T cells expressing a chimeric antigen receptor (CAR) targeting CD3 can be susceptible to fratricide because T cells express CD3 on their surface as part of the T cell receptor (TCR)/CD3 complex. To reduce fratricide, CD3 surface expression can be downregulated using an anti-CD3 antibody (e.g., an anti-CD3 single-chain antibody) coupled to an intracellular targeting signal such as an endoplasmic reticulum (ER) retention signal. Retention of CD3 in the ER can allow T cells expressing a CD3 CAR to grow in culture without compromising their cytotoxic activity against CD3 positive T cells. The T cells described herein can be particularly useful for treating T cell diseases (e.g., a disease caused by T cell defects or disorders). In addition, downregulating CD3 surface expression can reduce graft versus host disease when allogeneic T cells are introduced into a mammalian host.

The invention relates to heterodimeric inactivatable chimeric antigen receptors (CARs) and their use for treatment.

Provided are an anti-PSMA single-chain antibody, a chimeric antigen receptor associated therewith and use thereof. An amino acid sequence of a heavy chain of the anti-PSMA single-chain antibody includes a sequence shown in SEQ ID NO: 1, and an amino acid sequence of a light chain of the anti-PSMA single-chain antibody includes a sequence shown in SEQ ID NO: 2. The anti-PSMA single-chain antibody is a humanized scFv antibody of PSMA, is more functional in the human body, has better compatibility, and is less prone to be rejected by the immune system. The chimeric antigen receptor has better response effects after specifically bonding to PSMA so that CAR-T cells generate a stronger immune response to tumors, and the chimeric antigen receptor also has better long-term effectiveness than other PSMA chimeric antigen receptors.

Chimeric antigen receptors (CARs) with binding domains derived from a novel suite of human CD33-binding antibodies are described. The CARs include optimized short and intermediate spacer regions. The current disclosure also provides methods of cell expansion/activation processes utilizing IL-2, IL-7, IL-15, and/or IL-21 that improve cellular proliferation and cell lysis of the CARs as described.

The present disclosure provides, among other things, a method of cryopreserving and thawing cells that results in the thawed cells having high cellular viability and functionality post-thawing. In some embodiments, a large-scale method of cryopreserving cells is provided, the method comprising: (a) contacting the cells with a cryopreservation medium; (b) cooling the cells to 80 C. at a controlled rate to minimize latent heat of fusion; and (c) storing the cells in liquid nitrogen vapor phase, thereby cryopreserving the immune cells.

The disclosure relates to fusion proteins comprising a tBID polypeptide and a steroid hormone receptor domain, and methods of using same to induce apoptosis in cells.