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Introduction: Our group has conducted extensive basic and preclinical studies of the use of human induced pluripotent cell (iPSC)-derived neural stem/progenitor cell (hiPSC-NS/PC) grafts in models of spinal cord injury (SCI). Evidence from animal experiments suggests this approach is safe and effective. We are preparing to initiate a first-in-human clinical study of hiPSC-NS/PC transplantation in subacute SCI., Setting: NS/PCs were prepared at a Good Manufacturing Practice-grade cell processing facility at Osaka National Hospital using a clinical-grade integration-free hiPSC line established by the iPSC Stock Project organized by the Kyoto University Center for iPS Cell Research and Application. After performing all quality checks, the long-term safety and efficacy of cells were confirmed using immunodeficient mouse models., Methods: The forthcoming clinical study uses an open-label, single-arm design. The initial follow-up period is 1 year. The primary objective is to assess the safety of hiPSC-NS/PC transplantation in patients with subacute SCI. The secondary objective is to obtain preliminary evidence of its impact on neurological function and quality-of-life outcomes. Four patients with C3/4-Th10 level, complete subacute (within 24 days post-injury) SCI will be recruited. After obtaining consent, cryopreserved cells will be thawed and prepared following a multi-step process including treatment with a γ-secretase inhibitor to promote cell differentiation. A total of 2 × 10 6  cells will be transplanted into the injured spinal cord parenchyma 14-28 days post-injury. Patients will also receive transient immunosuppression. This study protocol has been reviewed and approved by the Certified Committee for Regenerative Medicine and the Japanese Ministry of Health, Labor and Welfare (University Hospital Medical Information Network Clinical Trials Registry [UMIN-CTR] number, UMIN000035074; Japan Registry of Clinical Trials [jRCT] number, jRCTa031190228)., Discussion/conclusion: We plan to start recruiting a patient as soon as the COVID-19 epidemic subsides. The primary focus of this clinical study is safety, and the number of transplanted cells may be too low to confirm efficacy. After confirming safety, a dose-escalation study is planned., Competing Interests: R.Y. is an employee of Sumitomo Dainippon Pharma Co., Ltd. M.N. has a consultancy role with K-Pharma, Inc. and has received research funding from RMiC. H.O. is a compensated scientific consultant for San Bio Co., Ltd., K-Pharma, Inc., RMiC, and intellim Holdings Corporation and has received research funding from SanBio Co., Ltd., K-Pharma, Inc., and RMiC. S.Y. declared consulting, research funding from iPS Academia Japan. TA has a consultancy role with Kringle Pharma, Inc. The other authors declare no potential conflicts of interest., (© 2021 The Japanese Society for Regenerative Medicine. Production and hosting by Elsevier B.V.)

Human monoclonal antibody (hMAb) cocktail SM-17220 (also known as BT-570), a heterofunctional antibody mixture of 3 human IgM MAbs (HI-223, MH-4H7, and IN-2A8; ratio of 1:10:10) directed against Pseudomonas aeruginosa, were administered to patients with pneumonia or burn wounds (or both) to assess the pharmacokinetics, safety, antigenicity, and preliminary efficacy. Twenty mg of SM-17220 was IV infused over 60 min once daily on 3 consecutive days. Twenty patients (8 pneumonia, 4 burns, and 8 both) completed the study. SM-17220 was safe and well tolerated, and no subjects developed antibodies to SM-17220 and mouse J-chain during the follow-up of 8 weeks. Each MAb of SM-17220 had a half-life ranging from 49 to 91 h, similar to native human IgM. Both MH-4H7 and IN-2A8 administration resulted in a high serum level for about 4 days over an effective concentration, whereas HI-223 showed a lower serum level than expected. Some indications of a potential efficacy were observed and are discussed here.

A hybridoma cell line producing a human anti-lipid A monoclonal antibody (mAb), FKF-IF3 (IgM (k)) was obtained by cell fusion of Epstein-Barr virus-transformed cells and mouse myeloma. The mAb bound to not only Gram-negative bacterial lipid A, but also to polysaccharide portions of Pseudomonas aeruginosa lipopolysaccharides (LPS). The mAb seemed to recognize two distinct regions of P. aeruginosa LPS other than lipid A, namely the outer core regions of some serotype strains and the O-polysaccharide region of serotype A strains. The mAb cross-reacted with N-acetyl-beta-glucosamine-conjugated bovine serum albumin, N-acetyl-beta-galactosamine-conjugated bovine serum albumin, myosin and actin, but not with other autoantigens such as ss- and ds-DNA, cardiolipin and glycosaminoglycans. The mAb conferred protective activity against a mouse pseudomonal infection model. The evidence suggested that the mAb was a naturally occurring polyspecific antibody that participated in defense against pseudomonal infections.

Human monoclonal antibody HI-1A4 (IgG3, lambda) neutralized a toxicity caused by pseudomonal exotoxin A (Ex-A) in cell culture and in vivo, and was effective in experimental Pseudomonas aeruginosa infections in mice. HI-1A4 inhibited an Ex-A catalyzed ADP-ribosylation of elongation factor 2 but did not inhibit an incorporation of toxin into a target cell at all. One molecule of HI-1A4 neutralized at least 2 molecules of Ex-A. HI-1A4 retained its binding activity at pH 4.0. The epitope region for HI-1A4 was demonstrated to be a carboxyl terminal end of amino acid residues 591-613 of Ex-A. HI-1A4 might bind to Ex-A carboxyl terminal region outside a target cell, be incorporated into cells as a complex with Ex-A, and inhibit the intracellular function in which the carboxyl terminal part of Ex-A was involved, resulting in the interruption of intoxication of Ex-A.