Disclosed herein are non-human animals (e.g., rodents, e.g., mice or rats) genetically engineered to express a humanized T cell co-receptor (e.g., humanized CD4 and/or CD8 (e.g., CD8α and/or CD8β)), a human or humanized T cell receptor (TCR) comprising a variable domain encoded by at least one human TCR variable region gene segment and/or a human or humanized major histocompatibility complex that binds the humanized T cell co-receptor (e.g., human or humanized MHC II (e.g., MHC II α and/or MHC II β chains) and/or MHC I (e.g., MHC Iα) respectively, and optionally human or humanized β2 microglobulin). Also provided are embryos, tissues, and cells expressing the same. Methods for making a genetically engineered animal that expresses at least one humanized T cell co-receptor (e.g., humanized CD4 and/or CD8), at least one humanized MHC that associates with the humanized T cell co-receptor (e.g., humanized MHC II and/or MHC I, respectively) and/or the humanized TCR are also provided. Methods for using the genetically engineered animals that mount a substantially humanized T cell immune response for developing human therapeutics are also provided.

A non-human mammalian model for human diseases or disorders comprising a non-human neutrophil depleted mammalian host engrafted with a human skin equivalent (huSE) and human immune cells.

Provided are non-human animals, including humanized bone marrow/liver/thymus (BLT) non-human animals, that include a recipient immunodeficient animal with human thymus tissue and human liver tissue, both implanted under a kidney capsule of the recipient immunodeficient animal, and transplanted hematopoietic stem cells derived from a human liver tissue. Such non-human animals have human thymus tissue and human liver tissue that are autologous with the hematopoietic stem cells derived from the human liver tissue. Methods of making such BLT non-human animals are also provided. Also disclosed herein are human immune system non-human animals and methods of making the same.

Provided is a modified double-stranded oligonucleotide, in which the sense strand comprises a nucleotide sequence 1, the anti-sense strand comprises a nucleotide sequence 2, the nucleotide sequences 1 and 2 are both 19 nucleotides in length, and in the direction from 5′ end to 3′ end, nucleotides at positions 7, 8 and 9 of the nucleotide sequence 1 and nucleotides at positions 2, 6, 14 and 16 of the nucleotide sequence 2 are all fluoro-modified nucleotides, and each nucleotide at other positions is independently one of non-fluoro-modified nucleotides. Further provided are a pharmaceutical composition and a conjugate comprising the oligonucleotide, and pharmaceutical use thereof.

Provided here are certain recombinant HIV compositions and animal models to evaluate prophylactic and therapeutic antiviral compositions.

Provided is a modified double-stranded oligonucleotide, in which the sense strand comprises a nucleotide sequence 1, the anti-sense strand comprises a nucleotide sequence 2, the nucleotide sequences 1 and 2 are both 19 nucleotides in length, and in the direction from 5′ end to 3′ end, nucleotides at positions 7, 8 and 9 of the nucleotide sequence 1 and nucleotides at positions 2, 6, 14 and 16 of the nucleotide sequence 2 are all fluoro-modified nucleotides, and each nucleotide at other positions is independently one of non-fluoro-modified nucleotides. Further provided are a pharmaceutical composition and a conjugate comprising the oligonucleotide, and pharmaceutical use thereof.

The present invention relates to a recombinant HBV cccDNA comprising HBV genome or the fragment or variant thereof and a site-hybrid insert, a method to generate said recombinant HBV cccDNA, a method for establishment of an in vitro or in vivo cccDNA based model for persistently hepatitis B virus replication by using the recombinant HBV cccDNA of the present invention, and a method for anti-HBV drug evaluation.

Provided is a modified double-stranded oligonucleotide, in which the sense strand comprises a nucleotide sequence 1, the anti-sense strand comprises a nucleotide sequence 2, the nucleotide sequences 1 and 2 are both 19 nucleotides in length, and in the direction from 5′ end to 3′ end, nucleotides at positions 7, 8 and 9 of the nucleotide sequence 1 and nucleotides at positions 2, 6, 14 and 16 of the nucleotide sequence 2 are all fluoro-modified nucleotides, and each nucleotide at other positions is independently one of non-fluoro-modified nucleotides. Further provided are a pharmaceutical composition and a conjugate comprising the oligonucleotide, and pharmaceutical use thereof.

A genetically modified non-human animal comprising a genome containing an endogenous non-human ACE2 locus genetically modified to encode a complete human ACE2 gene. According to a further embodiment the genome is genetically modified to encode a second, a third, and a fourth complete human ACE2 gene, the human ACE2 gene is at least 85 percent identical to SEQ ID No: 1, the animal of is a mouse, the human ACE2 gene encodes six protein variants, an endogenous Tmprss2 gene is unmodified, a LoxP gene flanks each of a 5′ and a 3′ end of a nucleic acid sequence of the human ACE2 gene, and the human ACE2 gene is expressed in a lung, kidney, spleen, stomach, liver, intestine, heart, and skeletal muscle of the animal, and a cortex, striatum, middle brain, hippocampus, olfactory bulb, and cerebellum of a brain of the animal.

Genetically modified rodents such as mice and rats, and methods and compositions for making and using the same, are provided. The rodents comprise a humanization of at least one endogenous rodent Tmprss gene, such as an endogenous rodent Tmprss2, Tmprss4, or Tmprss11d gene.