Abstract: The disclosure provides a tetra-specific antibody monomer having a N-terminal and a C-terminal, comprising in tandem from the N-terminal to the C-terminal, a first scFv domain at the N-terminal, a Fab domain, a Fc domain, a second scFv domain, and a third scFv at the C-terminal, wherein the first scFv domain, the Fab domain, the second scFv domain, and the third scFv domain each has a binding specificity against a different antigen. In one embodiment, the antigen is a tumor antigen, an immune signaling antigen, or a combination thereof. Multi-specific antibodies comprising the disclosed tetra-specific antibodies are also provided.

Abstract: The application provides tri-specific antibody monomers having a N-terminal and a C-terminal, comprising in tandem from the N-terminal to the C-terminal, a first scFv domain at the N-terminal, a Fab domain, a Fc domain, and a second scFv domain at the C-terminal. In one embodiment, the first scFv domain, the Fab domain, and the second scFv domain each has a binding specificity against a different antigen.

Abstract: The application provides the anti-PD-L1 monoclonal antibodies, antigen binding portions thereof, therapeutic compositions thereof and/or nucleic acid encoding the same, and their use to upregulate the function of T-cells to enhance cell-mediated immune responses in the treatment of cancer and other T-cell dysfunctional disorders.

Abstract: The applications provides the anti-CD3 monoclonal antibodies, antigen-binding portions thereof, therapeutic compositions thereof and/or nucleic acid encoding the same, and their use to active CD3+ T-cells to enhance cell-mediated immune responses in the treatment of cancer and other T-cell dysfunctional disorders.

Abstract: The application provides anti-ROR1 monoclonal antibodies, antigen binding portions thereof, therapeutic compositions thereof and/or nucleic acid encoding the same, and their use to upregulate the function of T-cells to enhance cell-mediated immune responses in the treatment of cancer and other T-cell dysfunctional disorders.

Abstract: By inserting cysteine (C) into a heavy chain and/or a light chain of a target antibody at specific insertion site, and performing a site-specific conjugation through a free thiol group (—SH) from the site-specific inserted cysteine and a linker conjugated with a highly potent small molecule cytotoxin, a cysteine modified antibody-drug conjugate with good homogeneity is provided. The specific insertion sites of cysteine are position 205 and/or position 206 (Kabat numbering scheme) of the light chain of the antibody, and/or position 439 (Kabat numbering scheme) of the heavy chain.