Human-derived virus-like particles (heVLPs), comprising a membrane comprising a phospholipid bilayer with one or more HERV-derived envelope proteins on the external side; one or more HERV-derived GAG proteins in the heVLP core, and a cargo molecule, e.g., a biomolecule and/or chemical cargo molecule, disposed in the core of the heVLP on the inside of the membrane, wherein the heVLP does not comprise a gag protein, except for gag proteins that are encoded in the human genome or gag proteins that are encoded by a consensus sequence that is derived from gag proteins found in the human genome, and methods of use thereof for delivery of the cargo molecule to cells.

The present invention provides a virus-like particle (VLP) having a viral envelope which comprises: (i) a membrane protein comprising the extracellular domain of CD86; and (ii) a CD3-binding membrane protein. The VLP may be used to activate T cells prior to viral transduction.

Type-C endogenous retroviruses (ERVs) embedded in Chinese hamster ovary (CHO) cells were altered to modify the release of retroviral and/or retroviral-like particles in the culture supernatant. Although evidence for the infectivity of these particles is missing, their presence has raised safety concerns. 173 type-C ERV sequences that clustered into functionally conserved groups were identified. Transcripts from one type-C ERV group were identified to be full-length with intact open reading frames, and to have corresponding viral RNA genomes that were loaded into retroviral-like particles. Also, sequence analysis of the genomic RNA from viral particles indicated that they may result from few expressed ERV sequences. Disclosed herein is the disruption/alteration of the gag gene of the expressed ERV group using CRISPR-Cas9 genome editing. Comparison of CRISPR-derived mutations at the DNA and mRNA level led to the identification of a single ERV locus responsible for the release of viral RNA-loaded particles from CHO cells. Clones bearing a Gag loss-of-function mutation in this particular ERV locus showed a reduction of viral RNA-containing particles in the cell supernatant by over 250-fold. Notably, ERV mutagenesis did not compromise cell growth, cell size or recombinant protein production. Provided herein is a new strategy and cells, in particular engineered CHO cells, to mitigate potential contaminations from CHO endogenous retroviruses during biopharmaceutical manufacturing.

The present invention relates to a virus-derived particle comprising one or more Cas protein(s), as well as to kits and methods using the same for altering a target nucleic acid.

Disclosed herein are virus-like particle (VLP)-based bivalent vaccine compositions. The compositions may comprise a spherical retroviral Group—specific Antigen (“Gag”) protein core and at least two Ebola glycoproteins. The at least two Ebola glycoproteins may be located at the exterior surface of the spherical Gag protein core, such that the VLP-based vaccine presents at least two Ebola glycoprotein antigens. In one aspect, the at least two Ebola glycoproteins are a Zaire (EBOV) glycoprotein, and a Sudan (SUDV) glycoprotein.

Disclosed are recombinant Arc capsids. Disclosed are vectors comprising a nucleic acid sequence capable of encoding an Arc protein. Disclosed are cells comprising vectors comprising a nucleic acid sequence capable of encoding an Arc protein. Disclosed are methods of delivering mRNA to a cell comprising administering an Arc capsid to a cell, wherein the Arc capsid comprises an mRNA of interest. Disclosed are methods of delivering mRNA to a cell comprising administering any one of the disclosed vectors to a cell; and administering a mRNA of interest to the cell; wherein the nucleic acid sequence encodes an Arc protein within the cell and Arc capsids are formed, wherein the Arc capsids encapsulate the mRNA of interest. Disclosed are methods of forming Arc capsids comprising administering a vector comprising a nucleic acid sequence capable of encoding an Arc protein to a solution comprising cells, wherein the nucleic acid sequence encodes an Arc protein within the cells and Arc capsids are formed.

The present invention relates to a stock solution (RLP Stock Solution) of mammalian cell-endogenous retrovirus like particles (RLP), a method of preparing a RLP stock solution, a kit containing a RLP stock solution, and a method of quantifying the amount of RLP removed from a solution. An RLP stock solution will contain a high concentration of RLP and an extremely low amount of any therapeutic proteins of interest. In some instances, an RLP stock solution will contain a very low amount of natural mammalian host cell protein (HCP) and DNA. The method of preparing a RLP stock solution will consist of the production of RLP during fermentation or cell culturing and the subsequent purification of RLP from fermentation or cell culture solution. The kit will comprise at least two containers. One container comprised of RLP stock solution and one comprised of PCR primers or one or more antibodies. The method of quantifying RLP comprises the steps of adding RLP stock solution to an in-process solution containing a recombinant therapeutic of interest, processing the resulting solution through a bioprocess purification technique, and then quantifying the amount of RLP removed.

The present invention relates to a virus-derived particle comprising one or more Cas protein(s), as well as to kits and methods using the same for altering a target nucleic acid.

The present invention relates to methods and kits for detecting in a sample the presence of a virus particle or a virus-like particle that has reverse transcriptase activity and methods for preparing a retroviral contaminant-free substance. An aspect of the present invention is a method for detecting the presence of a virus particle in a sample of a Virus-like Particle (VLP) drug substance comprising a step of performing PCR-based reverse transcriptase (PBRT) on a sample of the VLP drug substance that has been treated with a protease.

The present invention relates to an adenoviral vector capable of encoding a virus-like particle (VLP), said VLP displaying an inactive immune-suppressive domain (ISD). The vaccine of the invention shows an improved immune response from either of both of the response pathways initiated by CD4 T cells or CD8 T cells.