Antigenic Activity Research Articles

Identification of α-galactosylceramide as an endogenous mammalian antigen for iNKT cells.

Invariant natural killer T (iNKT) cells are unconventional T cells recognizing lipid antigens in a CD1d-restricted manner. Among these lipid antigens, α-galactosylceramide (α-GalCer), which was originally identified in marine sponges, is the most potent antigen. Although the presence of α-anomeric hexosylceramide and microbiota-derived branched α-GalCer is reported, antigenic α-GalCer has not been identified in mammals. Here, we developed a high-resolution separation and detection system, supercritical fluid chromatography tandem mass spectrometry (SFC/MS/MS), that can discriminate hexosylceramide diastereomers (α-GalCer, α-GlcCer, β-GalCer, or β-GlcCer). The B16 melanoma tumor cell line does not activate iNKT cells; however, ectopic expression of CD1d was sufficient to activate iNKT cells without adding antigens. B16 melanoma was unlikely to generate iNKT cell antigens; instead, antigen activity was detected in cell culture serum. Activity-based purification and SFC/MS/MS identified dihydrosphingosine-based saturated α-GalCer as an antigenic component in serum, bile, and lymphoid tissues. These results show the first evidence for the presence of potent antigenic α-GalCer in mammals.

Construction of novel magnetic systems for cancer immunotherapy via cancer-immunity cycle circuits.

The tumor microenvironment (TME) is enriched with immunosuppressive factors that inhibit the recruitment and activation of dendritic cells (DCs), thereby reducing the efficacy of tumor immunotherapy. To address this challenge, we propose an innovative strategy involving the sequential administration of MCM magnetic nanoparticles carrying PROTAC drugs (MCM/ARV) and M-BMDCs in the TEM. This approach not only replenishes DCs in the TEM, but also increases antigen uptake through the attraction between the magnetic particles and promotes DC activation and antigen presentation, thus continuously enhancing the tumor immune cycle. MCM nanoparticles (magnetic nanoclusters coated with calcium-doped manganese carbonate) efficiently load the tumor-targeting drug PROTAC (ARV-825), enhancing its bioavailability, leading to specific degradation of BRD4 in tumor cells, and releasing a large number of tumor-associated antigens. These antigens were captured by MCM nanoparticles to construct magnetized tumor vaccines. Magnetic M-BMDCs introduced at the tumor site are attracted to these magnetized vaccines, resulting in a significant increase in antigen uptake and activation of DCs, significantly enhancing the tumor immune cycle. This co-administration strategy of magnetized vaccines and magnetized BMDCs provides a unique combination therapy for reversing immunosuppressive TEM and enhancing the efficacy of tumor immunotherapy.

Biogenic silver nanoparticle as an adjuvant in an S1 subunit recombinant vaccine.

Adjuvants are crucial for maintaining specific, protective, and long-lasting immunity. Here, we aimed to evaluate the antigenic and immunogenic activity of a recombinant form of the S1 domain of the Spike protein, associated with biogenic silver nanoparticles (bio-AgNP) and Alhydrogel® as an alternative and conventional adjuvant, respectively, for a SARS-CoV-2 subunit vaccine. We produced and evaluated the antigenicity of the recombinant S1 (rS1) protein by testing its recognition by antibodies present in SARS-CoV-2 positive human serum. The immunogenicity of the rS1 protein was assessed in vivo by its ability to induce antibody production in mice. Furthermore, we sought to establish the types of humoral and cellular immune responses generated through intramuscular immunization in BALB/c mice with the rS1 + bio-AgNP vaccine. The recombinant S1 (rS1) protein was successfully cloned, expressed in Escherichia coli, and confirmed to have strong antigenic potential, being recognized by human antibodies up to a 1:51,200 serum dilution. In vivo assays showed that vaccines using rS1 with either bio-AgNP or Alhydrogel® as adjuvants induced high and consistent antibody titers (1:51,200) and a range of antibody isotypes in mice. Cellular immune response analysis revealed significant IL-10 expression with rS1 + bio-AgNP and both IL-10 and TNFα expression with rS1 + Alhydrogel®. These results support rS1 + bio-AgNP as a promising vaccine candidate for future development, highlighting its potential not only as a viable alternative to traditional adjuvants but also as an innovative contribution to advancing more effective and accessible immunological strategies.

Triple knockdown of CD11a, CD49d, and PSGL1 in T cells reduces CAR-T cell toxicity but preserves activity against solid tumors in mice.

Chimeric antigen receptor (CAR)-T cell therapies have revolutionized the landscape of cancer treatment, in particular in the context of hematologic malignancies. However, for solid tumors that lack tumor-specific antigens, CAR-T cells can infiltrate and attack nonmalignant tissues expressing the CAR target antigen, leading to on-target, off-tumor toxicity. Severe on-target, off-tumor toxicities have been observed in clinical trials of CAR-T therapy for solid tumors, highlighting the need to address this issue. Here, we demonstrated that targeting the cell adhesion and migration molecules lymphocyte function-associated antigen 1 (LFA-1; CD11a/CD18) and very late activation antigen 4 (VLA-4; CD49d/CD29) with blocking antibodies reduced the on-target, off-tumor toxicity of CAR-T cells in mice. To translate this observation into improved CAR-T cell therapy, we either knocked out both CD11a and CD49d or knocked down CD11a and CD49d along with PSGL1, another cell adhesion molecule, in CAR-T cells. We found that these modified CAR-T cells exhibited reduced on-target, off-tumor toxicity in vivo without affecting CAR-T cell efficacy. Furthermore, we showed that this approach promoted T cell memory formation and decreased tonic signaling. On the basis of these data, we engineered a human version of these low-toxicity CAR-T cells and further validated the feasibility of this approach in vitro and in vivo. Together, these results provide a potential solution to address the clinical challenge of on-target, off-tumor toxicity in CAR-T therapy.

Long, Synthetic Staphylococcus aureus Type 8 Capsular Oligosaccharides Reveal Structural Epitopes for Effective Immune Recognition.

Staphylococcus aureus is a Gram-positive bacterium that is responsible for severe nosocomial infections. The rise of multidrug-resistant strains, which can pose significant health threats, prompts the development of new treatment interventions, and much attention has been directed at the development of prophylactic and therapeutic vaccination strategies. Capsular polysaccharides (CPs) are key protective elements of the S. aureus cell wall and have been proposed as promising candidate antigens. Thirteen different CP serotypes have been identified to date, of which types 5 and 8 are the most prominent. CP8 is composed of trisaccharide repeating units that are built up from an N-acetyl-4-O-acetyl-β-d-mannosaminuronic acid, that carries a C-4-O-acetyl, an N-acetyl-α-d-fucosamine, and an N-acetyl-α-l-fucosamine. Synthetic oligosaccharides are valuable tools to unravel the immunogenicity of bacterial oligosaccharides at the molecular level. However, the rare monosaccharides, cis-glycosidic linkages, and O-acetylation represent significant challenges for the synthesis of CP8 fragments. Here the stereoselective assembly of well-defined CP8 fragments, comprising a trimer, hexamer, nonamer, and dodecamer, is presented. This is the first time that fragments larger than a single repeating trisaccharide, which has been proven to be insufficient for antigenic activity, have been assembled. Structural studies have revealed a linear conformation for the oligosaccharides, with each trisaccharide repeat tilted ∼90° with respect to the flanking repeats, which is stabilized by the acetyl groups that prevent rotation around the glycosidic linkages. The N-acetyl groups in each repeating unit point in the same direction, generating a hydrophobic flank in the trisaccharide repeats. We applied the oligomers to generate model glycoconjugate vaccine modalities, which we then used to raise anti-CP8 antibodies. The antibody interaction and immunization studies have revealed a clear length dependent structure-activity relationship for the oligosaccharides, with an oligosaccharide of at least three repeating units required for an adequate immune response.

Molecular Mechanism of VSV-Vectored ASFV Vaccine Activating Immune Response in DCs.

The vesicular stomatitis virus (VSV)-vectored African swine fever virus (ASFV) vaccine can induce efficient immune response, but the potential mechanism remains unsolved. In order to investigate the efficacy of recombinant viruses (VSV-p35, VSV-p72)-mediated dendritic cells (DCs) maturation and the mechanism of inducing T-cell immune response, the functional effects of recombinant viruses on DC activation and target antigens presentation were explored in this study. The results showed that surface-marked molecules (CD80, CD86, CD40, and MHC-II) and secreted cytokines (IL-4, TNF-α, IFN-γ) were highly expressed in the recombinant virus-infected DCs. In addition, the co-culture results of recombinant virus-treated DCs with naive T cells showed that the Th1- and Th17-type responses were effectively activated. Taken together, the study indicated that the VSV-vectored ASFV vaccine activated the maturation of DCs and the Th1- and Th17-type immune response, which provided a theoretical basis for the development of novel ASF vaccines.

NON-HORMONAL MALE CONTRACEPTIVES: A PROMISING PHARMACOLOGICAL ALTERNATIVE

INTRODUCTION: The need to diversify the contraceptive methods usually used, due to the side effects resulting from their administration, is widely discussed. As male contraceptives are generally analogues of endogenous hormones1, the development of medications with milder side effects and reversible contraceptive efficacy has become necessary1,2,3,4. The pharmaceutical industry has therefore begun experimental research into enzymes and peptides that can inhibit the mechanisms of spermatogenesis or prevent fertilization without endocrine alterations1. OBJECTIVE: To present an overview of non-hormonal male contraceptives. METHODS: A qualitative and quantitative descriptive study was carried out, based on a search for scientific productions in the BVS and PubMed databases. To this end, the descriptors “Contraceptive Agents”, “Male”, “Serine Proteases” and “Serine Kinases” articulated by the Boolean operators “AND” and “OR” were used to filter out studies with the desired characteristics. In addition, the inclusion criteria were the length of time the articles had been written, up to five years, and the language used: English or Portuguese. A total of 36 studies were found. By analyzing the titles and abstracts of the texts, exclusion criteria were applied: duplicate, incomplete or disconnected articles were excluded. From this, 9 articles were selected for full reading and preparation of this review. RESULTS: The studies analyzed confirm that the use of hormonal contraceptive methods has major harmful effects¹. As non-hormonal male methods are still in the process of research and development, they have little uptake and are not in demand4. From this perspective, the main mechanisms of action of drugs with this objective are that they inhibit the activity of prostate-specific antigen (PSA), which is essential for semen liquefaction prior to fertilization2,3; protein kinase anchor 4, crucial for sperm motility4; serine/threonine kinase 33 (STK33)5 or testis-specific serine/threonine kinase 2 (TSSK2)1, both critical for spermatogenesis. DISCUSSION: The identified drugs represent alternative mechanisms for male contraception which, although still undergoing testing, are promising technologies for avoiding the side effects of hormone-based medications1, such as weight gain, decreased sexual performance, and mood changes2. These factors are essential for increasing adherence to these medications, despite their current limited availability on the market4,1. CONCLUSION: As analyzed, studies and experiments involving innovative contraceptive medications are on the rise. Considering that this is a field still undergoing refinement, eliminating dependence on hormonal or surgical methods relies on the continuation of ongoing research and the emergence of new, even more innovative studies.

Modulating tumor-associated macrophages through CSF1R inhibition: a potential therapeutic strategy for HNSCC

PurposeTumor-associated macrophages (TAMs) are pivotal immune cells within the tumor microenvironment (TME), exhibiting dual roles across various cancer types. Depending on the context, TAMs can either suppress tumor progression and weaken drug sensitivity or facilitate tumor growth and drive therapeutic resistance. This study explores whether targeting TAMs can suppress the progression of head and neck squamous cell carcinoma (HNSCC) and improve the efficacy of chemotherapy.MethodsBioinformatics analyses were performed to evaluate TAMs infiltration levels in HNSCC tumor tissues and examine their associations with patients’ clinicopathological characteristics and prognosis. Flow cytometry was utilized to measure the expression of key macrophage markers and assess apoptosis following treatment with colony stimulating factor 1 receptor (CSF1R) inhibitors (BLZ945, PLX3397). Additionally, immunohistochemistry was employed to detect CD68 and CD8 expression. In vivo, the antitumor efficacy of CSF1R inhibitors was tested in mouse HNSCC tumor model, both as monotherapy and in combination with cisplatin, to evaluate potential synergistic effects.ResultsBioinformatic analysis identified TAMs as the predominant infiltrating immune cells in the TME of HNSCC, with significantly higher infiltration levels in tumor tissues compared to adjacent non-tumor tissues. High TAMs infiltration was associated with poorer overall survival (OS), disease-free survival (DFS), human papillomavirus (HPV) infection status, and advanced disease stages. The TAMs-related genes prediction model demonstrated high prognostic accuracy. CSF1R is primarily expressed in TAMs, where high CSF1R expression may suppress antigen binding and activation. In vitro experiments showed that CSF1R inhibitors induce TAMs apoptosis, enhance their phagocytic activity, and reduce CD206 expression and IL-10 secretion, thereby diminishing their immunosuppressive function. In vivo experiments revealed that while CSF1R inhibitors alone had limited efficacy in suppressing tumor growth, their combination with cisplatin significantly enhanced therapeutic efficacy, as evidenced by increased CD8+ T cells infiltration within the TME.ConclusionTargeting TAMs via CSF1R inhibition enhances the therapeutic efficacy of cisplatin in HNSCC. These findings suggest that CSF1R inhibitors hold promise as a component of combination therapy for HNSCC.Graphical abstract

Flexible deformation and special interface structure in nanoparticle-stabilized Pickering bubbles strengthen the immunological response as adjuvant.

Adjuvants can enhance an immunological response, which is an important part of vaccine research. Pickering bubbles have been a mega-hit for biomedical applications, including in vivo visualization and targeted drug delivery. However, there have been no studies on Pickering bubbles as an immunological adjuvant, and the special properties and structures of Pickering bubbles may play an important role in immunization. In this study, poly(lactic-co-glycolic acid) (PLGA) particles were used to construct nanoparticle-stabilized Pickering bubbles (PPBs). PPBs were evaluated as immunological adjuvants based on immune response effects and mechanisms and aiming at future applications. PPBs have a flexible gas core and a special surface structure that can increase the cell contact area to promote phagocytosis and enhance the immune response. Quartz crystal microbalance with dissipation (QCM-D) data showed the flexibility of PPBs, and confocal images captured the deformability of PPBs during cell uptake. Flow cytometry and antibody titer detection showed that PPBs significantly promoted antigen uptake and activation of bone-marrow-derived dendritic cells (BMDCs) and induced an immune response with upregulated SIINFEKL MHC I and CD127 molecules on the surface of CD8+ T cells, indicating excellent antigen cross-presentation and cellular immune triggering effects. The upregulation of CD44 and CD62L on CD4+ T cells and the IgG2a/IgG1 ratio bias further demonstrated the excellent adjuvant role of PPBs in immunity. Finally, the biosafety of PPBs as an immunological adjuvant was also demonstrated. Our study demonstrates the potential of particle-stabilized bubbles as immune adjuvants, which provides innovative ideas for vaccine development and design.

Antigenic Activity of Various Rhodococcus equi Strain Plasmids

Background and Aim. Rhodococcus equi (R. equi) infection is a fatal cause of equine rhodococcosis. Infections have also been reported in other species and humans. This study evaluated the immune response of R. equi in rabbits.Materials and Methods. Different strains of R. equi (with and without plasmids) were administered to rabbits. Blood samples were collected from the ear veins of the rabbits at 7, 14, 21, and 28 days after the initial administration of the antigen, and the serum was examined for specific antibodies against R. equi plasmid antigens using the complement fixation reaction.Results. The minimum antibody level was recorded on day 7. The average antibody level throughout the study period was slightly above the median, indicating a small asymmetry toward higher values. By day 28, the antibody level had reached 75% of values ≤4.25.Conclusion. All strains of R. equi exhibited antigenic properties to varying degrees. The antibody level upon plasmid pVapN administration was higher than that of the other cases.

Investigation of a hemophilia family with one female hemophilia A patient and 12 male hemophilia A patients.

Hemophilia A (HA) is an X-chromosome-linked recessive genetic disorder. Female carriers may have bleeding symptoms, but rarely have moderate or severe disease. We identified a female patient with moderate HA by pedigree tracking and genetic testing in a HA family involving consanguineous marriage. To investigate the clinical and laboratory data, as well as F8 genetic variant affecting members in her family. We constructed a detailed pedigree diagram and performed coagulation analyses, including factor VIII activity (FVIII:C), FVIII inhibitor, and von Willebrand factor antigen (VWF: Ag) on 20 family members. The genomic DNA of 11 members was screened for intron 1 and intron 22 inversions using long-distance real-time polymerase chain reaction (RT-PCR). Their F8 coding genes were sequenced with an automatic next-generation sequencing. Thirteen HA persons with hemophilia (12 males, one female) and 18 female carriers were identified in the family. VWF: Ag level was normal in all 13 persons with hemophilia and 7 carriers tested. The female HA patient had FVIII:C 1.9 IU/dL and was homozygous for F8:c.1918G > T:p.V640F. Genetic testing is conducive to the diagnosis of hemophilia carriers and persons with hemophilia. F8: c.1918G > T:p.V640F is the pathogenic HA variant in this family. In any hemophilia family, we need to pay more attention to female carriers and patients.

Single-cell transcriptomic and spatial analysis reveal the immunosuppressive microenvironment in relapsed/refractory angioimmunoblastic T-cell lymphoma

Angioimmunoblastic T-cell lymphoma (AITL) is a kind of aggressive T-cell lymphoma with significant enrichment of non-malignant tumor microenvironment (TME) cells. However, the complexity of TME in AITL progression is poorly understood. We performed single-cell RNA-Seq (scRNA-seq) and imaging mass cytometry (IMC) analysis to compare the cellular composition and spatial architecture between relapsed/refractory AITL (RR-AITL) and newly diagnosed AITL (ND-AITL). Our results showed that the malignant T follicular helper (Tfh) cells showed significantly increased proliferation driven by transcriptional activation of YY1 in RR-AITL, which is markedly associated with the poor prognosis of AITL patients. The CD8+ T cell proportion and cytotoxicity decreased in RR-AITL TME, resulting from elevated expression of the inhibitory checkpoints such as PD-1, TIGIT, and CTLA4. Notably, the transcriptional pattern of B cells in RR-AITL showed an intermediate state of malignant transformation to B-cell-lymphoma, and contributed to immune evasion by highly expressing CD47 and PD-L1. Besides, compared to ND-AITL samples, myeloid-cells-centered spatial communities were more prevalent but showed reduced phagocytic activity and impaired antigen processing and presentation in RR-AITL TME. Furthermore, specific inhibitory ligand-receptor interactions, such as CLEC2D-KLRB1, CTLA4-CD86, and MIF-CD74, were exclusively identified in the RR-AITL TME. Our study provides a high-resolution characterization of the immunosuppression ecosystem and reveals the potential therapeutic targets for RR-AITL patients.

Understanding the interplay between oHSV and the host immune system: Implications for therapeutic oncolytic virus development.

Oncolytic herpes simplex viruses (oHSV) preferentially replicate in cancer cells while inducing antitumor immunity, and thus, they are often referred to as in situ cancer vaccines. OHSV infection of tumors elicits diverse host immune responses comprising both innate and adaptive components. Although the innate and adaptive immune responses primarily target the tumor, they also contribute to antiviral immunity, limiting viral replication/oncolysis. OHSV-encoded proteins use various mechanisms to evade host antiviral pathways and immune recognition, favoring oHSV replication, oncolysis, and spread. In general, oHSV infection and replication within tumors results in a series of sequential events, such as oncolysis and release of tumor and viral antigens, dendritic cell-mediated antigen presentation, Tcell priming and activation, Tcell trafficking and infiltration to tumors, and Tcell recognition of cancer cells, leading to tumor (and viral) clearance. These sequential events align with all steps of the cancer-immunity cycle. However, a comprehensive understanding of the interplay between oHSV and host immune responses is crucial to optimize oHSV-induced antitumor immunity and efficacy. Therefore, this review aims to elucidate oHSV's communication with innate and adaptive immune systems and use such interactions to improve oHSV's potential as a potent immunovirotherapeutic agent against cancer.

Evaluation of the effectiveness of chemical inactivation and immunogenicity of the Omicron variant of the SARS-CoV-2 virus

The rapid spread of coronavirus infection COVID-19 among the population of many countries around the world has contributed to the emergence of many genetic variants of SARS-CoV-2. Compared to previous coronavirus variants, the new Omicron variants have shown a noticeable degree of mutation. Virus inactivation is one of the most important steps in the development of inactivated vaccines. The chemical inactivation agents currently used are β-propiolactone and formaldehyde, but there is no uniform standard for designing and specifying the inactivation process. Evaluation and comparison of the effectiveness of chemical inactivation of two agents, formaldehyde and β-propiolactone against immunogenicity of the Omicron variant of the SARS-CoV-2 virus. Nasopharyngeal swabs were used to obtain the SARS-CoV-2 Omicron variant virus. Vero cell culture was used to isolate, reproduce, titrate the virus, and perform a neutralization reaction. The kinetics of studying the inactivation of the virus by chemical agents such as formaldehyde and β-propiolactone was carried out. Studies have been conducted to comparatively evaluate the effectiveness of chemical agents used to inactivate the SARS-CoV-2 virus of the Omicron variant, planned for use in the production of an inactivated whole-virion vaccine. Formaldehyde and β-propiolactone were used as inactivation agents in concentrations of 0.05, 0.1, 0.5% of the total volume of the virus suspension. It has been established that complete inactivation of the virus by formaldehyde in the concentrations used at a temperature of 37 °C occurs within up to 2 hours, and when using beta-propiolactone, within up to 12 hours. Inactivated virus samples have different antigenic activity depending on the concentration of the inactivation agents used. The most pronounced antigenic activity is manifested in samples of the pathogen that were treated with an inactivation agent at a mild concentration of 0.05%. Increasing the concentration of inactivation agent by 5 or more times leads to a significant decrease in the antigenicity of the SARS-CoV-2 virus. With the inactivation modes used, the loss of biological activity of the virus occurs faster and antigenicity is retained largely when treated with formaldehyde.

Correlation of factor XIII subunit A with factor XIII activity in a population of parturient women.

The role of factor XIII in acute bleeding situations is gaining more and more importance. It has previously been shown that prepartum factor XIII activity has a significant impact on postpartum blood loss. Whether factor XIII antigen behaves in a similar manner is unknown. As postpartum hemorrhage is one of the leading causes of maternal morbidity and mortality worldwide and factor XIII antigen determination might be available more readily in some centers as compared to factor XIII activity, this is an important question to answer, especially in the emergency situation of a postpartum hemorrhage. To assess the correlation of prepartum factor XIII antigen with prepartum factor XIII activity and to evaluate the correlation between prepartum factor XIII antigen on measured postpartum blood loss. This is a secondary analysis of a prospective cohort study which analyzed the impact of prepartum blood coagulation factor XIII activity on postpartum blood loss in 1300 women at the University Hospital Zurich, Switzerland between October 2015 and November 2016 ("PPH-1300 study"). Blood loss was quantified using a previously validated technique. The association of factor XIII activity and factor XIII antigen was assessed by means of a Spearman rank correlation and differences were displayed using Bland-Altman plot and Passing-Bablok regression. The effect of the prepartum factor XIII antigen on blood loss was estimated by continuous outcome logistic regression. Prepartum factor XIII activity significantly correlated with prepartum factor XIII antigen (Spearman rank correlation coefficient for prepartum values 0.89, p < 0.001 and postpartum values 0.902, p < 0.001). Elevated values of prepartum factor XIII antigen showed a trend toward lower measured postpartum blood loss. The correlation of factor XIII activity with factor XIII antigen (subunit A) in a large real-world sample as well as an association of prepartum factor XIII antigen and postpartum blood loss is observed. Factor XIII antigen determination, a highly automatable test, could be useful in emergency situations such as a PPH (as well as other bleeding situations) if the determination of factor XIII activity is not possible. To evaluate whether FXIII replenishment reduces blood loss is the focus of ongoing studies.

First-in-human study to evaluate the safety, pharmacokinetics (PK), and pharmacodynamics (PD) of RBD4059, a GalNAc-siRNA drug targeting coagulation factor XI (FXI), in healthy subjects

Abstract Background Patients at risk of thrombosis/thromboembolism, require effective and safe anti-coagulation with high compliance. Inhibiting FXI has emerged as a promising strategy with potential for lower bleeding risk compared to currently approved anti-coagulants. Here we report on the safety, PK and PD effects of the GalNAc-conjugated siRNA RBD4059, specifically targeting and repressing FXI protein synthesis in the liver. Purpose Investigate safety, PK, and PD of first-in-human dosing of RBD4059 in healthy subjects. Methods A randomized, single-blind, placebo-controlled, single ascending dose (SAD) phase I study in healthy subjects (NCT05653037), in cohorts of eight randomized 3:1 to receive escalating doses of RBD4059 (50, 150, and 400 mg) or placebo administered subcutaneously. Results As of January 25, 2024, 24 subjects (with follow-up to week 24) with demographics and baseline clinical characteristics shown in Table 1 were enrolled. RBD4059 was well tolerated (Table 2), all related AEs were grade 1. There was no evidence of any clinically relevant bleeding events. Plasma exposure of RBD4059 tended to increase in proportion to the dose. Maximum concentration in plasma (Cmax) was reached in 2 to 4 h and then declined in line with one-compartment kinetics. The mean plasma half-life (t1/2) ranged from 3.2 to 7.0 h. RBD4059 treatment resulted in dose dependent and sustained reductions in FXI activity and FXI antigen (Figure 1A, B, D). Observed mean maximum percentage change from baseline in FXI activity from the 50 mg, 150 mg, and 400 mg SAD cohorts were 67.5%, 81.0%, and 85.8%, respectively, recovering with a maintained effect observed on D141 (50mg: 50.6% inhibition; 150mg: 68.2% inhibition). The reduction in FXI antigen showed a very similar pattern as the reduction in FXI activity, and reductions were accompanied by a concomitant increase in APTT. (Figure 1C, D). PKPD modelling supports that RBD4059 may be dosed every 3 months or less frequent with a &amp;gt;90% FXI reduction throughout the dosing interval, and will be tested in the upcoming phase 2 study. Conclusion(s) RBD4059 demonstrated favorable safety, predictable PK, and pronounced durable PD effect in the dose range of 50 mg - 400 mg. This first-in-human SAD study supports the further development of RBD4059 as an anticoagulant that can maintain a high level of PD effect with a once every 3 month or less frequent dosing regimen, with potential for enhanced compliance in chronic anti-coagulant therapy.Table 1 &amp; Table 2Figure 1.Panels A-D

Human OX40L-CAR-Tregs target activated antigen-presenting cells and control T cell alloreactivity.

Regulatory T cells (Tregs) make major contributions to immune homeostasis. Because Treg dysfunction can lead to both allo- and autoimmunity, there is interest in correcting these disorders through Treg adoptive transfer. Two of the central challenges in clinically deploying Treg cellular therapies are ensuring phenotypic stability and maximizing potency. Here, we describe an approach to address both issues through the creation of OX40 ligand (OX40L)-specific chimeric antigen receptor (CAR)-Tregs under the control of a synthetic forkhead box P3 (FOXP3) promoter. The creation of these CAR-Tregs enabled selective Treg stimulation by engagement of OX40L, a key activation antigen in alloimmunity, including both graft-versus-host disease and solid organ transplant rejection, and autoimmunity, including rheumatoid arthritis, systemic sclerosis, and systemic lupus erythematosus. We demonstrated that OX40L-CAR-Tregs were robustly activated in the presence of OX40L-expressing cells, leading to up-regulation of Treg suppressive proteins without induction of proinflammatory cytokine production. Compared with control Tregs, OX40L-CAR-Tregs more potently suppressed alloreactive T cell proliferation in vitro and were directly inhibitory toward activated monocyte-derived dendritic cells (DCs). We identified trogocytosis as one of the central mechanisms by which these CAR-Tregs effectively decrease extracellular display of OX40L, resulting in decreased DC stimulatory capacity. OX40L-CAR-Tregs demonstrated an enhanced ability to control xenogeneic graft-versus-host disease compared with control Tregs without abolishing the graft-versus-leukemia effect. These results suggest that OX40L-CAR-Tregs may have wide applicability as a potent cellular therapy to control both allo- and autoimmune diseases.

Immunological tolerance in breast cancer: some reasons for development

Immunological tolerance is one of the reasons for the development and progression of malignant tumors. The tumor immune cycle regulates the normal antitumor immune response, and it’s disruption is responsible for the development of immunological tolerance. This article provides a review of russian and foreign literature published in databases such as PubMed, Medline, and Cochrane, eLibrary in the last 5 years, focusing on the emergence of immunological tolerance in breast cancer from the perspective of disrupted regulation of tumor immune cycle phases: expression of antigens on the surface of tumor cells, cancer antigen presentation, priming and activation T cells, immune infiltration of the tumor site, recognition, and elimination of tumor cells. Understanding the mechanisms underlying tumor immune cycle disruption is important for identifying new immunopathogenetic links in the development of breast cancer, as well as identifying targets to improve the effectiveness of therapy for advanced breast cancer.

Increased Platelet Adhesiveness in Patients with Venous Thromboembolic Disease.

Background Association between global platelet function and the risk of venous thromboembolic disease (VTE) has been proposed, though the mechanisms do not involve increased platelet aggregation. However, platelet adhesiveness has not been systematically explored in VTE patients. Objectives To evaluate platelet adhesive functions in VTE patients. Methods Platelet adhesion was evaluated by using whole blood samples from VTE patients, selected based on short closure times on the PFA-100 ( n = 54), and matched healthy individuals ( n = 57) in: (i) the PFA-100, (ii) a cone plate analyzer (CPA), on a plastic surface, (iii) microfluidic devices, with two- and three-dimensional evaluation, and (iv) membrane glycoprotein analysis. Intraplatelet signaling was evaluated in isolated collagen type I (Col-I) activated platelets and platelets adhered on Col-I or von Willebrand factor (VWF) coated coverslips under flow. VWF antigen and ADAMTS-13 activity were measured in plasma samples. Results PFA-100 closure times remained significantly shorter in patients. The CPA test showed a significant increase in the platelet aggregates size when using blood from VTE patients. Platelet adhesion on Col-I revealed a higher area covered by platelets and increased aggregate volume when exposed to samples from VTE patients. Protein P-ZAP70/SYK72 showed a phosphorylation level significantly increased in patients' platelets. Plasma VWF was significantly elevated in VTE patients. Conclusions Platelets from VTE patients exhibit a proadhesive phenotype under flow conditions potentially related to the shortened occlusion times with the PFA-100. This enhanced adhesiveness may be explained by higher intraplatelet ZAP70/SYK72 phosphorylation and increased plasma VWF in patients. Therefore, primary hemostasis plays a significant role in the pathophysiology of VTE.

Pregnancy loss in individuals with von Willebrand disease and unspecified mucocutaneous bleeding disorders: a multicenter cohort study

BackgroundWhile bleeding around pregnancy is well described in von Willebrand disease (VWD), the risk of pregnancy loss is less certain. ObjectivesWe aimed to describe the frequency of pregnancy loss in females with VWD compared with those with a similar mucocutaneous bleeding phenotype and no VWD or compared with nonbleeding disorder controls. MethodsFemale patients were consecutively approached in 8 specialty bleeding disorder clinics between 2014 and 2023. The VWD group was defined as having von Willebrand factor (VWF) antigen and VWF activity levels, each <0.50 IU/mL on ≥2 occasions, and a condensed MCMDM-1 score of ≥4. The non-VWD mucocutaneous bleeding disorder group had VWF levels ≥ 0.50 IU/mL on ≥2 occasions and an MCMDM-1 score ≥ 4. A nonbleeding disorder control group was recruited in pregnancy from a low-risk maternity clinic. ResultsThere were 150 females in the VWD group, 145 in the non-VWD mucocutaneous bleeding disorder group, and 137 in the control group. There was a similar frequency of individuals with ≥1 loss in the VWD group (45.3%, 68/150), the non-VWD group (56.6%; 82/145; −11.2%; 97.5% CI, −24.2%, 1.8%), and the nonbleeding disorder control group (37.2%; 51/137; 8.1%; 97.5% CI, −4.9%, 21.1%). Using a logistic regression, the odds ratio of pregnancy losses in the VWD group vs the non-VWD group was 0.94 (95% CI 0.65, 1.36). All groups experienced more recurrent losses compared with the literature. ConclusionThere was no statistically significant difference in risk of pregnancy loss between females with VWD, females with a similar mucocutaneous bleeding phenotype, and nonbleeding disorder controls.