Displaying publications 21 - 40 of 59 in total

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  1. Fulltext Enterovirus type 70: the etiologic agent of pandemic acute haemorrhagic conjunctivitis
    Mirkovic RR, Kono R, Yin-Murphy M, Sohier R, Schmidt NJ, Melnick JL
    Bull World Health Organ, 1973;49(4):341-6.
    PMID: 4368683
    A new enterovirus, now classified as enterovirus type 70, was isolated from the conjunctiva of patients with acute haemorrhagic conjunctivitis during the 1971 epidemics that occurred in Japan, Singapore, and Morocco. These epidemics were parts of a pandemic involving Africa (Algeria, Ghana, Morocco, Nigeria, and Tunisia), Asia (Cambodia, China (Province of Taiwan), Hong Kong, India, Indonesia, Japan, Malaysia, the Philippines, Singapore, and Thailand), and England during 1969-71. A representative strain from each of the three epidemic areas was studied cooperatively. The strains exhibited the physicochemical characteristics of enteroviruses. Cross-neutralization tests showed that these viruses were distinct from all known human enterovirus immunotypes, but that they were antigenically closely related. The human origin of the viruses was demonstrated by the appearance of homologous neutralizing antibodies during convalescence in patients with acute haemorrhagic conjunctivitis.
    Matched MeSH terms: Neutralization Tests
  2. Functional Application of Snake Venom Proteomics in In Vivo Antivenom Assessment
    Tan CH, Tan KY
    Methods Mol Biol, 2019;1871:153-158.
    PMID: 30276739 DOI: 10.1007/978-1-4939-8814-3_11
    Reverse-phase high-performance liquid chromatography is commonly employed as a decomplexing strategy in snake venom proteomics. The chromatographic fractions often contain relatively pure toxins that can be assessed functionally for toxicity level through the determination of their median lethal doses (LD50). Further, antivenom efficacy can be evaluated specifically against these venom fractions to understand the limitation of the antivenom as the treatment for snake envenomation. However, methods of toxicity assessment and antivenom evaluation vary across laboratories; hence there is a need to standardize the protocols and parameters, in particular those related to the neutralizing efficacy of antivenom. This chapter outlines the important in vivo techniques and data interpretation that can be applied in the functional study of snake venom proteomes.
    Matched MeSH terms: Neutralization Tests
  3. Comparative venom proteomics of banded krait (Bungarus fasciatus) from five geographical locales: Correlation of venom lethality, immunoreactivity and antivenom neutralization
    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
  4. Fulltext Plasmodium-infected erythrocytes induce secretion of IGFBP7 to form type II rosettes and escape phagocytosis
    Lee WC, Russell B, Sobota RM, Ghaffar K, Howland SW, Wong ZX, et al.
    Elife, 2020 Feb 18;9.
    PMID: 32066522 DOI: 10.7554/eLife.51546
    In malaria, rosetting is described as a phenomenon where an infected erythrocyte (IRBC) is attached to uninfected erythrocytes (URBC). In some studies, rosetting has been associated with malaria pathogenesis. Here, we have identified a new type of rosetting. Using a step-by-step approach, we identified IGFBP7, a protein secreted by monocytes in response to parasite stimulation, as a rosette-stimulator for Plasmodium falciparum- and P. vivax-IRBC. IGFBP7-mediated rosette-stimulation was rapid yet reversible. Unlike type I rosetting that involves direct interaction of rosetting ligands on IRBC and receptors on URBC, the IGFBP7-mediated, type II rosetting requires two additional serum factors, namely von Willebrand factor and thrombospondin-1. These two factors interact with IGFBP7 to mediate rosette formation by the IRBC. Importantly, the IGFBP7-induced type II rosetting hampers phagocytosis of IRBC by host phagocytes.
    Matched MeSH terms: Neutralization Tests
  5. An outbreak of acute conjunctivitis caused by coxsackievirus A24 in Kuala-Lumpur, Malaysia, 1978
    Tan DS, Yin-Murphy M, Kandiah S
    Southeast Asian J Trop Med Public Health, 1980 Mar;11(1):24-7.
    PMID: 6250226
    An investigation of an outbreak of acute conjunctivitis in Kuala Lumpur from May to August 1978 was made. A total of 2,133 cases was involved, most of whom were adult Malay males of low income status from the surrounding villages and low-cost flats. The majority of cases had bilateral conjunctivitis with clear discharge. Pain and subconjunctival haemorrhage were not common and recovery, mostly without complications, occurred within 1 week. Eye scrapings and paired sera specimens were examined and the causal agent was found to be Coxsackievirus A24 (CA24).
    Matched MeSH terms: Neutralization Tests
  6. Japanese B encephalitis in a horse
    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
  7. Experimental Nipah virus infection in pigs and cats
    Middleton DJ, Westbury HA, Morrissy CJ, van der Heide BM, Russell GM, Braun MA, et al.
    J Comp Pathol, 2002 Feb-Apr;126(2-3):124-36.
    PMID: 11945001 DOI: 10.1053/jcpa.2001.0532
    A human isolate of Nipah virus from an outbreak of febrile encephalitis in Malaysia that coincided with a field outbreak of disease in pigs was used to infect eight 6-week-old pigs orally or subcutaneously and two cats oronasally. In pigs, the virus induced a respiratory and neurological syndrome consistent with that observed in the Malaysian pigs. Not all the pigs showed clinical signs, but Nipah virus was recovered from the nose and oropharynx of both clinically and sub-clinically infected animals. Natural infection of in-contact pigs, which was readily demonstrated, appeared to be acute and self-limiting. Subclinical infections occurred in both inoculated and in-contact pigs. Respiratory and neurological disease was also produced in the cats, with recovery of virus from urine as well as from the oropharynx. The clinical and pathological syndrome induced by Nipah virus in cats was comparable with that associated with Hendra virus infection in this species, except that in fatal infection with Nipah virus there was extensive inflammation of the respiratory epithelium, associated with the presence of viral antigen. Viral shedding via the nasopharynx, as observed in pigs and cats in the present study, was not a regular feature of earlier reports of experimental Hendra virus infection in cats and horses. The findings indicate the possibility of field transmission of Nipah virus between pigs via respiratory and oropharyngeal secretions.
    Matched MeSH terms: Neutralization Tests/veterinary
  8. Fulltext Immunogenicity and safety of quadrivalent versus trivalent inactivated influenza vaccine: a randomized, controlled trial in adults
    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
  9. Fulltext Antihaemolytic and snake venom neutralizing effect of some Indian medicinal plants
    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
  10. A pilot experiment for production of Malayan krait antivenom: immunization of rabbits with Bungarus candidus venom
    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
  11. The distribution and prevalence of group A arbovirus neutralizing antibodies among human populations in Southeast Asia and the Pacific islands
    Tesh RB, Gajdusek DC, Garruto RM, Cross JH, Rosen L
    Am J Trop Med Hyg, 1975 Jul;24(4):664-75.
    PMID: 1155702
    Plaque reduction neutralization tests, using five group A arboviruses (chikungunya, Ross River, Getah, Bebaru and Sindbis), were done on sera from human populations in 44 Southeast Asia and Pacific island localities. Specificity of the plaque neutralization test was determined by examining convalescent sera from patients with known alphavirus infections. Chikungunya-specific neutralizing antibodies were demonstrated in sera of persons living in South Vietnam, Northern Malaysia, Indonesia (Kalimantan and Sulawesi), as well as Luzon, Marinduque, Cebu and Mindanao islands in the Philippines. Evidence of Ross River virus infection was found among populations living in West New Guinea and Papua New Guinea mainland, the Bismark Archipelago, Rossel Island and the Solomon Islands. There appeared to be no geographic overlap in the distribution of chikungunya and Ross River viruses, with the separation in their distribution corresponding with Weber's line in the Pacific. Sindbis neutralizing antibodies were found in 7 of 21 populations sampled, but in general the prevalence of infection was low. Four sera, from Vietnam, Malaysia and Mindanao gave monospecific reactions with Getah virus. No evidence of specific Bebaru virus infection was detected. The epidemiology of these five alphaviruses in Southeast Asia and the Pacific islands is discussed.
    Matched MeSH terms: Neutralization Tests
  12. Japanese encephalitis in Sarawak: virus isolation and serology in a Land Dyak village
    Simpson DI, Bowen ET, Platt GS, Way H, Smith CE, Peto S, et al.
    Trans R Soc Trop Med Hyg, 1970;64(4):503-10.
    PMID: 4394986
    Matched MeSH terms: Neutralization Tests
  13. Production and characterization of monoclonal antibodies against formalin-inactivated Nipah virus isolated from the lungs of a pig
    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
  14. Fulltext Immunological surveys of arbovirus infections in South-East Asia, with special reference to dengue, chikungunya, and Kyasanur Forest disease
    Rao TR
    Bull World Health Organ, 1971;44(5):585-91.
    PMID: 4400821
    Serological surveys have been widely used in South-East Asia to determine the presence and activity of arboviruses. The haemagglutination-inhibition test has been most frequently employed but complement-fixation and neutralization tests have also been used in some investigations.Although virus isolations provide the most conclusive evidence, they can be carried out in a few specialized centres only, and serological surveys are very important for studying the distribution of arboviruses.The surveys have shown that group B arboviruses (principally all four types of dengue, Japanese encephalitis, and West Nile) are widely prevalent. Dengue and Japanese encephalitis viruses are more widespread than West Nile virus, which was not known previously to extend east of India although recent survyes have shown that its range extends to Burma. Japanese encephalitis is frequent in most of South-East Asia but in India is found mainly in eastern and south-eastern parts of the country. Kyasanur Forest disease (KFD) and Langat viruses are the only tick-borne group B arboviruses definitely known to occur in the region, the former in India, the latter in Malaysia. KFD virus has been isolated only from a small focus in Mysore, although human and animal sera containing neutralizing antibodies to this virus have been found sporadically in widely scattered areas. Among the group A arboviruses, chikungunya and Sindbis have been detected in serological surveys, but the former has not yet been found in Malaysia.
    Matched MeSH terms: Neutralization Tests
  15. Serological evidence of infection with Tana and Yaba pox viruses among several species of monkey
    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
  16. Serological evidence of possible human infection with Tioman virus, a newly described paramyxovirus of bat origin
    Yaiw KC, Crameri G, Wang L, Chong HT, Chua KB, Tan CT, et al.
    J Infect Dis, 2007 Sep 15;196(6):884-6.
    PMID: 17703419
    Tioman virus, a relatively new paramyxovirus, was isolated from fruit bats (Pteropus species) on Tioman Island, Malaysia, in 2001. The objective of this study was to determine the prevalence of antibodies to T. virus in island inhabitants, by use of comparative ELISA and serum neutralization assays. Of the 169 human sera analyzed, 5 (approximately 3.0%) were positive for T. virus, by comparative ELISA. Of these 5 sera, 3 (1.8% of the total) had neutralizing antibodies against T. virus, suggesting previous infection of this study population by this virus or a similar virus.
    Matched MeSH terms: Neutralization Tests
  17. Fulltext An in vitro α-neurotoxin-nAChR binding assay correlates with lethality and in vivo neutralization of a large number of elapid neurotoxic snake venoms from four continents
    Pruksaphon K, Tan KY, Tan CH, Simsiriwong P, Gutiérrez JM, Ratanabanangkoon K
    PLoS Negl Trop Dis, 2020 Aug;14(8):e0008581.
    PMID: 32857757 DOI: 10.1371/journal.pntd.0008581
    The aim of this study was to develop an in vitro assay for use in place of in vivo assays of snake venom lethality and antivenom neutralizing potency. A novel in vitro assay has been developed based on the binding of post-synaptically acting α-neurotoxins to nicotinic acetylcholine receptor (nAChR), and the ability of antivenoms to prevent this binding. The assay gave high correlation in previous studies with the in vivo murine lethality tests (Median Lethal Dose, LD50), and the neutralization of lethality assays (Median Effective Dose, ED50) by antisera against Naja kaouthia, Naja naja and Bungarus candidus venoms. Here we show that, for the neurotoxic venoms of 20 elapid snake species from eight genera and four continents, the in vitro median inhibitory concentrations (IC50s) for α-neurotoxin binding to purified nAChR correlated well with the in vivo LD50s of the venoms (R2 = 0.8526, p < 0.001). Furthermore, using this assay, the in vitro ED50s of a horse pan-specific antiserum against these venoms correlated significantly with the corresponding in vivo murine ED50s, with R2 = 0.6896 (p < 0.01). In the case of four elapid venoms devoid or having a very low concentration of α-neurotoxins, no inhibition of nAChR binding was observed. Within the philosophy of 3Rs (Replacement, Reduction and Refinement) in animal testing, the in vitro α-neurotoxin-nAChR binding assay can effectively substitute the mouse lethality test for toxicity and antivenom potency evaluation for neurotoxic venoms in which α-neurotoxins predominate. This will greatly reduce the number of mice used in toxicological research and antivenom production laboratories. The simpler, faster, cheaper and less variable in vitro assay should also expedite the development of pan-specific antivenoms against various medically important snakes in many parts of the world.
    Matched MeSH terms: Neutralization Tests
  18. Fulltext Dengue virus infection-enhancing activity in serum samples with neutralizing activity as determined by using FcγR-expressing cells
    Moi ML, Lim CK, Chua KB, Takasaki T, Kurane I
    PLoS Negl Trop Dis, 2012;6(2):e1536.
    PMID: 22389741 DOI: 10.1371/journal.pntd.0001536
    Progress in dengue vaccine development has been hampered by limited understanding of protective immunity against dengue virus infection. Conventional neutralizing antibody titration assays that use FcγR-negative cells do not consider possible infection-enhancement activity. We reasoned that as FcγR-expressing cells are the major target cells of dengue virus, neutralizing antibody titration assays using FcγR-expressing cells that determine the sum of neutralizing and infection-enhancing activity, may better reflect the biological properties of antibodies in vivo.
    Matched MeSH terms: Neutralization Tests
  19. A rapid immune plaque assay for the detection of Hendra and Nipah viruses and anti-virus antibodies
    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
  20. Fulltext A serological study of Japanese encephalitis virus infections in northern Peninsular Malaysia
    Cardosa MJ, Choo BH, Zuraini I
    Southeast Asian J Trop Med Public Health, 1991 Sep;22(3):341-6.
    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
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