Corrigendum to “Evaluation of Potency on Diphtheria and Tetanus Toxoid for Adult Vaccines by In Vivo Toxin Neutralization Assay Using National Reference Standards”Osong Public Health Res Perspect 2018;9(5):278–82

The authors wanted to include the statement along with the existing sentence in the Acknowledgments section.

Evaluation of Potency on Diphtheria and Tetanus Toxoid for Adult Vaccines by In Vivo Toxin Neutralization Assay Using National Reference Standards

OBJECTIVES: Vaccinations against diphtheria and tetanus are essential in providing immunity against these bacterial infections. The potency of diphtheria and tetanus toxoid vaccines can be measured using the in vivo toxin neutralization assay. The limit of potency of this assay was determined only for children. Therefore, we assessed the potency of adult vaccines using this assay to identify the feasibility of limit for adult vaccines. METHODS: Fifteen lots of tetanus-reduced diphtheria and tetanus-diphtheria-acellular pertussis vaccines were used. In vivo toxin neutralization and lethal challenge assays were conducted on each vaccine to calculate the potencies of the toxoids. National reference standards for toxins and antitoxins were used for in vivo toxin neutralization assay. RESULTS: All 15 lots satisfied the limits of potency for lethal challenge assay. The potency of diphtheria and tetanus toxoids exceeded 1 and 8 units/mL, respectively, for in vivo toxin neutralization assay. CONCLUSION: Although additional studies are required for new assays and limits, the current level of potency for adult vaccines as determined by in vivo toxin neutralization assay, was demonstrated in this study. Such efforts to improve assays are expected to promote the development of diphtheria and tetanus vaccines for adults and to contribute to vaccine self-sufficiency.

Development of Multiplex PCR Detection of Blood-borne Viruses by Nucleic Acid Hybridization

Polymerase chain reaction (PCR) has been used as a substitute for conventional serological methods in order to provide blood or blood products free from contaminating viruses and recently attempts have focused to detect 2 or 3 viruses by a single multiplex PCR (M-PCR) reaction. We were able to detect human immunodeficiency virus type 1 (HIV-1), hepatitis C virus (HCV), hepatitis B virus (HBV) and human cytomegalovirus (HCMV) simultaneously by a single M-PCR. However detection by gel electrophoresis of the products from M-PCR suffers from drawbacks such as low sensitivity and product sizes. Here we report enhanced detection systems of M-PCR based on nucleic acid hybridization with arrays built on membrane. Membrane array was manufactured by spotting appropriate probe DNAs on nylon membrane. Single or multiplex PCR was performed and the PCR products were labeled with DIG and allowed to hybridize with the membrane array. Results indicate that nonspecific hybridization was not observed for membrane DNA array. Additionally, membrane array method could detect small amount of viruses that were not detectable by conventional gel electrophoresis. At least 25-fold, and in some cases more than 125-fold increases in sensitivity was obtained with DNA array method. Thus, the nucleic acid hybridization with membrane array could be applied for the detection of M-PCR of viruses in blood or blood products.

Analysis of HCV positive plasma and manufacturing of HCV RNA national standard candidate / 대한수혈학회지

BACKGROUNDS: Standardization of nucleic acid amplification techniques (NAT) which can be achieved by the use of standard to validate reproducibility and sensitivity in each assay run is necessary before the introduction of such methods for routine screening of blood and blood products for viral contaminants. The objective of this study was to analyze the serological and genotypic characteristics of HCV positive plasmas and to manufacture the HCV RNA national standard candidate. METHODS: We obtained three plasmas from Blood Transfusion Research Institute, Korea, with highly positive HCV RNA plasmas (#37, #40, #46) and with normal plasma for dilution. All the plasmas were confirmed by enzyme immunoassay (EIA) test for anti-HIV, HBsAg, anti-HCV and by polymerase chain reaction(PCR) for HBV DNA, HIV RNA, HCV RNA. The genotypes of those were confirmed by INNO-LiPA HCV II. HCV RNA national standard candidate was manufactured by dispensing the diluted plasma into about 2,000 vials. Each vial was rapidly frozen using liquid nitrogen and was kept in refrigerator at -70 degrees C. RESULTS: All plasmas were identified as anti-HIV, HBsAg, HBV DNA, and HIV RNA negative plasmas. The genotypes of those were confirmed as 1b for #37, 1b or 2 for #40 and 2a or 2c for #46, respectively. Sample #37 was selected as the candidate material. After manufacturing, we obtained 1,944 vials for the candidate. CONCLUSION: In this study, we analyzed HCV positive plasmas and manufactured the HCV RNA national standard candidate. In near future, this material would be established for national standard to increase in the safety of blood and blood products in Korea.

Investigation on the Immunity to Pertussis in the Korea

Acellular pertussis vaccine has been used widely in Korea since 1984. However, because many of the former generations were not inoculated with pertussis vaccine, they may infect infants with pertussis. With this background, we investigated the prevalence of pertussis antibodies in all age groups. Enzyme-linked immunosorbent assay (ELISA) to assess IgG antibodies to pertussis toxin (PT) and filamentous hemagglutinin (FHA) and bacterial agglutination (BA) to assess antibodies to agglutinogen were compared on 842 serum samples which were donated from 11 hospitals in Seoul area. In comparison with age groups under 20 years, antibodies of adults against PT and FHA were maintained. But antibodies against agglutinogen showed no pattem in all age groups. Antibodies to PT were correlated with antibodies to FHA. There was no significant difference in antibody levels between male and female (p<0.05).