 detected CAR-T cells at day 3, 5 and 7 post-injections, respectively. This was paralleled by a more than a 2-fold decrease in endogenous FAP expression in skeletal muscles, as assessed by PCR at day 5 post-injections, and measurable FAP-CAR levels in the spleen compared with GFP-T cell controls. In vivo , FAP-CAR T cells significantly improved LV function with an EF change from baseline (Mean±SEM) of 33.1% ± 6.7% in FAP-CAR vs. 3.7% ± 6.4% and -9.6% ± 7.9% in GFP-T and BSA ( p &lt;0.037 and p &lt;0.005, respectively) at 2 weeks. The benefit was maintained at 5 weeks post-treatment. Several markers of fibrosis, particularly collagens 1 and 3, were also down-regulated in heart and muscles. Conclusions: FAP-CAR-T cells might represent a new therapeutic option for mitigating fibrosis in DMD, likely in conjunction with approaches aimed at addressing the root cause of the disease through a re-expression of a functional dystrophin.

Prolonged haematologic toxicity in CAR-T-cell therapy: A review.

Chimeric antigen receptor-T-cell (CAR-T-cell) therapy is a novel immunotherapy with encouraging results for treatment of relapsed/refractory haematologic malignancies. With increasing use, our understanding of immune-mediated side effects such as cytokine release syndrome and neurotoxicity has improved; nevertheless, prolonged haematologic toxicity (PHT), with a high incidence rate, remains underrecognized. Owing to heterogeneity in populations, the CAR-T cells used and diseases treated as well as differences in the definition of PHT, its rate, risk factors and management vary across studies. In this review, we provide a narrative of PHT occurring in patients following CAR-T-cell therapy; evidence of PHT treatment strategies is also presented, with the aim of contributing to systematic understanding of PHT.

Abnormal bone marrow findings in patients following treatment with chimeric antigen receptor-T cell therapy.

Bone marrow (BM) assessment after CAR-T cell immunotherapy infusion is not routinely performed to monitor adverse events such as cytopenias, hemophagocytic lymphohistiocytosis, or infections. Our institution has performed BM biopsies as part of CAR-T cell treatment protocols, encompassing pre- and post-treatment time points and during long-term follow-up. We conducted a systematic retrospective review of BM abnormalities observed in samples from 259 patients following CAR-T cell immunotherapy. We correlated BM pathology findings with mortality, relapse/residual disease, and laboratory values. At a median of 35.5 days post-CAR-T infusion, 25.5% showed severe marrow hypocellularity, and 6.2% showed serous atrophy, and peripheral blood cytopenias corroborated these observations. Marrow features associated with reduced disease burden post-CAR-T infusion include increased lymphocytes seen in 16 patients and an increase of macrophages or granulomatous response seen in 25 patients. However, a 100-day landmark analysis also showed increased marrow histiocytes were associated with lower survival (median OS 6.0 vs. 21.4 months, p = .026), as was grade 2-3 marrow reticulin (18 patients) (median OS 12.5 vs. 24.2 months, p = .034). These data represent the first systematic observations of BM changes in patients receiving CAR-T cell immunotherapy.

Bivalent vaccines effectively protect mice against influenza A and respiratory syncytial viruses

ABSTRACT Influenza and Respiratory Syncytial virus (RSV) infections together contribute significantly to the burden of acute lower respiratory tract infections. Despite the disease burden, no approved RSV vaccine is available. While approved vaccines are available for influenza, seasonal vaccination is required to maintain protection. In addition to both being respiratory viruses, they follow a common seasonality, which warrants the necessity for a concerted vaccination approach. Here, we designed bivalent vaccines by utilizing highly conserved sequences, targeting both influenza A and RSV, as either a chimeric antigen or individual antigens separated by a ribosome skipping sequence. These vaccines were found to be effective in protecting the animals from challenge by either virus, with mechanisms of protection being substantially interrogated in this communication.

Designing and Computational Analysis of Chimeric Avian Influenza Antigen: A Yeast-Displayed Universal and Cross-Protective Vaccine Candidate

This study describes the development of a cross-protective vaccine candidate against avian influenza virus, which was designed using M2e, a highly preserved antigen. The consensus sequence of M2e was obtained using 31 sequences of avian influenza virus subtypes (H5N8, H5N1, H9N2, and H7N9) isolated from seven avian species in five Asian countries. An adjuvant, a partial sequence of flagellin, was also considered. Two chimeric antigens were designed and virtually cloned and expressed using the PYD1 vector and EBY100 yeast strain. Molecular dynamic simulations were used to assess the stability and conformational features of these antigens. The likelihood of detection by a specific monoclonal antibody, MAb148, was estimated for the designed peptides using docking studies. The second chimeric antigen was more compact and stable than the first design, but it was less detectable by MAb148. In the first design, two of the four desired epitopes ("SLLTEVETP") were exposed, while only a partial sequence of this epitope was detectable in the second design. In contrast to the second chimeric antigen, electrostatic, and binding energies related to the interaction of the first antigen and MAb148 were significantly closer to the positive control. This suggests that epitopes of the first chimeric antigen could be correctly located in the specific paratope of MAb148. In conclusion, the first chimeric antigen exhibits favorable conformational features and epitope-paratope interactions, highlighting its potential as a promising cross-protective vaccine candidate against a range of avian influenza virus subtypes.

Chimeric Antigen by the Fusion of SARS-CoV-2 Receptor Binding Domain with the Extracellular Domain of Human CD154: A Promising Improved Vaccine Candidate.

COVID-19 is a respiratory viral disease caused by a new coronavirus called SARS-CoV-2. This disease has spread rapidly worldwide with a high rate of morbidity and mortality. The receptor-binding domain (RBD) of protein spike (S) mediates the attachment of the virus to the host’s cellular receptor. The RBD domain constitutes a very attractive target for subunit vaccine development due to its ability to induce a neutralizing antibody response against the virus. With the aim of boosting the immunogenicity of RBD, it was fused to the extracellular domain of CD154, an immune system modulator molecule. To obtain the chimeric protein, stable transduction of HEK-293 was carried out with recombinant lentivirus and polyclonal populations and cell clones were obtained. RBD-CD was purified from culture supernatant and further characterized by several techniques. RBD-CD immunogenicity evaluated in mice and non-human primates (NHP) indicated that recombinant protein was able to induce a specific and high IgG response after two doses. NHP sera also neutralize SARS-CoV-2 infection of Vero E6 cells. RBD-CD could improve the current vaccines against COVID-19, based in the enhancement of the host humoral and cellular response. Further experiments are necessary to confirm the utility of RBD-CD as a prophylactic vaccine and/or booster purpose.

Treatment with anti-spike monoclonal antibodies in allogeneic HCT and CAR T-cell recipients with mild to moderate COVID-19: The Mayo Clinic experience.

e19049 Background: Prognosis of COVID-19 is poor in the setting of immunosuppression. Casirivimab/imdevimab (REGEN-COV), bamlanivimab, and sotrovimab are investigational monoclonal antibodies (MoAbs) authorized for treatment of mild/moderate COVID-19 for patients (pts) 12 years or older and who are at high-risk for progression to severe COVID-19. These neutralizing antibodies, against SARS-CoV-2 spike proteins, have been shown to decrease risk of progression to severe disease. Recipients of allogeneic stem cell transplants (allo-SCT) or chimeric antigen T cell therapy (CAR T cell) represent a high risk population. However, treatment outcomes with these MoAbs in these pts are not well described. Methods: This retrospective study included 33 consecutive adult pts who developed mild/moderate COVID-19 and received anti-spike SARS-CoV-2 MoAbs between December 2020 and November 2021. Allo-SCT (N=27) or CAR T cell (N=6) recipients were included, and outcomes were analyzed separately. Pts received REGEN-COV (N=19), bamlanivimab (N=11), or sotrovimab (N=1), missing (N=2). Results: In the allo-SCT cohort (N=27), median age at time of COVID-19 was 55 (23-76) years. Median time from allo-SCT to COVID-19 was 31 (22-64) months. Two pts received CAR T-cell therapy prior to allo-SCT. Diagnoses included leukemia or myeloid diseases (82%), lymphoma (11%), or myeloma (7%). Transplant characteristics are summarized (Table). Thirteen pts were vaccinated against SARS-CoV-2 prior to breakthrough COVID-19. Events considered included hospitalization due to COVID-19, disease progression, or death from any cause. The 6-month event-free and overall survivals were 81% and 91%, respectively. In the CAR T cell recipients cohort (N=6), 4 pts received axicabtagene ciloleucel for diffuse large B-cell or follicular lymphoma and 2 received brexucabtagene autoleucel for mantle cell lymphoma. The median follow-up was 8 (1-11) months. Two pts received autologous SCT prior to COVID-19. Median time from CAR T cell therapy to COVID-19 was 10 (3-24) months. Three pts were vaccinated prior to COVID-19. Only 1 pt was hospitalized due to severe COVID-19 requiring mechanical ventilation leading to death. Conclusions: These results show a potential benefit of MoAbs in high-risk pts, namely allo-SCT or CAR T cell recipients. Future studies should evaluate the role of prophylactic use MoAbs in these populations. A comparative analysis with a matched control cohort (who did not receive MoAbs) will be provided at the meeting. [Table: see text]

Tumor immunotherapy: Mechanisms and clinical applications

AbstractImmunotherapy, which aims to enhance the functions of the host's immune system to eliminate invading pathogens and mutant cells, has been widely used for cancer treatment. Despite the enormous progress in immunotherapy, the efficiency of immunotherapy is urgent to be improved. The tumor microenvironment is composed of multiple types of infiltrating immune cells and stromal cells (such as endothelial cells, fibroblasts, and tumor cells), extracellular matrix, various cytokines, chemokines, growth factors, and metabolites, all of which play crucial roles in tumor progress, metastasis, relapse and the outcome of immunotherapy. Emerging evidence indicates a better understanding of the characteristics of the tumor microenvironment and its associated factors, which could lead to uncovering novel promising immunotherapy approaches. This review will summarize the current knowledge of heterogeneity and function of the immune cells in the tumor microenvironment, the current progress of immunotherapy focusing on immune checkpoint blockade and chimeric antigen T cell therapy, as well as the challenge and limitations of the current immunotherapy strategy. Overall, we aim to provide the conceptions of tumor immune microenvironment and application of immunotherapy, highlighting the potential strategies to improve tumor immunotherapy.

An Insight into the Novel Immunotherapy and Targeted Therapeutic Strategies for Hepatocellular Carcinoma and Cholangiocarcinoma.

Hepatocellular carcinoma (HCC) and cholangiocarcinoma (CCA) constitute highly malignant forms of primary liver cancers. Hepatocellular and bile duct carcinogenesis is a multiplex process, caused by various genetic and epigenetic alterations, the influence of environmental factors, as well as the implication of the gut microbiome, which was undervalued in the previous years. The molecular and immunological analysis of the above malignancies, as well as the identification of the crucial role of intestinal microbiota for hepatic and biliary pathogenesis, opened the horizon for novel therapeutic strategies, such as immunotherapy, and enhanced the overall survival of cancer patients. Some of the immunotherapy strategies that are either clinically applied or under pre-clinical studies include monoclonal antibodies, immune checkpoint blockade, cancer vaccines, as well as the utilization of oncolytic viral vectors and Chimeric antigen, receptor-engineered T (CAR-T) cell therapy. In this current review, we will shed light on the recent therapeutic modalities for the above primary liver cancers, as well as on the methods for the enhancement and optimization of anti-tumor immunity.

Comparative performance of five recombinant and chimeric antigens in a time-resolved fluorescence immunoassay for detection of Toxoplasma gondii infection in cats

Felids are definitive hosts of Toxoplasma gondii, being the only hosts that can spread the infection through oocyst shedding in their feces. The elevated presence of this parasite in the domestic cat (Felis catus), and its close contact with humans, make it necessary to obtain reliable diagnostic methods to detect positive animals as a public health measure. For this reason, in this study, the diagnostic performance of five different recombinant antigen-based techniques was assessed to diagnose T. gondii infection in cat blood plasma samples. Specifically, four T. gondii recombinant antigens (GRA7, truncated GRA7, SAG2, and truncated SAG2) and a chimeric antigen (SAG1-GRA8) were used. A time-resolved fluorescence immunoassay (TRFIA) was developed for each antigen, and the results of each of these techniques were compared with those obtained by a commercial enzyme-linked immunoassay (ELISA) and a modified agglutination test (MAT) as reference techniques. The TRFIA based on SAG1-GRA8 antigen showed better discrimination between seropositive and seronegative cats (p < 0.001), as well as a better area under the curve (0.95), sensitivity (93.6%), and specificity (89.5%) values for the optimal cut-off, versus the other TRFIAs. In addition, SAG1-GRA8 TRFIA showed substantial agreement (kappa value = 0.78) and a moderate significant correlation (Spearman’s correlation: r = 0.62, p < 0.001) compared with the reference techniques. On the other hand, since plasma samples were obtained from 101 cats in Bangkok city and four of them were Neospora caninum seropositive by indirect immunofluorescence assay (IFAT), this is the first time that anti-N. caninum antibodies are detected in cats in Thailand. In conclusion, our study highlights that the TRFIA with TgSAG1-GRA8 antigen is an accurate and recommended diagnostic technique for detecting anti-T. gondii antibodies in cats.

CAR-T cell therapy for lung cancer: Potential and perspective.

Lung cancer is the highest incidence and mortality of all cancers around the world. In the present immunotherapy era, an increasing number of immunotherapeutic agents including monoclonal antibody‐targeted drugs have been used in the clinical treatment of malignancy, but it still has many limitations. Chimeric antigen receptor‐modified T (CAR‐T) cells, a novel adoptive immunotherapy strategy, have not only been used successfully against hematological tumors, but have also opened up new avenues for immunotherapy of solid tumors, including lung cancer. However, targeting lung cancer‐specific antigens using engineered CAR‐T cells is complicated by the lack of proper tumor‐specific antigens, an immunosuppressive tumor microenvironment, a low level of CAR‐T cell infiltration into tumor tissues, along with off‐target effect, etc. Simultaneously, the clinical application of CAR‐T cells remains limited because of many challenges such as tumor lysis syndrome, neurotoxicity syndrome, and cytokine release syndrome. In this review, we outline the basic structure and generation characteristic of CAR‐T cells and summarize the common tumor‐associated antigens in clinical trials of CAR‐T cell therapy for lung cancer, and point out the current challenges and new strategies, aiming to provide new ideas and approaches for the pre‐clinical experiments and clinical trials of CAR‐T cell therapy in lung cancer.

SLAMF3 and SLAMF4 are immune checkpoints that constrain macrophage phagocytosis of hematopoietic tumors.

The interaction of SIRPα with CD47 represents a major mechanism for preventing macrophage phagocytosis. However, CD47-independent mechanisms are poorly defined. Here, we report a critical role of SLAM family receptors (SFRs), ubiquitously expressed on hematopoietic cells and forming homotypic interactions, in constraining macrophage phagocytosis. We found that SFR deficiency triggered macrophage phagocytosis of hematopoietic cells, leading to severe rejection of donor hematopoietic graft in recipient mice. Specific SFR members, mainly SLAMF3 and SLAMF4, were identified as "don't eat me" receptors on macrophages. These receptors inhibited "eat me" signals, such as LRP1-mediated activation of mTOR and Syk, through SH2 domain-containing phosphatases. SFRs combined with, but were independent of, CD47 to mitigate macrophage phagocytosis, and the combined deletion of SFRs and CD47 resulted in hematopoietic cytopenia in mice. This SFR-mediated tolerance was compromised in patients with hemophagocytic lymphohistiocytosis, a syndrome characterized by inappropriate phagocytosis toward hematopoietic cells. Loss of SFRs potently elicited macrophage rejection of hematopoietic tumors. Deletion of SFRs also significantly enhanced the phagocytosis of CD19-positive hematopoietic targets by the macrophages expressing the chimeric CD19 antigen receptor. Therefore, SFR-mediated inhibition of macrophage phagocytosis is critical to hematopoietic homeostasis, and SFRs may represent previously unknown targets for tumor immunotherapy.

Clinical Development and Therapeutic Applications of Bispecific Antibodies for Hematologic Malignancies.

Bispecific antibodies are composed of two monoclonal antibodies that engage T cells with tumor cell antigens and lead to tumor cell lysis. The most common types fall into the category of bispecific T cell engagers, or BiTEs, that have the canonical CD3-CD19 bispecific construct. Blinatumomab is the first bispecific antibody that received FDA approval for relapsed refractory B cell precursor acute lymphoblastic leukemia. Blinatumomab has been shown to have robust clinical outcomes and is associated with adverse events such as cytokine release syndrome and neurotoxicity. Other bispecific antibodies are under clinical investigation for multiple myeloma and acute myeloid leukemia. Along with immune checkpoint inhibitors and chimeric antigen T cell receptor therapies, bispecific antibodies are considered a mainstay as a therapeutic option for cancer immunotherapies for Hematologic malignancies.

Immune-Based Therapeutic Strategies for Acute Myeloid Leukemia.

Simple SummaryThis review summarizes various therapeutic immune approaches representing their targets, the efficacy and toxicity in the treatment of acute myeloid leukemia. In particular, immune checkpoint inhibitors, bispecific T-cell engager antibodies and chimeric antigen receptor-T-cell approaches are highlighted. The development and design of immune-based strategies have become an increasingly important topic during the last few years in acute myeloid leukemia (AML), based on successful immunotherapies in solid cancer. The spectrum ranges from antibody drug conjugates, immune checkpoint inhibitors blocking programmed cell death protein 1 (PD1), cytotoxic T lymphocyte antigen 4 (CTLA4) or T cell immunoglobulin and mucin domain containing-3 (TIM3), to T-cell based monoclonal and bispecific T-cell engager antibodies, chimeric antigen receptor-T-cell (CAR-T) approaches and leukemia vaccines. Currently, there are many substances in development and multiple phase I/II studies are ongoing. These trials will help us to deepen our understanding of the pathogenesis of AML and facilitate the best immunotherapeutic strategy in AML. We discuss here the mode of action of immune-based therapies and provide an overview of the available data.

Primary mediastinal large B cell lymphoma.

Primary mediastinal large B cell lymphoma (PMBCL) is an aggressive large B cell lymphoma originating in the mediastinum, that mainly expresses B cell surface molecules, such as CD19, CD20, CD22, andCD79a. Clinically, they are characterized by rapidly increasing anterior mediastinal masses, which can cause compression of the surrounding tissues. The diagnosis of PMBCL mainly depends on the pathological features, imaging examination and clinical features. Currently, the most commonly used therapeutic regimens are R‐CHOP and R‐EPOCH. Radiotherapy is beneficial in some patients, but it can also lead to long‐term toxicity. The research and development of novel therapies are ongoing, and some studies have achieved encouraging results, including those conducted on chimeric antigen receptor‐modified T (CAR‐T) cell therapy and anti‐PD‐1 drugs. However, randomized controlled trials with larger sample sizes are still needed. Positron emission tomography‐computed tomography (PET‐CT) is mainly used to assess the curative effect after treatment and to guide the subsequent treatment strategy.