Displaying publications 1 - 20 of 59 in total

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  1. Abd-Jamil J, Cheah CY, AbuBakar S
    Protein Eng. Des. Sel., 2008 Oct;21(10):605-11.
    PMID: 18669522 DOI: 10.1093/protein/gzn041
    A method to map the specific site on dengue virus envelope protein (E) that interacts with cells and a neutralizing antibody is developed using serially truncated dengue virus type 2 (DENV-2) E displayed on M13 phages as recombinant E-g3p fusion proteins. Recombinant phages displaying the truncated E consisting of amino acids 297-423 (EB2) and amino acids 379-423 (EB4) were neutralized by DENV-2 patient sera and the DENV-2 E-specific 3H5-1 monoclonal antibodies suggesting that the phages retained the DENV-2 E antigenic properties. The EB4 followed by EB2 recombinant phages bound the most to human monocytes (THP-1), African green monkey kidney (Vero) cells, mosquito (C6/36) cells, ScFv specific against E and C6/36 cell proteins. Two potential cell attachment sites were mapped to loop I (amino acids 297 to 312) and loop II (amino acids 379-385) of the DENV-2 E using the phage-displayed truncated DENV-2 E fragments and by the analysis of the E structure. Loop II was present only in EB4 recombinant phages. There was no competition for binding to C6/36 cell proteins between EB2 and EB4 phages. Loop I and loop II are similar to the sub-complex specific and type-specific neutralizing monoclonal antibody binding sites, respectively. Hence, it is proposed that binding and entry of DENV involves the interaction of loop I to cell surface glycosaminoglycan-motif and a subsequent highly specific interaction involving loop II with other cell proteins. The phage displayed truncated DENV-2 E is a powerful and useful method for the direct determination of DENV-2 E cell binding sites.
    Matched MeSH terms: Neutralization Tests
  2. Beran J, Peeters M, Dewé W, Raupachová J, Hobzová L, Devaster JM
    BMC Infect Dis, 2013;13:224.
    PMID: 23688546 DOI: 10.1186/1471-2334-13-224
    Two phylogenetic lineages of influenza B virus coexist and circulate in the human population (B/Yamagata and B/Victoria) but only one B-strain is included in each seasonal vaccine. Mismatch regularly occurs between the recommended and circulating B-strain. Inclusion of both lineages in vaccines may offer better protection against influenza.
    Matched MeSH terms: Neutralization Tests
  3. Cardosa MJ, Hah FL, Choo BH, Padmanathan S
    PMID: 8160055
    A dot enzyme immunoassay for determination of antibodies to Japanese encephalitis virus was designed for use as a field technique for the surveillance of Japanese encephalitis virus activity among domestic pigs. The test was compared with the neutralization test and the hemagglutination inhibition test and found to be more sensitive than the hemagglutination inhibition test and comparable to the neutralization test in sensitivity but more simple to perform than either the neutralization or the hemagglutination inhibition tests. An IgM capture ELISA for the determination of JEV specific porcine IgM was also utilized to determine current infection rates in pigs. The tests which do not involve the determination of specific IgM are better used for testing sentinel animals for providing clues as to the rate of transmission of JEV among pigs. IgM tests determining acute infection are less likely to be useful unless animals are tested very frequently or if a great number of animals are tested at any one time.
    Matched MeSH terms: Neutralization Tests*
  4. Cardosa MJ, Choo BH, Zuraini I
    PMID: 1667957
    This study describes the status of viral encephalitis in Perak, Malaysia during the year 1990. In addition, 14 cases selected from Penang and Perak during the years 1989 and 1990 are presented, with data showing titers of neutralizing antibodies against Japanese encephalitis virus (JEV) and dengue 2 virus, titers of antibodies against JEV and dengue virus antigens as determined by DEIA, and a comparison of these with the presence of IgM to JEV and dengue virus. These data show that there probably is far more viral encephalitis due to JEV in Malaysia than the national figures reflect.
    Matched MeSH terms: Neutralization Tests
  5. Cecilia D, Gould EA
    Virology, 1991 Mar;181(1):70-7.
    PMID: 1704661
    The Sarawak strain of Japanese encephalitis virus (JE-Sar) is virulent in 3-week-old mice when inoculated intraperitoneally. The nucleotide sequence for the envelope glycoprotein (E) of this virus was determined and compared with the published sequences of four other strains. There were several silent nucleotide differences and five codon changes. Monoclonal antibodies (MAbs) against the E protein of JE-Sar virus were prepared and characterized. MAb-resistant mutants of JE-Sar were selected to determine if mutations in the E protein gene could affect its virulence for mice. Eight mutants were isolated using five different MAbs that identified virus-specific or group-reactive epitopes on the E protein. The mutants lost either complete or partial reactivity with selecting MAb. Several showed decreased virulence in 3-week-old mice after intraperitoneal inoculation. Two (r27 and r30) also showed reduced virulence in 2-week-old mice. JE-Sar and the derived mutants were comparable in their virulence for mice, when inoculated intracranially. Mutant r30 but not r27 induced protective immunity in adult mice against intracranial challenge with parent virus. However, r27-2 did induce protective immunity against itself. Nucleotide sequencing of the E coding region for the mutants revealed single base changes in both r30 and r27 resulting in a predicted change from isoleucine to serine at position 270 in r30 and from glycine to aspartic acid at position 333 in r27. The altered capacity of the mutants to induce protective immunity is consistent with the immunogenicity changes predicted by computer analysis using the Protean II program.
    Matched MeSH terms: Neutralization Tests
  6. Ch'ng WC, Stanbridge EJ, Ong KC, Wong KT, Yusoff K, Shafee N
    J Med Virol, 2011 Oct;83(10):1783-91.
    PMID: 21837796 DOI: 10.1002/jmv.22198
    Enterovirus 71 (EV71) infection may cause severe neurological complications, particularly in young children. Despite the risks, there are still no commercially available EV71 vaccines. Hence, a candidate vaccine construct, containing recombinant Newcastle disease virus capsids that display an EV71 VP1 fragment (NPt-VP1(1-100) ) protein, was evaluated in a mouse model of EV71 infection. Previously, it was shown that this protein construct provoked a strong immune response in vaccinated adult rabbits. That study, however, did not address the issue of its effectiveness against EV71 infection in young animals. In the present study, EV71 viral challenge in vaccinated newborn mice resulted in more than 40% increase in survival rate. Significantly, half of the surviving mice fully recovered from their paralysis. Histological analysis of all of the surviving mice revealed a complete clearance of EV71 viral antigens from their brains and spinal cords. In hind limb muscles, the amounts of the antigens detected correlated with the degrees of tissue damage and paralysis. Findings from this study provide evidence that immunization with the NPt-VP1(1-100) immunogen in a newborn mouse model confers partial protection against EV71 infection, and also highlights the importance of NPt-VP1(1-100) as a possible candidate vaccine for protection against EV71 infections.
    Matched MeSH terms: Neutralization Tests
  7. Chan SW, Ong GI, Nathan S
    J. Biochem. Mol. Biol., 2004 Sep 30;37(5):556-64.
    PMID: 15479619
    A recombinant Fab monoclonal antibody (Fab) C37, previously obtained by phage display and biopanning of a random antibody fragment library against Burkholderia pseudomallei protease, was expressed in different strains of Escherichia coli. E. coli strain HB2151 was deemed a more suitable host for Fab expression than other E. coli strains when grown in media supplemented with 0.2 % glycerol. The expressed Fab fragment was purified by affinity chromatography on a Protein G-Sepharose column, and the specificity of the recombinant Fab C37 towards B. pseudomallei protease was proven by Western blotting, enzyme-linked immunosorbent assay (ELISA) and by proteolytic activity neutralization. In addition, polyclonal antibodies against B. pseudomallei protease were produced in rabbits immunized with the protease. These were isolated from high titer serum by affinity chromatography on recombinant-Protein A-Sepharose. Purified polyclonal antibody specificity towards B. pseudomallei protease was proven by Western blotting and ELISA.
    Matched MeSH terms: Neutralization Tests
  8. Chanhome L, Puempunpanich S, Omori-Satoh T, Chaiyabutr N, Sitprija V
    J Nat Toxins, 2002 Dec;11(4):353-6.
    PMID: 12503879
    Immunization with Bungarus candidus venom was performed in four rabbits at high dose (initial dose, 75 microg/kg) and low dose (initial dose, 50 microg/kg). Each dose group consisted of two rabbits; one rabbit received the venom subcutaneously (s.c.) and the other intradermally (i.d.). The venom was injected as emulsified solutions with the same volume of Freund's complete adjuvant until the 4th immunization, thereafter as plain solutions. By stepwise increments of the immunizing dose, the higher dose group received a dose of 200 microg/kg and the lower dose group 150 microg/kg after the 5th immunization, respectively. Thereafter, seven additional immunizations were performed within six months. All rabbits were sacrificed two weeks after the last immunization (12th). Antilethal activity of the immunized antisera thus obtained was determined not only with the homologous venom but also with two heterologous venoms from Bungarus fasciatus and Bungarus flaviceps. Immunodiffusion analysis was also performed with these venoms. The results obtained in this pilot trial provided useful information for production of Malayan krait antivenom at Queen Saovabha Memorial Institute.
    Matched MeSH terms: Neutralization Tests
  9. Chong Sue Kheng, Teoh Kim Chee, Marchette NJ, Garcia R, Rudnick A, Coughlan RF
    Aust. Vet. J., 1968 Jan;44(1):23-5.
    PMID: 5689238
    Matched MeSH terms: Neutralization Tests
  10. Chua CL, Sam IC, Merits A, Chan YF
    PLoS Negl Trop Dis, 2016 08;10(8):e0004960.
    PMID: 27571254 DOI: 10.1371/journal.pntd.0004960
    BACKGROUND: Chikungunya virus (CHIKV) is a re-emerging mosquito-borne virus which causes epidemics of fever, severe joint pain and rash. Between 2005 and 2010, the East/Central/South African (ECSA) genotype was responsible for global explosive outbreaks across India, the Indian Ocean and Southeast Asia. From late 2013, Asian genotype CHIKV has caused outbreaks in the Americas. The characteristics of cross-antibody efficacy and epitopes are poorly understood.

    METHODOLOGY/PRINCIPAL FINDINGS: We characterized human immune sera collected during two independent outbreaks in Malaysia of the Asian genotype in 2006 and the ECSA genotype in 2008-2010. Neutralizing capacity was analyzed against representative clinical isolates as well as viruses rescued from infectious clones of ECSA and Asian CHIKV. Using whole virus antigen and recombinant E1 and E2 envelope glycoproteins, we further investigated antibody binding sites, epitopes, and antibody titers. Both ECSA and Asian sera demonstrated stronger neutralizing capacity against the ECSA genotype, which corresponded to strong epitope-antibody interaction. ECSA serum targeted conformational epitope sites in the E1-E2 glycoprotein, and E1-E211K, E2-I2T, E2-H5N, E2-G118S and E2-S194G are key amino acids that enhance cross-neutralizing efficacy. As for Asian serum, the antibodies targeting E2 glycoprotein correlated with neutralizing efficacy, and I2T, H5N, G118S and S194G altered and improved the neutralization profile. Rabbit polyclonal antibody against the N-terminal linear neutralizing epitope from the ECSA sequence has reduced binding capacity and neutralization efficacy against Asian CHIKV. These findings imply that the choice of vaccine strain may impact cross-protection against different genotypes.

    CONCLUSION/SIGNIFICANCE: Immune serum from humans infected with CHIKV of either ECSA or Asian genotypes showed differences in binding and neutralization characteristics. These findings have implications for the continued outbreaks of co-circulating CHIKV genotypes and effective design of vaccines and diagnostic serological assays.

    Matched MeSH terms: Neutralization Tests
  11. Crameri G, Wang LF, Morrissy C, White J, Eaton BT
    J Virol Methods, 2002 Jan;99(1-2):41-51.
    PMID: 11684302
    Rapid immune plaque assays have been developed to quantify biohazard level 4 agents Hendra and Nipah viruses and detect neutralising antibodies to both viruses. The methods rely on the fact that both viruses rapidly generate large syncytia in monolayers of Vero cells within 24 h and that monospecific antiserum to the Hendra virus phosphoprotein (P) detects that protein in both Hendra and Nipah virus-induced syncytia after methanol fixation of virus-infected cells. The P protein is a constituent of the ribonucleoprotein core of the viruses and a component of the viral RNA-dependent RNA polymerase and is made in significant amounts in infected cells. In the immune plaque assay, anti-P antibody is localised by an alkaline phosphatase-linked second antibody and the Western blot substrates 5-bromo-4-chloro-3-indolyl phosphate and p-nitro blue tetrazolium. A modification of the rapid immune plaque assay was also used to detect antibodies to Nipah virus in a panel of porcine field sera from Malaysia and the results showed good agreement between the immune plaque assay and a traditional serum neutralisation test. After methanol fixation, plates can be stored for up to 7 months and may be used in the immune plaque assay to complement the enzyme-linked immunosorbent assay screening of sera for antibodies to Nipah virus. At present, all enzyme-linked immunosorbent assay positive sera are subject to confirmatory serum neutralisation tests. Use of the immune plaque assay may reduce the number of sera requiring confirmatory neutralisation testing for Nipah virus antibodies under biohazard level 4 conditions by identifying those that generate false positive in the enzyme-linked immunosorbent assay.
    Matched MeSH terms: Neutralization Tests
  12. Downie AW
    J Hyg (Lond), 1974 Apr;72(2):245-50.
    PMID: 4362411
    Sera from cynomolgus monkeys from Malaysia, from Indian rhesus monkeys, from various species of monkeys from Africa and from South America have been examined for neutralizing antibody to Tanapox and Yaba viruses. No antibody was found to either virus in the sera of rhesus monkeys or South American monkeys. A certain proportion of sera from cynomolgus monkeys and various species of African monkey showed antibody to one or other of the viruses, but few of the positive sera showed antibody to both. The results would seem to suggest that infection with the two viruses is endemic in African and Malaysian monkeys but does not occur or is very rare in Indian rhesus and New World monkeys.
    Matched MeSH terms: Neutralization Tests
  13. Fischer K, Diederich S, Smith G, Reiche S, Pinho Dos Reis V, Stroh E, et al.
    PLoS One, 2018;13(4):e0194385.
    PMID: 29708971 DOI: 10.1371/journal.pone.0194385
    Hendra virus (HeV) and Nipah virus (NiV) belong to the genus Henipavirus in the family Paramyxoviridae. Henipavirus infections were first reported in the 1990's causing severe and often fatal outbreaks in domestic animals and humans in Southeast Asia and Australia. NiV infections were observed in humans in Bangladesh, India and in the first outbreak in Malaysia, where pigs were also infected. HeV infections occurred in horses in the North-Eastern regions of Australia, with singular transmission events to humans. Bats of the genus Pteropus have been identified as the reservoir hosts for henipaviruses. Molecular and serological indications for the presence of henipa-like viruses in African fruit bats, pigs and humans have been published recently. In our study, truncated forms of HeV and NiV attachment (G) proteins as well as the full-length NiV nucleocapsid (N) protein were expressed using different expression systems. Based on these recombinant proteins, Enzyme-linked Immunosorbent Assays (ELISA) were developed for the detection of HeV or NiV specific antibodies in porcine serum samples. We used the NiV N ELISA for initial serum screening considering the general reactivity against henipaviruses. The G protein based ELISAs enabled the differentiation between HeV and NiV infections, since as expected, the sera displayed higher reactivity with the respective homologous antigens. In the future, these assays will present valuable tools for serosurveillance of swine and possibly other livestock or wildlife species in affected areas. Such studies will help assessing the potential risk for human and animal health worldwide by elucidating the distribution of henipaviruses.
    Matched MeSH terms: Neutralization Tests
  14. Garba B, Bahaman AR, Zakaria Z, Bejo SK, Mutalib AR, Bande F, et al.
    Microb Pathog, 2018 Nov;124:136-144.
    PMID: 30138761 DOI: 10.1016/j.micpath.2018.08.028
    Leptospirosis is a serious epidemic disease caused by pathogenic Leptospira species. The disease is endemic in most tropical and sub-tropical regions of the world. Currently, there is no effective polyvalent vaccine for prevention against most of the circulating serovars. Moreover, development of an efficient leptospiral vaccine capable of stimulating cross-protective immune responses against a wide range of serovars remains a daunting challenge. This, in part, is associated with the extensive diversity and variation of leptospiral serovars from region to region. In this study, a multi-epitope DNA vaccine encoding highly immunogenic epitopes from LipL32 and LipL41 was designed using in-silico approach. The DNA encoding antigenic epitopes was constructed from conserved pathogenic Leptospira genes (LipL32 and LipL41). Immunization of golden Syrian hamsters with the multi-epitope chimeric DNA vaccine resulted in the production of both agglutinating and neutralizing antibodies as evidence by MAT and in-vitro growth inhibition tests respectively. The antibodies produced reacted against eight different serovars and significantly reduced renal colonization following in vivo challenge. The vaccine was also able to significantly reduce renal colonization which is a very important factor responsible for persistence of leptospires among susceptible and reservoir animal hosts. In conclusion, the leptospiral multi-epitope chimeric DNA vaccine can serve as a potentially effective and safe vaccine against infection with different pathogenic leptospiral serovars.
    Matched MeSH terms: Neutralization Tests
  15. Gordon Smith CE, Turner LH, Armitage P
    Bull World Health Organ, 1962;27:717-27.
    PMID: 13993152
    Because of the risk of introduction of yellow fever to South-East Asia, comparative studies were made of yellow fever vaccination in Malayans who had a high prevalence of antibody to related viruses and in volunteers without related antibody. The proportions of positive neutralizing antibody responses to subcutaneous vaccination with 17D vaccine were not significantly different between volunteers with and without heterologous antibody but the degree of antibody response was greater in those without. The ID(50) of 17D in both groups was about 5 mouse intracerebral LD(50). Multiple puncture vaccination with 17D gave a much lower response rate than subcutaneous vaccination in volunteers with heterologous antibody. In both groups subcutaneous doses of about 50 mouse intracerebral LD(50) gave larger antibody responses than higher doses. The neutralizing indices and analysis of results were calculated by a method based on the survival time of the mice. This method, which has advantages over that of Reed & Muench, is fully described in an annex to this paper.
    Matched MeSH terms: Neutralization Tests*
  16. Gordon Smith CE, McMahon DA, Turner LH
    Bull World Health Organ, 1963;29:75-80.
    PMID: 14043754
    In view of the risk of introduction of yellow fever into South-East Asia, comparative studies have been made of yellow fever vaccination in Malayan volunteers with a high prevalence of antibody to related viruses and in volunteers without related antibody. In a previous paper the neutralizing antibody responses of these volunteers were reported. The present paper describes the haemagglutinin-inhibiting (HI) antibody responses of the same groups of volunteers and discusses the relationship of these responses to the neutralizing antibody responses.The HI responses to yellow fever following vaccination closely paralleled the neutralizing antibody responses whether vaccination was subcutaneous or by multiple puncture. Volunteers with a high level of YF HI antibody due to infection with other group B viruses were found to be less likely to show a significant YF HI response than those without antibody. 90% of HI responses could be detected by the 21st day after vaccination.As with neutralizing antibody responses, volunteers given vaccine doses of 50-500 mouse intracerebral LD(50) subcutaneously gave greater responses than those given higher doses.
    Matched MeSH terms: Neutralization Tests*
  17. Hia YL, Tan KY, Tan CH
    Acta Trop, 2020 Jul;207:105460.
    PMID: 32278639 DOI: 10.1016/j.actatropica.2020.105460
    The banded krait, Bungarus fasciatus is a medically important venomous snake in Asia. The wide distribution of this species in Southeast Asia and southern China indicates potential geographical variation of the venom which may impact the clinical management of snakebite envenomation. This study investigated the intraspecific venom variation of B. fasciatus from five geographical locales through a venom decomplexing proteomic approach, followed by toxinological and immunological studies. The venom proteomes composed of a total of 9 toxin families, comprising 22 to 31 proteoforms at varying abundances. The predominant proteins were phospholipase A2 (including beta-bungarotoxin), Kunitz-type serine protease inhibitor (KSPI) and three-finger toxins (3FTx), which are toxins that cause neurotoxicity and lethality. The venom lethality varied with geographical origins of the snake, with intravenous median lethal doses (LD50) ranging from 0.45-2.55 µg/g in mice. The Thai Bungarus fasciatus monovalent antivenom (BFMAV) demonstrated a dose-dependent increasing immunological binding activity toward all venoms; however, its in vivo neutralization efficacy varied vastly with normalized potency values ranging from 3 to 28 mg/g, presumably due to the compositional differences of dominant proteins in the different venoms. The findings support that antivenom use should be optimized in different geographical areas. The development of a pan-regional antivenom may be a more sustainable solution for the treatment of snakebite envenomation.
    Matched MeSH terms: Neutralization Tests
  18. Imada T, Abdul Rahman MA, Kashiwazaki Y, Tanimura N, Syed Hassan S, Jamaluddin A
    J Vet Med Sci, 2004 Jan;66(1):81-3.
    PMID: 14960818
    Eight clones of monoclonal antibodies (Mabs) to Nipah virus (NV) were produced against formalin-inactivated NV antigens. They reacted positive by indirect immunofluorescent antibody test, and one of them also demonstrated virus neutralizing activity. They were classified into six different types based on their biological properties. These Mabs will be useful for immunodiagnosis of NV infections in animals and further research studies involving the genomes and proteins of NV.
    Matched MeSH terms: Neutralization Tests
  19. Kashiwazaki Y, Na YN, Tanimura N, Imada T
    J Virol Methods, 2004 Nov;121(2):259-61.
    PMID: 15381364
    A monoclonal antibody (MAb) based solid-phase blocking ELISA was developed for detection of antibodies to Nipah virus. The ELISA was designed to detect remaining antigens on the plate with anti-Nipah MAb conjugate after the reaction with sample serum, and enabled simple procedure, detection of neutralizing antibody to Nipah virus, and application of samples from different animal species. Forty of 200 swine reference sera examined were positive by the ELISA, of which thirty seven were found positive by serum neutralization test. Sera from a total of 131 fruit bats captured in Malaysia were also tested and all found negative by the both tests. It is considered that the solid-phase blocking ELISA can be used as a screening test for Nipah virus infection followed by the serum neutralization test as confirmatory test.
    Matched MeSH terms: Neutralization Tests/standards
  20. Kumarapppan C, Jaswanth A, Kumarasunderi K
    Asian Pac J Trop Med, 2011 Sep;4(9):743-7.
    PMID: 21967700 DOI: 10.1016/S1995-7645(11)60185-5
    OBJECTIVE: To validate traditional claims of usefulness of the Indian plants in management of poisonous snakebite and evaluate the antivenom properties displayed by the alcoholic extracts of Andrographis paniculata (A. paniculata), Crateva magna (C. magna), Gloriosa superba (G. superba) and Hydrocotyle javanica (H. javanica).

    METHODS: These plants were collected, identified and the extracts were prepared by using conventional Soxhlet ethanol extraction technique. The venom neutralization activity was accessed in mice (20-25g) and number of mortalities was observed against clinically important snake (Naja nigricollis) venom. Present study also deals with in vitro membrane stabilizing activity of these plants against hyposaline induced human red blood corpuscles (HRBC).

    RESULTS: Extracts of H. javanica and G. superba gave 80 % and 90 % protection to mice treated with minimum lethal dose of venom (LD(99)). These two plants showed significant neutralization effect against the venoms of Naja nigricollis venom. H. javanica and G. superba (25-100 mg/mL) produced significant changes of membrane stabilization of human red blood cells (HRBC) exposed to hyposaline-induced haemolysis.

    CONCLUSIONS: We conclude that probably due to presence of various phytochemicals plays an important role in the anti-venom potential of these Indian medicinal plants against Naja nigricollis venom. The above observations confirmed that A. paniculata, C. magna, G. superba and H. javanica plant extracts possess potent snake venom neutralizing capacity and could potentially be used as an adjuvants for antivenin therapy in case of snakebite envenomation, especially against the local effects of cobra venoms.

    Matched MeSH terms: Neutralization Tests
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