Generation and characterization of four novel monoclonal antibodies against human programmed death-1 molecule

Monoclonal Antibody-Based Immunotherapy and Its Role in the Development of Cardiac Toxicity

Immunotherapy is one of the most effective therapeutic options for cancer patients. Five specific classes of immunotherapies, which includes cell-based chimeric antigenic receptor T-cells, checkpoint inhibitors, cancer vaccines, antibody-based targeted therapies, and oncolytic viruses. Immunotherapies can improve survival rates among cancer patients. At the same time, however, they can cause inflammation and promote adverse cardiac immune modulation and cardiac failure among some cancer patients as late as five to ten years following immunotherapy. In this review, we discuss cardiotoxicity associated with immunotherapy. We also propose using human-induced pluripotent stem cell-derived cardiomyocytes/ cardiac-stromal progenitor cells and cardiac organoid cultures as innovative experimental model systems to (1) mimic clinical treatment, resulting in reproducible data, and (2) promote the identification of immunotherapy-induced biomarkers of both early and late cardiotoxicity. Finally, we introduce the integration of omics-derived high-volume data and cardiac biology as a pathway toward the discovery of new and efficient non-toxic immunotherapy.

Expression of programmed death ligand-1 and programmed death-1 in samples of invasive ductal carcinoma of the breast and its correlation with prognosis

The aim of the current study is to investigate programmed death-1 (PD-1) and programmed death ligand-1 (PD-L1) expressions and to analyze the relationship between the expression of PD-L1 and PD-1 proteins and the molecular type, clinicopathological factors, and prognosis of invasive ductal carcinoma. We enrolled 136 patients with invasive ductal carcinoma of the breast. The expression of PD-L1 in tumor cells and that of PD-1 on paratumor-infiltrating immune cells was detected by immunohistochemistry, and the data were analyzed using SPSS software. The positive expression rates of PD-L1 and PD-1 in triple-negative breast cancer (TNBC) were 47.8 and 43.5%, which were higher than those of other subtypes (P<0.05). The expression of PD-L1 in tumor cells was correlated with the expression of estrogen receptor, progesterone receptor, and Ki-67 (P<0.05). The expression of PD-1 in the tumor-infiltrating immune cells was correlated with the expression of estrogen receptor, progesterone receptor, and Ki-67 and the histological grade (P<0.05). The expression of PD-L1 in tumor cells was correlated with the expression of PD-1 in paratumor-infiltrating immune cells (P<0.001). The expression of PD-L1 in tumor cells was found to be an independent prognostic risk factor with the progression-free survival rate for breast invasive ductal carcinoma (P=0.003). These results indicate that PD-L1 and PD-1 were highly expressed in TNBC which suggests that patients with TNBC may benefit from targeted immune therapies to a greater degree than patients with other subtypes. PD-L1 expression is an independent risk factor for breast invasive ductal carcinoma and expression of PD-L1 is expected to be a prognostic factor for breast cancer.

Optimized Expression and Characterization of a Novel Fully Human Bispecific Single-Chain Diabody Targeting Vascular Endothelial Growth Factor165 and Programmed Death-1 in Pichia pastoris and Evaluation of Antitumor Activity In Vivo

Bispecific antibodies, which can bind to two different epitopes on the same or different antigens simultaneously, have recently emerged as attractive candidates for study in various diseases. Our present study successfully constructs and expresses a fully human, bispecific, single-chain diabody (BsDb) that can bind to vascular endothelial growth factor 165 (VEGF165) and programmed death-1 (PD-1) in Pichia pastoris. Under the optimal expression conditions (methanol concentration, 1%; pH, 4.0; inoculum density, OD600 = 4, and the induction time, 96 h), the maximum production level of this BsDb is achieved at approximately 20 mg/L. The recombinant BsDb is purified in one step using nickel-nitrilotriacetic acid (Ni-NTA) column chromatography with a purity of more than 95%. Indirect enzyme-linked immune sorbent assay (ELISA) and sandwich ELISA analyses show that purified BsDb can bind specifically to VEGF165 and PD-1 simultaneously with affinities of 124.78 nM and 25.07 nM, respectively. Additionally, the BsDb not only effectively inhibits VEGF165-stimulated proliferation, migration, and tube formation in primary human umbilical vein endothelial cells (HUVECs), but also significantly improves proliferation and INF-γ production of activated T cells by blocking PD-1/PD-L1 co-stimulation. Furthermore, the BsDb displays potent antitumor activity in mice bearing HT29 xenograft tumors by inhibiting tumor angiogenesis and activating immune responses in the tumor microenvironment. Based on these results, we have prepared a potential bispecific antibody drug that can co-target both VEGF165 and PD-1 for the first time. This work provides a stable foundation for the development of new strategies by the combination of an angiogenesis inhibition and immune checkpoint blockade for cancer therapy.

Soluble PD-1 aggravates progression of collagen-induced arthritis through Th1 and Th17 pathways

INTRODUCTION

The programmed cell death 1 (PD-1) protein is a critical regulator of T-cell activation and is also an important therapeutic target for autoimmune diseases. Little is known about the regulation and functional properties of the soluble PD-1 (sPD-1) variant. The aim of this study was to examine the role of sPD-1 in the regulation of human and murine rheumatoid arthritis (RA).

METHODS

Expression of cytokines and sPD-1 in sera, synovial fluid, and peripheral blood (PB) mononuclear cells of patients with RA were analyzed by enzyme-linked immunosorbent assay and quantitative polymerase chain reaction. PD-1 function was assessed in PB T cells after stimulation of the cells with anti-CD3 and PD-L1-Fc to crosslink PD-1. Recombinant PD-1-Fc was injected intraperitoneally into DBA/1 mice with collagen-induced arthritis (CIA) to analyze the function of sPD-1 in vivo.

RESULTS

High concentrations of sPD-1 were found in sera and synovial fluid of patients with RA. The levels of serum sPD-1 were significantly correlated with titers of rheumatoid factor (RF) (r = 0.306, p = 0.005) and 28-joint Disease Activity Score (r = 0.545, p < 0.001). Further characterization of sPD-1 revealed that it functionally blocked the inhibitory effect of membrane-bound PD-1 on T-cell activation. Interferon γ, tumor necrosis factor α, and interleukin 17A were identified as inducers of sPD-1 in vitro. Moreover, PD-1-Fc enhanced proinflammatory cytokine expression, generation of Th1 cells and Th17 cells, and joint pathology in a CIA model.

CONCLUSIONS

sPD-1 regulates peripheral T-cell responses in both human and murine RA. Thus, sPD-1 may represent an additional biomarker or target in immunomodulatory therapy for RA.

Generation and characterization of two novel monoclonal antibodies produced against human TLT-2 molecule

Trem-like transcript 2 (TLT-2), one of the TREM family members, which is expressed on B cells, T cells, and macrophages, plays a critical role in immune response mechanism. In this study, two novel mouse anti-human TLT-2 monoclonal antibodies (MAbs) were prepared using hybridoma technology and their immunological characteristics were determined. The results showed that the two MAbs (clones 10F5 and 8C10) were both IgG1 (κ) and bound specifically to human TLT-2. Furthermore, 10F5 and 8C10 seemed to recognize a different site (epitope) of TLT-2 by competition assay. MAb 10F5 was proven in Western blot analysis to specifically bind to denatured TLT-2 protein while both MAbs were proven in dot blot analyses and immunofluorescence to specifically bind to natural TLT-2 protein. In addition, crosslinking of TLT-2 with MAb 8C10 markedly blocked TLT-2 positive signal and T cell proliferation. Taken together, these two monoclonal antibodies might be of great value as tools for further exploration of the expression and function of TLT-2.