The present invention relates to a recombinant spike protein of the COVID-19 virus forming a trimer and a method for mass-producing the recombinant spike protein, and more specifically to a method for designing a recombinant gene expressing a recombinant spike protein of the COVID-19 virus forming a trimer for the purposes of enhancing immunogenicity and effective antigen delivery, and a method for mass-producing the recombinant spike protein in plants.

Recombinant expression vectors are disclosed that include a control sequence for recombinant expression of proteins of interest; the control sequence combines a mCMV enhancer sequence with a rat EF-1alpha intron sequence. Some of the vectors are useful for tetracycline-inducible expression. Some of the vectors contain a 5′ PiggyBac ITR and a 3′ PiggyBac ITR to promote genomic integration into a host cell chromosome. A method of selecting a stable production cell line for manufacturing a protein of interest is also disclosed. Also disclosed are mammalian host cells comprising the inventive recombinant expression vectors and a method of producing a protein of interest, in vitro, involving the mammalian host cell.

A method for isolating and proliferating at least one type of precursor cell from dental origin from a single donor includes the following isolating the precursor cells from dental origin of a single donor in a sample collection media and preparing a primary stock culture. The primary stock culture is proliferated sequentially to obtain first, second and third sub-cultured stocks with cell counts ranging between 5×10.sup.6 cells and 10×10.sup.6 cells, 20×10.sup.6 cells and 400×10.sup.6 cells, 150×10.sup.6 and 300×10.sup.6 cells respectively. The precursor cells from the third subculture are harvested and cryo-preserved to obtain a precursor cell population for cell transplantation. The dental origin of the precursor cells is from pulp, apical papilla or periodontal ligament. The precursor cell originates from mesenchymal stem cells, ecto-mesenchymal cells, neural stem cells, dental progenitor cells or CD117.sup.+ cells.

Methods of and system for growing and maintaining an optimized/ideal active yeast solution in the yeast tank and fermenter tank during the fermentation filling cycle are provided. A new yeast stage tank is used between the yeast tank and the fermenter tank allowing yeast to rapidly produce a huge amount of active young yeast cells for a fermenter during the filling period. A measurable and useful controlling factor, % DT/% Yeast by weight ratio (or “food” to yeast ratio), is used (e.g., % DT=glucose), which offers information on the health status of the yeast. The controlling factor is used to control the status of the yeast throughout the entire process.

The specification describes an improved serum-free animal cell culture medium, which can used for the production of a protein of interest. Ornithine, or a combination of ornithine and putrescine can be added to serum-free media or chemically defined media to improve viable cell density, to reduce cell doubling time, and to increase the production of a protein of interest.

Disclosed is an adapted Madin-Darby canine kidney cell line capable of suspension culture in the absence of serum, and a chemically-defined medium for culture of the adapted MDCK cell line. Further disclosed are culture methods for growing the adapted MDCK cell line and methods for producing a vaccine from the adapted MDCK cell line grown in the chemically-defined medium.

The present invention provides preparations of MSCs with important therapeutic potential. The MSC cells are non-primary cells with an antigen profile comprising less than about 1.25% CD45+ cells (or less than about 0.75% CD45+), at least about 95% CD105+ cells, and at least about 95% CD166+ cells. Optionally, MSCs of the present preparations are isogenic and can be expanded ex vivo and cryopreserved and thawed, yet maintain a stable and uniform phenotype. Methods are taught here of expanding these MSCs to produce a clinical scale therapeutic preparations and medical uses thereof.

The invention is directed to modified T cells, methods of making and using isolated, modified T cells, and methods of using these isolated, modified T cells to address diseases and disorders. In one embodiment, this invention broadly relates to TCR-deficient T cells, isolated populations thereof, and compositions comprising the same. In another embodiment of the invention, these TCR-deficient T cells are designed to express a functional non-TCR receptor. The invention also pertains to methods of making said TCR-deficient T cells, and methods of reducing or ameliorating, or preventing or treating, diseases and disorders using said TCR-deficient T cells, populations thereof, or compositions comprising the same.

Provided in the present invention is a method for constructing a multispecific antibody. The method comprises the steps of: (i) constructing a first polynucleotide and a second polynucleotide, respectively, wherein the first polynucleotide and the second polynucleotide respectively encode a first polypeptide containing a CL region and a second polypeptide containing a CH1 region, and a disulfide bond may be formed between the CL region of the first polypeptide and the CH1 region of the second polypeptide, such that the antibody has a heterodimeric form; and (ii) expressing the first polynucleotide and the second polynucleotide to obtain the first polypeptide and the second polypeptide, and dimerize the first polypeptide and the second polypeptide to form a multispecific antibody with a heterodimeric form. The antibody of the present invention can simultaneously bind to different targets and maintain the binding activity of the original antibody, which plays a role when the target is a membrane surface receptor or a target in a solution and has a biological activity against multiple targets.

The invention provides methods and materials for culturing mammalian cells and harvesting recombinant protein.