Displaying publications 121 - 140 of 205 in total

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  1. Distribution of CBP genes in Streptococcus pneumoniae isolates in relation to vaccine types, penicillin susceptibility and clinical site
    Desa MN, Sekaran SD, Vadivelu J, Parasakthi N
    Epidemiol Infect, 2008 Jul;136(7):940-2.
    PMID: 17678563
    Choline-binding proteins (CBP) have been associated with the pathogenesis of Streptococcus pneumoniae. We screened, using PCR, for the presence of genes (cbpA, D, E, G) encoding these proteins in 34 isolates of pneumococci of known serotypes and penicillin susceptibility from invasive and non-invasive disease. All isolates harboured cbpD and cbpE whereas cbpA and cbpG were found in 47% and 59% respectively; the latter were more frequent in vaccine-associated types and together accounted for 77% of these isolates. No association was observed with penicillin susceptibility but 85% of non-invasive isolates were positive for these genes.
    Matched MeSH terms: Pneumococcal Vaccines/immunology
  2. Effectiveness of influenza vaccination in prevention of influenza-like illness among inhabitants of old folk homes
    Isahak I, Mahayiddin AA, Ismail R
    Southeast Asian J. Trop. Med. Public Health, 2007 Sep;38(5):841-8.
    PMID: 18041300
    The aims of the study were to determine the attack rate of influenza-like illness among inhabitants of five old folk homes nationwide using influenza vaccine as a probe and the effectiveness of influenza vaccination in prevention of influenza-like illness. We conducted a nonrandomized, single-blind placebo control study from June 2003 to February 2004. VAXIGRIP(R) 2003 Southern hemisphere formulation was used. Among 527 subjects, the attack rates of influenza-like illness in the influenza vaccine group were 6.4, 4.6 and 2.4% during the first, second and third 2-month periods, respectively. The attack rates of influenza-like illness in the placebo group were 17.7, 13.8 and 10.1%. Influenza vaccination reduced the risk of contracting influenza-like illness by between 14, and 45%. The vaccine effectiveness in reducing the occurrence of influenza-like illness ranged from 55 to 76%, during the 6-month study followup. The presence of cerebrovascular diseases significantly increased the risk of influenza-like illness (p < 0.005). Vaccine recipients had fewer episodes of fever, cough, muscle aches, runny nose (p < 0.001) and experience fewer sick days due to respiratory illness. Subjects who received influenza vaccination had clinically and statistically significant reductions in the attack rate of influenza-like illness. Our data support influenza vaccination of persons with chronic diseases and >50 year olds living in institutions.
    Matched MeSH terms: Influenza Vaccines/immunology
  3. Protective effect following intranasal exposure of goats to live Pasteurella multocida B:2
    Zamri-Saad M, Ernie ZA, Sabri MY
    Trop Anim Health Prod, 2006 Oct-Nov;38(7-8):541-6.
    PMID: 17265769
    This study aimed to determine the effect of intranasal exposure to low doses of Pasteurella multocida B:2 on survival of goats challenged with high doses of the same organism. Eighteen goats were selected and divided into three groups. Goats of group 1 were exposed intranasally twice, with a two-week interval, to 7 x 10(6) cfu/ml of live P. multocida B:2. Goats of group 2 were not exposed to P. multocida B:2 but were kept together with the exposed group 1. Goats of group 3 remained as unexposed controls and were kept separated from the other two groups. Serum samples were collected at weekly intervals to determine the antibody levels. At week 5 post exposure, all goats were challenged subcutaneously with 3.7 x 10(10) cfu/ml of live P. multocida B:2. Following challenge exposure, 8 (67%) goats (4 goats from each of groups 1 and 2) were killed owing to haemorrhagic septicaemia. Four goats were killed peracutely within 48 h post challenge, while the other four goats were killed acutely between 2 and 4 days post challenge. None of the goats of group 3 were killed for haemorrhagic septicaemia. Goats of groups 1 and 2 showed significantly (p < 0.05) higher antibody levels following the first intranasal exposure to P. multocida B:2. However, only group 1 retained the significantly (p < 0.05) high antibody levels following a second intranasal exposure, and remained significantly (p < 0.05) higher than groups 2 and 3 at the time of challenge. P. multocida B:2 was successfully isolated from various organs of goats that were killed between 1 and 4 days post challenge.
    Matched MeSH terms: Bacterial Vaccines/immunology*
  4. Immunogenicity of a recombinant Mycobacterium bovis bacille Calmette-Guèrin expressing malarial and tuberculosis epitopes
    Rapeah S, Norazmi MN
    Vaccine, 2006 Apr 24;24(17):3646-53.
    PMID: 16494975 DOI: 10.1016/j.vaccine.2006.01.053
    Recombinant Mycobacterium bovis bacille Calmette-Guèrin (rBCG) expressing the malarial epitopes F2R(II)EBA and (NANP)3 as well as two T cell epitopes of the M. tuberculosis ESAT-6 antigen, generated in favour of mycobacterium codon usage elicited specific immune response against these epitopes. Immunised Balb/c mice demonstrated an increase in almost all of the IgG subclasses against both malarial epitopes and enhanced splenocyte proliferative response against the malarial epitopes as well as selected peptides of ESAT-6. Furthermore, flow cytometric analyses showed elevated numbers of CD4+ lymphocytes expressing IFN-gamma and IL-2 against the ESAT-6 peptides, suggesting a specific Th1-mediated response. This study demonstrated that expressing malarial and TB epitopes in a single rBCG construct induced appropriate humoral and cellular immune response against immunogenic epitopes from both organisms.
    Matched MeSH terms: Malaria Vaccines/immunology*
  5. Hepatitis B: review of development from the discovery of the "Australia Antigen" to end of the twentieth Century
    Yap SF
    Malays J Pathol, 2004 Jun;26(1):1-12.
    PMID: 16190102
    "Parenteral" or "serum" hepatitis is known to have afflicted man for centuries. However, it was not until the mid-1960s that the causative agent of this infection, the hepatitis B virus, was discovered. Since then, the biology and the replication strategy of the virus, and the clinical features and the epidemiology of the hepatitis B infection have been determined. Knowledge about the virus and the infection it causes led to the development of firstly, a plasma-derived vaccine and later a recombinant vaccine for the prevention of the infection. Integration of the hepatitis B vaccine into newborn vaccination programmes on a worldwide basis represents a major step in the effort to eliminate this infectious disease and its complications. Laboratory tests are available for the diagnosis and monitoring of the disease. Therapies have been developed to halt the progress of the chronic infection in affected individuals. While these developments have resulted in a decrease of the frequency of infection in many countries, particularly those that have implemented universal immunization of newborns, the chronic infection remains a significant global problem. Worldwide, over 300 million individuals are infected and each year, an estimated 1 million persons die from chronic complications of the disease including hepatocellular carcinoma and hepatic failure. The therapies currently available result in elimination of the virus in only a relatively small proportion of subjects and carry with it serious side effects. Geopolitical, economic and other factors hinder the vision of elimination of the infection through immunization programmes. Nevertheless, work continues to clarify further the underlying pathological mechanism of the infection, the host and viral factors that promote elimination or persistence of the virus in the human host. It is hoped that such investigations will reveal viral targets for the design of newer and potentially more effective drugs to treat the infection.
    Matched MeSH terms: Hepatitis B Vaccines/immunology
  6. Fulltext Synthetic B-Cell Epitopes Eliciting Cross-Neutralizing Antibodies: Strategies for Future Dengue Vaccine
    Ramanathan B, Poh CL, Kirk K, McBride WJ, Aaskov J, Grollo L
    PLoS One, 2016;11(5):e0155900.
    PMID: 27223692 DOI: 10.1371/journal.pone.0155900
    Dengue virus (DENV) is a major public health threat worldwide. A key element in protection from dengue fever is the neutralising antibody response. Anti-dengue IgG purified from DENV-2 infected human sera showed reactivity against several peptides when evaluated by ELISA and epitope extraction techniques. A multi-step computational approach predicted six antigenic regions within the E protein of DENV-2 that concur with the 6 epitopes identified by the combined ELISA and epitope extraction approach. The selected peptides representing B-cell epitopes were attached to a known dengue T-helper epitope and evaluated for their vaccine potency. Immunization of mice revealed two novel synthetic vaccine constructs that elicited good humoral immune responses and produced cross-reactive neutralising antibodies against DENV-1, 2 and 3. The findings indicate new directions for epitope mapping and contribute towards the future development of multi-epitope based synthetic peptide vaccine.
    Matched MeSH terms: Dengue Vaccines/immunology*
  7. Fulltext A Malaysia 97 monovalent foot-and-mouth disease vaccine (>6PD50/dose) protects pigs against challenge with a variant FMDV A SEA-97 lineage virus, 4 and 7 days post vaccination
    Nagendrakumar SB, Hong NT, Geoffrey FT, Jacqueline MM, Andrew D, Michelle G, et al.
    Vaccine, 2015 Aug 26;33(36):4513-9.
    PMID: 26192355 DOI: 10.1016/j.vaccine.2015.07.014
    Pigs play a significant role during outbreaks of foot-and-mouth disease (FMD) due to their ability to amplify the virus. It is therefore essential to determine what role vaccination could play to prevent clinical disease and lower virus excretion into the environment. In this study we investigated the efficacy of the double oil emulsion A Malaysia 97 vaccine (>6PD50/dose) against heterologous challenge with an isolate belonging to the A SEA-97 lineage at 4 and 7 days post vaccination (dpv). In addition, we determined whether physical separation of pigs in the same room could prevent virus transmission. Statistically there was no difference in the level of protection offered by 4 and 7 dpv. However, no clinical disease or viral RNA was detected in the blood of pigs challenged 4 dpv, although three of the pigs had antibodies to the non-structural proteins (NSPs), indicating viral replication. Viral RNA was also detected in nasal and saliva swabs, but on very few occasions. Two of the pigs vaccinated seven days prior to challenge had vesicles distal from the injection site, but on the inoculated foot, and two pigs had viral RNA detected in the blood. One pig sero-converted to the NSPs. In contrast, all unvaccinated and inoculated pigs had evidence of infection. No infection occurred in any of the susceptible pigs in the same room, but separated from the infected pigs, indicating that strict biosecurity measures were sufficient under these experimental conditions to prevent virus transmission. However, viral RNA was detected in the nasal swabs of one group of pigs, but apparently not at sufficient levels to cause clinical disease. Vaccination led to a significant decrease in viral RNA in vaccinated pigs compared to unvaccinated and infected pigs, even with this heterologous challenge, and could therefore be considered as a control option during outbreaks.
    Matched MeSH terms: Viral Vaccines/immunology*
  8. Fulltext Development of enhanced antibody response toward dual delivery of nano-adjuvant adsorbed human Enterovirus-71 vaccine encapsulated carrier
    Saeed MI, Omar AR, Hussein MZ, Elkhidir IM, Sekawi Z
    Hum Vaccin Immunother, 2015;11(10):2414-24.
    PMID: 26186664 DOI: 10.1080/21645515.2015.1052918
    This study introduces a new approach for enhancing immunity toward mucosal vaccines. HEV71 killed vaccine that is formulated with nanosize calcium phosphate adjuvant and encapsulated onto chitosan and alginate delivery carriers was examined for eliciting antibody responses in serum and saliva collected at weeks 0, 1, 3, 5, 7 and 9 for viral-specific IgA & IgG levels and viral neutralizing antibody titers. The antibody responses induced in rabbits by the different formulations delivered by a single (buccal) route were compared to those of dual immunization (intradermal / mucosal) and un-immunized control. Chitosan-loaded vaccine adjuvant induced elevated IgA antibody, while Alginate-adjuvant irreversible bonding sequestered the vaccine and markedly reduced immunogenicity. The induced mucosal and parenteral antibody profiles appeared in an inverse manner of enhanced mucosal IgA antibody accompanied by lower systemic IgG following a single oral immunization route. The combined intradermal and oral dual-immunized group developed an elevated salivary IgA, systemic IgG, and virus neutralizing response. A reduced salivary neutralizing antibody titer was observed and attributed to the continual secretion exchanges in saliva. Designing a successful mucosal delivery formulation needs to take into account the vaccine delivery site, dosage, adjuvant and carrier particle size, charge, and the reversibility of component interactions. The dual immunization seems superior and is a important approach for modulating the antibody response and boosting mucosal protection against HEV71 and similar pathogens based on their transmission mode, tissue tropism and shedding sites. Finally, the study has highlighted the significant role of dual immunization for simultaneous inducing and modulating the systemic and mucosal immune responses to EV71.
    Matched MeSH terms: Viral Vaccines/immunology*
  9. Fulltext Naturally occurring hepatitis B virus surface antigen mutant variants in Malaysian blood donors and vaccinees
    Hudu SA, Harmal NS, Saeed MI, Alshrari AS, Malik YA, Niazlin MT, et al.
    Eur J Clin Microbiol Infect Dis, 2015 Jul;34(7):1349-59.
    PMID: 25792010 DOI: 10.1007/s10096-015-2358-1
    Hepatitis B virus surface mutants are of enormous importance because they are capable of escaping detection by serology and can infect both vaccinated and unvaccinated populations, thus putting the whole population at risk. This study aimed to detect and characterise hepatitis B-escaped mutants among blood donors and vaccinees. One thousand serum samples were collected for this study from blood donors and vaccinees. Hepatitis B surface antigen, antibodies and core antibodies were tested using a commercial enzyme-linked immunosorbent assay (ELISA) kit. DNA detection was performed via nested polymerase chain reaction (PCR), and the S gene was sequenced and analysed using bioinformatics. Of the 1,000 samples that were screened, 5.5% (55/1,000) were found to be HBsAg-negative and anti-HBc- and HBV DNA-positive. All 55 isolates were found to belong to genotype B. Several mutations were found across all the sequences from synonymous and non-synonymous mutations, with the most nucleotide mutations occurring at position 342, where adenine was replaced by guanine, and cytosine at position 46 was replaced by adenine in 96.4% and 98% of the isolates, respectively. Mutation at position 16 of the amino acid sequence was found to be common to all the Malaysian isolates, with 85.7% of the mutations occurring outside the major hydrophilic region. This study revealed a prevalence of 5.5% for hepatitis B-escaped mutations among blood donors and vaccinated undergraduates, with the most common mutation being found at position 16, where glutamine was substituted with lysine.
    Matched MeSH terms: Hepatitis B Vaccines/immunology
  10. Immunogenicity of purified lipopolysaccharide or protein-oligosaccharide conjugates of Pasteurella multocida type 6:B in mice
    Muniandy N, Love DN, Mukkur TK
    Comp Immunol Microbiol Infect Dis, 1998 Oct;21(4):257-79.
    PMID: 9775357
    Purified lipopolysaccharide (LPS) of Pasteurella multocida type 6:B, while toxic at higher doses, was protective at lower dose levels against experimentally-induced pasteurellosis in mice. However, the observed protection was abrogated if such LPS was digested with proteinase K prior to use in immunisation. The O-antigen polysaccharide side-chain (OS) of LPS did not appear to contribute to the observed protection as judged by the fact that immunisation of mice with purified OS or OS-protein conjugates, all of which were nontoxic, failed to confer protection against challenge with homologous virulent organisms. This was despite generation of significant levels of OS-specific antibodies, predominantly either of the IgM or IgG isotypes, in immunised mice.
    Matched MeSH terms: Bacterial Vaccines/immunology
  11. Pathogenicity and immunogenicity of mynah pox virus in chickens and bobwhite quail
    Reed WM, Schrader DL
    Poult Sci, 1989 May;68(5):631-8.
    PMID: 2547209
    An avian pox virus was isolated from cutaneous proliferative lesions removed from greater hill mynahs (Gracula religiosa) imported from Malaysia. Cutaneous inoculation of specific pathogen-free chickens and bobwhite quail with the mynah pox virus resulted in severe proliferative cutaneous lesions similar to those seen in the naturally infected mynah birds. Microscopically, the reaction in the chickens and quail at sites of virus inoculation was characterized by marked epithelial hyperplasia with ballooning degeneration and formation of cytoplasmic inclusion bodies. Inoculation of conjunctival and oral mucosae of chickens by applying pox virus with a cotton swab did not result in gross or microscopic lesions. In cross-protection studies, chickens and bobwhite quail immunized with either quail, fowl, pigeon, turkey, or psittacine pox vaccines were not protected from challenge with mynah pox virus. Following vaccination of quail and chickens with mynah pox virus vaccine, there was no resistance to challenge by quail, fowl, pigeon, turkey, or psittacine pox viruses. Significant protection against development of lesions following inoculation with mynah pox virus was attained only when the homologous virus was used as a vaccine.
    Matched MeSH terms: Viral Vaccines/immunology
  12. Flavivirus infection-A review of immunopathogenesis, immunological response, and immunodiagnosis
    Chong HY, Leow CY, Abdul Majeed AB, Leow CH
    Virus Res, 2019 12;274:197770.
    PMID: 31626874 DOI: 10.1016/j.virusres.2019.197770
    Flaviviruses are group of single stranded RNA viruses that cause severe endemic infection and epidemics on a global scale. It presents a significant health impact worldwide and the viruses have the potential to emerge and outbreak in a non-endemic geographical region. Effective vaccines for prophylaxis are only available for several flaviviruses such as Yellow Fever virus, Tick-borne Encephalitis Virus, Dengue Virus and Japanese Encephalitis Virus and there is no antiflaviviral agent being marketed. This review discusses the flavivirus genome, replication cycle, epidemiology, clinical presentation and pathogenesis upon infection. Effective humoral response is critical to confer protective immunity against flaviviruses. Hence, we have also highlighted the immune responses elicited upon infection, various diagnostic facilities available for flaviviral disease and monoclonal antibodies available to date against flavivirus infection.
    Matched MeSH terms: Viral Vaccines/immunology
  13. Fulltext Chimeric Virus-Like Particles of Prawn Nodavirus Displaying Hepatitis B Virus Immunodominant Region: Biophysical Properties and Cytokine Response
    Ninyio NN, Ho KL, Yong CY, Chee HY, Hamid M, Ong HK, et al.
    Int J Mol Sci, 2021 Feb 15;22(4).
    PMID: 33672018 DOI: 10.3390/ijms22041922
    Hepatitis B is a major global health challenge. In the absence of an effective treatment for the disease, hepatitis B vaccines provide protection against the viral infection. However, some individuals do not have positive immune responses after being vaccinated with the hepatitis B vaccines available in the market. Thus, it is important to develop a more protective vaccine. Previously, we showed that hepatitis B virus (HBV) 'a' determinant (aD) displayed on the prawn nodavirus capsid (Nc) and expressed in Spodoptera frugiperda (Sf9) cells (namely, Nc-aD-Sf9) self-assembled into virus-like particles (VLPs). Immunisation of BALB/c mice with the Nc-aD-Sf9 VLPs showed significant induction of humoral, cellular and memory B-cell immunity. In the present study, the biophysical properties of the Nc-aD-Sf9 VLPs were studied using dynamic light scattering (DLS) and circular dichroism (CD) spectroscopy. Enzyme-linked immunosorbent assay (ELISA) was used to determine the antigenicity of the Nc-aD-Sf9 VLPs, and multiplex ELISA was employed to quantify the cytokine response induced by the VLPs administered intramuscularly into BALB/c mice (n = 8). CD spectroscopy of Nc-aD-Sf9 VLPs showed that the secondary structure of the VLPs predominantly consisted of beta (β)-sheets (44.8%), and they were thermally stable up to ~52 °C. ELISA revealed that the aD epitope of the VLPs was significantly antigenic to anti-HBV surface antigen (HBsAg) antibodies. In addition, multiplex ELISA of serum samples from the vaccinated mice showed a significant induction (p < 0.001) of IFN-γ, IL-4, IL-5, IL-6, IL-10, and IL-12p70. This cytokine profile is indicative of natural killer cell, macrophage, dendritic cell and cytotoxic T-lymphocyte activities, which suggests a prophylactic innate and adaptive cellular immune response mediated by Nc-aD-Sf9 VLPs. Interestingly, Nc-aD-Sf9 induced a more robust release of the aforementioned cytokines than that of Nc-aD VLPs produced in Escherichia coli and a commercially used hepatitis B vaccine. Overall, Nc-aD-Sf9 VLPs are thermally stable and significantly antigenic, demonstrating their potential as an HBV vaccine candidate.
    Matched MeSH terms: Hepatitis B Vaccines/immunology*
  14. Fulltext Engineering a stable CHO cell line for the expression of a MERS-coronavirus vaccine antigen
    Nyon MP, Du L, Tseng CK, Seid CA, Pollet J, Naceanceno KS, et al.
    Vaccine, 2018 03 27;36(14):1853-1862.
    PMID: 29496347 DOI: 10.1016/j.vaccine.2018.02.065
    Middle East respiratory syndrome coronavirus (MERS-CoV) has infected at least 2040 patients and caused 712 deaths since its first appearance in 2012, yet neither pathogen-specific therapeutics nor approved vaccines are available. To address this need, we are developing a subunit recombinant protein vaccine comprising residues 377-588 of the MERS-CoV spike protein receptor-binding domain (RBD), which, when formulated with the AddaVax adjuvant, it induces a significant neutralizing antibody response and protection against MERS-CoV challenge in vaccinated animals. To prepare for the manufacture and first-in-human testing of the vaccine, we have developed a process to stably produce the recombinant MERS S377-588 protein in Chinese hamster ovary (CHO) cells. To accomplish this, we transfected an adherent dihydrofolate reductase-deficient CHO cell line (adCHO) with a plasmid encoding S377-588 fused with the human IgG Fc fragment (S377-588-Fc). We then demonstrated the interleukin-2 signal peptide-directed secretion of the recombinant protein into extracellular milieu. Using a gradually increasing methotrexate (MTX) concentration to 5 μM, we increased protein yield by a factor of 40. The adCHO-expressed S377-588-Fc recombinant protein demonstrated functionality and binding specificity identical to those of the protein from transiently transfected HEK293T cells. In addition, hCD26/dipeptidyl peptidase-4 (DPP4) transgenic mice vaccinated with AddaVax-adjuvanted S377-588-Fc could produce neutralizing antibodies against MERS-CoV and survived for at least 21 days after challenge with live MERS-CoV with no evidence of immunological toxicity or eosinophilic immune enhancement. To prepare for large scale-manufacture of the vaccine antigen, we have further developed a high-yield monoclonal suspension CHO cell line.
    Matched MeSH terms: Viral Vaccines/immunology*
  15. Fulltext Haemato-immunological responses and effectiveness of feed-based bivalent vaccine against Streptococcus iniae and Aeromonas hydrophila infections in hybrid red tilapia (Oreochromis mossambicus × O. niloticus)
    Monir MS, Yusoff SBM, Zulperi ZBM, Hassim HBA, Mohamad A, Ngoo MSBMH, et al.
    BMC Vet Res, 2020 Jul 02;16(1):226.
    PMID: 32615969 DOI: 10.1186/s12917-020-02443-y
    BACKGROUND: Streptococcosis and Motile Aeromonad Septicemia (MAS) are important diseases of tilapia, Oreochromis spp. and causes huge economic losses in aquaculture globally. The feed-based vaccination may be an alternative to minimize major infectious diseases in tilapia. Thus, this study aims to evaluate the haemato-immunological responses and effectiveness of a newly developed feed-based killed bivalent vaccine against Streptococcus iniae and Aeromonas hydrophila in hybrid red tilapia. A total of 495 hybrid red tilapia of 61.23 ± 4.95 g were distributed into 5 groups (each with triplicate). The fish were immunized orally through bivalent (combined S. iniae and A. hydrophila) spray vaccine (BS group), bivalent formulate vaccine (BF group), monovalent S. iniae vaccine (MS group), monovalent A. hydrophila vaccine (MA group) and unvaccinated as a control group. The vaccine was orally administered on days 0, 14 and 42 applied feed-based bacterin at 5% body weight. The blood and spleen samples were collected from all groups on 7, 21 and 49 days post-vaccination, and also 96 h post-infection to assess their haemato-immune responses.

    RESULTS: Compared with the unvaccinated group, leukocyte, lymphocytes, monocytes, granulocytes counts in vaccinated groups were significantly (P 

    Matched MeSH terms: Bacterial Vaccines/immunology*
  16. Identification and selection of immunodominant B and T cell epitopes for dengue multi-epitope-based vaccine
    Lim HX, Lim J, Poh CL
    Med Microbiol Immunol, 2021 Feb;210(1):1-11.
    PMID: 33515283 DOI: 10.1007/s00430-021-00700-x
    Dengue virus (DENV) comprises four serotypes (DENV1-4) which cause 390 million global infections with 500,000 hospitalizations and 25,000 fatalities annually. Currently, the only FDA approved DENV vaccine is the chimeric live-attenuated vaccine, Dengvaxia®, which is based on the yellow fever virus (YFV) genome that carries the prM and E genes of the respective DENV 1, 2, 3, and 4 serotypes. However, it has lower efficacies against serotypes DENV1 (51%) and DENV2 (34%) when compared with DENV3 (75%) and DENV4 (77%). The absence of T cell epitopes from non-structural (NS) and capsid (C) proteins of the yellow fever vaccine strain might have prevented Dengvaxia® to elicit robust cellular immune responses, as CD8+ T cell epitopes are mainly localized in the NS3 and NS5 regions. Multi-epitope-based peptide vaccines carrying CD4+, CD8+ T cell and B cell epitopes represent a novel approach to generate specific immune responses. Therefore, assessing and selecting epitopes that can induce robust B and T cell responses is a prerequisite for constructing an efficient multi-epitope peptide vaccine. Potent B and T cell epitopes can be identified by utilizing immunoinformatic analysis, but the immunogenicity of the epitopes have to be experimentally validated. In this review, we presented T cell epitopes that have been predicted by bioinformatic approaches as well as recent experimental validations of CD4+ and CD8+ T cell epitopes by ex-vivo stimulation of PBMCs with specific peptides. Immunoproteomic analysis could be utilized to uncover HLA-specific epitopes presented by DENV-infected cells. Based on various approaches, immunodominant epitopes capable of inducing strong immune responses could be selected and incorporated to form a universally applicable multi-epitope-based peptide dengue vaccine.
    Matched MeSH terms: Dengue Vaccines/immunology*
  17. Lessons learned from Asian H5N1 outbreak control
    Sims LD
    Avian Dis, 2007 Mar;51(1 Suppl):174-81.
    PMID: 17494550
    Numerous lessons have been learned so far in controlling H5N1 avian influenza in Asia. Early detection of incursions of virus prevented establishment of the disease in several countries, notably Japan, South Korea, and Malaysia. In countries where detection of early cases was delayed, infection is endemic and has been for three or more years. Control measures implemented in these countries need to reflect this finding. Vaccination will continue to be one of the key measures used in these endemically infected countries. Used alone, vaccination will not result in elimination of H5N1 viruses from a country, but, if used correctly, it will markedly reduce the prevalence of and susceptibility to infection. Vaccination has already played a valuable role in reducing the adverse effects of H5N1 viruses. Mass culling also reduces the level of infection in infected areas. However, the long-term benefits are limited in endemically infected countries owing to the high probability of reinfection on restocking unless other measures are used in parallel. Full epidemiological studies have not been conducted in many infected countries. Nevertheless, it is recognized that the number of clinical cases does not truly reflect the levels of infection. Domestic ducks and large live poultry markets have played a key role in the persistence of infection, because they can be infected silently. In tackling this disease, countries should adopt integrated control programs using the combination of measures best suited to the local environment. All surveillance data should be shared, both positive and negative, and should include information on cases of infection and disease. Socioeconomic and ecological implications of all control measures should be assessed before implementation, especially the impact on the rural poor.
    Matched MeSH terms: Influenza Vaccines/immunology
  18. Characterization of Chicken Splenic-Derived Dendritic Cells Following Vaccine and Very Virulent Strains of Infectious Bursal Disease Virus Infection
    Yasmin AR, Yeap SK, Hair-Bejo M, Omar AR
    Avian Dis, 2016 12;60(4):739-751.
    PMID: 27902915
    Studies have shown that infectious bursal disease virus (IBDV) infects lymphoid cells, mainly B cells and macrophages. This study was aimed to examine the involvement of chicken splenic-derived dendritic cells (ch-sDCs) in specific-pathogen-free chickens following inoculation with IBDV vaccine strain (D78) and a very virulent (vv) strain (UPM0081). Following IBDV infection, enriched activated ch-sDCs were collected by using the negative selection method and were examined based on morphology and immunophenotyping to confirm the isolation method for dendritic cells (DCs). The presence of IBDV on enriched activated ch-sDCs was analyzed based on the immunofluorescence antibody test (IFAT), flow cytometry, and quantitative real-time PCR (RT-qPCR) while the mRNAs of several cytokines were detected using RT-qPCR. The isolated ch-sDCs resembled typical DC morphologies found in mammals by having a veiled shape and they grew in clusters. Meanwhile, the expression of DC maturation markers, namely CD86 and MHCII, were increased at day 2 and day 3 following vvIBDV and vaccine strain inoculation, respectively, ranging from 10% to 40% compared to the control at 2.55% (P < 0.05). At day 3 postinfection, IBDV VP3 proteins colocalized with CD86 were readily detected via IFAT and flow cytometry in both vaccine and vvIBDV strains. In addition, enriched activated ch-sDCs were also detected as positive based on the VP4 gene by RT-qPCR; however, a higher viral load was detected on vvIBDV compared to the vaccine group. Infection with vaccine and vvIBDV strains induced the enriched activated ch-sDCs to produce proinflammatory cytokines and Th1-like cytokines from day 3 onward; however, the expressions were higher in the vvIBDV group (P < 0.05). These data collectively suggest that enriched activated ch-sDCs were permissive to IBDV infection and produced a strong inflammatory and Th1-like cytokine response following vvIBDV infection as compared to the vaccine strain.
    Matched MeSH terms: Viral Vaccines/immunology
  19. Fulltext Human papillomavirus infection and its vaccines: knowledge and attitudes of primary health clinic nurses in Kelantan, Malaysia
    Jeyachelvi K, Juwita S, Norwati D
    Asian Pac J Cancer Prev, 2016;17(8):3983-8.
    PMID: 27644649
    BACKGROUND: Cervical cancer though preventable is still the leading cause of cancer death among women secondary to breast cancer. Persistent infection with HPV has been causally linked to the disease. A school based HPV vaccination program was introduced in late 2010 in Malaysia and nurse support is essential for its success.
    OBJECTIVES: To determine nurses knowledge and attitudes about HPV infection and its vaccines, and factors associated with their knowledge.
    MATERIALS AND METHODS: This cross-sectional study was conducted among nurses working at primary health clinics in Kelantan from mid-June till the end of July 2014. Its involved 330 nurses selected through multistage random sampling. A validated self-administered questionnaire consisting of 11 items for the knowledge domain and eight items for the attitude domain was used.
    RESULTS: The response rate of the study was 93.7%. The mean knowledge and mean attitude (SD) scores were 5.37 (1.76) and 29.8 (3.51) respectively. Only 24% knew that HPV is the most common sexually transmitted infection and 67% correctly answered that Gardasil vaccine can protect against four types of HPV. Nearly 60% of participants wrongly answered that HPV vaccines cannot be offered to sexually active women. Likewise, 70.9% participants were not aware that HPV vaccine may be appropriate for females aged 9 through 26 years. Though 90% of participants believed that the vaccine is safe, nearly half of them were unsure about efficacy. From multiple linear regression analysis, among the factors tested only participant's level of education showed a statistically significant association with the HPV knowledge score (<0.001).
    CONCLUSIONS: This study indicates nurses have favorable attitudes towards HPV vaccination; however they have significant knowledge deficit and major misunderstanding in critical knowledge items. Among the factors tested, nursing qualification is the only factor that is significantly associated with the nurses knowledge score.
    Matched MeSH terms: Papillomavirus Vaccines/immunology*
  20. Fulltext Potential impact of dengue vaccination: Insights from two large-scale phase III trials with a tetravalent dengue vaccine
    Coudeville L, Baurin N, L'Azou M, Guy B
    Vaccine, 2016 12 07;34(50):6426-6435.
    PMID: 27601343 DOI: 10.1016/j.vaccine.2016.08.050
    BACKGROUND: A tetravalent dengue vaccine demonstrated its protective efficacy in two phase III efficacy studies. Results from these studies were used to derive vaccination impact in the five Asian (Indonesia, Malaysia, Philippines, Thailand, Vietnam) and the five Latin American countries (Brazil, Colombia, Honduras, Mexico and Puerto Rico) participating in these trials.

    METHODS: Vaccination impact was investigated with an age-structured, host-vector, serotype-specific compartmental model. Parameters related to vaccine efficacy and levels of dengue transmission were estimated using data collected during the phase III efficacy studies. Several vaccination programs, including routine vaccination at different ages with and without large catch-up campaigns, were investigated.

    RESULTS: All vaccination programs explored translated into significant reductions in dengue cases at the population level over the first 10years following vaccine introduction and beyond. The most efficient age for vaccination varied according to transmission intensity and 9years was close to the most efficient age across all settings. The combination of routine vaccination and large catch-up campaigns was found to enable a rapid reduction of dengue burden after vaccine introduction.

    CONCLUSION: Our analysis suggests that dengue vaccination can significantly reduce the public health impact of dengue in countries where the disease is endemic.

    Matched MeSH terms: Dengue Vaccines/immunology*
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