The virus neutralization (VN) test was used to determine potency of the infectious bronchitis (IB) vaccine. The results of VN, hemagglutination inhibition (HI), and enzyme-linked immunosorbent assay (ELISA) were compared with those of the IBV M41. The r² values between VN and HI titers and the ELISA antibody titer were 0.8782 and 0.0336, respectively, indicating a high correlation between VN and HI, but not VN and ELISA. The Cohen's kappa coefficient between the VN titer of 2 log₁₀ and HI titer of 5 log₂ was 0.909. Our results showed that VN could be replaced with HI for testing the potency of IBV M41.
Bronchitis ; Enzyme-Linked Immunosorbent Assay* ; Hemagglutination Inhibition Tests* ; Hemagglutination* ; Infectious bronchitis virus* ; Neutralization Tests* ; Vaccine Potency*

PURPOSE: For evaluating the immunogenicity of an influenza vaccine, the microneutralization (MN) test has a higher sensitivity and specificity as compared to the hemagglutination inhibition (HI) test. However, the MN test is more time consuming and is difficult to standardize. We performed the MN test to determine its usefulness as an alternative or complementary test to the HI test for evaluating the immunogenicity of influenza vaccines. METHODS: We compared the MN test with the HI test using 50 paired samples taken from a previous clinical study (2008-2009) in Korean children under 18 years of age. RESULTS: The linear correlation coefficients of the 2 tests for H3N2, H1N1, and influenza B were 0.69, 0.70, and 0.66, respectively. We identified a high index of coincidence between the 2 tests. For an influenza vaccine, the postvaccination seroprotection rates and seroconversion rates determined by the MN test were 78.0% and 96.0%, 90% and 42.0%, and 42.0% and 48.0% for H3N2, H1N1, and influenza B, respectively. Geometric mean titer fold increases of H3N2, H1N1, and influenza B were 2.89, 5.04, and 4.29, respectively, and were 2.5-fold higher. We obtained good results in the evaluation of the immunogenicity of the 2008-2009 seasonal influenza vaccines. CONCLUSION: We found that the MN test was as effective as the HI test. Therefore, we suggest that the MN test can be used as an alternative or complementary test to the HI test for evaluating the immunogenicity of influenza vaccines.
Child ; Hemagglutination ; Hemagglutination Inhibition Tests ; Humans ; Influenza Vaccines ; Influenza, Human ; Neutralization Tests ; Seasons ; Sensitivity and Specificity

A new alternative rabies bait vaccine strain named ERAG3G, which is applicable to wild animals, was developed to eliminate rabies in South Korea. In this study, the safety and immunogenicity of the strain was evaluated in Korean raccoon dogs. The ERAG3G was propagated in BHK/T7-9 cells. Korean raccoon dogs were administered ERAG3G (1 ml, 10(8.0) FAID50/ml) orally or intramuscularly to evaluate its safety and immunogenicity. The raccoon dogs were observed for 70 days after administration, and immunogenicity was measured using a fluorescent antibody virus neutralization test. The ERAG3G strain was not pathogenic to Korean raccoon dogs immunized via the intramuscular or oral route. Raccoon dogs administered the candidate vaccine via the oral route developed high virus neutralizing antibody (VNA) titers ranging from 13.7 to 41.6 IU/ml 70 days post administration. Raccoon dogs inoculated intramuscularly with the ERAG3G strain developed moderate VNA titers ranging from 0.5 to 13.7 IU/ml. These findings suggest that the ERAG3G strain is safe and induces a protective immune response in raccoon dogs.
Animals ; Animals, Wild ; Antibodies, Neutralizing ; Korea ; Neutralization Tests ; Rabies virus* ; Rabies* ; Raccoon Dogs* ; Raccoons*

The seroprevalence of Japanese encephalitis virus (JEV) among equines was evaluated from January 2006 to December 2009 in 13 different states of India by hemagglutination inhibition (HI) test and virus neutralization test (VNT). Antibodies against JEV were detected in 327 out of 3,286 (10%) equines with a maximum prevalence reported in the state of Manipur (91.7%) followed by Gujarat (18.5%), Madhya Pradesh (14.4%), and Uttar Pradesh (11.6%). Evidence of JEV infection was observed in equines in Indore (Madhya Pradesh) where a 4-fold or higher rise in antibody titer was observed in 21 out of 34 horses in November 2007 to October 2006. In March 2008, seven of these horses had a subsequent 4-fold rise in JEV antibody titers while this titer decreased in nine animals. JEV-positive horse sera had a JEV/WNV (West Nile virus) ratio over 2.0 according to the HI and/or VNT. These results indicated that JEV is endemic among equines in India.
Animals ; Encephalitis, Japanese/blood/epidemiology/*veterinary ; *Equidae ; India/epidemiology ; Neutralization Tests ; Seroepidemiologic Studies ; Time Factors

Anti-Sda is of no clinical significance, because it rarely causes hemolytic transfusion reactions. Even when its presence is suspected during antibody screening test, further identification of the antibody is usually not performed. We experienced a case of anti-Sda in 73 yr-old male patient showing mixed field agglutination by microcolumn agglutination. Antibody specificity could not be identified by conventional antibody identification test, and it was proven to be anti-Sda by urine neutralization test. In spite of its little clinical significance, it may give incompatible crossmatching results reacting with Sda antigen, which occurs at a high frequency in general population. When incompatible crossmatch results arising from anti-Sda are suspected, the problem may be solved by using the urine-neutralized serum of in crossmatching test.
Agglutination ; Antibody Specificity ; Blood Group Incompatibility ; Humans ; Male ; Mass Screening ; Neutralization Tests

PURPOSE: The 2000-2001 measles epidemic resulted in more than 50,000 cases with the highest attack rate occuring in infants less than one year of age, indicating the necessity of measles immunization before 12 months of age when a measles outbreak occurs again. The study was conducted to measure maternal measles antibody in infants by plaque reduction neutralization test(PRN), for the first time in Korea, to assess the optimal age for measles vaccination before the first birthday, when necessary. METHODS: Sera were obtained from 95 infants younger than 12 months of age who were healthy or recovered from mild llnesses, and had not had measles vaccination, measles infection, or blood transfusion. Measles antibodies were measured by PRN. RESULTS: Geometric mean titers and seropositive rates of measles antibody measured by PRN were 879.7 mIU/mL(100.0%), 690.0 mIU/mL(83.3%), 182.7 mIU/mL(50.0%), 91.3 mIU/mL(50.0%), 32.2 mIU/ mL(0.0)%, 25.1 mIU/mL(0.0%), 18.1 mIU/mL(0.0%), 38.4 mIU/mL(25.0%), 27.1 mIU/mL(0.0%), 31.2 mIU/mL(0.0%), 54.3 mIU/mL(0.0%), and 27.1 mIU/mL(0.0%) from 0 to 11 months respectively. CONCLUSION: By PRN, which was used for the first time to measure the measles antibody in Korea, placentally transferred measles antibody was detected in all newborns tested and decreased reciprocally to the age of infants, leaving almost all infants older than four months seronegative. These results indicate that measles vaccination at six months of age or older, which is the current recommendation during the period of epidemic issued by the Korean Society of Pediatrics, should not cause the primary vaccine failure. It seems advisable to utilize PRN further in order to find the optimal schedule for measles vaccination to infants born to women who were vaccinated.
Antibodies* ; Appointments and Schedules ; Blood Transfusion ; Female ; Humans ; Immunization ; Infant* ; Infant, Newborn ; Korea ; Measles* ; Neutralization Tests* ; Pediatrics ; Vaccination

PURPOSE: Porcine reproductive and respiratory syndrome virus (PRRSV) leads to major economic losses in the swine industry. Vaccination is the most effective method to control the disease by PRRSV. MATERIALS AND METHODS: In this study, the efficacy of a glycoprotein (GP) 5-modified inactivated vaccine was investigated in pigs. The study was performed in three farms: farm A, which was porcine reproductive and respiratory syndrome (PRRS)-negative, farm B (PRRS-active), which showed clinical signs of PRRS but had not used vaccines, and farm C (PRRS-stable), which had a history of endemic PRRS over the past years, but showed no more clinical signs after periodic administration of modified live virus vaccine. RESULTS: The inactivated vaccine induced great enhancement in serum neutralizing antibody titer, which was sufficient to protect pigs from further infections of PRRSV in a farm where pre-existing virus was circulating. CONCLUSION: These results indicated that vaccination with the inactivated vaccine composed of viruses possessing deglycosylated GP5 would provide enhanced protection to pigs from farms suffering from endemic PRRSV.
Antibodies, Neutralizing ; Glycoproteins ; Neutralization Tests ; Porcine Reproductive and Respiratory Syndrome* ; Porcine respiratory and reproductive syndrome virus* ; Swine* ; Vaccination ; Vaccines ; Vaccines, Inactivated

OBJECTIVETo investigate the prevalence of serum antibodies against Japanese encephalitis virus (JEV) in bats.

METHODSBlood samples from the heart were obtained from bats captured in Guangdong and Hainan Provinces in 2013. The anti-JEV antibodies in bat sera were tested using indirect ELISA and virus neutralization test.

RESULTSA total of 201 bat serum samples were tested, in which the total positivity rate of anti-JEV antibodies was 46.27% (93/201). The positive rate of anti-JEV antibodies in bats from Hainan and Guangdong Provinces was 88.89% (48/54) and 30.61% (45/147), respectively. All the samples from Rousettus leschenaultia, Miniopterus schreibersii, Pipistrellus abramus, and Rhinolophus macrotis were positive for anti-JEV antibodies, and up to 95.56% (43/45) of the samples from Miniopterus schreibersii (from Hainan Province) yielded positive results. Of the 28 samples with positive results by indirect ELISA, 15 showed positive results in virus neutralization test (53.57%) with neutralization antibody titers ranging from 1:10 to 1:28.22.

CONCLUSIONBats from different regions and of different species can be naturally infected with JEV and have a high prevalence of anti-JEV antibodies in their sera. The role of bats in the natural cycle of JEV awaits further study.

Animals ; Antibodies, Viral ; blood ; China ; Chiroptera ; immunology ; virology ; Encephalitis Virus, Japanese ; Enzyme-Linked Immunosorbent Assay ; Neutralization Tests

OBJECTIVETo investigate the characteristics and dynamic changes of serum neutralizing antibody response in patients with primary infection of dengue virus type 1 (DENV-1).

METHODSSerum samples were obtained from the same patients with primary infection of DENV-1 within 2 weeks after symptom onset in 2006 and in 2010. A group-specific DENV NS1 capture ELISA-based micro-neutralizing test (ELISA-MNT) capable of detecting neutralizing antibodies against all the 4 serotypes of DENV was used to test the neutralizing antibody titers against DENV in the serum samples. The neutralizing antibody titers against a standard strain and 2 clinically isolated strains of DENV-1 were detected in serum samples collected in 2010.

RESULTSCross-reactive neutralizing antibody response against all the 4 serotypes of DENV was found in both of the serum samples collected in 2006 and 2010, but the samples collected in 2006 showed stronger cross-reactive neutralizing antibody responses. The neutralizing antibody against DENV-2, rather than the anticipated DENV-1 antibody, had the highest titer in the samples collected in 2006, whereas the antibody against homologous DENV-1 had the highest titer in the samples obtained in 2010. The neutralizing antibody titers against the homologous DENV-1 was significantly higher in samples collected in 2010 (U=86.500, P=0.000), which also demonstrated significantly different neutralizing antibody titers against the 3 different strains of DENV-1 (Χ(2)=12.123, P=0.002).

CONCLUSIONThe production of cross-reactive neutralizing antibodies between the 4 serotypes of DENV is a characteristic of DENV infection, particularly during early infection, but only the homologous neutralizing antibody increases obviously over time. The titers of the neutralizing antibodies against different strains, even of the same serotype, may differ distinctly.

Antibodies, Neutralizing ; blood ; Antibodies, Viral ; blood ; Cross Reactions ; Dengue ; blood ; immunology ; Dengue Virus ; classification ; immunology ; Humans ; Neutralization Tests

OBJECTIVETo explore on the immunity of live attenuated Japanese Encephalitis (JE) vaccine (SA14-14-2) to different wild JE virus (JEV) strains.

METHODSThe neutralizing effect of the vaccine against different wild JE virus strains was detected by plaque reduction neutralization test (PRNT), and the immunogenicity was studied on mice by vaccination -challenge protection test. In the PRNT, pooled sera from vaccinated human were tested against 10 strains of JEV, one isolated in Taiwan and 9 from other Asian countries. In the vaccination challenge test, mice received one dose of the live vaccine subcutaneously and were challenged intraperitoneally 14 days later against 22 JEV virus strains, 11 were isolated in China and the other 11 from Tailand, Vietnahailam, Indonesia, India, Philippines and Japan.

RESULTSThe protection rates to all the 22 challenge virus were 90% - 100% when 340 PFU/0.1 ml vaccinate virus was administered. The neutralizing effect showed that all the JEV isolates many have neutralized by the sera.

CONCLUSIONSA14-14-2 live attenuated prepared with strain SA14-14-2 is broadly immunogenic and may have effective protection against in Asian JE affected countries.

Adolescent ; Animals ; Child ; Encephalitis, Japanese ; prevention & control ; Humans ; Japanese Encephalitis Vaccines ; immunology ; Mice ; Neutralization Tests ; Vaccination ; Vaccines, Attenuated