Displaying publications 1 - 20 of 49 in total

Abstract:
Sort:
  1. Abd-Aziz N, Tan BC, Rejab NA, Othman RY, Khalid N
    Mol Biotechnol, 2020 Apr;62(4):240-251.
    PMID: 32108286 DOI: 10.1007/s12033-020-00242-2
    In the past decade, interest in the production of recombinant pharmaceutical proteins in plants has tremendously progressed because plants do not harbor mammalian viruses, are economically competitive, easily scalable, and capable of carrying out complex post-translational modifications required for recombinant pharmaceutical proteins. Mucuna bracteata is an essential perennial cover crop species widely planted as an underground cover in oil palm and rubber plantations. As a legume, they have high biomass, thrive in its habitat, and can fix nitrogen. Thus, M. bracteata is a cost-efficient crop that shows ideal characteristics as a platform for mass production of recombinant protein. In this study, we established a new platform for the transient production of a recombinant protein in M. bracteata via vacuum-assisted agro-infiltration. Five-week-old M. bracteata plants were vacuum infiltrated with Agrobacterium tumefaciens harboring a plasmid that encodes for an anti-toxoplasma immunoglobulin (IgG) under different parameters, including trifoliate leaf positional effects, days to harvest post-infiltration, and the Agrobacterium strain used. Our results showed that vacuum infiltration of M. bracteata plant with A. tumefaciens strain GV3101 produced the highest concentration of heterologous protein in its bottom trifoliate leaf at 2 days post-infiltration. The purified anti-toxoplasma IgG was then analyzed using Western blot and ELISA. It was demonstrated that, while structural heterogeneity existed in the purified anti-toxoplasma IgG from M. bracteata, its transient expression level was two-fold higher than the model platform, Nicotiana benthamiana. This study has laid the foundation towards establishing M. bracteata as a potential platform for the production of recombinant pharmaceutical protein.
    Matched MeSH terms: Toxoplasma/immunology
  2. Nasiru Wana M, Mohd Moklas MA, Watanabe M, Nordin N, Zasmy Unyah N, Alhassan Abdullahi S, et al.
    PMID: 32635389 DOI: 10.3390/ijerph17134809
    Toxoplasmosis is a disease caused by the protozoan parasite Toxoplasma gondii (T. gondii). Human toxoplasmosis seroprevalence in Malaysia has increased since it was first reported in 1973 as shown in previous reviews of 1991 and 2007. However, over a decade since the last review, comprehensive data on toxoplasmosis in Malaysia is lacking. This work aimed at reviewing articles on toxoplasmosis research in Malaysia in order to identify the research gaps, create public awareness, and efforts made so far and proffer management options on the disease. The present review examines the available published research articles from 2008 to 2018 related to toxoplasmosis research conducted in Malaysia. The articles reviewed were retrieved from nine credible databases such as Web of Science, Google Scholar, ScienceDirect, PubMed, Scopus, Springer, Wiley online library, Ovid, and Cochrane using the keywords; Malaysia, toxoplasmosis, Toxoplasma gondii, toxoplasma encephalitis, seroprevalence, human immunodeficiency virus (HIV) patients, pregnant women, genotype strain, anti-toxoplasma antibodies, felines, and vaccine. The data highlighted seropositive cases from healthy community members in Pangkor Island (59.7%) and among migrant workers (57.4%) at alarming rates, as well as 42.5% in pregnant women. Data on animal seroprevalence were limited and there was no information on cats as the definitive host. Genetic characterization of Toxoplasma gondii from HIV patients; pregnant women, and domestic cats is lacking. This present review on toxoplasmosis is beneficial to researchers, health workers, animal health professionals, and policymakers. Therefore, attention is required to educate and enlighten health workers and the general public about the risk factors associated with T. gondii infection in Malaysia.
    Matched MeSH terms: Toxoplasma/immunology
  3. Saadatnia G, Ghaffarifar F, Khalilpour A, Amerizadeh A, Rahmah N
    Trop Biomed, 2011 Dec;28(3):606-14.
    PMID: 22433890 MyJurnal
    Toxoplasmosis can cause serious disease in immunocompromised patients and to congenitally infected foetuses. Appropriate laboratory investigations in potential cases of acute Toxoplasma infection are important. Excretory secretory antigen (ESA) is immunogenic during both human and experimental infections, therefore is considered as a good candidate for investigation into new infection markers. In this study, ESA was prepared from in vitro cultures of Toxoplasma gondii to identify T. gondii ESA antigenic component(s) that is/are most reactive with serum samples from probable acute cases of toxoplasmosis. Serum samples were obtained from several categories of individuals with the following Toxoplasma serology: Group I: IgM+ IgG+ (low IgG avidity) or IgM+ IgG- from sera of patients who had clinical query of toxoplasmosis (n=35). Group II: IgM- IgG+ (high IgG avidity) from chronically infected individuals (n=30). Group III: normal/healthy individuals with anti-Toxoplasma IgMIgG- (n=20). Group IV: individuals with other infections who had anti-Toxoplasma IgM- IgG- (n=10). The ESA was subjected to SDS-PAGE, followed by Western blot analysis using the above sera and probed with peroxidase conjugated anti-human IgM and IgA antibodies. The blots were then developed using chemiluminescence substrate. The selected antigenic band was excised from the gel after two dimensional electrophoresis and sent for mass spectrometry analysis using MALDI TOF-TOF. The most promising antigenic band was a 10 kDa protein which showed sensitivity of 80% in both IgM and IgA blots, and specificity of 96.7% with sera from other infections and healthy controls. The two best identifications for the 10 kDa band were ubiquitin (ribosomal protein CEP52 fusion protein) and polyubiquitin.
    Matched MeSH terms: Toxoplasma/immunology*
  4. Mahdy MA, Alareqi LM, Abdul-Ghani R, Al-Eryani SM, Al-Mikhlafy AA, Al-Mekhlafi AM, et al.
    Infect Dis Poverty, 2017 Feb 13;6(1):26.
    PMID: 28190399 DOI: 10.1186/s40249-017-0243-0
    BACKGROUND: Toxoplasma gondii is a zoonotic coccidian parasite causing morbidity and mortality. In Yemen, T. gondii infection has been reported among pregnant women seeking healthcare in the main cities. However, no data are available on the prevalence of T. gondii infection and its associated risk factors among pregnant women in the rural communities of the country. Thus, the present study aimed to determine the seroprevalence of T. gondii and identify its risk factors among pregnant women in the rural communities of Taiz governorate, Yemen.

    METHODS: A total of 359 pregnant women living in the rural communities of Taiz governorate were enrolled in this study by house-to-house visits. Data were collected using a pre-designed questionnaire, and blood samples were collected and tested for the detection of anti- T. gondii IgM and IgG antibodies by enzyme-linked immunosorbent assay.

    RESULTS: The prevalence of T. gondii infection among pregnant women in this study was 46.2% (166/359). Bivariate analysis identified the age of  ≥ 30 years (odds ratio [OR] = 1.7; 95% confidence interval [CI] = 1.09-2.65, P = 0.019) and unimproved water sources (OR = 2.2; 95% CI = 1.10-4.55, P = 0.023) as factors associated with T. gondii infection among pregnant women. The multivariable analysis, however, identified unimproved water sources as an independent risk factor (adjusted OR = 2.4; 95% CI = 1.16-5.0, P = 0.018) associated with T. gondii infection among pregnant women.

    CONCLUSIONS: Pregnant women in the rural communities of Taiz, Yemen are at high risk of contracting T. gondii infection. Unimproved water sources (wells, water streams and water tanks) are significantly associated with T. gondii infection and should be considered in prevention and control strategies, especially among pregnant women.

    Matched MeSH terms: Toxoplasma/immunology
  5. Singh S, Khang TF, Andiappan H, Nissapatorn V, Subrayan V
    Trans R Soc Trop Med Hyg, 2012 May;106(5):322-6.
    PMID: 22480791 DOI: 10.1016/j.trstmh.2012.01.009
    Toxoplasma gondii is a public health risk in developing countries, especially those located in the tropics. Widespread infection may inflict a substantial burden on state resources, as patients can develop severe neurological defects and ocular diseases that result in lifelong loss of economic independence. We tested sera for IgG antibody from 493 eye patients in Malaysia. Overall age-adjusted seroprevalence was estimated to be 25% (95% CI: [21%, 29%]). We found approximately equal age-adjusted seroprevalence in Chinese (31%; 95% CI: [25%, 38%]) and Malays (29%; 95% CI: [21%, 36%]), followed by Indians (19%; 95% CI: [13%, 25%]). A logistic regression of the odds for T. gondii seroprevalence against age, gender, ethnicity and the occurrence of six types of ocular diseases showed that only age and ethnicity were significant predictors. The odds for T. gondii seroprevalence were 2.7 (95% CI for OR: [1.9, 4.0]) times higher for a patient twice as old as the other, with ethnicity held constant. In Malays, we estimated the odds for T. gondii seroprevalence to be 2.9 (95% CI for OR: [1.8, 4.5]) times higher compared to non-Malays, with age held constant. Previous studies of T. gondii seroprevalence in Malaysia did not explicitly adjust for age, rendering comparisons difficult. Our study highlights the need to adopt a more rigorous epidemiological approach in monitoring T. gondii seroprevalence in Malaysia.
    Matched MeSH terms: Toxoplasma/immunology
  6. Emelia O, Zeehaida M, Sulaiman O, Rohela M, Saadatnia G, Yeng C, et al.
    J Immunoassay Immunochem, 2010;31(1):79-91.
    PMID: 20391020 DOI: 10.1080/15321810903405134
    We have developed an ELISA that employs monoclonal anti-Toxoplasma SAG1 (p30) as the capture antibody to detect T. gondii circulating antigens in patients' serum samples. Using serum spiked with Toxoplasma soluble and with SAG1 recombinant proteins, the detection limits were 31.25 ng/mL and 62.50 ng/mL, respectively. We obtained positive results in 28% (21/75) and 11% (23/206) of probable active and chronic toxoplasmosis serum samples, respectively. Western blot analysis on pooled antigen-positive serum samples showed antigenic bands of molecular weights 25 and 75 kDa from sera of probable active infection and five antigenic bands ranging in size from 26 to 33 kDa from chronic infection sera. This assay would be useful as an initial serum selection step in developing a Toxoplasma antigen detection test and for characterization studies.
    Matched MeSH terms: Toxoplasma/immunology*
  7. Hajissa K, Zakaria R, Suppian R, Mohamed Z
    BMC Infect Dis, 2017 12 29;17(1):807.
    PMID: 29284420 DOI: 10.1186/s12879-017-2920-9
    BACKGROUND: The inefficiency of the current tachyzoite antigen-based serological assays for the serodiagnosis of Toxoplasma gondii infection mandates the need for acquirement of reliable and standard diagnostic reagents. Recently, epitope-based antigens have emerged as an alternative diagnostic marker for the achievement of highly sensitive and specific capture antigens. In this study, the diagnostic utility of a recombinant multiepitope antigen (USM.TOXO1) for the serodiagnosis of human toxoplasmosis was evaluated.

    METHODS: An indirect enzyme-linked immunosorbent assay (ELISA) was developed to evaluate the usefulness of USM.TOXO1 antigen for the detection of IgG antibodies against Toxoplasma gondii in human sera. Whereas the reactivity of the developed antigen against IgM antibody was evaluated by western blot and Dot enzyme immunoassay (dot-EIA) analysis.

    RESULTS: The diagnostic performance of the new antigens in IgG ELISA was achieved at the maximum values of 85.43% and 81.25% for diagnostic sensitivity and specificity respectively. The USM.TOXO1 was also proven to be reactive with anti- T. gondii IgM antibody.

    CONCLUSIONS: This finding makes the USM.TOXO1 antigen an attractive candidate for improving the toxoplasmosis serodiagnosis and demonstrates that multiepitope antigens could be a potential and promising diagnostic marker for the development of high sensitive and accurate assays.

    Matched MeSH terms: Toxoplasma/immunology*
  8. Thomas V, Dissanaike AS
    Trans R Soc Trop Med Hyg, 1978;72(3):303-6.
    PMID: 97821
    Sera from 243 donors belonging to the four main ethnic groups in West Malaysia (Orang Asli, Malays, Chinese and Indians) were tested, using the indirect fluorescent antibody technique for the prevalence of antibodies to Sarcocystis. Almost 20% reacted positively at dilutions of 1:64 or higher and eight among the Orang Asli and Malays gave the highest titres of 1:256. Prevalence was highest in the Orang Asli and lowest in Chinese. 22 sera also reacted positively to Toxoplasma, whether due to polyparasitism or cross-reaction is, as yet, unknown.
    Matched MeSH terms: Toxoplasma/immunology
  9. Rajamanickam C, Cheah TS, Paramasvaran S
    Trop Anim Health Prod, 1990 Feb;22(1):61-2.
    PMID: 2321262
    Matched MeSH terms: Toxoplasma/immunology*
  10. Fong MY, Lau YL, Zulqarnain M
    Biotechnol Lett, 2008 Apr;30(4):611-8.
    PMID: 18043869
    The surface antigen 2 (SAG2) gene of the protozoan parasite, Toxoplasma gondii, was cloned and extracellularly expressed in the yeast Pichia pastoris. The effectiveness of the secreted recombinant SAG2 (rSAG2-S) as a serodiagnosis reagent was assessed by western blots and ELISA. In the western blot assay, rSAG2-S reacted with all Toxoplasma-antibody positive human serum samples but not with Toxoplasma-negative samples. In the ELISA, rSAG2-S yielded sensitivity rates ranging from 80% (IgG negative, IgM positive) to 100% (IgG positive, IgM negative). In vivo experiments showed that serum from mice immunized with rSAG2-S reacted specifically with the native SAG2 of T. gondii. These mice were protected when challenged with live cells of T. gondii.
    Matched MeSH terms: Toxoplasma/immunology
  11. Rahmah N, Khairul Anuar A
    Biochem Biophys Res Commun, 1992 Dec 15;189(2):640-4.
    PMID: 1472034
    Mice were chronically infected with cysts of ME49 strain of Toxoplasma gondii. At different periods post-infection, their spleens were removed and single cell suspensions were made. Lymphocyte transformation experiments were performed on the lymphocyte suspensions using three different kinds of antigens of ME49 strain of T. gondii, namely soluble, excretory/secretory and cystic forms. The results showed that the pattern of lymphocyte responsiveness was dependent on the kind of antigen employed for induction of the blastogenesis. Using soluble and cystic forms of the antigen, different periods of lymphocyte suppression and lymphocyte proliferation were demonstrated. However, with the use of excretory/secretory antigen, no significant suppression of lymphocyte stimulation was noted throughout the course of infection. Thus excretory/secretory antigen may be the best form of antigen for stimulation of the cell-mediated immune response and hence it appears to be a good candidate for vaccine in toxoplasmosis.
    Matched MeSH terms: Toxoplasma/immunology*
  12. Hoe LN, Wan KL, Nathan S
    Parasitology, 2005 Dec;131(Pt 6):759-68.
    PMID: 16336729
    The protozoan parasite Toxoplasma gondii produces a family of microneme proteins that are thought to play diverse roles in aiding the parasite's intracellular existence. Among these, TgMIC2 has a putative function in parasite adhesion to the host cell to initiate the invasion process. The invasion process may be localized and inhibited by monoclonal antibodies against the protein(s) involved. Here we report on the construction of a phage-displayed single-chain variable fragment (scFv) library from mice immunized with whole T. gondii parasites. The library was subsequently panned against recombinant TgMIC2 (rpTgMIC2) and 2 different groups of antibody clones were obtained, based on fingerprinting and sequencing data. The expressed recombinant scFv antibody was able to recognize rpTgMIC2 in a Western blot detection experiment. These results show that the phage display technology allows quick and effective production of monoclonal antibodies against parasite antigens. By panning the scFv-displayed library, we should be able to obtain a plethora of multi-functional scFv antibodies towards T. gondii proteins.
    Matched MeSH terms: Toxoplasma/immunology*
  13. Rahmah N, Anuar AK
    Biochem Biophys Res Commun, 1992 Aug 31;187(1):294-8.
    PMID: 1520310
    C57BL/6 mice were orally infected with different doses of cysts of ME49 strain of Toxoplasma gondii to produce groups of acutely and chronically infected mice. Sera were obtained at different periods post-infection. SDS-PAGE was ran with excretory/secretory antigens of ME49 and RH strains of T. gondii, followed by Western blot analyses using the above sera and anti- IgA, IgM, IgG as conjugates. The SDS-PAGE profiles of the two antigens were similar. However the antigenic bands showed variations in all blots, most evidently in IgA blots of chronic sera. IgG blots showed greatest similarities in reactive bands. In IgM blots, more common bands were shown in chronic sera than in acute sera. Variations and similarities in prominence of some bands and time of their appearance were also noted, especially in IgM and IgG blots of chronic sera. Thus antigenic variations and similarities are present in excretory/secretory products of different strains of T. gondii.
    Matched MeSH terms: Toxoplasma/immunology*
  14. Hajissa K, Zakaria R, Suppian R, Mohamed Z
    Parasit Vectors, 2015;8:315.
    PMID: 26062975 DOI: 10.1186/s13071-015-0932-0
    Serological investigation remains the primary approach to achieve satisfactory results in Toxoplasma gondii identification. However, the accuracy of the native antigen used in the current diagnostic kits has proven to be insufficient as well as difficult to standardize, so significant efforts have been made to find alternative reagents as capture antigens. Consequently, multi-epitope peptides are promising diagnostic markers, with the potential for improving the accuracy of diagnostic kits. In this study, we described a simple, inexpensive and improved strategy to acquire such diagnostic markers. The study was aimed at producing novel synthetic protein consisting of multiple immunodominant epitopes of several T. gondii antigens.
    Matched MeSH terms: Toxoplasma/immunology*
  15. Meganathan P, Singh S, Ling LY, Singh J, Subrayan V, Nissapatorn V
    PMID: 20578507
    Detection of Toxoplasma gondii in blood by means of the polymerase chain reaction (PCR) may facilitate early diagnosis of toxoplasmosis in different groups of patients. We evaluated this approach in 42 patients presenting with ocular or psychotic diseases by comparing the sensitivity and specificity of PCR after heat treatment using a microwave oven with a standard genomic DNA extraction method for paired serum and whole blood samples. The presence of serum IgM and IgG antibodies against T. gondii was detected using a standard commercial enzyme-linked immunosorbent assay and enzyme immunoassay for IgG avidity test. Of 42 whole blood samples, PCR after microwave treatment was positive in 8 samples with a sensitivity of 73% and specificity of 100% compared to 11 samples positive by the extraction method. Although none of 42 sera samples was PCR positive by the extraction method, 7 specimens were positive after microwave treatment. This is the first study to use a microwave heat treatment, which is simple, rapid and a promising alternative method, in detecting small amounts of T. gondii DNA in human blood. Furthermore, irradiation of blood samples with microwaves allows incorporation of PCR into a practical tool for routine clinical assessment of patients with Toxoplasma infection.
    Matched MeSH terms: Toxoplasma/immunology*
  16. Latif BM, Jakubek EB
    Trop Biomed, 2008 Dec;25(3):225-31.
    PMID: 19287361
    Flourescent antibody test (FAT) was applied to determine the cross-reactivities of monoclonal (mAb), polyclonal (pAb) antibodies to Neospora, Toxoplasma and Cryptosporidium and antisera from cattle naturally infected with Neospora canium against antigens from a number of sources. Both mAb and pAb to Neospora reacted strongly (FAT titre up to 2560) with the homologous antigens and demonstrated weak titre (80) or no reaction with both Toxoplasma and Cryptosporidium antigens. Also mAb and pAb to Toxoplasma gondii reacted at titres of 80 - 640 with homologous antigens and at titres of 10-40 with N. caninum. No cross-reactions with either mAb or pAb antibodies to N. caninum and T. gondii were observed with Cryptosporidium parvum. The same results were observed with C. parvum mAb when tested with both N. caninum and T. gondii antigens. Sera from cattle naturally infected with N. caninum had titres ranging from 80- 640 with N. caninum antigens, and 10- 40 with T. gondii and C. parvum antigens. At low dilutions, the complete surfaces of Neospora and Toxoplasma parasites were fluorescent, while in higher dilutions only dotted fluorescence appeared on the apical complex. These results indicated the presence of cross-reactivity between Neospora and Toxoplasma but not with Cryptosporidium. Accordingly the recommended cut-off antibody titre for diagnosis of neosporosis is 80.
    Matched MeSH terms: Toxoplasma/immunology*
  17. Hakim SL, Radzan T, Nazma M
    PMID: 7777912
    The distribution of anti-toxoplasma antibodies among the aborigines in Malaysia and its association with other soil transmitted infections and eosinophilia were studied. A total of 415 serum samples were collected and tested by IFA test. Overall prevalence was 10.6%, lower than previously reported. The antibody titers showed a unimodal distribution peaking at 1:8 dilution. There was a higher proportion of high antibody titer (> 1:128) in the adult compared to the children with no significant difference in prevalence rate by sex. The pattern of infection does not differ from other soil transmitted infections and there was no association between raised Toxoplasma antibodies with eosinophilia.
    Matched MeSH terms: Toxoplasma/immunology*
  18. Ching XT, Lau YL, Fong MY, Nissapatorn V
    Parasitol Res, 2013 Mar;112(3):1229-36.
    PMID: 23274488 DOI: 10.1007/s00436-012-3255-5
    Toxoplasma gondii infects all warm-blooded animals including humans, causing serious public health problems and great economic loss in the food industry. Commonly used serological tests involve preparation of whole Toxoplasma lysate antigens from tachyzoites which are costly and hazardous. An alternative method for better antigen production involving the prokaryotic expression system was therefore used in this study. Recombinant dense granular protein, GRA2, was successfully cloned, expressed, and purified in Escherichia coli, BL21 (DE3) pLysS. The potential of this purified antigen for diagnosis of human infections was evaluated through western blot analysis against 100 human serum samples. Results showed that the rGRA2 protein has 100 and 61.5 % sensitivity towards acute and chronic infection, respectively, in T. gondii-infected humans, indicating that this protein is useful in differentiating present and past infections. Therefore, it is suitable to be used as a sensitive and specific molecular marker for the serodiagnosis of Toxoplasma infection in both humans and animals.
    Matched MeSH terms: Toxoplasma/immunology
  19. Khan MB, Sonaimuthu P, Lau YL, Al-Mekhlafi HM, Mahmud R, Kavana N, et al.
    Parasit Vectors, 2014;7:505.
    PMID: 25388913 DOI: 10.1186/s13071-014-0505-7
    The neglected tropical diseases, echinococcosis, schistosomiasis and toxoplasmosis are all globally widespread zoonotic diseases with potentially harmful consequences. There is very limited data available on the prevalence of these infections, except for schistosmiasis, in underdeveloped countries. This study aimed to determine the seroprevalence of Echinococcus multilocularis, Schistosoma mansoni, and Toxoplasma gondii antibodies in populations from the Monduli and Babati districts in Tanzania.
    Matched MeSH terms: Toxoplasma/immunology
  20. Amerizadeh A, Khoo BY, Teh AY, Golkar M, Abdul Karim IZ, Osman S, et al.
    BMC Infect Dis, 2013;13:287.
    PMID: 23800344 DOI: 10.1186/1471-2334-13-287
    Toxoplasma gondii is an obligate intracellular zoonotic parasite of the phylum Apicomplexa which infects a wide range of warm-blooded animals, including humans. In this study in-vivo induced antigens of this parasite was investigated using in-vivo induced antigen technology (IVIAT) and pooled sera from patients with serological evidence of acute infection.
    Matched MeSH terms: Toxoplasma/immunology*
Filters
Contact Us

Please provide feedback to Administrator (afdal@afpm.org.my)

External Links