A multiclade env-gag VLP mRNA vaccine elicits tier-2 HIV-1-neutralizing antibodies and reduces the risk of heterologous SHIV infection in macaques.

The development of a protective vaccine remains a top priority for the control of the HIV/AIDS pandemic. Here, we show that a messenger RNA (mRNA) vaccine co-expressing membrane-anchored HIV-1 envelope (Env) and simian immunodeficiency virus (SIV) Gag proteins to generate virus-like particles (VLPs) induces antibodies capable of broad neutralization and reduces the risk of infection in rhesus macaques. In mice, immunization with co-formulated env and gag mRNAs was superior to env mRNA alone in inducing neutralizing antibodies.

Functional Anatomy of the Trimer Apex Reveals Key Hydrophobic Constraints That Maintain the HIV-1 Envelope Spike in a Closed State.

The human immunodeficiency virus type 1 (HIV-1) envelope trimer maintains a closed, metastable configuration to protect vulnerable epitopes from neutralizing antibodies. Here, we identify key hydrophobic constraints at the trimer apex that function as global stabilizers of the HIV-1 envelope spike configuration. Mutation of individual residues within four hydrophobic clusters that fasten together the V1V2, V3, and C4 domains at the apex of gp120 dramatically increases HIV-1 sensitivity to weak and restricted neutralizing antibodies targeting epitopes that are largely concealed in the prefusion Env spike, consistent with the adoption of a partially open trimer configuration.

Combating viral contaminants in CHO cells by engineering innate immunity.

Viral contamination in biopharmaceutical manufacturing can lead to shortages in the supply of critical therapeutics. To facilitate the protection of bioprocesses, we explored the basis for the susceptibility of CHO cells to RNA virus infection. Upon infection with certain ssRNA and dsRNA viruses, CHO cells fail to generate a significant interferon (IFN) response.

Structural Constraints at the Trimer Apex Stabilize the HIV-1 Envelope in a Closed, Antibody-Protected Conformation.

The human immunodeficiency virus type 1 (HIV-1) envelope (Env) trimer evades antibody recognition by adopting a closed prefusion conformation. Here, we show that two conserved tyrosines (Y173, Y177) within the second variable (V2) loop of the gp120 Env glycoprotein are key regulators of the closed, antibody-protected state of the trimer by establishing intramolecular interaction with the base of the third variable (V3) loop. Mutation of Y177 and/or Y173 to phenylalanine or alanine dramatically altered the susceptibility of diverse HIV-1 strains to neutralization, increasing sensitivity to weakly and nonneutralizing antibodies directed against diverse Env regions, consistent with the adoption of an open trimer configuration.

(), an Interferon-Stimulated Gene with Antiviral Activity against Dengue Virus, Interacts with MOV10.

Dengue virus (DENV) is a member of the genus and can cause severe febrile illness. Here, we show that FLJ11286, which we refer to as IRAV, is induced by DENV in an interferon-dependent manner, displays antiviral activity against DENV, and localizes to the DENV replication complex. IRAV is an RNA binding protein and localizes to cytoplasmic processing bodies (P bodies) in uninfected cells, where it interacts with the MOV10 RISC complex RNA helicase, suggesting a role for IRAV in the processing of viral RNA.

New function of type I IFN: induction of autophagy.

Autophagy is a highly conserved cellular process responsible for recycling of intracellular material. It is induced by different stress signals, including starvation, cytokines, and pathogens. Type I interferons (IFN) are proteins with pleiotropic functions, such as antiviral, antiproliferative, and immunomodulatory activities.

Nucleolin interacts with the dengue virus capsid protein and plays a role in formation of infectious virus particles.

Dengue virus (DENV) is a mosquito-transmitted flavivirus that can cause severe disease in humans and is considered a reemerging pathogen of significant importance to public health. The DENV capsid (C) protein functions as a structural component of the infectious virion; however, it may have additional functions in the virus replicative cycle. Here, we show that the DENV C protein interacts and colocalizes with the multifunctional host protein nucleolin (NCL).

Type I interferons induce autophagy in certain human cancer cell lines.

Autophagy is an evolutionarily conserved cellular recycling mechanism that occurs at a basal level in all cells. It can be further induced by various stimuli including starvation, hypoxia, and treatment with cytokines such as IFNG/IFNγ and TGFB/TGFβ. Type I IFNs are proteins that induce an antiviral state in cells.

Structural variants of IFNα preferentially promote antiviral functions.

IFNα, a cytokine with multiple functions in innate and adaptive immunity and a potent inhibitor of HIV, exerts antiviral activity, in part, by enhancing apolipoprotein B mRNA-editing enzyme-catalytic polypeptide-like 3 (APOBEC3) family members. Although IFNα therapy is associated with reduced viral burden, this cytokine also mediates immune dysfunction and toxicities. Through detailed mapping of IFNα receptor binding sites, we generated IFNα hybrids and mutants and determined that structural changes in the C-helix alter the ability of IFN to limit retroviral activity.

Near eradication of clinically relevant concentrations of human tumor cells by interferon-activated monocytes in vitro.

We have previously reported that low concentrations of interferon (IFN)-activated monocytes exert near-eradicative cytocidal activity against low concentrations of several human tumor cells in vitro. In the present study, we examined 7 human tumor cell lines and 3 diploid lines in the presence or absence of 10 ng/mL IFNα2a and monocytes. The results confirmed strong cytocidal activity against 4 of 7 tumor lines but none against 3 diploid lines.

A novel role for IFN-stimulated gene factor 3II in IFN-γ signaling and induction of antiviral activity in human cells.

Type I (e.g., IFN-α, IFN-β) and type II IFNs (IFN-γ) have antiviral, antiproliferative, and immunomodulatory properties.

A set of aspartyl protease-deficient strains for improved expression of heterologous proteins in Kluyveromyces lactis.

Secretion of recombinant proteins is a common strategy for heterologous protein expression using the yeast Kluyveromyces lactis. However, a common problem is degradation of a target recombinant protein by secretory pathway aspartyl proteases. In this study, we identified five putative pfam00026 aspartyl proteases encoded by the K.

IRF9 is a key factor for eliciting the antiproliferative activity of IFN-alpha.

A number of tumors are still resistant to the antiproliferative activity of human interferon (IFN)-alpha. The Janus kinases/Signal Transducers and Activators of Transcription (JAK-STAT) pathway plays an important role in initial IFN signaling. To enhance the antiproliferative activity of IFN-alpha, it is important to elucidate which factors in the JAK-STAT pathway play a key role in eliciting this activity.

Two interferons alpha influence each other during their interaction with the extracellular domain of human type interferon receptor subunit 2.

The interaction between two human interferons alpha (IFN-alphas) and the extracellular (EC) domain of human type I IFN receptor subunit 2 (IFNAR2) was analyzed. Previous experiments using Daudi cells showed that IFN-alpha21b and some IFN-alpha hybrids (made from IFN-alpha2c and 21b) competed poorly for the IFN-alpha2b binding site. This study examined the causes of the poor competition between these IFN-alphas.

Binding Characteristics of IFN-alpha Subvariants to IFNAR2-EC and Influence of the 6-Histidine Tag.

The expression, purification, detection, and assay of recombinant proteins have been made more convenient and rapid by the use of small affinity tags. To facilitate the purification of interferon-alpha2c (IFN-alpha2c) by metal chelate affinity chromatography, N-terminal 6-histidine tag was introduced via genetic manipulation. Two preparations of IFN material were purified; one contained IFN-alpha2c with the 6-histidine tag, and the other contained IFN-alpha2c without the 6-histidine tag.

Human interferons alpha, beta and omega.

Type I interferons (IFNs), IFN-alpha, IFN-beta, IFN-omega, IFN-delta and IFN-tau are a family of structurally related, species-specific proteins found only in vertebrates. They exhibit a variety of biological functions, including antiviral, antiproliferative, immunomodulatory and developmental activities. Human Type I IFNs interact with the human IFN alpha receptor (IFNAR), which is composed of two identified subunits (IFNAR-1 and IFNAR-2).

Incidence of autoantibodies against type I and type II interferons in a cohort of systemic lupus erythematosus patients in Slovakia.

Autoantibodies against interferon (IFN) can be found in patients with systemic lupus erythematosus (SLE). However, detailed information about the occurrence of type-specific antihuman IFN antibodies is not available. In this study, we investigated the incidence of autoantibodies specifically recognizing various type I IFNs (alpha1, alpha2, beta, omega) and type II IFN (gamma).

Amino acid substitutions in loop BC and helix C affect antigenic properties of helix D in hybrid IFN-alpha21a/alpha2c molecules.

We compared the antigenic properties of human interferon-alpha2c (IFN-alpha2c), IFN-alpha21a, hybrids IFN-alpha21a/alpha2c, and their mutants, using a panel of 27 anti-IFN-alpha1, anti-IFN-alpha2, and anti-IFN-alpha8/1/8 monoclonal antibodies (mAb). After immunoanalysis by ELISA, we found parental IFN-alpha2c and IFN-alpha21a to be antigenically distinct. Lack of reactivity of anti-IFN-alpha1 mAb with IFN-alpha21a indicated an antigenic distinction between subtypes alpha1 and alpha21a.