Monoclonal Antibodies in Immunodiagnosis and Immunotherapy最新文献

Coagulation factor XIII (FXIII) is an enzyme that strengthens hemostatic clots, and its deficiency can cause life-threatening bleeding. We immunized mice with human plasma-derived FXIII to generate monoclonal antibodies (mAbs) against the B subunit (FXIII-B), which stabilizes the A subunit (FXIII-A) of FXIII, and analyzed their properties. The epitopes of the seven mouse antihuman FXIII-B mAbs obtained were found to be the 3rd, 5th, 6th, 9th, and 10th Sushi domains. One of these mAbs, mAb 5-6C, recognized the 10th Sushi domain and inhibited the fibrin cross-linking reaction without affecting the amine incorporation activity of FXIII. We previously reported that the 10th Sushi domain is the site where FXIII-B binds to fibrin and functions to bring FXIII-A closer to the substrate fibrin. Except for mAb 5-6C, mouse mAbs with high yields were used to measure the amount of FXIII-B antigen by an immunochromatography test (ICT), which showed a high correlation with enzyme-linked immunosorbent assay-obtained results. In addition, we developed a prototype ICT to detect anti-FXIII-B autoantibodies using mAb 1-3C, which showed good results in measuring the amount of FXIII-B antigen. Thus, mouse mAbs may be useful for clinical applications. mAb 5-6C targeting the 10th Sushi domain may also be useful for inhibiting thrombosis progression when humanized as antibody medicines.

This Long-Covid disease, mild or severe, is multiorgan or system-wide, spanning from fatigue to clotting abnormalities and autoantibody. The spectrum of different symptoms in Long-Covid diseases makes it difficult to point to a common immunopathogenic etiology. Different immune pathways are presented and critically evaluated. A hypothesis is advanced that indicates autoimmune reactions as cause for Long-Covid disease. The immune network pathway describes a redirection of the nominal anti-SARS-CoV response towards an autoimmune target. Several therapeutic interventions are suggested to suppress the autoimmune pathway.

Phosphoribosylaminoimidazole carboxylase, phosphoribosylaminoimidazole succinocarboxamide synthetase (PAICS) is a de novo purine biosynthetic enzyme. It has been found to be overexpressed in various types of cancer and is related to cell proliferation, invasion, the epithelial-mesenchymal transition, and efficient tumor growth. In this study, we describe a rat monoclonal antibody (mAb) 6A10, which was generated as an antigen of human PAICS. This mAb was generated to interact with the N-terminal region of human PAICS and was found to recognize endogenous PAICS enzymes in several cancer cells. Our results also indicated that it can recognize monkey and dog PAICS, which possess the same amino acid sequence in the antigenic region as human PAICS, but it does not recognize rat and mouse PAICS. Furthermore, our data indicated that this mAb is suitable for immunoprecipitation and immunoblotting use for several cancer cell lines. We, therefore, anticipate that mAb 6A10 will be useful for functional analyses of human PAICS in several cancers and for diagnosis of malignant transformation.

Mammalian cell line stability is an important consideration when establishing a biologics manufacturing process in the biopharmaceutical and in vitro diagnostics (IVD) industries. Traditional Chinese hamster ovary (CHO) cell line development methods use a random integration approach that requires transfection, selection, optional amplification, screenings, and single-cell cloning to select clones with acceptable productivity, product quality, and genetic stability. Site-specific integration reduces these disadvantages, and new technologies have been developed to mitigate risks associated with genetic instability. In this study, we applied the Leap-In® transposase-mediated expression system from ATUM to generate stable CHOK1 pools for the production of four recombinant antibody reagents for IVD immunoassays. CHO cell line stability is defined by consistent antibody production over time. Three of the CHOK1 pools maintained productivity suitable for manufacturing, with high antibody yields. The productivity of the remaining CHOK1 pool decreased over time; however, derivative clones showed acceptable stability. l-glutamine had variable effects on CHOK1 cell line or stable pool stability and significantly affected antibody product titer. Compared with traditional random integration methods, the ATUM Leap-In system can reduce the time needed to develop new immunoassays by using semi site-specific integration to generate high-yield stable pools that meet manufacturing stability requirements.

The C-C motif chemokine receptor 8 (CCR8) is highly and selectively expressed in regulatory T (Treg) cells and is associated with tumor progression. The massive accumulation of Treg cells into tumors suppresses the effector function of CD8⁺ cells against tumor cells. Therefore, selective depletion of Treg cells using anti-CCR8 monoclonal antibodies (mAbs) reinvigorates antitumor immune responses and improves responses to cancer immunotherapy. Previously, we developed an anti-mouse CCR8 (mCCR8) mAb, C₈Mab-2, using the Cell-Based Immunization and Screening method. In this study, the binding epitope of C₈Mab-2 was investigated using flow cytometry. The mCCR8 extracellular domain-substituted mutant analysis showed that C₈Mab-2 recognizes the N-terminal region (1-33 amino acids) of mCCR8. Next, 1×alanine (or glycine) scanning and 2×alanine (or glycine) scanning were conducted in the N-terminal region. The results revealed that the _17-DFFTAP_-22 sequence is important for the recognition by C₈Mab-2, and Thr20 is a central amino acid of the epitope. These results revealed the involvement of the N-terminus of mCCR8 in the recognition by C₈Mab-2.

C-C chemokine receptor 5 (CCR5), a member of the G protein-coupled receptor family, is the most common coreceptor for the human immunodeficiency virus type 1. CCR5 is also involved in the pathogenesis of tumors and inflammatory diseases. The CCR5 antagonists including monoclonal antibodies (mAbs) have been developed and evaluated in clinical trials. In this study, we developed novel mAbs for mouse CCR5 (mCCR5) using the Cell-Based Immunization and Screening (CBIS) method. One of the established anti-mCCR5 mAbs, C₅Mab-2 (rat IgG_2b, kappa), reacted with mCCR5-overexpressed Chinese hamster ovary-K1 (CHO/mCCR5) and an endogenously mCCR5-expressing cell line (L1210) by flow cytometry. Using flow cytometry, the dissociation constant (K_D) of C₅Mab-2 for CHO/mCCR5 was determined as 4.3 × 10^-8 M. These results indicated that C₅Mab-2 is useful for the detection of mCCR5 in flow cytometry and may be applicable to obtain the proof of concept in preclinical studies.

One of the G protein-coupled receptors, C-C chemokine receptor 5 (CCR5), is an important regulator for the activation of T and B lymphocytes, dendritic cells, natural killer cells, and macrophages. Upon binding to its ligands, CCR5 activates downstream signaling, which is an important regulator in the innate and adaptive immune response through the promotion of lymphocyte migration and the secretion of proinflammatory cytokines. Anti-CCR5 monoclonal antibodies (mAbs) have been developed and evaluated in clinical trials for tumors and inflammatory diseases. In this study, we developed novel mAbs for mouse CCR5 (mCCR5) using the N-terminal peptide immunization. Among the established anti-mCCR5 mAbs, C₅Mab-4 (rat IgG_2a, kappa) and C₅Mab-8 (rat IgG₁, kappa), recognized mCCR5-overexpressing Chinese hamster ovary-K1 (CHO/mCCR5) and an endogenously mCCR5-expressing cell line (L1210) by flow cytometry. The dissociation constant (K_D) values of C₅Mab-4 and C₅Mab-8 for CHO/mCCR5 were determined as 3.5 × 10^-8 M and 7.3 × 10^-9 M, respectively. Furthermore, both C₅Mab-4 and C₅Mab-8 could detect mCCR5 by western blotting. These results indicated that C₅Mab-4 and C₅Mab-8 are useful for detecting mCCR5 by flow cytometry and western blotting and provide a possibility to obtain the proof of concept in preclinical studies.

C-X-C motif chemokine receptor 3 (CXCR3, CD183) is a G-protein-coupled receptor for CXCL9, CXCL10, and CXCL11. CXCR3 induces chemotaxis of immune cells and promotes inflammation. Various mouse models have been developed to mimic the pathogenesis of diseases and used in the evaluation of therapeutics for these diseases. Although CXCR3 is an attractive target to suppress inflammation, anti-CXCR3 therapeutic agents have not been approved. In this study, we established a novel anti-mouse CXCR3 (mCXCR3) monoclonal antibody, Cx₃Mab-4 (rat IgG₁, kappa), using the Cell-Based Immunization and Screening method. Flow cytometric analysis demonstrated that Cx₃Mab-4 bound to mCXCR3-overexpressed Chinese hamster ovary-K1 (CHO/mCXCR3) cells, but did not react to parental CHO-K1 cells. The dissociation constant of Cx₃Mab-4 was determined as 1.3 × 10^-9 M, indicating that Cx₃Mab-4 possesses a high affinity to mCXCR3-expressing cells. Cx₃Mab-4 could be useful for targeting CXCR3-expressing cells in preclinical mouse models.