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A multi-component microarray, applying a novel analysis algorithm, was developed for quantitative evaluation of the SARS-CoV-2 vaccines' immunogenicity. The array enables simultaneous quantitation of IgG, IgM, and IgA, specific to the SARS-CoV-2 spike, receptor binding domain, and nucleocapsid proteins. The developed methodology is based on calculating an apparent immunoglobulin signal from the linear range of the fluorescent read-outs generated by scanning the microarray slides at different exposure times. A dedicated algorithm, employing a rigorous set of embedded conditions, then generates a normalized signal for each of the unique assays. Qualification of the multi-component array performance (evaluating linearity, extended dynamic-range, specificity, precision, and accuracy) was carried out with an in-house COVID-19, qRT-PCR positive serum, as well as pre-pandemic commercial negative sera. Results were compared to the WHO international standard for anti-SARS-CoV-2 immunoglobulins. Specific IgG, IgM, and IgA signals obtained by this array enabled successful discrimination between SARS-CoV-2 q-RT-PCR positive (seroconverted SARS-CoV-2 patients) and negative (naïve) samples. This array is currently used for evaluation of the humoral response to BriLife, the VSV-based Israeli vaccine during phase I/II clinical trials.

rVSV-ΔG-SARS-CoV-2-S is a clinical stage (Phase 2) replication competent recombinant vaccine against SARS-CoV-2. To evaluate the safety profile of the vaccine, a series of non-clinical safety, immunogenicity and efficacy studies were conducted in four animal species, using multiple doses (up to 108 Plaque Forming Units/animal) and dosing regimens. There were no treatment-related mortalities or any noticeable clinical signs in any of the studies. Compared to unvaccinated controls, hematology and biochemistry parameters were unremarkable and no adverse histopathological findings. There was no detectable viral shedding in urine, nor viral RNA detected in whole blood or serum samples seven days post vaccination. The rVSV-ΔG-SARS-CoV-2-S vaccination gave rise to neutralizing antibodies, cellular immune responses, and increased lymphocytic cellularity in the spleen germinal centers and regional lymph nodes. No evidence for neurovirulence was found in C57BL/6 immune competent mice or in highly sensitive type I interferon knock-out mice. Vaccine virus replication and distribution in K18-human Angiotensin-converting enzyme 2-transgenic mice showed a gradual clearance from the vaccination site with no vaccine virus recovered from the lungs. The nonclinical data suggest that the rVSV-ΔG-SARS-CoV-2-S vaccine is safe and immunogenic. These results supported the initiation of clinical trials, currently in Phase 2. Supplementary Information The online version contains supplementary material available at 10.1007/s00204-021-03214-w.

BriLife

rVSV-ΔG-SARS-CoV-2-S is a clinical stage (Phase 2) replication competent recombinant vaccine against SARS-CoV-2. Nonclinical safety, immunogenicity and efficacy studies were conducted in 4 animal species, using multiple dose levels (up to 108 PFU/animal) and various dosing regimens. There were no treatment related mortalities in any study, or any noticeable clinical signs. Compared to unvaccinated controls, hematology and biochemistry parameters were unremarkable and no adverse histopathological findings gave cause for safety concern in any of the studies. There was no viral shedding in urine, nor viral RNA detected in whole blood or serum samples 7 days post vaccination. The rVSV-ΔG-SARS-CoV-2-S vaccine immune response gave rise to neutralizing antibodies, cellular immune response, and increased lymphocytic cellularity in the spleen germinal centers and regional lymph node. No evidence for neurovirulence was found in C57BL/6 immune competent mice or in highly sensitive IFNAR KO mice. Vaccine virus replication and distribution in K18 hACE2 transgenic mice showed a gradual clearance from the vaccination site with no vaccine virus recovered from the lungs. The rVSV-ΔG-SARS-CoV-2-S vaccine was well tolerated locally and systemically and elicited an effective immunogenic response up to the highest dose tested, supporting further clinical development.

Galectin-3 is a β-galactoside-binding lectin that plays an important role in the modulation of immune responses. It has been shown to aggravate joint inflammation and destruction in experimental arthritis. We investigated the role of galectin-3 in TLR-induced cell activation in human synovial fibroblasts (SF) in order to better understand the mechanism(s) of the proinflammatory function of galectin-3 in arthritis. Galectin-3 expression in SF obtained from rheumatoid arthritis and osteoarthritis patients was inhibited by siRNA mediated gene-knockdown. Galectin-3 was also inhibited with modified citrus pectin (MCP), a polysaccharide galectin-3 ligand. Galectin-3 knockdown inhibited TLR-2, -3 and -4-induced IL-6 secretion, but not TLR-2, -3 and -4-mediated matrix metalloproteinase-3 or CC chemokine ligand-5 secretion. When the SF were stimulated with phorbol 12-myristate 13-acetate, a protein kinase C activator that bypasses the membranal receptors, galectin-3 knockdown no longer influenced IL-6 secretion. MCP reduced IL-6 levels in a dose-dependent manner. Our results indicate that galectin-3 is a positive sensor-regulator of TLR-induced IL-6 secretion in human synovial fibroblasts, thus adding new insights into the mechanisms by which galectin-3 augments synovial inflammation. These findings corroborate the potential role of glycan inhibitors of galectin-3 as a therapeutic approach for the treatment of inflammatory arthritis.

The dynamic light scattering imaging (DLSI) system combined with the conventional fluorescence intravital microscope (FIM) has been applied for the examination of blood and lymph vessels in the mouse ear in vivo. While the CCD camera can be shared by both techniques the combined application of DLSI and FIM allows rapid switching between the modalities. In current study temporal speckles fluctuations are used for rendering blood vessels structure and monitoring blood perfusion with the higher spatial resolution, whereas FIM provides the images of lymphatic vessels. The results clearly demonstrate that combined application of DLSI and FIM approaches provides synchronic in vivo images of blood and lymph vessels with higher contrast and specificity. The use of this new dual-modal diagnostic system is particularly important and has a great potential to significantly expand the capabilities of vascular diagnostics providing synchronic in vivo images of blood and lymph vessels.

Objective.To estimate the longterm humoral response of an antipneumococcal polysaccharide vaccine (PPSV23) in patients with rheumatoid arthritis (RA), psoriatic arthritis (PsA), ankylosing spondylitis (AS), or inflammatory bowel disease (IBD)-associated spondyloarthropathy (SpA), and the effect of demographic and clinical factors and treatment on the longterm efficacy of the vaccine.Methods.A total of 145 consecutive patients treated with biologics [tumor necrosis factor-α (TNF-α) or interleukin 6 (IL-6) receptor inhibitors] or methotrexate (MTX) participated in this study. Fifteen were excluded because of absent information regarding their vaccination status (n = 9) or because of technical problems in obtaining their serum sample (n = 6). They were diagnosed with RA (n = 63, 48.5%), PsA (n = 29, 22.3%), AS (n = 28, 21.5%), or IBD-associated SpA (n = 3, 2.3%). Their mean age was 54.6 years, and 61.5% were women. Data were collected on the timing of vaccination, demographic and clinical characteristics, and treatment, and patients’ serum antipneumococcal antibody levels were tested.Results.Two-thirds of the patients (67.7%) had received PPSV23 45 months (mean) earlier. Treatment included TNF-α inhibitors (73.9%), IL-6 receptor inhibitors (13.1%), or MTX without a biological treatment (13%). The uptake of vaccination was significantly higher in the older population (> 65 yrs). Vaccinated patients had significantly higher antibody levels compared with vaccine-naive patients. The antibody levels had been preserved after 10 years. MTX use, but not biologics, was associated with significantly lower antibody levels.Conclusion.The longterm efficacy of the PPSV23 vaccination seems to be preserved among patients with RA, PsA, AS, and IBD-associated SpA for at least 10 years. Efficacy is slightly impaired by MTX, but it is not affected by biologics. These findings suggest that revaccination after 5 years might not be needed for all, and testing the antibody titers should be considered to identify those who may benefit from revaccination.

Objective: Monitoring of immune responses is essential in the care of immunosuppressed individuals, including rheumatic patients. Evaluation of cellular immunity is essential for confirming virus-specific effector cell functions, but it is poorly standardized, and suffers from technical limitations and inaccurate results. There is, therefore, a need for reliable techniques for assessing cell-mediated immunity. In this study we compared the cell-mediated immunity response to influenza vaccine between a population of rheumatoid arthritis (RA) patients and healthy subjects by three methods. Methods: Trivalent influenza subunit vaccine was administered to 18 RA patients who were taking disease-modifying antirheumatic drugs and to 18 healthy controls. Peripheral blood mononuclear cells (PBMCs) and sera were obtained immediately before and ~28 days after vaccination. Cell-mediated immunity responses to vaccination were evaluated by (1) flow cytometric analysis of IL-2/IFN-γ production in activated CD4/CD8 T-cells, (2) enzyme-linked immunosorbent assay for the analysis of IFN-γ secretion, and (3) Granzyme B activity assay. Humoral response was evaluated by the hemagglutination inhibition assay. Results: Vaccination induced a significant increase in PBMC IFN-γ secretion and Granzyme B activity in the RA patients. Granzyme B activity also significantly increased in the controls, but there was no change in the levels of secreted IFN-γ. No group differences in the frequencies of IFN-γ/IL-2-producing activated CD4/CD8 T-cells were observed by flow cytometry. The geometric mean of hemagglutination inhibition antibody titers increased significantly for the H1N1/H3N2 influenza strains in both groups. Conclusions: Granzyme B activity assay was the only method to detect a significant cell-mediated immunity response in both groups while significant increase in IFN-γ secretion was demonstrated only in RA patients. Flow cytometric analysis failed to show IL-2 and IFN-γ production in both groups. Currently available methods for measuring cellular responsiveness to influenza vaccination are inconsistent and limited in their ability to reflect acquired cellular immunity.

Objective.The longterm use of tumor necrosis factor (TNF)-α blockers is limited by the formation of neutralizing antibodies. To the best of our knowledge, immunogenicity in psoriatic arthritis (PsA) has not been investigated in depth. Our objective was to evaluate the prevalence and significance of TNF-α blocker immunogenicity in PsA.Methods.Consecutive patients with PsA treated with either infliximab (IFX), adalimumab (ADA), or etanercept (ETN) > 3 months participated in our cross-sectional study. Their demographic and clinical characteristics, skin and joint disease activity, and records of use of methotrexate (MTX) and other medications were collected. Drug levels (ELISA) and antidrug antibodies (ADAb; Bridging ELISA) were evaluated before the next injection or infusion.Results.A total of 93 patients with PsA were recruited (48 receiving ADA, 24 IFX, and 21 ETN), with a mean age of 53 years (range 21–83 yrs), composed of 53% women. One-fourth of the patients were concomitantly treated with MTX. Altogether, 77% of the patients demonstrated therapeutic drug levels. High levels of ADAb were found in 29% of patients taking ADA, 21% taking IFX, and 0% taking ETN. ADAb significantly correlated with lower drug levels, higher 28-joint Disease Activity Scores, and higher global assessments. MTX use correlated significantly with a lower prevalence of ADAb.Conclusion.Significant levels of ADAb were present in up to 29% of patients with PsA treated with ADA or IFX. ADAb clearly correlated with low therapeutic drug levels and higher disease activity variables. The use of MTX significantly decreased ADAb prevalence, and its use should be strongly considered in combination with TNF-α blocker antibodies in patients with PsA.

We present a multi-modal optical diagnostic approach utilizing a combined use of Fluorescence Intravital Microscopy (FIM), Dynamic Light Scattering (DLS) and Spectrally Enhanced Microscopy (SEM) modalities for in vivo imaging of tumor vascular network and blood microcirculation. FIM is used for imaging of tumor surroundings and microenvironment, SEM provides information regarding blood vessels topography, whereas DLS is applied for functional imaging of vascular network and blood microcirculation. This complementary combination of the imaging approaches is extremely useful for functional in vivo imaging of blood vasculature and tumor microenvironment. The technique has also a great potential in vascular biology and can significantly expand the capabilities of tumor angiogenesis studies and notably contribute to the development of cancer treatment.

In current report we present synchronized in vivo imaging of tumor vascular network and tumor microenvironment obtained by combined use of Dynamic Light Scattering Imaging, Spectrally Enhanced Microscopy, and Fluorescence Intravital Microscopy. Dynamic Light Scattering Imaging is used for functional imaging of the vascular network and blood microcirculation. Spectrally Enhanced Microscopy provides information regarding blood vessel topography. Fluorescence Intravital Microscopy is used for imaging of tumor microvasculature and tumor microenvironment. These well known modalities have been comprehensively validated in the past and are widely used in various bio-medical applications. As shown here, their combined application has great potential for studies of vascular biology. This multi-modal non-invasive diagnostic technique expands our current capacity to investigate blood microcirculation and tumor angiogenesis in vivo, thereby contributing to the development of cancer research and treatment.

We present a multi-modal optical diagnostic approach utilizing a combined use of Fluorescence Intravital Microscopy and Dynamic Light Scattering for in vivo functional imaging of tumor vascular network and blood microcirculation. Fluorescence Intravital Microscopy is used for imaging of tumor and tumor surroundings, whereas Dynamic Light Scattering is applied for imaging of vascular network and blood microcirculation. The obtained results demonstrate that presented multi-modal imaging approach has a great potential in vascular biology and can significantly expand the capabilities of tumor angiogenesis studies and notably contribute to the development of cancer treatment.

Background Antiangiogenic and anti-vascular therapies present intriguing alternatives to cancer therapy. However, despite promising preclinical results and significant delays in tumor progression, none have demonstrated long-term curative features to date. Here, we show that a single treatment session of Tookad-based vascular targeted photodynamic therapy (VTP) promotes permanent arrest of tumor blood supply by rapid occlusion of the tumor feeding arteries (FA) and draining veins (DV), leading to tumor necrosis and eradication within 24–48 h. Methodology/Principal Findings A mouse earlobe MADB106 tumor model was subjected to Tookad-VTP and monitored by three complementary, non-invasive online imaging techniques: Fluorescent intravital microscopy, Dynamic Light Scattering Imaging and photosensitized MRI. Tookad-VTP led to prompt tumor FA vasodilatation (a mean volume increase of 70%) with a transient increase (60%) in blood-flow rate. Rapid vasoconstriction, simultaneous blood clotting, vessel permeabilization and a sharp decline in the flow rates then followed, culminating in FA occlusion at 63.2 sec±1.5SEM. This blockage was deemed irreversible after 10 minutes of VTP treatment. A decrease in DV blood flow was demonstrated, with a slight lag from FA response, accompanied by frequent changes in flow direction before reaching a complete standstill. In contrast, neighboring, healthy tissue vessels of similar sizes remained intact and functional after Tookad-VTP. Conclusion/Significance Tookad-VTP selectively targets the tumor feeding and draining vessels. To the best of our knowledge, this is the first mono-therapeutic modality that primarily aims at the larger tumor vessels and leads to high cure rates, both in the preclinical and clinical arenas.

Background Monitoring of immune responses is essential in a number of clinical research areas that address immunosuppressed individuals, including oncologic and rheumatic patients. During the past 10 years, our group has been deeply involved in the study of vaccinations in rheumatic patients, with a special concern regarding the impact of drugs. While humoral responsiveness is considered the gold standard for most vaccines, including seasonal influenza, evaluation of cellular immune responses is much less standardized, requires specialized equipment and often suffers from technical limitations that eventually lead to inaccurate and inconsistent results. Since cellular response is essential for supporting virus-specific effector cell functions, reliable assessment techniques are of great importance. Objectives To comparatively assess the cellular immune response to influenza vaccine by 3 different methods, in concomitant with humoral immune response evaluation, in rheumatoid arthritis (RA) patients relative to healthy subjects. Methods Trivalent influenza subunit vaccine was administered to 18 RA patients treated by synthetic DMARDs, mostly methotrexate (MTX), and to 18 healthy controls. Peripheral blood mononuclear cells (PBMCs) and sera were obtained immediately before and ~28 days after vaccination. Three different methods to measure cellular mediated immune responses to influenza vaccination were compared in RA patients and in healthy subjects. These methods included (1) flow cytometric analysis of IL-2 and IFNg production in activated CD4/CD8 T-cells; (2) enzyme-linked immunosorbent assay (ELISA) for the analysis of IFNg secretion and (3) granzyme B activity assay in influenza-stimulated PBMC. The humoral response was evaluated by the hemagglutination inhibition (HI) assay. Results Cellular response: Vaccination induced a significant increase in PBMC IFNg secretion and Granzyme B activity in the RA patients. A significant increase in Granzyme B activity was also measured in the healthy control group, but there was no change in the levels of secreted IFNg. There was no difference in the frequencies of IFN-g/IL-2 producing activated CD4 or CD8 T-cells, as measured by flow cytometry, in both groups, either before or 4 weeks following influenza vaccination. Humoral response: A significant increase in the geometric mean titer (GMT) of HI was demonstrated for the H1N1 and H3N2 influenza strains in both groups. The response rate to HIN1 was significantly higher in DMARDs patients in comparison with healthy controls. The response rate to the H3N2 and B strains was similar in both groups. Conclusions The results of this study confirm previous findings on the preserved humoral immune response of RA patients to influenza vaccination. Among the three methods utilized to cellular immune responsiveness - Granzyme B activity assay was the only one to detect such response in both groups tested. It appears that current available measurement methods for cellular responsiveness to influenza vaccination suffer from inconsistency, and are limited in their ability to reflect gained cellular immunity. Disclosure of Interest None Declared