Displaying publications 1 - 20 of 36 in total

Abstract:
Sort:
  1. A sensitive malaria immunoperoxidase assay for the detection of Plasmodium falciparum antibody
    Lim TS
    Am J Trop Med Hyg, 1988 Mar;38(2):255-7.
    PMID: 3281491
    A new and rapid malaria immunoperoxidase assay using the enzyme horseradish peroxidase in place of fluorescein isothiocyanate was developed to allow the serological measurement of antimalarial antibody by light microscopy. Acetone-fixed thin blood films prepared from cultured Plasmodium falciparum were used as the source of antigen. This malaria immunoperoxidase assay is as sensitive as, and occasionally more sensitive than, the indirect fluorescent antibody assay. It is easy to perform and the antigen used does not show cross-reactivity with sera from nonmalarial diseases.
    Matched MeSH terms: Plasmodium falciparum/immunology*
  2. The ELISA-U: an enzyme-linked immunosorbent assay using urease as the enzyme marker for rapid detection of Plasmodium falciparum antibody in human serum
    Lee M, Lambros C
    Am J Trop Med Hyg, 1988 Nov;39(5):421-6.
    PMID: 3057927
    A visual, enzyme-linked immunosorbent assay using urease (ELISA-U) as the enzyme marker was adapted for rapid detection of antibody against Plasmodium falciparum. Flat-bottom, 96-well microtiter plates were coated with P. falciparum soluble antigen obtained by saponin and NP-40 treatment of parasite cultures. Antibody was detected by successive incubations with test sera, urease-conjugated rabbit-human antibody, and urease substrate. Reactive sera developed a definite and easily visualized purple color. Sera from patients with single infections of P. vivax or P. ovale were unreactive. No cross-reactivity was noted with sera from patients with rheumatoid arthritis, filariasis, amebiasis, schistosomiasis, dengue, scrub typhus, leptospirosis, or toxoplasmosis. The procedure can be performed at room temperature and completed within 1 hr. The sensitivity of the assay is comparable to that of the indirect fluorescent antibody test at all but the lowest dilutions tested.
    Matched MeSH terms: Plasmodium falciparum/immunology*
  3. Knob-positive and knob-negative Plasmodium falciparum differ in expression of a strain-specific malarial antigen on the surface of infected erythrocytes
    Aley SB, Sherwood JA, Howard RJ
    J. Exp. Med., 1984 Nov 01;160(5):1585-90.
    PMID: 6208311
    We have investigated the expression of a strain-specific malarial antigen on the surface of erythrocytes infected with knobless (K-) variants of knob-positive (K+) strains of Plasmodium falciparum. Aotus blood infected with K+ or K- parasites derived from two independent geographical isolates (Malayan camp and Santa Lucia) was surface iodinated by the lactoperoxidase method. Infected and uninfected erythrocytes were then separated by a new procedure involving equilibrium density sedimentation on a Percoll gradient containing sorbitol. Strain-specific antigens were readily identified on the surface of erythrocytes infected with either of the K+ strains by their characteristic size and detergent solubility. These proteins were not detected on the surface of erythrocytes infected with either of the K- variants nor on uninfected erythrocytes isolated from K+- or K- -infected blood. These results are consistent with a role for the strain-specific surface antigen in cytoadherence of P. falciparum-infected erythrocytes. Our findings represent the second biochemical difference (with the knob-associated histidine-rich protein) between K+ and K- P. falciparum.
    Matched MeSH terms: Plasmodium falciparum/immunology*
  4. Hereditary ovalocytosis and reduced susceptibility to malaria in Papua New Guinea
    Cattani JA, Gibson FD, Alpers MP, Crane GG
    Trans R Soc Trop Med Hyg, 1987;81(5):705-9.
    PMID: 3329776
    Ovalocytosis, an hereditary condition in which most erythrocytes are oval in shape, is a polymorphism that occurs in up to 20% or more of the population in Papua New Guinea and Malaysia. Due to the geographical correlation of the trait with endemic malaria, the possibility of a selective advantage in resistance to malaria has been raised. In a study of 202 individuals with greater than or equal to 50% oval red cells matched by age, sex and village of residence with controls having less than or equal to 30% oval cells, ovalocytic subjects had blood films negative for Plasmodium vivax (P = 0.009), for P. falciparum (P = 0.044), and for all species of malaria parasites (P = 0.013), more often than controls. Among individuals parasitaemic at any time there were no clear differences in density of parasitaemia. However, in children 2 to 4 years old, parasite densities of both species were lower in ovalocytic subjects than in controls (0.01 less than P less than 0.025). The differential susceptibility to malaria infection suggested by this study has implications for the evaluation of interventions, including possible future vaccine field trials, in populations where high-frequency ovalocytosis is present.
    Matched MeSH terms: Plasmodium falciparum/immunology
  5. Seroepidemiology of malaria: age-specific pattern of Plasmodium falciparum antibody, parasite and spleen rates among children in an endemic area in peninsular Malaysia
    Thomas V, Hock SK, Leng YP
    Trop Doct, 1981 Oct;11(4):149-54.
    PMID: 7027557
    A seroepidemiological study was carried out on Orang Asli (Aborigines) children who lead a semi-nomadic life in the deep jungles of Ulu Kelantan, Malaysia. Out of a total of about 190 children below 14 years, 143 were studied. Blood was collected from finger pricks on standard "strip type" filter papers for indirect fluorescent antibody (IFA) tests with Plasmodium falciparum antigen. A positive reaction at 1:10 dilution in infants and young children was considered positive and the reasons are given. The P. falciparum antibody prevalence rate was 84.6% compared to 81.8% spleen and 43.4% parasite rates. Both P. Falciparum and P. vivax were present in children. The age-specific patterns of antibody, spleen and parasite rates were those of a hyperendemic community. There was a positive correlation between antibody and spleen rates up to the age of 9 years. In older children, the antibody rates increased while the spleen and the parasite rates dropped.
    Matched MeSH terms: Plasmodium falciparum/immunology
  6. Conserved and variant epitopes of target antigens of transmission-blocking antibodies among isolates of Plasmodium falciparum from Malaysia
    Foo A, Carter R, Lambros C, Graves P, Quakyi I, Targett GA, et al.
    Am J Trop Med Hyg, 1991 Jun;44(6):623-31.
    PMID: 1713424
    Monoclonal antibodies (MAbs) directed against different epitope regions on three sexual stage-specific gamete surface proteins of Plasmodium falciparum, Pfs 25, Pfs 230, and Pfs 48/45, were used to study the genetic diversity of these epitopes among fresh isolates of P. falciparum from Malaysia, using immunofluorescence microscopy (IFA). Among 45 Malaysian isolates, one epitope of Pfs 25, designated region I, showed evidence of variable reactivity with MAbs among different isolates; the Pfs 25 epitope, region II, was universally recognized by MAbs in all isolates. Two apparently distinct epitope regions of Pfs 230 were defined by MAbs, one of which was universally recognized by MAbs among the 45 isolates; the other was conserved in all but three isolates. The epitope regions of gamete-surface protein Pfs 48/45, designated regions I, IIa, IIb, IIc, III, and IV, were examined for reactivity by IFA in 33 isolates. Epitope regions I, IIb, III, and IV were conserved in all isolates; regions IIa and IIc existed in variant forms.
    Matched MeSH terms: Plasmodium falciparum/immunology*
  7. Use of avidin-biotin-glucose oxidase complex to detect antimalarial antibody in serum by light microscopy
    Lee M, Lambros C
    Am J Trop Med Hyg, 1988 Aug;39(2):145-9.
    PMID: 3044152
    An immunohistochemical assay was developed combining an avidin-biotin-glucose oxidase complex procedure (ABC-GO) with light microscopy to detect specific antibody against Plasmodium falciparum. Thin blood films were prepared from culture material of P. falciparum and fixed with acetone. Antibody was detected by successive incubations with test serum, biotinylated goat antihuman antibody, avidin-biotin-glucose oxidase complex, and glucose oxidase substrate. In the presence of reactive serum, a blue precipitate formed on the parasites and could be visually observed with a 40x objective. Sera from patients with single infections for P. vivax or P. ovale were unreactive. No cross-reactivity was observed with sera from patients with rheumatoid arthritis, filariasis, amebiasis, schistosomiasis, dengue, scrub typhus, leptospirosis, or toxoplasmosis. The sensitivity of ABC-GO is comparable to that of the indirect fluorescent antibody test.
    Matched MeSH terms: Plasmodium falciparum/immunology*
  8. A longitudinal study of malaria antibodies in a Malaysian population. I. Group responses
    Mathews HM, Dondero TJ
    Am J Trop Med Hyg, 1982 Jan;31(1):14-8.
    PMID: 7036766
    The indirect hemagglutination test was used to measure malaria antibody levels in residents of an endemic area of Malaysia. Blood specimens were collected at 4-week intervals for a year. Seropositivity rates increased with age and number of episodes of malaria in young children. Although antibody levels were variable, titers tended to rise with parasitemia and fall in the absence of detected parasites. In general, the serologic indices tended to reflect the parasitologic findings.
    Matched MeSH terms: Plasmodium falciparum/immunology*
  9. A longitudinal study of malaria antibodies in a Malaysian population. II. Follow-up of individuals
    Mathews HM, Dondero TJ
    Am J Trop Med Hyg, 1982 Jan;31(1):19-23.
    PMID: 7036769
    A cohort of 62 persons living in a malaria-endemic area was examined by serology and by blood film 14 times over a 56-week period. Serologic responses (indirect hemagglutination test) of the group as a whole reflected the malaria transmission as determined by blood slide examination. The serologic responses of individuals showed titer changes that were not always consistent with blood slide results. The use of chloroquine may have modified the host's immune response.
    Matched MeSH terms: Plasmodium falciparum/immunology*
  10. Diffusion-in-gel enzyme-linked immunosorbent assay, ELISA and IFA test in the detection of malarial antibodies
    Kumar GS, Mak JW, Lam PL, Tan MA, Lim PK
    Southeast Asian J. Trop. Med. Public Health, 1987 Dec;18(4):502-6.
    PMID: 3129797
    Malarial antibodies in 80 patients were measured using the diffusion-in-gel enzyme linked immunosorbent assay (DIG-ELISA), enzyme-linked immunosorbent assay (ELISA) and the indirect fluorescent antibody (IFA) test. Good correlations were obtained between all three tests in terms of sensitivity and reliability. DIG-ELISA has the advantage of being a rapid diagnostic tool for the detection of malarial antibodies.
    Matched MeSH terms: Plasmodium falciparum/immunology
  11. Malaria endemicity among Orang Asli (Malaysian aborigines) as determined by indirect fluorescent antibody tests
    Thomas V, Dissanaike AS
    Am J Trop Med Hyg, 1977 Jul;26(4):602-6.
    PMID: 329695
    Fluorescent antibodies were detected in 89% of 288 Orang Asli (Malaysian aborigines) with Plasmodium falciparum antigen and in 62% with P. brasilianum (for P. malariae) antigen. Blood films from 18 donors were positive for P. falciparum; 2 of them had mixed infection with P. vivax. Seven of the P. falciparum-positive blood films were from children in the 2- to 9-year age group. Of 17 sera from cord blood, 16 had significant levels of P. falciparum antibody and 14 of P. malariae antibody, the levels being the same as those of the mothers. None of these babies had congenital malaria. A higher percentage of male donors reacted to both antigens. There was an age dependent increase in the number positive and the maximum titers.
    Matched MeSH terms: Plasmodium falciparum/immunology
  12. Seroepidemiology of malaria in Peninsular Malaysia: Plasmodium falciparum antibody profile of adults in four states
    Thomas V, Bin HK, Leng YP
    Trans R Soc Trop Med Hyg, 1980;74(3):375-80.
    PMID: 7001690
    In 1973, 2610 sera were collected from adults living in 22 localities in four states in Peninsular Malaysia and tested by IFAT for Plasmodium falciparum antibodies. A larger number of thin films were examined. The attack phase of the Malaria Eradication Programme (MEP) in these areas was started between 1968 and 1973. The results showed that the highest prevalence rates and geometrical mean reciprocal titres (CMRT) were among adults from Kelantan where the antibody prevalence varied greatly among the adults and there was active transmission in at least three areas. The values were lowest for Kedah. The P. falciparum antibody prevalence rates were higher than the parasite rates as revealed in single thin film examinations but a number of the positive sera were reactive only at low titres. The low concentration probably indicated the residual antibody from cured cases or past infections and cross reactions to P. vivax and P. malariae infections. The strong reactions probably indicated current P. falciparum transmission as shown by positive thin films. The present study showed that the antibody profile of adults, as shown by IFAT, is of considerable value in assessing the malaria situation in a given area and that it would be useful as a malariometric tool in epidemiological studies to evaluate the progress of malaria eradication/control programmes.
    Matched MeSH terms: Plasmodium falciparum/immunology
  13. The indirect fluorescent antibody test for malaria
    Collins WE, Skinner JC
    Am J Trop Med Hyg, 1972 Sep;21(5):690-5.
    PMID: 4627546
    Matched MeSH terms: Plasmodium falciparum/immunology
  14. Fulltext Serological evaluation of malaria patients in Thailand: antibody response against electrophoresed antigenic polypeptides of Plasmodium falciparum
    Kano S, Onda T, Matsumoto Y, Buchachart K, Krudsood S, Looareesuwan S, et al.
    Southeast Asian J. Trop. Med. Public Health, 1998 Jun;29(2):341-3.
    PMID: 9886125
    It was reported that a 47kDa antigenic polypeptide of Plasmodium falciparum had been strongly presented by the sera from 1) imported Japanese malaria patients with severe symptoms and 2) symptomatic and parasitemic inhabitants in endemic areas in the Sudan, Malaysia and the Philippines. In the present study, we observed the reactivity of the sera from falciparum malaria patients who had been hospitalized in the Bangkok Hospital for Tropical Diseases, Faculty of Tropical Medicine, Mahidol University, and compared the antibody response against the 47kDa antigenic polypeptide according to the severity of the patients. It was observed that antibodies to this molecule were more commonly shared in sera from severer patients, although the IFAT titers against the whole P. falciparum parasite antigen were lower in the group, which suggested that this antibody against the 47kDa molecule was playing a specific role at a severe stage of the infection. Determination of the immunological features of the antigenic molecules of parasites by this type of sero-epidemiological study will provide a new assay system for evaluation of immune status of individuals in different severity and suggest a way of vaccine development.
    Matched MeSH terms: Plasmodium falciparum/immunology*
  15. Antibodies to Plasmodium falciparum in an indigenous population from a malaria endemic area of Malaysia
    Archibald CP, Mak JW, Mathias RG, Selvajothi S
    Acta Trop, 1990 Dec;48(2):149-57.
    PMID: 1980570
    Indirect fluorescent antibody (IFA) tests and enzyme-linked immunosorbent assays (ELISA) were used to measure antibodies to Plasmodium falciparum in an indigenous population in an area of Malaysia with high malaria prevalence. The results of three surveys were analyzed to examine the relation of these serologic measures with age, parasite rate, and spleen size. For children 0-4 years old, increasing spleen size was associated with an increasing likelihood of malaria parasitemia, while for 5-9 year olds the two variables were unrelated. Parasite rate declined with age and ELISA titre increased with age in all surveys; IFA titre was consistently high and did not vary with age. Neither antibody measure was significantly correlated with either the presence or the actual density of parasitemia. These antibody measures are most useful as adjuncts to the more traditional techniques of malaria assessment.
    Matched MeSH terms: Plasmodium falciparum/immunology*
  16. Significance of circumsporozoite-specific antibody in the natural transmission of Plasmodium falciparum, Plasmodium vivax, and Plasmodium malariae in an aboriginal (Orang Asli) population of central peninsula Malaysia
    Gordon DM, Davis DR, Lee M, Lambros C, Harrison BA, Samuel R, et al.
    Am J Trop Med Hyg, 1991 Jul;45(1):49-56.
    PMID: 1867348
    Two hundred and seventy-five Orang Asli volunteers living in nine villages in the Pos Legap Valley of Perak State, peninsular Malaysia, participated in a prospective study designed to characterize the epidemiological, parasitological, and entomological characteristics of Plasmodium falciparum, P. vivax, and P. malariae malaria transmission. Prevalence rates for the three plasmodial species at initiation of the study ranged from 56% in the 0-4-year-old age group to 0% in individuals over the age of 40. Entomological surveys were conducted, enabling us to determine mosquito salivary gland-positive rates and entomological inoculation rates of 1.2 infectious mosquito bites per person per month for P. falciparum, 2.4 for P. vivax, and 0.3 for P. malariae. Cumulative incidence rates over the 16 weeks of the study, following radical cure of all volunteers, were 22.5% for P. falciparum, 12.7% for P. vivax, and 1.5% for P. malariae. The median baseline antibody titer against the immunodominant repetitive B cell epitope of P. falciparum or P. vivax circumsporozoite protein was significantly higher for volunteers who did not become parasitemic. Volunteers were selected for further study if they had evidence of being challenged with P. falciparum sporozoites during the study, based on a two-fold or greater increase in antibody titer against the immunodominant repetitive B cell epitope of the circumsporozoite protein. Resistance to infection was seen in six of 10 individuals who had high (greater than 25 OD units) baseline ELISA titers, compared with only three of 24 individuals who had low baseline ELISA titers (chi 2 P less than 0.02). A similar analysis for P. vivax did not show a significant correlation.
    Matched MeSH terms: Plasmodium falciparum/immunology*
  17. Plasmodium falciparum: gene structure and hydropathy profile of the major merozoite surface antigen (gp195) of the Uganda-Palo Alto isolate
    Chang SP, Kramer KJ, Yamaga KM, Kato A, Case SE, Siddiqui WA
    Exp Parasitol, 1988 Oct;67(1):1-11.
    PMID: 3049134
    The gene encoding the 195,000-Da major merozoite surface antigen (gp195) of the FUP (Uganda-Palo Alto) isolate of Plasmodium falciparum, a strain widely used for monkey vaccination experiments, has been cloned and sequenced. The translated amino acid sequence of the FUP gp195 protein is closely related to the sequences of corresponding proteins of the CAMP (Malaysia) and MAD-20 (Papua New Guinea) isolates and more distantly related to those of the Wellcome (West Africa) and K1 (Thailand) isolates, supporting the proposed allelic dimorphism of gp195 within the parasite population. The prevalence of dimorphic sequences within the gp195 protein suggests that many gp195 epitopes would be group-specific. Despite the extensive differences in amino acid sequence between gp195 proteins of these two groups, the hydropathy profiles of proteins representative of both groups are very similar. The conservation of overall secondary structure shown by the hydropathy profile comparison indicates that gp195 proteins of the various P. falciparum isolates are functionally equivalent. This information on the primary structure of the FUP gp195 protein will enable us to evaluate the possible roles of conserved, group-specific and variable epitopes in immunity to the blood stage of the malaria parasite.
    Matched MeSH terms: Plasmodium falciparum/immunology
  18. A case of congenital malaria in Malaysia with IgM malaria antibodies
    Thomas V, Chit CW
    Trans R Soc Trop Med Hyg, 1980;74(1):73-6.
    PMID: 7001686
    Congenital malaria from Malaysia is reported here for the first time. It occurred in a baby boy born to a 16-year-old primigravida who contracted Plasmodium falciparum infection during pregnancy. She suffered malaria during the later stages of pregnancy and at parturition. The placenta was heavily infested with various asexual stages of P. falciparum. Gametocytes were not seen. Extensive search did not show other species. Cord blood showed very light infection with young trophozoites of P. falciparum. Serological studies using IFA technique showed specific IgG and IgM antibodies to P. falciparum in maternal cord and two early neonatal sera. These serum samples showed lower levels of IgG antibodies against P. vivax and P. malariae, but there were no specific IgM antibodies against these species. The value of specific IgM antibody in the diagnosis of congenital malaria is discussed.
    Matched MeSH terms: Plasmodium falciparum/immunology*
  19. Fulltext IgM in human immunity to Plasmodium falciparum malaria
    Boyle MJ, Chan JA, Handayuni I, Reiling L, Feng G, Hilton A, et al.
    Sci Adv, 2019 09;5(9):eaax4489.
    PMID: 31579826 DOI: 10.1126/sciadv.aax4489
    Most studies on human immunity to malaria have focused on the roles of immunoglobulin G (IgG), whereas the roles of IgM remain undefined. Analyzing multiple human cohorts to assess the dynamics of malaria-specific IgM during experimentally induced and naturally acquired malaria, we identified IgM activity against blood-stage parasites. We found that merozoite-specific IgM appears rapidly in Plasmodium falciparum infection and is prominent during malaria in children and adults with lifetime exposure, together with IgG. Unexpectedly, IgM persisted for extended periods of time; we found no difference in decay of merozoite-specific IgM over time compared to that of IgG. IgM blocked merozoite invasion of red blood cells in a complement-dependent manner. IgM was also associated with significantly reduced risk of clinical malaria in a longitudinal cohort of children. These findings suggest that merozoite-specific IgM is an important functional and long-lived antibody response targeting blood-stage malaria parasites that contributes to malaria immunity.
    Matched MeSH terms: Plasmodium falciparum/immunology*
  20. Fulltext Sensitivity and specificity of malaria rapid diagnostic test (mRDT CareStatTM) compared with microscopy amongst under five children attending a primary care clinic in southern Nigeria
    Ogunfowokan O, Ogunfowokan BA, Nwajei AI
    Afr J Prim Health Care Fam Med, 2020 Jun 17;12(1):e1-e8.
    PMID: 32634015 DOI: 10.4102/phcfm.v12i1.2212
    BACKGROUND: Malaria diagnosis using microscopy is currently the gold standard. However, malaria rapid diagnostic tests (mRDTs) were developed to simplify the diagnosis in regions without access to functional microscopy.

    AIM: The objective of this study was to compare the diagnostic accuracy of mRDT CareStatTM with microscopy.

    SETTING: This study was conducted in the paediatric primary care clinic of the Federal Medical Centre, Asaba, Nigeria.

    METHODS: A cross-sectional study for diagnostic accuracy was conducted from May 2016 to October 2016. Ninety-eight participants were involved to obtain a precision of 5%, sensitivity of mRDT CareStatTM of 95% from published work and 95% level of confidence after adjusting for 20% non-response rate or missing data. Consecutive participants were tested using both microscopy and mRDT. The results were analysed using EPI Info Version 7.

    RESULTS: A total of 98 children aged 3-59 months were enrolled. Malaria prevalence was found to be 53% (95% confidence interval [CI] = 46% - 60%), whilst sensitivity and specificity were 29% (95% CI = 20% - 38%) and 89% (95% CI = 83% - 95%), respectively. The positive and negative predictive values were 75% (95% CI = 66.4% - 83.6%) and 53% (95% CI = 46% - 60%), respectively.

    CONCLUSION: Agreement between malaria parasitaemia using microscopy and mRDT positivity increased with increase in the parasite density. The mRDT might be negative when malaria parasite density using microscopy is low.

    Matched MeSH terms: Plasmodium falciparum/immunology
Related Terms
Filters
Contact Us

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

External Links