Monoclonal Antibodies in Immunodiagnosis and Immunotherapy最新文献

Immune checkpoint blockade therapy has shown successful clinical outcomes in multiple human cancers. In dogs, several types of tumors resemble human tumors in many respects. Therefore, several groups have developed the anti-dog programmed cell death ligand 1 (dPD-L1) monoclonal antibodies (mAbs) and showed efficacy in several canine tumors. To examine the abundance of dPD-L1 in canine tumors, anti-dPD-L1 diagnostic mAbs for immunohistochemistry are required. In this study, we immunized the peptide in the dPD-L1 intracellular domain, and established anti-dPD-L1 mAbs, L₁Mab-352 (mouse IgG₁, kappa), and L₁Mab-354 (mouse IgG₁, kappa). In enzyme-linked immunosorbent assay, L₁Mab-352 and L₁Mab-354 showed high-binding affinity to the dPD-L1 peptide, and the dissociation constants (K_D) were determined as 6.9 × 10^-10 M and 7.2 × 10^-10 M, respectively. Furthermore, L₁Mab-352 and L₁Mab-354 were applicable for the detection of dPD-L1 in immunohistochemical analysis in paraffin-embedded dPD-L1-overexpressed cells. These results indicated that L₁Mab-352 and L₁Mab-354 are useful for detecting dPD-L1 in immunohistochemical analysis.

CD39 is involved in adenosine metabolism by converting extracellular ATP to adenosine. As extracellular adenosine plays a critical role in the immune suppression of the tumor microenvironment, the inhibition of CD39 activity by monoclonal antibodies (mAbs) is one of the important strategies for tumor therapy. This study developed specific and sensitive mAbs for mouse CD39 (mCD39) using the Cell-Based Immunization and Screening method. The established anti-mCD39 mAb, C₃₉Mab-1 (rat IgG_2a, kappa), reacted with mCD39-overexpressed Chinese hamster ovary-K1 (CHO/mCD39) by flow cytometry. The kinetic analysis using flow cytometry indicated that the dissociation constant of C₃₉Mab-1 for CHO/mCD39 was 7.3 × 10^-9 M. Furthermore, C₃₉Mab-1 detected the lysate of CHO/mCD39 by western blot analysis. These results indicated that C₃₉Mab-1 is useful for the detection of mCD39 in many functional studies.

The CXC chemokine receptor 4 (CXCR4, CD184) is a member of the G protein-coupled receptor family that is expressed in most leukocytes. Overexpression of CXCR4 is associated with poor prognosis in not only hematopoietic malignancy but also solid tumors. Because CXCR4 is an attractive target for tumor therapy, reliable preclinical murine models using anti-CXCR4 monoclonal antibodies (mAbs) have been warranted. This study established a novel anti-mouse CXCR4 (mCXCR4) mAb using the Cell-Based Immunization and Screening method. Flow cytometric analysis showed that an anti-mCXCR4 mAb, Cx₄Mab-1 (rat IgG_2a, kappa), recognized mCXCR4-overexpressed Chinese hamster ovary-K1 (CHO/mCXCR4) cells and endogenously mCXCR4-expressing mouse myeloma P3X63Ag8U.1 (P3U1) cells. Furthermore, Cx₄Mab-1 did not recognize mCXCR4-knockout P3U1 cells. The dissociation constants of Cx₄Mab-1 for CHO/mCXCR4 and P3U1 were determined as 6.4 × 10^-9 M and 2.3 × 10^-9 M, respectively, indicating that Cx₄Mab-1 possesses a high affinity to both endogenous and exogenous mCXCR4-expressing cells. These results indicate that Cx₄Mab-1 could be a useful tool for preclinical mouse models.

In small animal models of severe acute respiratory syndrome coronaviruses (SARS-CoV and SARS-CoV-2) infection, ferrets (Mustela putorius furo) have been used to investigate the pathogenesis. Podoplanin (PDPN) is an essential marker in lung type I alveolar epithelial cells, kidney podocytes, and lymphatic endothelial cells. Monoclonal antibodies (mAbs) against ferret PDPN (ferPDPN) are useful for the pathological analyses of those tissues. We previously established an anti-ferPDPN mAb, PMab-292 using the Cell-Based Immunization and Screening (CBIS) method. In this study, we determined the critical epitope of PMab-292 using flow cytometry. The ferPDPN deletion mutants analysis revealed that the Val34 is located at the N-terminus of the PMab-292 epitope. Furthermore, the PA tag-substituted analysis (PA scanning) showed that Asp39 is located at the C-terminus of PMab-292 epitope. The epitope sequence (VRPEDD) also exists between Val26 and Asp31 of ferPDPN, indicating that PMab-292 recognizes the tandem repeat of the VRPEDD sequence of ferPDPN.

Immunohistochemistry staining is an essential method in pathological diagnoses. Podoplanin (PDPN) is a specific maker of alveolar epithelium, lymphatic vessels, and glomeruli. In this study, we established a novel anti-giraffe PDPN (girPDPN) mAb, PMab-301, using the Cell-Based Immunization and Screening (CBIS) method. PMab-301 (mouse IgG₁, kappa) detected girPDPN in various applications, such as flow cytometry, western blot, and immunohistochemistry. PMab-301 specifically stained type-I alveolar cells using formalin-fixed paraffin-embedded giraffe lung tissues. Our findings suggest the potential usefulness of PMab-301 for the pathophysiological analyses of giraffe tissues.

By converting extracellular adenosine triphosphate to adenosine, CD39 is involved in adenosine metabolism. The extracellular adenosine plays a critical role in the immune suppression of the tumor microenvironment. Therefore, the inhibition of CD39 activity by monoclonal antibodies (mAbs) is thought to be one of the important strategies for tumor therapy. In this study, we developed novel mAbs for mouse CD39 (mCD39) using the Cell-Based Immunization and Screening (CBIS) method. One of the established anti-mCD39 mAbs, C₃₉Mab-2 (rat IgG_2a, lambda), reacted with mCD39-overexpressed Chinese hamster ovary-K1 (CHO/mCD39) and an endogenously mCD39-expressed cell line (SN36) by flow cytometry. The kinetic analysis using flow cytometry indicated that the dissociation constant (K_D) values of C₃₉Mab-2 for CHO/mCD39 and SN36 were 5.5 × 10^-9 M and 4.9 × 10^-9 M, respectively. These results indicated that C₃₉Mab-2 is useful for the detection of mCD39 in flow cytometry.