Persistence of neutralizing antibody and its protective efficacy induced by a live attenuated tetravalent dengue vaccine, KD-382, in cynomolgus monkeys.

An effective dengue vaccine should induce a long-lasting immune response against all four serotypes simultaneously with a minimum number of immunizations. Our live attenuated tetravalent dengue vaccine candidate, KD-382, was developed using a classical host range mutation strategy (no addition of artificial genetic modification). In our previous study, cynomolgus monkeys immunized with a single dose of KD-382 seroconverted to all four serotypes. However, it is important to determine if neutralizing antibodies (NAbs) induced by KD-382 can work as a long-lasting immune response to prevent dengue. In this study, a single dose of KD-382 induced a strong NAb response against all four serotypes in cynomolgus monkeys. We also confirmed that NAb titers against all four serotypes persist for at least five years, indicating its high potential as a dengue vaccine candidate. Next, we evaluated the effect of pre-existing dengue immunity on NAb responses induced by KD-382. We administered KD-382 to cynomolgus monkeys pre-administered one of the monovalent parental wild-type strains 60 days before vaccination. Regardless of the pre-immunized serotype, all the monkeys showed sufficient tetravalent NAb responses, which lasted for over two years. All the KD-382 vaccinated monkeys were then challenged with different parental wild-type viruses than that used for pre-administration; viral RNA in the serum was less than the lower limit of quantification, indicating complete protection against secondary heterologous dengue infection without any harmful disease enhancement. Consequently, KD-382 successfully induced a long-lasting and protective tetravalent NAb response in monkeys, suggesting that KD-382 is a promising vaccine candidate usable for both dengue seronegative and seropositive individuals.

Well-balanced immune response and protective efficacy induced by a single dose of live attenuated tetravalent dengue vaccine (KD-382) in monkeys.

One of the challenges developing a live attenuated tetravalent dengue vaccine (TDV) is to overcome the presumed viral interference that may be preventing the induction of a balanced immune response to all 4 serotypes of the dengue virus (DENV1-4). Our live attenuated TDV candidate was developed from wild-type (wt) parental strains (DENV1/03135, DENV2/99345, DENV3/16562, and DENV4/1036, respectively) using a classical host range mutation strategy: the same strategy used for the approved live attenuated smallpox, polio, and MMR vaccines. Our vaccine candidate is expected to mimic natural dengue virus infection, as it provides all the components of dengue virus, including both structural and nonstructural proteins. Therefore, induction of more solid and comprehensive immune responses against pathogenic dengue viruses is also expected. In this study, we evaluated the neutralizing antibody responses for each serotype induced by a single subcutaneous administration of 6 formulations, which were composed of different combinations of vaccine strains and were all of different dosages. These formulations were tested in dengue-naïve cynomolgus macaques. As a result, regardless of the TDV formulation, all the monkeys immunized with TDVs seroconverted to all the 4 serotypes at day 30. Next, we evaluated protection ability of the selected formulations of TDV candidate, no RNAemia was detected from any of the immunized monkeys upon s.c. challenge with wtDENV. The findings of this non-human primate study indicate that our vaccine candidate is very promising; it can be further evaluated for safety and efficacy in human clinical studies.

The immediate effect of the Honda Walking Assist Device on foot and ankle function in hemiplegic stroke patients.

[Purpose] We evaluated the reliability of the measurement function of the Honda Walking Assist Device and investigated the effect of the device on walking improvements, and foot and ankle function, in hemiplegic stroke patients. [Participants and Methods] We recruited 16 hemiplegic stroke patients who performed 10-meter walk tests, twice without assistance and once with device assistance. Based on the rate of change of velocity, we divided the participants into two groups and compared the walking parameters, the toe grip strength, the cross tests, and the maximum step width. Two examiners assessed the 10-meter walk test results, and the authors calculated the intraclass correlation coefficients for walking speed, stride length, cadence, flexion, extension, and scissor angles. [Results] The intraclass correlation coefficients were greater than 0.70 for all the walking parameters we measured. The device increased hip joint movement but did not alter the maximum walking speed of the stroke patients. The patients in the group with a greater change in velocity displayed lower toe grip strength and decreased maximum step width and used orthoses more commonly. [Conclusion] The walking measurement function of the device was reliable. The immediate effect of the device in stroke patients may be influenced by the level of paralysis and the presence of an orthosis.

Simple and rapid detection method for the mutations in SLC22A12 that cause hypouricemia by allele-specific real-time polymerase chain reaction.

BACKGROUND: Hypouricemia is a disorder that serum urate level is less than 2.0 mg/dl, and relatively common in the Japanese population, where the main genetic cause of hypouricemia is W258X and R90H mutations in human urate trasnsporter 1(SLC22A12). Small scale screening has relied on time-consuming traditional ways like polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Therefore, it is beneficial that we have an easy and rapid detection method for these mutations. METHODS: In this report, we established a touchdown allele-specific real-time polymerase chain reaction (ASPCR) assay for detecting W258X and R90H mutations in SLC22A12, respectively. RESULTS: Quantifiable discrimination was successfully achieved by ∆Ct value. Furthermore, we conducted W258X and R90H screening against 120 control genome sets, whereby frequency was 2.92% for W258X, and not detected for R90H, respectively. CONCLUSIONS: The two mutations, W258X and R90H in SLC22A12 were successfully genotyped by an easy and rapid ASPCR assay.