Mpox Neutralizing Antibody Response to LC16m8 Vaccine in Healthy Adults.

BACKGROUND: Vaccination against mpox (formerly known as monkeypox), an infectious disease caused by the monkeypox virus (MPXV), is needed to prevent outbreaks and consequent public health concerns. The LC16m8 vaccine, a dried cell-cultured proliferative live attenuated vaccinia virus­based vaccine, was approved in Japan against smallpox and mpox. However, its immunogenicity and efficacy against MPXV have not been fully assessed. We assessed the safety and immunogenicity of LC16m8 against MPXV in healthy adults. METHODS: We conducted a single-arm study that included 50 participants who were followed up for 168 days postvaccination. The primary end point was the neutralizing antibody seroconversion rate against MPXVs, including the Zr599 and Liberia strains, on day 28. The secondary end points included the vaccine "take" (major cutaneous reaction) rate, neutralizing titer kinetics against MPXV and vaccinia virus (LC16m8) strains, and safety outcomes. RESULTS: Seroconversion rates on day 28 were 72% (36 of 50), 70% (35 of 50), and 88% (44 of 50) against the Zr599 strain, the Liberia strain, and LC16m8, respectively. On day 168, seroconversion rates decreased to 30% (15 of 50) against the Zr599 and Liberia strains and to 76% (38 of 50) against LC16m8. The vaccine "take" (broad definition) rate on day 14 was 94% (46 of 49). Adverse events (AEs), including common solicited cutaneous reactions, occurred in 98% (45 of 48) of participants; grade 3 severity AEs occurred in 16% (8 of 50). No deaths, serious AEs, or mpox onset incidences were observed up to day 168. CONCLUSIONS: The LC16m8 vaccine generated neutralizing antibody responses against MPXV in healthy adults. No serious safety concerns occurred with LC16m8 use. (Funded by the Ministry of Health, Labour and Welfare of Japan; Japan Registry of Clinical Trials number, jRCTs031220171.)

An open-label, non-randomized study investigating the safety and efficacy of smallpox vaccine, LC16, as post-exposure prophylaxis for mpox.

Mpox is an acute exanthematous disease caused by the monkeypox virus. Since May 2022, it has spread as a community-acquired infection, mainly in Europe and the United States, and urgent measures to prevent this infection were also required in Japan. In this study, we investigated the post-exposure prophylaxis of mpox and safety after inoculating the smallpox vaccine. Participants in close contact with patients with mpox were inoculated with "Freeze-dried cell culture Smallpox Vaccine LC16," within 14 days after close contact. Six cases were registered, and all the participants were inoculated. No mpox symptoms or related complications were observed in the participants for 21 days after the close contact. Adverse events due to inoculation, such as rash, fever, lymphadenopathy, and local reaction at the inoculation site (comprising erythema, swelling, induration, and pain) were observed in the participants; however, all inoculation-related events were non-severe and non-serious, and the participants recovered during the 28-day observation period. The findings of this study suggest that inoculation with LC16 is an effective post-exposure prophylaxis in individuals who had close contact with patients with mpox. Further large-scale studies are warranted to validate these findings.

Efficacy and Safety of the Smallpox Vaccine for Postexposure Prophylaxis in Monkeypox: Protocol for an Open-Labeled, Single-Armed Study.

BACKGROUND: In May 2022, a case of monkeypox (currently known as "mpox") with no history of overseas travel was reported in the United Kingdom, followed by reports of infections reported in Europe, the United States, and other countries worldwide. Due to the significant overlap in immune responses among viruses of the genus Orthopoxvirus (including smallpox virus, mpox virus, and vaccinia virus), it is believed that cross-immunity can be achieved by administering the smallpox virus vaccine. In Japan, a smallpox vaccine (LC16m8 strain vaccine) has been approved; however, there was no regulatory approval for the mpox vaccine during the design of this study. Although it is believed that individuals exposed to the mpox virus may receive smallpox vaccination as mpox prophylaxis, the existing evidence is not clear. OBJECTIVE: The primary objective was to evaluate the efficacy of the LC16m8 strain vaccine, approved for smallpox in Japan, for postexposure prophylaxis against mpox when administered to close contacts of individuals with mpox. The secondary objective was to investigate the safety of the vaccine for postexposure prophylaxis against mpox. METHODS: The study aimed to enroll 100 vaccinated participants who had been identified as close contacts of individuals with mpox. Consent was obtained, and the participants are inoculated with the vaccine. Daily recordings of symptoms (body temperature, headache, rash, and side effects) were made until day 21 and then again on day 28. Furthermore, additional evaluations of adverse events were performed by the investigators on days 7, 14, 21, and 28. Considering that the maximum incubation period for mpox is 21 days, the primary end point is the presence or absence of the disease 21 days after close contact. The primary analysis focused on cases within 4 days of intense contact as it has been reported that vaccination within this timeframe can reduce the incidence of the disease. RESULTS: The first trial participant was enrolled on July 28, 2022, and the research period concluded in March 2023. The study results will be published in a peer-reviewed scientific journal. CONCLUSIONS: This study allowed us to investigate the efficacy and safety of the LC16m8 strain vaccine in postexposure prophylaxis against mpox. TRIAL REGISTRATION: Japan Registry of Clinical Trials jRCTs031220137; https://jrct.niph.go.jp/en-latest-detail/jRCTs031220137. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): DERR1-10.2196/46955.

Evaluating the Immunogenicity and Safety of a Smallpox Vaccine to Monkeypox in Healthy Japanese Adults: A Single-Arm Study.

Monkeypox (mpox) is an acute exanthematous disease caused by the monkeypox virus (MPXV). Since May 2022, patients with mpox have been reported worldwide, mainly in Europe and the Americas. In Japan, LC16"KMB," which is a smallpox vaccine derived from a dried cell culture, against mpox, has been approved. Although inoculation with a smallpox vaccine has been recommended to prevent MPXV infection, the immunogenicity of the smallpox vaccine against the MPXV is unclear, and information regarding postvaccination safety is scarce. We present the protocol for a single-arm open-label study to investigate the immunogenicity and safety of LC16"KMB" against the MPXV in healthy Japanese adults. The primary endpoint is the seroconversion rate of neutralizing antibodies against the MPXV on postvaccination day 28. The secondary endpoints are the seroconversion rates against the MPXV on postvaccination days 14 and 168; the seroconversion rates against the vaccinia virus on postvaccination days 14, 28, and 168; the incidence of mpox until day 168; and adverse and serious adverse events until postvaccination days 28 and 168. These results will pave the way for larger comparative studies using other smallpox vaccines to evaluate the test vaccine's safety and efficacy in preventing mpox.

A 1,2,3-triazole-derived pincer-type mesoionic carbene complex of iron(II): carbonyl elimination and hydrosilylation of aromatic aldehydes via the concerted reaction with hydrosilane and a base.

Iron complexes bearing 1,2,3-triazol-5-ylidene were synthesized and applied to the reaction with hydrosilane and homogeneous catalytic hydrosilylation of aromatic ketones and aldehydes. Addition of a free carbene to a solution of Fe(CO)4Br2 yielded an octahedral, diamagnetic and cationic iron(II) complex [Fe(1,2,3-triazolylidene)(CO)2Br]+. Pyrolysis of the dicarbonyl complex eliminated the two CO ligands to form a paramagnetic four-coordinate complex. A theoretical study using DFT calculations indicated that the spin state changed from singlet to quintet during ligand elimination. Investigations of the successful hydrosilylation of acetophenone and benzaldehyde derivatives using MIC-iron(II) bromide suggested the importance of the base for efficient conversion in the catalytic process. The bromide-to-hydride exchange reaction, transmetallation, of MIC-iron(II) bromide in the presence of KOtBu and HSi(OEt)3 which could occur in the initial process of hydrosilylation was proposed, and supported by a theoretical study.

Bimetallic Cu(I) complex with a pyridine-bridged bis(1,2,3-triazole-5-ylidene) ligand.

A dinuclear copper(i) complex bearing a mesoionic carbene ligand has been prepared from the corresponding silver analogue and its structure determined spectroscopically. The results revealed that two Cu(i) halide salt molecules were bound to the carbon atoms of the pyridine-bridged bis(triazolylidene) moieties rather than the pyridine. Cyclic voltammogram measurements revealed that the two Cu(i) centres underwent a stepwise oxidation, suggesting that both the triazolylidene rings of the ligand could be on the same expanded π-conjugated system. The catalytic hydroboration of styrene derivatives with bis(pinacolato)diborane in the presence of this complex allowed for the ß-selective formation of the corresponding alkylboronate esters.

Structural Change in the Dynein Stalk Region Associated with Two Different Affinities for the Microtubule.

Dynein is a large microtubule-based motor complex that requires tight coupling of intra-molecular ATP hydrolysis with the generation of mechanical force and track-binding activity. However, the microtubule-binding domain is structurally separated by about 15nm from the nucleotide-binding sites by a coiled-coil stalk. Thus, long-range two-way communication is necessary for coordination between the catalytic cycle of ATP hydrolysis and dynein's track-binding affinities. To investigate the structural changes that occur in the dynein stalk region to produce two different microtubule affinities, here we improve the resolution limit of the previously reported structure of the entire stalk region and we investigate structural changes in the dynein stalk and strut/buttress regions by comparing currently available X-ray structures. In the light of recent crystal structures, the basis of the transition from the low-affinity to the high-affinity coiled-coil registry is discussed. A concerted movement model previously reported by Carter and Vale is modified more specifically, and we proposed it as the open zipper model.