Design and nonviral delivery of live attenuated vaccine to prevent chronic hepatitis C virus-like infection.

An effective vaccine for the hepatitis C virus (HCV) remains an unmet medical need. There is no animal model for assessing HCV vaccines; however, rodent hepacivirus (RHV) infection in laboratory rats recapitulates the lifelong chronic hepatotropic infection and immune evasion of HCV. Here, we designed a live-attenuated vaccine (LAV) for RHV and determined its immunogenicity and efficacy for preventing chronic infection.

Hyperfunctional T cell responses unchecked by regulatory T cells are unable to resolve hepaciviral infection without humoral contribution.

Background & Aims: The most recent T cell-based vaccine against HCV tested in humans failed to swing the pendulum from chronicity to resolution, despite eliciting cellular responses in most individuals. These results naturally evoke the question of whether hyperactivated responses of a single adaptive immune arm are capable of inducing HCV clearance or if coordinated efforts between antibodies and T cells are indeed necessary. Here, we sought to address this point in determining whether the suppression of antiviral T cell and IgG responses by regulatory T cells (Tregs) is a critical prerequisite of delayed viral clearance or overt chronicity.

Concerted synergy between viral-specific IgG and CD8 + T cells is critical for clearance of an HCV-related rodent hepacivirus.

Background And Aims: Evidence assessing the role of B cells and their antibodies, or lack thereof, in the spontaneous resolution of acute HCV infection is conflicting. Utilization of a strictly hepatotropic, HCV-related rodent hepacivirus (RHV) model circumvents many of the challenges facing the field in characterizing the immunological correlates of dichotomous infection outcomes. This study seeks to elucidate the importance of B cells in the clearance of acute RHV infection.

Phenotype and fate of liver-resident CD8 T cells during acute and chronic hepacivirus infection.

Immune correlates of hepatitis C virus (HCV) clearance and control remain poorly defined due to the lack of an informative animal model. We recently described acute and chronic rodent HCV-like virus (RHV) infections in lab mice. Here, we developed MHC class I and class II tetramers to characterize the serial changes in RHV-specific CD8 and CD4 T cells during acute and chronic infection in C57BL/6J mice.

Immunization with Recombinant Accessory Protein-Deficient SARS-CoV-2 Protects against Lethal Challenge and Viral Transmission.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has led to a worldwide coronavirus disease 2019 (COVID-19) pandemic. Despite the high efficacy of the authorized vaccines, there may be uncertain and unknown side effects or disadvantages associated with current vaccination approaches. Live-attenuated vaccines (LAVs) have been shown to elicit robust and long-term protection by the induction of host innate and adaptive immune responses.

Recombinant measles virus expressing prefusion spike protein stabilized by six rather than two prolines is more efficacious against SARS-CoV-2 infection.

Measles virus (MeV) has been an excellent vector platform for delivering vaccines against many pathogens because of its high safety and efficacy, and induction of long-lived immunity. Early in the COVID-19 pandemic, a recombinant MeV (rMeV) expressing the prefusion full-length spike protein stabilized by two prolines (TMV-083) was developed and tested in phase 1 and 1/2 clinical trials but was discontinued because of insufficient immunogenicity and a low seroconversion rate in adults. Here, we compared the immunogenicity of rMeV expressing a soluble prefusion spike (preS) protein stabilized by two prolines (rMeV-preS-2P) with a rMeV expressing a soluble preS protein stabilized by six prolines (rMeV-preS-6P).

CD8 T cells contribute to diet-induced memory deficits in aged male rats.

We have previously shown that short-term (3-day) high fat diet (HFD) consumption induces a neuroinflammatory response and subsequent impairment of long-term memory in aged, but not young adult, male rats. However, the immune cell phenotypes driving this proinflammatory response are not well understood. Previously, we showed that microglia isolated from young and aged rats fed a HFD express similar levels of priming and proinflammatory transcripts, suggesting that additional factors may drive the exaggerated neuroinflammatory response selectively observed in aged HFD-fed rats.

SARS-CoV-2 prefusion spike protein stabilized by six rather than two prolines is more potent for inducing antibodies that neutralize viral variants of concern.

The spike (S) protein of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the main target for neutralizing antibodies (NAbs). The S protein trimer is anchored in the virion membrane in its prefusion (preS) but metastable form. The preS protein has been stabilized by introducing two or six proline substitutions, to generate stabilized, soluble 2P or HexaPro (6P) preS proteins.

A highly efficacious live attenuated mumps virus-based SARS-CoV-2 vaccine candidate expressing a six-proline stabilized prefusion spike.

With the rapid increase in SARS-CoV-2 cases in children, a safe and effective vaccine for this population is urgently needed. The MMR (measles/mumps/rubella) vaccine has been one of the safest and most effective human vaccines used in infants and children since the 1960s. Here, we developed live attenuated recombinant mumps virus (rMuV)-based SARS-CoV-2 vaccine candidates using the MuV Jeryl Lynn (JL2) vaccine strain backbone.

A Methyltransferase-Defective Vesicular Stomatitis Virus-Based SARS-CoV-2 Vaccine Candidate Provides Complete Protection against SARS-CoV-2 Infection in Hamsters.

The current pandemic of coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has led to dramatic economic and health burdens. Although the worldwide SARS-CoV-2 vaccination campaign has begun, exploration of other vaccine candidates is needed due to uncertainties with the current approved vaccines, such as durability of protection, cross-protection against variant strains, and costs of long-term production and storage. In this study, we developed a methyltransferase-defective recombinant vesicular stomatitis virus (mtdVSV)-based SARS-CoV-2 vaccine candidate.

Adenovirus-vectored T cell vaccine for hepacivirus shows reduced effectiveness against a CD8 T cell escape variant in rats.

There is an urgent need for a vaccine to prevent chronic infection by hepatitis C virus (HCV) and its many genetic variants. The first human vaccine trial, using recombinant viral vectors that stimulate pan-genotypic T cell responses against HCV non-structural proteins, failed to demonstrate efficacy despite significant preclinical promise. Understanding the factors that govern HCV T cell vaccine success is necessary for design of improved immunization strategies.

A safe and highly efficacious measles virus-based vaccine expressing SARS-CoV-2 stabilized prefusion spike.

The current pandemic of COVID-19 caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) highlights an urgent need to develop a safe, efficacious, and durable vaccine. Using a measles virus (rMeV) vaccine strain as the backbone, we developed a series of recombinant attenuated vaccine candidates expressing various forms of the SARS-CoV-2 spike (S) protein and its receptor binding domain (RBD) and evaluated their efficacy in cotton rat, IFNARmice, IFNAR-hCD46 mice, and golden Syrian hamsters. We found that rMeV expressing stabilized prefusion S protein (rMeV-preS) was more potent in inducing SARS-CoV-2-specific neutralizing antibodies than rMeV expressing full-length S protein (rMeV-S), while the rMeVs expressing different lengths of RBD (rMeV-RBD) were the least potent.

Tumor secreted ANGPTL2 facilitates recruitment of neutrophils to the lung to promote lung pre-metastatic niche formation and targeting ANGPTL2 signaling affects metastatic disease.

The pre-metastatic niche (PMN) represents an abnormal microenvironment devoid of cancer cells, but favoring tumor growth. Little is known about the mechanisms that generate the PMN or their effects on host cells within metastasis-prone organs. Here, we investigated by using spontaneous metastatic models whether lung epithelial cells are essential for primary tumor induced neutrophil recruitment in lung and subsequently initiating PMN formation in osteosarcoma.

ΔNp73/ETS2 complex drives glioblastoma pathogenesis- targeting downstream mediators by rebastinib prolongs survival in preclinical models of glioblastoma.

Background: Glioblastoma (GBM) remains one of the least successfully treated cancers. It is essential to understand the basic biology of this lethal disease and investigate novel pharmacological targets to treat GBM. The aims of this study were to determine the biological consequences of elevated expression of ΔNp73, an N-terminal truncated isoform of TP73, and to evaluate targeting of its downstream mediators, the angiopoietin 1 (ANGPT1)/tunica interna endothelial cell kinase 2 (Tie2) axis, by using a highly potent, orally available small-molecule inhibitor (rebastinib) in GBM.

GD2-directed CAR-T cells in combination with HGF-targeted neutralizing antibody (AMG102) prevent primary tumor growth and metastasis in Ewing sarcoma.

Ewing sarcoma (EWS) is the second most common and aggressive type of metastatic bone tumor in adolescents and young adults. There is unmet medical need to develop and test novel pharmacological targets and novel therapies to treat EWS. Here, we found that EWS expresses high levels of a p53 isoform, delta133p53.

Vaccination to prevent T cell subversion can protect against persistent hepacivirus infection.

Efforts to develop an effective vaccine against the hepatitis C virus (HCV; human hepacivirus) have been stymied by a lack of small animal models. Here, we describe an experimental rat model of chronic HCV-related hepacivirus infection and its response to T cell immunization. Immune-competent rats challenged with a rodent hepacivirus (RHV) develop chronic viremia characterized by expansion of non-functional CD8 T cells.

Characterization of immunoreactive proteins of Setaria cervi isolated by preparative polyacrylamide gel electrophoresis.

Filarial parasites are complex mixtures of antigenic proteins and characterization of these antigenic molecules is essential to identify the diagnostically important filaria-specific antigens. In the present study, we have fractionated the somatic extracts from adults of Setaria cervi (bovine filarial parasite) on preparative SDS-polyacrylamide gel electrophoresis and tested the immunoreactivity of the separated gel fractions with polyclonal antibodies against filarial excretory-secretory antigens as well as filarial patients sera. The SDS-PAGE analysis of gel eluted fractions revealed 1 protein band in F-1 fraction, 2 protein bands in F-2 fraction and 2-3 protein bands in all other fractions (F3- F11).

Isolation and characterization of endochitinase and exochitinase of Setaria cervi.

Chitin metabolism has been shown to have a role in the development of parasitic nematodes including filarial parasites and the enzymes associated with chitin metabolism have been considered as potential vaccine and drug target. Chitinases are members of the enzyme superfamily of glycoside hydrolases, which are characterized by the ability to hydrolyze glycosidic bonds in chitin chain by either an endolytic or an exolytic mechanism. In the present study, we have demonstrated the chitinase (exochitinase and endochitinase) activity in different stages of Setaria cervi (bovine filarial parasite) and have also purified and characterized the endochitinase from microfilarial stage of the parasite.