In certain embodiments, the disclosure provides an IgG4 antibody comprising a heavy chain and a light chain, wherein the heavy chain comprises: (a) a modified IgG4 CH1 region having a substitution of the lysine residue at position 196; or (b) a modified IgG4 hinge region having a substitution of the serine residue at position 217, the glycine residue at position 220, the proline residue at position 224 or the proline residue at position 225. Preferably, the IgG4 antibody further comprises a substitution of the serine residue at position 228 in the heavy chain hinge region.

The invention discloses a fusion protein, a preparation method thereof and application thereof in preparing ophthalmic disease treatment, anti-inflammation and anti-tumor medicament, and belongs to the field of biopharmaceutical technology. The present invention uses a flexible (F) or rigid (R) linker to fuse two polypeptides to respectively obtain two bifunctional fusion proteins, namely two multi-functional fusion protein macromolecules obtained by linking antiangiogenesis polypeptides HM-3, interleukin 4 and immunoglobulin Fc fragments via an amino acid linker, which can improve drug efficacy, prolong half-life and enhance stability, has the characteristics of strong effect, low toxicity and the like, and can be used for the prevention and treatment of solid tumors and various types of inflammations and neovascular ophthalmic diseases. The fusion protein is expressed in a eukaryotic cell by a genetic engineering method and purified by affinity chromatography or the like.

Human interleukin-2 (IL-2) muteins or variants thereof are provided. In particular, provided are IL-2 muteins that have an increased binding capacity for IL-2Rβ receptor as compared to wild-type IL-2 for use in combination therapies with anti-PD-1 antibodies for the treatment of cancer. Also provided are pharmaceutical compositions that include such anti-PD-1 antibodies and the disclosed IL-2 muteins.

Disclosed is an anti-IL-4R single-domain antibody and the use thereof. In particular, disclosed are a IL-4R single-domain antibody and a VHH chain thereof, a coding sequence encoding the above-mentioned single-domain antibody or the VHH chain thereof, a corresponding expression vector, host cells capable of expressing the single-domain antibody, and a method for producing the single-domain antibody. The single-domain antibody can specifically recognize human and marmoset IL-4R, but does not recognize mouse IL-4R, and the specificity is good; the single-domain antibody can effectively inhibit the proliferation of TF-1 cells and the activation of a pSTAT6 signaling pathway in cells.

Provided is an anti-PD-L1 antigen binding protein, capable of binding to primate-derived PD-L1 with a KD value of 1×10.sup.−8 M or less. The antigen binding protein can block the binding of PD-1 and CD80 to PD-L1, stimulate the secretion of cytokines in immune cells, and can inhibit tumor growth and/or tumor cell proliferation. Also provided is a fusion protein, comprising human TGFBRII or a fragment thereof and the antigen binding protein. Also provided is an application of the antigen binding protein and/or the fusion protein in the prevention and treatment of tumors or cancers.

A molecule capable of binding to human 4-1BB includes the amino acid sequences of HCDR1, HCDR2 and HCDR3 in the heavy chain variable region of the antibody provided by present invention are shown sequentially at positions 31-35, positions 50-64, and positions 98-106 in SEQ ID No.1 from the N-terminus. The amino acid sequences of LCDR1, LCDR2 and LHCDR3 in the light chain variable region are shown sequentially at positions 24-34, positions 50-56, and positions 89-97 in SEQ ID No.2 from the N-terminus. The antibodies provided by the present invention can bind to human and monkey 4-1BB, exhibit high affinity to human 4-1BB and effectively enhance T cell responses; they can be used to regulate the immune responses mediated by T cells and antibodies; as immune modulators, they have a wide range of therapeutic uses in diseases such as cancer, autoimmune diseases, inflammatory diseases, and infectious diseases, etc.

Provided herein are modified immunoglobulins comprising an amyloid reactive peptide joined to an antibody, as well as humanized antibodies that bind to human amyloid fibrils and antibody-peptide fusion proteins. Also provided herein are methods of treating amyloid-based diseases by administering a modified immunoglobulin, humanized antibody, or antibody-peptide fusion protein.

Described herein are compositions and techniques related to generation and therapeutic application of artificial synapses. Artificial synapses are engineered extracellular vesicles, including exosomes, which incorporate sticky binders on their surface to anchor signaling domains against biological targets, such as receptors. These engineered additives can be organized in genetic vector constructs, expressed in mammalian cells, wherein the sticky binders attach to extracellular vesicles such as exosomes, thereby presenting their joined signaling domains which are rapidly taken up by recipient cells. Artificial synapses adopt the hallmark biophysical and biochemical features of extracellular vesicles, allowing for rapid deployment and scale-up. Importantly, this strategy can allow for kinetically favorable signal generation and signal propagation. This includes, for example, increasing density of agonist presentation to support receptor clustering—an onerous barrier for traditional receptor targeting strategies.

Cell-targeted serine protease constructs are provided. Such constructs can be used in methods for targeted cell killing such as for treatment cell of proliferative diseases (e.g., cancer). In some aspects, recombinant serine proteases, such as Granzyme B polypeptides, are provided that exhibit improved stability and cell toxicity. Methods and compositions for treating lapatinib or trastuzumab-resistant cancers are also provided.

Anti-PD-L1 antibodies are disclosed. Also disclosed are pharmaceutical compositions comprising such antibodies, and uses and methods using the same.