HeberNasvac, a Therapeutic Vaccine for Chronic Hepatitis B, Stimulates Local and Systemic Markers of Innate Immunity: Potential Use in SARS-CoV-2 Postexposure Prophylaxis.

INTRODUCTION: More than 180 million people have been infected by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and more than 4 million coronavirus disease-2019 (COVID-19) patients have died in 1.5 years of the pandemic. A novel therapeutic vaccine (NASVAC) has shown to be safe and to have immunomodulating and antiviral properties against chronic hepatitis B (CHB). MATERIALS AND METHODS: A phase I/II, open-label controlled and randomized clinical trial of NASVAC as a postexposure prophylaxis treatment was designed with the primary aim of assessing the local and systemic immunomodulatory effect of NASVAC in a cohort of suspected and SARS-CoV-2 risk-contact patients. A total of 46 patients, of both sexes, 60 years or older, presenting with symptoms of COVID-19 were enrolled in the study. Patients received NASVAC (100 µg per Ag per dose) via intranasal at days 1, 7, and 14 and sublingual, daily for 14 days. RESULTS AND DISCUSSION: The present study detected an increased expression of toll-like receptors (TLR)-related genes in nasopharyngeal tonsils, a relevant property considering these are surrogate markers of SARS protection in the mice model of lethal infection. The HLA-class II increased their expression in peripheral blood mononuclear cell's (PBMC's) monocytes and lymphocytes, which is an attractive property taking into account the functional impairment of innate immune cells from the periphery of COVID-19-infected subjects. NASVAC was safe and well tolerated by the patients with acute respiratory infections and evidenced a preliminary reduction in the number of days with symptoms that needs to be confirmed in larger studies. CONCLUSIONS: Our data justify the use of NASVAC as preemptive therapy or pre-/postexposure prophylaxis of SARS-CoV-2 and acute respiratory infections in general. The use of NASVAC or their active principles has potential as immunomodulatory prophylactic therapies in other antiviral settings like dengue as well as in malignancies like hepatocellular carcinoma where these markers have shown relation to disease progression. HOW TO CITE THIS ARTICLE: Fleites YA, Aguiar J, Cinza Z, et al. HeberNasvac, a Therapeutic Vaccine for Chronic Hepatitis B, Stimulates Local and Systemic Markers of Innate Immunity: Potential Use in SARS-CoV-2 Postexposure Prophylaxis. Euroasian J Hepato-Gastroenterol 2021;11(2):59-70.

Desarrollo de un péptido cíclico marcado con 99mTc dirigido contra el receptor de la vitronectina / Development of a 99mTc-labeled cyclic peptide with affinity for the vitronectine receptor

El objetivo del presente trabajo fue desarrollar un péptido híbrido, que presente una secuencia capaz de quelatar al 99mTc y otra con afinidad por el receptor de la vitronectina, que permita la detección in vivo de tumores malignos. El marcaje del péptido PICIC3 con 99mTc se realizó de forma directa. Se estudió la estabilidad del complejo en exceso de L-cisteína y en plasma, la unión a proteínas plasmáticas, el coeficiente de partición en el sistema NaCl 0.9 por ciento:n-octanol, la carga del complejo mediante electroforesis y la afinidad por el receptor de la vitronectina se valoró a partir de un ensayo de saturación con membranas de células B16-F10. Se determinó la biodistribución en ratones C57BL/6 con injertos de melanoma B16-F10. Conclusiones: El péptido desarrollado mostró una afinidad satisfactoria por el receptor de la vitronectina y que permitió la detección in vivo de los melanomas múridos del tipo B16-F10 en los ratones injertados.

The aim of the present work was to develop a hybrid peptide, with a sequence for the chelation of 99mTc and other with affinity for the vitronectine receptor, to allow in vivo detection of malignant tumors. 99mTc-labeling of peptide PICIC3 was directly performed. The stability in presence of L-cysteine excess and plasma of the complex, its binding to plasma proteins, the partition coefficient in NaCl 0.9 percent:n-octanol, the charge of the chelate by electrophoresis and the peptide affinity for the vitronectine receptor by a saturation assay using membranes of B16-F10 cells, were studied. Biodistribution in C57BL/6 mice injerted with melanoma B16-F10 was assessed. Conclusions: Developed peptide showed a satisfactory affinity for the vitronectine receptor and allowed in vivo detection of murine melanomas in mice with allografts.

Biologically active vascular endothelial growth factor as a bacterial recombinant glutathione S-transferase fusion protein.

Human VEGF121 (vascular endothelial growth factor isoform 121) was produced as a recombinant fusion protein with GST (glutathione S-transferase) in Escherichia coli. After affinity purification with glutathione, the GST-VEGF121 fusion protein preparation was used to obtain antibodies in mice against commercial hrVEGF (human recombinant VEGF) through immunization. It was also employed successfully to select specific antihuman VEGF antibody fragments of human origin employing phage-display technology. The fusion protein preparation was separated in monomeric, dimeric and oligomeric forms using size-exclusion chromatography. The dimers were recognized by a soluble VEGF receptor 2-Fc chimaera, and stimulated the growth of human umbilical-vein endothelial cells in vitro in a similar fashion to a commercial hrVEGF. The presence of GST in the fusion protein apparently did not affect the correct assembly of dimers and display of residues critical for receptor recognition. The two-step purification method reported in the present paper involves no laborious renaturalization methods, yields 10 mg/l of the mixture of different aggregation states after affinity chromatography, and 5 mg/l of the biologically active dimer after gel filtration, thus providing a source of material for the development of new anti-angiogenic therapeutic molecules.

A multivalent recombinant antibody fragment specific for carcinoembryonic antigen.

In the present paper we report the development of a bivalent scFv (single-chain Fv) antibody fragment, starting from a mouse mAb (monoclonal antibody) specific for CEA (carcinoembryonic antigen) that has received approval for in vivo radioimmunodiagnosis in humans. The diabody is well expressed in Escherichia coli, is easily purified by a combination of immobilized metal ion affinity chromatography and gel filtration and exhibits high affinity and specificity for CEA, comparable with those of the original mAb. Biodistribution experiments in athymic nude mice transplanted with human CEA+ cancer cells showed that the 125I-labelled diabody preferentially localizes in the tumour tissue and that retention is still high 48 h after injection. The diabody can be advantageous for some in vivo tumour targeting applications, due to the faster clearance derived from its smaller molecular mass.