Soluble Expression of Humanized Anti-CD20 Single Chain Antibody in Escherichia coli by Cytoplasmic Chaperones Co-expression.

BACKGROUND: CD20 is an important cell surface receptor that is used for target therapy of B cell lymphoma and some related blood diseases due to vital function of CD20. In previous studies, a Rituximab based humanized single chain variable fragment (scFv) antibody showed good reactivity against B cell related cancer cells. But this recombinant protein produced Inclusion Bodies (IBs) in Escherichia coli (E. coli) cytoplasm. The aim of this study was to investigate the effect of coexpression with cytoplasmic chaperones on expression and solubility of humanized anti-CD20 scFv in E. coli. METHODS: For this purpose, the fragment coding for anti-CD20 huscFv subcloned into the pET22b (+) and transformed into the E. coli BL21 (DE3) was evaluated. In order to inhibit the production of IBs, the effects of co-expression with cytoplasmic chaperones GroEL, DnaK, GroES, Tig, DnaJ and GrpE were investigated. RESULT: Coexpression with cytoplasmic chaperones led to increased soluble expression of anti-CD20 recombinant protein. Among investigated chaperones, pKJE7 chaperone plasmid containing DnaJ, GrpE, DnaK chaperone genes had significant effects with an expression yield of 325 µg/ml soluble anti-CD20 scFv. CONCLUSION: The result of this study demonstrated remarkable effect of pKJE7 chaperone on enhancement of soluble expression of anti-CD20 huscFv antibody in E. coli.

Immunotoxins in cancer therapy: Review and update.

Immunotoxins are a novel class of cancer therapeutics that contains a cytotoxic agent fused to a targeting moiety. Various toxic agents from different sources are used in immunotoxin development, including bacterial, plant and human origin cytotoxic elements. Although bacterial and plant-derived toxins are highly toxic and commonly used in immunotoxins, their immunogenicity for human restricted their application in cancer therapy. Here, we discuss the advantages and limitations of bacterial toxins such as Pseudomonas and Diphtheria toxins, plant toxins such as ricin and gelonin, and some endogenous protein of human origin such as RNases and Granzymes. This article will also review different generations of immunotoxins with special focus on immunotoxins which are under clinical trials or approved for clinical use. Finally, current deimmunization strategies for development of new less-immunogenic recombinant immunotoxins will be discussed. ABBREVIATIONS: mAbs: Monoclonal antibodies; EF2: elongation factor 2; ITs: Immunotoxins; DT: Diphtheria toxin; PE: Pseudomonas exotoxin; dgA: de-glycosylated A-chain of ricin; rGel: recombinant de-glycosylated form of gelonin; NKC: natural killer cells; HTR: human transferrin receptor; EGF: epidermal growth factor; GM-CSF: granulocyte-macrophage colony-stimulating factor; DAB389: truncated Diphtheria toxin; B-CCL: B-cell chronic lymphocytic leukemia; RCC: renal cell carcinoma; GVHD: Graft-versus-host disease; EGFR: epidermal growth factor receptor; AML: acute myeloid leukemia; Fab: fragment antigen-binding; dsFv: disulfide-stabilized fragment variable; scFv: single-chain fragment variable; B-ALL: B-lineage Acute Lymphoblastic Leukemia; Fv: fragment variable; HCL: hairy cell leukemia; IL-2R: Interleukin-2 receptor; CR: complete response; CLL: chronic lymphocytic leukemia; ATL: adult T-cell leukemia; DARPins: designed Ankyrin repeat proteins; pmol: picomolar; HAMA: human-anti mouse antibody.

Anti-bacterial activity of graphene oxide as a new weapon nanomaterial to combat multidrug-resistance bacteria.

Antibiotic resistance in microbial pathogens has become a serious health problem in the world. The increasing spread of hospital acquired infections especially in immunocompromised and cancer patients caused by multidrug-resistant (MDR) microbial pathogens is restricting the choices for impressive antibiotic therapy. So many efforts have been made to develop new compounds with antimicrobial activity. In recent years, nanoparticles, particularly graphene oxide (GO) nanoparticles have found many applications in various fields, including antibacterial action, pathogens bio detection, cancer therapy, and drug and gene delivery. The use of graphene oxide as an antibacterial agent for the treatment of infections with multidrug resistance is growing due to the unique physicochemical properties as wide surface area, excellent electrical and thermal conductivity, and biocompatibility. To reduce toxicity and increase the efficiency of graphene oxide as an antimicrobial agent, different surface modification and functionalization with inorganic nanostructures, biomolecules and polymers were developed. In this review article, we give our overview of the progress made on the graphene oxide nanocomposites as a new generation of antimicrobial agents.