Humanized CTLA-4 single chain antibody and human perforin path formed peptide P34 recombinant immunotoxin

Abstract

The present invention relates to new recombinant humanized immunotoxin hS83-P34, which contains fusion protein comprising the antigen associated molecule of humanized cytotoxic T cell antigen 4 and human porforin channel forming active molecule. The immunotoxin of the present invention has strict targeting, less tendency of damaging health cell, less toxic side effect, no need of internalization and intracellular transport, high acting efficiency, less likelihood of generating corresponding antibody, weak immunogenicity and less tendency of generating drug resistance. It may be used in treating some tumors and autoimmune diseases and suppressing immunologic rejection reaction in organ transplantation.

Description

technical field [0001] The present invention relates to a new type of recombinant immunotoxin, in particular to an active small molecular fragment based on the antigen binding molecule of cytotoxic T cell antigen 4 (Cytotoxic T Lymphocyte Antigen 4, CTLA-4) and the channel of membrane active toxin. Recombinantly constructed fusion protein hS83-P34. [0002] The present invention also relates to the nucleotide sequence and amino acid sequence of the immunotoxin. [0003] The present invention also relates to a pharmaceutical composition comprising the recombinant immunotoxin. Background technique [0004] According to the principle of mutual recognition between antigens and antibodies, cytokines, growth factors, hormones and receptors, molecules that can kill cells are connected with guiding molecules such as antibodies to construct immunotoxins, which can specifically kill cells and realize drug delivery. targeted therapy. [0005] Humanized cytotoxic T cell antigen 4 (Cy...

AI Technical Summary

Problems solved by technology

[0007] 1. High toxicity and side effects: These toxins are harmful to normal cells and often cause non-specific damage. Even after molecular modification, the toxicity still exists (Onda M et al., The Journal of Immunology, 2000, 165: 7150-6);

[0008] 2. Low efficiency: These toxins must be internalized by molecules, that is, penetrate the cell membrane and be transported into the cell to initiate a series of enzymatic reactions leading to cell apoptosis, and the internalization steps are often not high, which greatly affects the immune system. Toxin effect play (Panchal RG., Biochemical Phamacology, 1998, 55:247-52);

[0009] 3. Strong immunogenicity: the molecular weight of these toxins is still very large, they have strong antigenicity, and are easy to produce antibodies

Moreover, there are often natural antibodies to pathogenic bacterial toxins in the human body, which have a certain neutralizing effect on both natural toxins and modified toxins, which will inevitably reduce the killing efficiency of targeted molecules (Hall PD. et al., Clinical Immunology , 2001, 100:191-7)

[0010] 4. Easy to produce drug resistance: At present, killer molecules mainly kill target cells through the mechanism of inhibiting intracellular protein synthesis, which is easy to produce drug resistance

[0011] In addition to the above-mentioned toxins, there is another class of membrane-active toxins that do not require internalization and kill cells by forming channels on the cell membrane, but the lack of structural understanding has restricted their application

[0013] Currently, there is no relevant literature on recombinant immunotoxins based on CTLA-4 scFv and small channel-forming peptides

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