scholarly journals Rabbit Monoclonal Antibody Specifically Recognizing a Linear Epitope in the RBD of SARS-CoV-2 Spike Protein

Vaccines ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 829
Author(s):  
Junping Hong ◽  
Qian Wang ◽  
Qian Wu ◽  
Junyu Chen ◽  
Xijing Wang ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
Western Blot ◽  
Viral Entry ◽  
Mononuclear Cells ◽  
Cell Receptor ◽  
Spike Protein ◽  
Linear Epitope ◽  
Peripheral Blood Mononuclear ◽  
Functional Studies ◽  
Rabbit Monoclonal Antibody

To date, SARS-CoV-2 pandemic has caused more than 188 million infections and 4.06 million deaths worldwide. The receptor-binding domain (RBD) of the SARS-CoV-2 spike protein has been regarded as an important target for vaccine and therapeutics development because it plays a key role in binding the human cell receptor ACE2 that is required for viral entry. However, it is not easy to detect RBD in Western blot using polyclonal antibody, suggesting that RBD may form a complicated conformation under native condition and bear rare linear epitope. So far, no linear epitope on RBD is reported. Thus, a monoclonal antibody (mAb) that recognizes linear epitope on RBD will become valuable. In the present study, an RBD-specific rabbit antibody named 9E1 was isolated from peripheral blood mononuclear cells (PBMC) of immunized rabbit by RBD-specific single B cell sorting and mapped to a highly conserved linear epitope within twelve amino acids 480CNGVEGFNCYFP491 on RBD. 9E1 works well in Western blot on S protein and immunohistochemistry on the SARS-CoV-2 infected tissue sections. The results demonstrated that 9E1 can be used as a useful tool for pathological and functional studies of SARS-CoV-2.

scholarly journals SAR-CoV-2 Spike Protein-Induced Interleukin 6 Signaling Is Blocked by a Plant-Produced Anti-Interleukin 6 Receptor Monoclonal Antibody

Vaccines ◽  
2021 ◽  
Vol 9 (11) ◽  
pp. 1365
Author(s):  
Collin Jugler ◽  
Haiyan Sun ◽  
Qiang Chen
Keyword(s):  
Monoclonal Antibody ◽  
Interleukin 6 ◽  
Mononuclear Cells ◽  
Human Peripheral Blood ◽  
Spike Protein ◽  
Cytokine Signaling ◽  
Peripheral Blood Mononuclear ◽  
Interleukin 6 Receptor ◽  
Vitro Model

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative agent of the current COVID-19 pandemic, has caused more than 4.5 million deaths worldwide. Severe and fatal cases of COVID-19 are often associated with increased proinflammatory cytokine levels including interleukin 6 (IL-6) and acute respiratory distress syndrome. In this study, we explored the feasibility of using plants to produce an anti-IL-6 receptor (IL-6R) monoclonal antibody (mAb) and examined its utility in reducing IL-6 signaling in an in vitro model, which simulates IL-6 induction during SARS-CoV-2 infection. The anti-IL6R mAb (IL6RmAb) was quickly expressed and correctly assembled in Nicotiana benthamiana leaves. Plant-produced IL6RmAb (pIL6RmAb) could be enriched to homogeneity by a simple purification scheme. Furthermore, pIL6RmAb was shown to effectively inhibit IL-6 signaling in a cell-based model system. Notably, pIL6RmAb also suppressed IL-6 signaling that was induced by the exposure of human peripheral blood mononuclear cells to the spike protein of SARS-CoV-2. This is the first report of a plant-made anti-IL-6R mAb and its activity against SARS-CoV-2-related cytokine signaling. This study demonstrates the capacity of plants for producing functionally active mAbs that block cytokine signaling and implies their potential efficacy to curb cytokine storm in COVID-19 patients.

scholarly journals Inhibition of Human Immunodeficiency Virus Replication by a Dual CCR5/CXCR4 Antagonist

2004 ◽  
Vol 78 (23) ◽  
pp. 12996-13006 ◽  
Author(s):  
Katrien Princen ◽  
Sigrid Hatse ◽  
Kurt Vermeire ◽  
Stefano Aquaro ◽  
Erik De Clercq ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Viral Entry ◽  
Mononuclear Cells ◽  
Human Immunodeficiency Virus Replication ◽  
Cxcr4 Antagonist ◽  
Peripheral Blood Mononuclear ◽  
Transfected Cells ◽  
Immunodeficiency Virus ◽  
Intracellular Ca ◽  
Hiv 1

ABSTRACT Here we report that the N-pyridinylmethyl cyclam analog AMD3451 has antiviral activity against a wide variety of R5, R5/X4, and X4 strains of human immunodeficiency virus type 1 (HIV-1) and HIV-2 (50% inhibitory concentration [IC50] ranging from 1.2 to 26.5 μM) in various T-cell lines, CCR5- or CXCR4-transfected cells, peripheral blood mononuclear cells (PBMCs), and monocytes/macrophages. AMD3451 also inhibited R5, R5/X4, and X4 HIV-1 primary clinical isolates in PBMCs (IC50, 1.8 to 7.3 μM). A PCR-based viral entry assay revealed that AMD3451 blocks R5 and X4 HIV-1 infection at the virus entry stage. AMD3451 dose-dependently inhibited the intracellular Ca2+ signaling induced by the CXCR4 ligand CXCL12 in T-lymphocytic cells and in CXCR4-transfected cells, as well as the Ca2+ flux induced by the CCR5 ligands CCL5, CCL3, and CCL4 in CCR5-transfected cells. The compound did not interfere with chemokine-induced Ca2+ signaling through CCR1, CCR2, CCR3, CCR4, CCR6, CCR9, or CXCR3 and did not induce intracellular Ca2+ signaling by itself at concentrations up to 400 μM. In freshly isolated monocytes, AMD3451 inhibited the Ca2+ flux induced by CXCL12 and CCL4 but not that induced by CCL2, CCL3, CCL5, and CCL7. The CXCL12- and CCL3-induced chemotaxis was also dose-dependently inhibited by AMD3451. Furthermore, AMD3451 inhibited CXCL12- and CCL3L1-induced endocytosis in CXCR4- and CCR5-transfected cells. AMD3451, in contrast to the specific CXCR4 antagonist AMD3100, did not inhibit but enhanced the binding of several anti-CXCR4 monoclonal antibodies (such as clone 12G5) at the cell surface, pointing to a different interaction with CXCR4. AMD3451 is the first low-molecular-weight anti-HIV agent with selective HIV coreceptor, CCR5 and CXCR4, interaction.

scholarly journals Defective Autophagy in MPN Were Predominantly Detected in Megakaryocytes in Philadelphia Negative (Ph -) Myeloproliferative Neoplasm

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 5386-5386
Author(s):  
Jen-Chin Wang ◽  
Guanfang Shi ◽  
Karan Josan ◽  
Preethi Ramachandran ◽  
Vladimir Gotlieb ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Western Blot ◽  
Cell Signaling ◽  
Mononuclear Cells ◽  
Myeloproliferative Neoplasm ◽  
Beclin 1 ◽  
Positive Staining ◽  
Rt Pcr ◽  
Peripheral Blood Mononuclear ◽  
Cytoplasmic Staining

We previously reported that autophagy was defective in classical Philadelphia negative (Ph -) Myeloproliferative Neoplasm (MPN) by demonstrating increased p62, decreased Beclin-1 by RT-PCR and Western Blot (WB) methods and decreased LC3-II by WB (ASH annual meeting poster 2018) in peripheral blood mononuclear cells. Now, we further performed immunohistochemical staining of these autophagy markers on the bone marrow biopsy specimens. Methods: Formalin-fixed and paraffin-embedded bone marrow samples were stained with primary antibodies against Beclin-1 (mouse monoclonal, Millipore), LC3B (rabbit monoclonal, Cell Signaling Technology), and p62 (mouse monoclonal, Cell Signaling Technology). The tissue sections were analyzed using VENTANA BenchMark Ultra System (Ventana Medical Systems, Inc.) according to the manufacturer's protocol. Patients who were studied included 12 essential thrombocythemia (ET), 10 polycythemia (PV), and 5 myelofibrosis (MF) (including 1 post-ET MF and 1 post-PV MF). Scoring was given based on the degree of cytoplasmic staining. Score 1 included weak cytoplasmic stain, score 2 included moderate cytoplasmic stain and score 3 was given for strong cytoplasmic staining . Results: 1) As shown in Fig1, the predominant cells which stained positive including p62, Beclin-1 , or LC3 B were mostly found on the megakaryoctes, although very few of other cell types were found to have positive staining as well 2) As shown in Table 1, the immunostaining results were in general correlated to the RT-PCR , or western blot findings that a defective autophagy was demonstrated in MPN patients with combined finding of a stronger staining in p62,and weak staining in Beclin-1 and LC3B. Conclusion: We have demonstrated defective autophagy in these Ph (-) MPN, by immunostaining of the bone marrow specimens, and demonstrating positivity for defective autophagy predominantly in megakaryocytes. Since megakaryocytes are the most important cells involved in the pathogenesis of MPN, we propose that defective autophagy in megakaryocytes play an important role in the pathogenesis of these diseases. Disclosures Wang: Incyt: Research Funding.

The Lymphoproliferative Disease of Granular Lymphocytes: Updated Criteria for Diagnosis

Blood ◽  
1997 ◽  
Vol 89 (1) ◽  
pp. 256-260 ◽  
Author(s):  
Gianpietro Semenzato ◽  
Renato Zambello ◽  
Gordon Starkebaum ◽  
Kazuo Oshimi ◽  
Thomas P. Loughran
Keyword(s):  
T Cell Receptor ◽  
Mononuclear Cells ◽  
Cell Receptor ◽  
Absolute Number ◽  
Lymphoproliferative Disease ◽  
Peripheral Blood Mononuclear ◽  
Criteria For Diagnosis ◽  
Restricted Pattern ◽  
Granular Lymphocytes

Abstract The lymphoproliferative disease of granular lymphocytes (LDGL), also referred to as LGL leukemia, is a heterogeneous disorder, but is clinically, morphologically, and immunologically distinct. Although LDGL has recently been included in the revised classification of lymphomas as an independent clinical entity, no consensus exists on the criteria to establish the diagnosis. The aim of this report was to refine the parameters needed to make the diagnosis of LDGL. We studied 11 patients with chronic granular lymphocytosis selected from among 195 cases observed by our institutions from three different geographic areas (North America, Europe, and Asia). These cases did not meet the current criteria for inclusion in LDGL, since all patients had less than 2,000 GL/μL. However, in each of these patients, we found evidence for expansion of a discrete GL population. Clonal rearrangement of the T-cell receptor (TCR) β gene was found in peripheral blood mononuclear cells (PBMC) of all nine patients with CD3+ LDGL. Using recently generated monoclonal antibodies (MoAbs) against the TCR Vβ gene regions, we identified a unique TCR Vβ on GL from each of three patients studied. In two patients with CD3− LDGL, we also identified a restricted pattern of reactivity, by staining with MoAbs against p58 antigen found on normal natural killer (NK) cells. The clinical features of these 11 patients with relatively low absolute number of GL were similar to those reported previously for patients with greater than 2,000 GL/μL. These data demonstrate that newer techniques such as MoAbs against Vβ gene regions and p58 molecules and molecular analyses are useful to identify expansions of discrete GL proliferations. Demonstration of an expansion of a restricted GL subset is evidence for the diagnosis of LDGL, even in patients with a relatively low GL count. Our results also contribute to distinguish between the end of normality and the beginning of pathology in the broad spectrum of GL lymphocytoses.

Acquired DNA mutations associated with in vivo hydroxyurea exposure

Blood ◽  
2000 ◽  
Vol 95 (11) ◽  
pp. 3589-3593 ◽  
Author(s):  
Valerie N. Hanft ◽  
Steven R. Fruchtman ◽  
Chrisley V. Pickens ◽  
Wendell F. Rosse ◽  
Thad A. Howard ◽  
...  
Keyword(s):  
Mononuclear Cells ◽  
Young Patients ◽  
Myeloproliferative Disorders ◽  
Cell Receptor ◽  
Hypoxanthine Phosphoribosyl Transferase ◽  
Peripheral Blood Mononuclear ◽  
Dna Mutations ◽  
Carcinogenic Potential ◽  
Increased Risk

Abstract Hydroxyurea (HU) is an effective therapeutic agent for patients with myeloproliferative disorders (MPDs) or sickle cell disease (SCD). Short-term HU toxicities primarily include transient myelosuppression, but long-term HU risks have not been defined. The mutagenic and carcinogenic potential of HU is not established, although HU has been associated with an increased risk of leukemia in some patients with MPD. In this study, 2 assays were used to quantitate acquired somatic DNA mutations in peripheral blood mononuclear cells (PBMCs) after in vivo HU exposure. The HPRT assay measures hypoxanthine phosphoribosyl transferase (hprt) mutations, while the VDJ assay identifies “illegitimate” T-cell receptor Vγ-Jβ interlocus recombination events. PBMCs were analyzed from patients with MPD, adults and children with SCD, and normal controls. MPD patients with prolonged HU exposure had numbers of DNA mutations equivalent to patients with low HU exposure or controls. Similarly, adults with SCD had equivalent numbers of DNA mutations regardless of HU exposure. Children with SCD and 30-month HU exposure had equivalenthprt− mutations but significantly more VDJ mutations (1.82 ± 1.20 events per μg DNA) than children with 7-month HU exposure (1.58 ± 0.87 events) or no HU exposure (1.06 ± 0.45 events), P = .04 by analysis of variance. Taken together, these data suggest that the mutagenic and carcinogenic potential of in vivo HU therapy is low. Although increased numbers of illegitimate VDJ recombination events do not directly portend leukemia, young patients with SCD and HU exposure should be monitored serially for increases in DNA mutations.

T-cell receptor V-gene usage in neoplasms of the central nervous system

1993 ◽  
Vol 78 (4) ◽  
pp. 630-637 ◽  
Author(s):  
Adrian Merlo ◽  
Luis Filgueira ◽  
Markus Zuber ◽  
Antonio Juretic ◽  
Felix Harder ◽  
...  
Keyword(s):  
T Cell ◽  
T Cell Receptor ◽  
Peripheral Blood Mononuclear Cells ◽  
Peripheral Blood ◽  
Mononuclear Cells ◽  
Tumor Infiltrating Lymphocytes ◽  
Cell Receptor ◽  
Gene Products ◽  
Peripheral Blood Mononuclear ◽  
Infiltrating Lymphocytes

✓ The use of tumor-infiltrating lymphocytes in the treatment of central nervous system (CNS) neoplasms has met with serious obstacles due to difficulty of culture and poor characterization. Since in other tumors the therapeutic effects of tumor-infiltrating lymphocytes have been shown to rely on T-cell receptor engagement, the authors addressed the question as to whether expression of T-cell receptor variable (V) domains in cultured tumor-infiltrating lymphocytes from CNS is different from that of autologous cultured peripheral blood mononuclear cells. Infiltrating lymphocytes from CNS neoplasms, including primary malignancies, metastatic cancers, and meningiomas, were cultured in the presence of interleukin-2 and anti-CD3 monoclonal antibodies (MoAb's) in order to obtain optimum growth of T cells. Autologous peripheral blood mononuclear cells from the same patients were similarly cultured. After 4 to 5 weeks of culture, 97.3% ± 2.6% (mean ± standard deviation) of the resulting cell populations were CD3-positive lymphocytes. The expression of T-cell receptor V domains was then studied by using a panel of 12 MoAb recognizing gene products from T-cell receptor V-α 2, V-β 5, 6, 8, and 12, V-γ 4 and 9 families, and from two subfamilies of V-δ 2. Remarkably, in over 70% of all paired measurements, percentages of T cells expressing discrete T-cell receptor V-gene products were found to be virtually identical in tumor- and peripheral blood-derived cultured cell populations, with differences never exceeding 1%. In contrast, a different expression of individual V-gene products, concerning both α/β and γ/δ T-cell receptors, could be detected between cultured tumor-infiltrating lymphocytes and autologous peripheral blood-derived T lymphocytes in seven of 12 patients. In two cases, significant differences between the two populations were also observed in the proliferative responses obtained upon stimulation with staphylococcal enterotoxins that trigger defined V-β T-cell receptors. Altogether, these data suggest that the T-cell receptor repertoire of cultured tumor-infiltrating lymphocytes from CNS tumors, suitable for use in adoptive immunotherapies, differs from that of autologous cultured peripheral blood mononuclear cells.

scholarly journals Transcriptomic Profiling of Tumor-Infiltrating CD4+TIM-3+ T Cells Reveals Their Suppressive, Exhausted, and Metastatic Characteristics in Colorectal Cancer Patients

Vaccines ◽  
2020 ◽  
Vol 8 (1) ◽  
pp. 71 ◽  
Author(s):  
Varun Sasidharan Nair ◽  
Salman M Toor ◽  
Rowaida Z Taha ◽  
Ayman A Ahmed ◽  
Mohamed A Kurer ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
T Cells ◽  
T Cell ◽  
Mononuclear Cells ◽  
T Regulatory Cell ◽  
Peripheral Blood Mononuclear ◽  
Functional Studies ◽  
Normal Tissues ◽  
Pathway Analyses ◽  
Colorectal Cancer Patients

T cell immunoglobulin mucin-3 (TIM-3) is an immune checkpoint identified as one of the key players in regulating T-cell responses. Studies have shown that TIM-3 is upregulated in the tumor microenvironment (TME). However, the precise role of TIM-3 in colorectal cancer (CRC) TME is yet to be elucidated. We performed phenotypic and molecular characterization of TIM-3+ T cells in the TME and circulation of CRC patients by analyzing tumor tissues (TT, TILs), normal tissues (NT, NILs), and peripheral blood mononuclear cells (PBMC). TIM-3 was upregulated on both CD4+ and CD3+CD4− (CD8+) TILs. CD4+TIM-3+ TILs expressed higher levels of T regulatory cell (Tregs)-signature genes, including FoxP3 and Helios, compared with their TIM-3− counterparts. Transcriptomic and ingenuity pathway analyses showed that TIM-3 potentially activates inflammatory and tumor metastatic pathways. Moreover, NF-κB-mediated transcription factors were upregulated in CD4+TIM-3+ TILs, which could favor proliferation/invasion and induce inflammatory and T-cell exhaustion pathways. In addition, we found that CD4+TIM-3+ TILs potentially support tumor invasion and metastasis, compared with conventional CD4+CD25+ Tregs in the CRC TME. However, functional studies are warranted to support these findings. In conclusion, this study discloses some of the functional pathways of TIM-3+ TILs, which could improve their targeting in more specific therapeutic approaches in CRC patients.

scholarly journals Characterization of the T-Cell Receptor Vβ Repertoire in the Human Immune Response against Leishmania Parasites

2006 ◽  
Vol 74 (8) ◽  
pp. 4757-4765 ◽  
Author(s):  
Jorge Clarêncio ◽  
Camila I. de Oliveira ◽  
Glória Bomfim ◽  
Margarida M. Pompeu ◽  
Maria Jania Teixeira ◽  
...  
Keyword(s):  
T Cell ◽  
T Cell Activation ◽  
Cell Activation ◽  
Mononuclear Cells ◽  
Cell Receptor ◽  
Peripheral Blood Mononuclear ◽  
Cell Clones ◽  
Human Immune Response ◽  
Lymph Node Cells

ABSTRACT In order to explore a possible presence of hyperreactive T-cell clones in human cutaneous leishmaniasis (CL), we have investigated, by flow cytometry, the expression of Vβ chains of T-cell receptors (TCRs) in the following types of cells: (i) peripheral blood mononuclear cells (PBMCs) from CL patients, which were then compared to those from normal volunteers; (ii) unstimulated and soluble Leishmania antigen-stimulated draining lymph node cells from CL patients; (iii) PBMCs from volunteers before versus after Leishmania immunization; and (iv) PBMCs from healthy volunteers that were primed in vitro with live Leishmania parasites. Our results show a modulation in the TCR Vβ repertoire during CL and after antigen stimulation of patients' cells. Vaccination, however, leads to a broad expansion of different Vβ TCRs. We also observed an association between TCR Vβ12 expression, T-cell activation, and gamma interferon production upon in vitro priming with Leishmania. Collectively, these results both indicate that infection with live parasites or exposure to parasite antigen can modulate the TCR Vβ repertoire and suggest that TCR Vβ12 may be implicated in the response to Leishmania.

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