The C-X-C motif chemokine receptor-1 (CXCR1) is a rhodopsin-like G-protein-coupled receptor, expressed on the cell surface of immune cells and tumors. CXCR1 interacts with some C-X-C chemokines, such as CXCL6, CXCL7, and CXCL8/interleukin-8, which are produced by various cells. Since CXCR1 is involved in several diseases including tumors and diabetes mellitus, drugs targeting CXCR1 has been developed. Therefore, the development of sensitive monoclonal antibodies (mAbs) for CXCR1 has been desired for the diagnosis and treatment. This study established a novel anti-mouse CXCR1 (mCXCR1) mAb; Cx1Mab-1 (rat IgG1, kappa), using the Cell-Based Immunization and Screening (CBIS) method. Cx1Mab-1 reacted with mCXCR1-overexpressed Chinese hamster ovary-K1 (CHO/mCXCR1) and mCXCR1-overexpressed LN229 glioblastoma (LN229/mCXCR1) in flow cytometry. Cx1Mab-1 demonstrated a high binding affinity for CHO/mCXCR1 and LN229/mCXCR1 with a dissociation constant of 2.6×10-9 M and 2.1×10-8 M, respectively. Furthermore, Cx1Mab-1 could detect mCXCR1 by western blot analysis. These results indicated that Cx1Mab-1 is useful for detecting mCXCR1, and provides a possibility for targeting mCXCR1-expressing cells in vivo experiments.
Abstract Antitumor immunity has been well established to be augmented by cytotoxic lymphodepletion therapies. Adoptively transferred naïve and effector T cells proliferate extensively and show enhanced antitumor effects during homeostatic proliferation when they were adoptively transferred into tumor-bearing hosts that were lymphodepleted with cytotoxic agents or by whole body irradiation. Although the impact of lymphodepletion on transferred donor T cells has been well evaluated, its influence on recipient T cells is largely unknown. The current study demonstrates that both regulatory T cells (Tregs) and effector CD8+ T cells from lymphopenic recipients play critical roles in the development of antitumor immunity after lymphodepletion. Cyclophosphamide (CPA) treatment depleted lymphocytes more efficiently than other cytotoxic agents, such as fludarabine, cisplatin, etoposide, paclitaxel or gemcitabine; however, the percentage of CD4+CD25+Foxp3+ Tregs was significantly increased in CPA-treated lymphopenic mice. Depletion of these chemo-resistant Tregs following CPA treatment and transfer of naïve CD4+ T cells augmented the antitumor immunity and significantly suppressed tumor progression. Further analyses revealed that recipient CD8+ T cells were responsible for this augmentation. Using Rag2−/− mice or depletion of recipient CD8+ T cells after CPA treatment abrogated the augmentation of antitumor effects in CPA-treated reconstituted mice. The transfer of donor CD4+ T cells enhanced the proliferation of CD8+ T cells and the priming of tumor-specific CD8+ T cells originating from the lymphopenic recipients. These results highlight the importance of the recipient cells surviving cytotoxic regimens in cancer immunotherapies. Citation Format: Ko Sato, Satoshi Watanabe, Yu Saida, Tomohiro Tanaka, Junko Baba, Aya Ohtsubo, Satoshi Shoji, Daisuke Ishikawa, Rie Kondo, Masaaki Okajima, Satoru Miura, Junta Tanaka, Hiroshi Kagamu, Hirohisa Yoshizawa, Ichiei Narita. Critical roles of chemo-resistant effector and regulatory T cells in cancer immunotherapy during hemostatic proliferation. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 3153. doi:10.1158/1538-7445.AM2015-3153
Passive mechanisms have been well developed to realize the safe level walk for transfemoral prosthesis users, preventing unintended knee flexion during prosthetic stance phase. However, for stair ascent, a mechanism had not existed for a long time. We previously developed the knee joint unit whose mechanism realized prosthetic knee extension using load or external force on the knee joint unit itself. Although the level walk and stair ascent functions have been accomplished with different mechanisms, these functions should be combined into one mechanism for the prosthetic knee to contribute to regaining locomotion capacities. Therefore, the purpose of the present study was to develop a passive knee mechanism that realized both functions. We proposed a passive mechanism combining the pre-existing mechanisms. The proposed knee was designed to function as a four-link mechanism that prevented unintended knee flexion during level walking. For stair ascending, it was designed to extend the knee, using load on the prosthetic leg when the prosthetic leg contacted a step of the staircase with the knee flexed. The gait experiment with the proposed knee on a transfemoral prosthesis showed successful level walking, stair ascending, and their transition without any assistive device such as the use of a handrail. According to the experimental results, the functions worked and switched appropriately during the transition from level walk to stair ascent, depending on gait conditions without manual handling.
The adoptive transfer of effector T cells combined with lymphodepletion has demonstrated promising antitumor effects in mice and humans, although the availability of tumor-specific T cells is limited. We and others have also demonstrated that the transfer of polyclonal naïve T cells induces tumor-specific effector T cells and enhances antitumor immunity after lymphodepletion. Because tumors have been demonstrated to induce immunosuppressive networks and regulate the function of T cells, obtaining a sufficient number of fully functional naïve T cells that are able to differentiate into tumor-specific effector T cells remains difficult. To establish culture methods to obtain a large number of polyclonal T cells that are capable of differentiating into tumor-specific effector T cells, naïve T cells were activated with anti-CD3 mAbs in vitro. These cells were stimulated with IL-2 and IL-7 for the CD8 subset or with IL-7 and IL-23 for the CD4 subset. Transfer of these hyperexpanded T cells after lymphodepletion showed significant antitumor efficacy, and tumor-specific effector T cells were primed from these expanded T cells in tumor-bearing hosts. Moreover, these ex vivo-expanded T cells maintained T cell receptor diversity and showed long-term persistence of memory against specific tumors. Further analyses revealed that combination therapy consisting of vaccination with dendritic cells that were co-cultured with irradiated whole tumor cells and the transfer of ex vivo-expanded T cells significantly enhanced antitumor immunity. These results indicate that the transfer of ex vivo-expanded polyclonal T cells can be combined with other immunotherapies and augment antitumor effects.
The epithelial cell adhesion molecule (EpCAM) is a cell surface glycoprotein, which is widely expressed on normal and cancer cells. EpCAM is involved in cell adhesion, proliferation, survival, stemness, and tumorigenesis. Therefore, EpCAM is thought to be a promising target for cancer diagnosis and therapy. In this study, we established anti-EpCAM monoclonal antibodies (mAbs) using the Cell-Based Immunization and Screening (CBIS) method. We characterized them using flow cytometry, Western blotting, and immunohistochemistry. One of the established recombinant anti-EpCAM mAbs, recEpMab-37 (mouse IgG1, kappa), reacted with EpCAM-overexpressed Chinese hamster ovary-K1 cells (CHO/EpCAM) or a colorectal carcinoma cell line (Caco-2). In contrast, recEpMab-37 did not react with EpCAM-knocked out Caco-2 cells. The KD of recEpMab-37 for CHO/EpCAM and Caco-2 was 2.0 × 10-8 M and 3.2 × 10-8 M, respectively. We observed that EpCAM amino acids between 144 to 164 are involved in recEpMab-37 binding. In Western blot analysis, recEpMab-37 detected the EpCAM of CHO/EpCAM and Caco-2 cells. Furthermore, recEpMab-37 could stain formalin-fixed paraffin-embedded colorectal carcinoma tissues by immunohistochemistry. Taken together, recEpMab-37, established by the CBIS method, is useful for detecting EpCAM in various applications.
Supramolecular interference: A synthetic peptide mimetic of the trimeric form of gp41 showed significantly increased inhibitory activity against the HIV-1 fusion mechanism. This study demonstrates a useful strategy for the design of effective inhibitors against viral infections that proceed by membrane fusion with host cells.
e20616 Background: J-ALEX showed superiority of ALC 300mg BID vs crizotinib (CRIZ) in Japanese ALK inhibitor naïve ALK-positive NSCLC patients (pts). PopPK and ER analyses were used to bridge J-ALEX data to the global population to confirm the appropriateness of ALC 600mg BID dose, used in global trials. Methods: The previous popPK analysis (Hsu et al, ASCO 2016) was updated to include PK data from J-ALEX and the ongoing global ALEX study to confirm any significant covariates influencing PK of ALC and major metabolite, M4, using Bayesian feedback analysis. ER analyses from J-ALEX (n=96) investigated the relationship between ALC and progression-free survival (PFS) by a Cox proportional hazards (CPH) analysis and key safety events using logistic regression. Results: The popPK models previously developed for pts who have progressed on, or are intolerant to CRIZ were able to adequately predict ALC and M4 PK in J-ALEX and ALEX. Body weight remained the only significant covariate influencing ALC and M4 PK. Administration of ALC 600mg BID in the global population ensures that ALC and M4 exposures across the body weight range are not inferior to those seen in Japanese pts receiving ALC 300mg BID, while lower doses would result in lower exposures. CPH analysis demonstrated a statistically significant relationship between ALC exposure and PFS in J-ALEX such that one third of pts in J-ALEX may benefit from a higher exposure of ALC (Table). ALC 600mg BID ensures the distribution of achieved exposures maximize the expected PFS benefit while lower ALC exposures could result in reduced efficacy. No significant exposure-safety relationships were identified in J-ALEX consistent with previous analyses conducted following ALC 600mg BID. Conclusions: ALC 600mg BID is the appropriate dose in the global ALK inhibitor naïve population. Clinical trial information: JapicCTI-132316. [Table: see text]
