Displaying publications 1 - 20 of 286 in total

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  1. Yadav M, Iyngkaran N
    Med J Malaysia, 1982 Sep;37(3):239-44.
    PMID: 7177005
    Eighteen infants clinically suspected to be intolerant of cow's milk were placed on a milk-free formula and six to eight weeks later were orally challenged with cow's milk. Following challenge three groups were recognised. Group A: Four infants tolerated oral feeds ofcow's milk and lacked mucosal abnormality or clinical symptoms. Group B: Seven infants had mucosal deterioration but lacked clinical symptoms and tolerated cow's milk. Group C: Seven infants had mucosal abnormality, developed clinical symptoms and were intolerant of cow's milk. The intestinal transudation of IgA was increased in Group A and unchanged in Group Band C : the IgM levels in the duodenal juice was increased in Group A and B but unchanged in Group C : the IgG levels in the juice were increased in all Groups following challenge. It appears that increased transmission of IgA and IgM or IgM alone in the duodenal juice is associated with lack of development of clinical symptoms. Symptoms are present in infants in whom the IgA and IgM levels in duodenal juice remained unchanged after challenge. It is suggested that patients responding to cow's millt challenge with intestinal production of IgA and IgM (or IgM alone) are able to counter balance the deleterious mechanisms leading to clinical cow's milk intolerance whereas those who, for some unknown reason, do not mount a secretory immune response become ill.
    Matched MeSH terms: Milk Proteins/immunology*
  2. Yadav M, Iyngkaran N, Seow IKG
    Med J Malaysia, 1983 Dec;38(4):266-71.
    PMID: 6599980
    Infants, one to 56-weeks-old, presenting with persistent diarrhoea were placed on a diet free of cow's milk protein which improved their clinical condition. Six weeks later, 67 infants were challenged with a low-lactose cow's milk formula and jejunal biopsy was taken before and 24-hours after challenge. On the basis of histological changes in the intestinal mucosa and development of clinical symptoms the infants were categorised into three groups: Group 1 (n = 16) with no clinical or mucosal abnormality, Group 2 (n = 20) with mucosal abnormality but lacking clinical symptoms, and Group 3 (n 31) with manifestation of mucosal abnormality and clinical symptoms. In addition to the total IgE the radioallergosorbent test (RAST) was performed on sera from the infants taken before and after milk provocation. The mean total serum IgE level ranged from 288 to 560 IU/ml. In Groups 2 and 3 the prechallenge serum IgE levels were significantly higher than the postchallenge levels but in Group 1 the levels remained unchanged on challenge. A positive RAST to milk proteins was observed in five infants (7.4%), that is, one in Group 2 and four in Group 3, of 67 infants studied. In a survey of 405 consecutive paediatric-age patients admitted for a variety of symptoms, 90 were positive for RAST specific for milk proteins. Interestingly the majority of the patients positive for RAST presented with gastrointestinal ailments. The measurement of specific IgE appears not to be a useful adjunct in the diagnosis of CMPSE in Malaysian children.
    Matched MeSH terms: Milk Proteins/immunology
  3. Johnson RB, Dawkins HJ, Spencer TL, Saharee AA, Bahaman AR, Ramdani, et al.
    Res Vet Sci, 1989 Sep;47(2):277-9.
    PMID: 2508206
    ELISA and immunoblotting techniques were used to examine the humoral immune response to Pasteurella multocida, in bovine sera from Indonesia and Malaysia. Elevated levels of antibody to a crude lipopolysaccharide preparation were found in vaccinated animals. In addition to the response to lipopolysaccharide, antibodies from the vaccinated cattle strongly labelled five to six of the 40 protein bands in this organism.
    Matched MeSH terms: Bacterial Proteins/immunology
  4. Foong YT, Cheng HM, Sam CK, Dillner J, Hinderer W, Prasad U
    Int J Cancer, 1990 Jun 15;45(6):1061-4.
    PMID: 1693600
    The Epstein-Barr virus nuclear antigen I (EBNA I) is the only latent EBV antigen consistently expressed in malignant tissues of the nasopharynx. A 20-amino-acid synthetic peptide, p107 contains a major epitope of EBNA I. We tested sera from 210 patients with nasopharyngeal carcinoma (NPC) and from 128 normal individuals (NHS) for IgA antibodies to p107 using an enzyme-linked immunosorbent assay (ELISA). Whereas 191/210 (91%) of NPC patients had IgA antibodies to p107, only 17/128 (13.3%) of NHS had such antibodies and only 6/57 (10.5%) of sera from patients with malignancies other than NPC had IgA-p107 reactivity. Thirty-nine salivary samples from 46 NPC patients (84.8%) also contained IgA-p107 antibodies whereas only 3/42 (7.1%) of normal saliva samples were IgA-p107 positive. The results suggest that IgA antibodies to EBNA I may become a useful, easily measurable, marker for NPC.
    Matched MeSH terms: Recombinant Proteins/immunology; Viral Proteins/immunology
  5. Cecilia D, Gould EA
    Virology, 1991 Mar;181(1):70-7.
    PMID: 1704661
    The Sarawak strain of Japanese encephalitis virus (JE-Sar) is virulent in 3-week-old mice when inoculated intraperitoneally. The nucleotide sequence for the envelope glycoprotein (E) of this virus was determined and compared with the published sequences of four other strains. There were several silent nucleotide differences and five codon changes. Monoclonal antibodies (MAbs) against the E protein of JE-Sar virus were prepared and characterized. MAb-resistant mutants of JE-Sar were selected to determine if mutations in the E protein gene could affect its virulence for mice. Eight mutants were isolated using five different MAbs that identified virus-specific or group-reactive epitopes on the E protein. The mutants lost either complete or partial reactivity with selecting MAb. Several showed decreased virulence in 3-week-old mice after intraperitoneal inoculation. Two (r27 and r30) also showed reduced virulence in 2-week-old mice. JE-Sar and the derived mutants were comparable in their virulence for mice, when inoculated intracranially. Mutant r30 but not r27 induced protective immunity in adult mice against intracranial challenge with parent virus. However, r27-2 did induce protective immunity against itself. Nucleotide sequencing of the E coding region for the mutants revealed single base changes in both r30 and r27 resulting in a predicted change from isoleucine to serine at position 270 in r30 and from glycine to aspartic acid at position 333 in r27. The altered capacity of the mutants to induce protective immunity is consistent with the immunogenicity changes predicted by computer analysis using the Protean II program.
    Matched MeSH terms: Viral Envelope Proteins/immunology
  6. 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: Protozoan Proteins/immunology*
  7. Cheng HM, Foong YT, Mathew A, Sam CK, Dillner J, Prasad U
    J Virol Methods, 1993 Apr;42(1):45-51.
    PMID: 7686558
    An ELISA using the Epstein-Barr virus nuclear antigen 1 (EBNA 1) was found to detect selectively specific IgA in sera from patients with nasopharyngeal carcinoma (NPC). The antigen, p107, was a 20-amino acid synthetic peptide, representing a major epitope of EBNA 1.267/294 (90.8%) of NPC patients had IgA antibodies to p107 but in normal individuals, only 41/577 (7.1%) had IgA/p107. In sera from patients with other cancers, 11/77 (14.3%) had IgA/p107 reactivity. 124 IgA/VCA positive and 86 IgA/VCA negative NPC sera were also tested for IgA/p107 binding in ELISA. The majority of IgA/VCA positive sera (117) also contained IgA/p107 antibodies. Of interest was the detection of 74/86 IgA/p107 reactive sera in the IgA/VCA negative group. The results suggest that the IgA/p107 ELISA could become a useful, complementary screening assay to the IgA/VCA immunofluorescence test for detection of NPC.
    Matched MeSH terms: DNA-Binding Proteins/immunology
  8. Verdugo-Rodriguez A, Gam LH, Devi S, Koh CL, Puthucheary SD, Calva E, et al.
    Asian Pac J Allergy Immunol, 1993 Jun;11(1):45-52.
    PMID: 8216558
    An indirect ELISA was used to detect antibodies against outer membrane protein preparations (OMPs) from Salmonella typhi. Sera from patients with a definitive diagnosis of typhoid fever (TF) gave a mean absorbance reading, at 414 nm, of 1.52 +/- 0.23 as compared to 0.30 +/- 0.11 for sera from healthy individuals. This gave a positive to negative ratio of absorbance readings of approximately 5.1. Suspected TF patients (no isolation of S. typhi), with positive and negative Widal titers had mean absorbance readings of 1.282 +/00.46 and 0.25 +/- 0.19, respectively. Sera from patients with leptospirosis, rickettsial typhus, dengue fever, and other infections gave mean absorbances of 0.20 +/- 0.08, 0.24 +/- 0.08, 0.27 +/- 0.08, and 0.31 +/- 0.16, respectively. The sensitivity, specificity, positive and negative predictive values were 100%, 94%, 80% and 100%, respectively. The antibody response detected in the definitive TF cases was predominantly IgG in nature and no cross-reactivity was seen with OMP preparations extracted from E. coli. Variable reactivity was noted with OMP preparations obtained from other Salmonella spp. Three major OMPs are presented in the antigen preparation and strong binding of positive sera was detected to all three bands.
    Matched MeSH terms: Bacterial Outer Membrane Proteins/immunology*
  9. Tan NH, Lim KK, Jaafar MI
    Toxicon, 1993 Jul;31(7):865-72.
    PMID: 8212031
    The antigenic cross-reactivity of four Ophiophagus hannah (king cobra) venom components, the neurotoxin (OH-NTX), phospholipase A2 (OH-PLA2), hemorrhagin (OH-HMG) and L-amino acid oxidase (OH-LAAO) were examined by indirect and double sandwich ELISAs. The indirect ELISAs for OH-NTX, OH-PLA2 and OH-HMG were very specific when assayed against the various heterologous snake venoms and O. hannah venom components, at 25 ng/ml antigen level. At higher antigen concentrations (100-400 ng/ml), there were moderate to strong indirect ELISA cross-reactions between anti-O. hannah neurotoxin and venoms from various species of cobra as well as two short neurotoxins. However, anti-O. hannah hemorrhagin did not cross-react with any of the venoms tested, even at these high antigen concentrations, indicating that O. hannah hemorrhagin is antigenically very different from other venom hemorrhagins. Examination of the indirect ELISA cross-reactions between anti-O. hannah PLA2 and several elapid PLA2 enzymes suggests that the elapid PLA2 antigenic class has more than two subgroups. The antibodies to O. hannah L-amino acid oxidase, however, yielded indirect ELISA cross-reactions with many venoms as well as with OH-NTX, OH-PLA2 and OH-HMG, indicating that OH-LAAO shares common epitopes even with unrelated proteins. The double sandwich ELISAs for the four anti-O. hannah venom components, on the other hand, generally exhibited a higher degree of selectivity than the indirect ELISA procedure.
    Matched MeSH terms: Cobra Neurotoxin Proteins/immunology*
  10. Teh LS, Lee MK, Wang F, Manivasagar M, Charles PJ, Nicholson GD, et al.
    Br J Rheumatol, 1993 Aug;32(8):663-5.
    PMID: 8348266
    We report a significantly increased prevalence of antiribosomal P protein antibodies in Malaysian Chinese patients (38%) with SLE compared to white Caucasian (13%) and Afro-Caribbean (20%) patients. The increased prevalence was not due to a generalized increase in autoantibody production because anti-dsDNA and anti-SSA antibodies were present in comparable frequencies in the three ethnic groups while anti-Sm and anti-SSB antibodies were rarely found in the Malaysian Chinese patients.
    Matched MeSH terms: Ribosomal Proteins/immunology*
  11. Lachumanan R, Devi S, Cheong YM, Rodda SJ, Pang T
    Infect Immun, 1993 Oct;61(10):4527-31.
    PMID: 7691753
    Binding studies of 160 overlapping, synthetic octapeptides from the hydrophilic regions of the Sta58 major outer membrane protein of Rickettsia tsutsugamushi with sera from patients with scrub typhus revealed 15 immunodominant peptides which are recognized by all the sera tested. Further analysis of the specificity of peptide binding with five of these peptides indicated that the peptides showed significantly stronger binding to scrub typhus patients' sera than they did to sera from patients with other febrile illnesses common in the region, i.e., malaria, dengue fever, typhoid fever, and leptospirosis. The main antibody class binding to these peptides appears to be immunoglobulin M, and there appears to be little correlation between reactivity with peptides and antibody titers measured by the indirect immunoperoxidase test.
    Matched MeSH terms: Bacterial Outer Membrane Proteins/immunology*; Bacterial Proteins/immunology*
  12. Czuppon AB, Chen Z, Rennert S, Engelke T, Meyer HE, Heber M, et al.
    J Allergy Clin Immunol, 1993 Nov;92(5):690-7.
    PMID: 8227860
    BACKGROUND: Allergy to latex-containing articles is becoming more and more important because it can result in unexpected life-threatening anaphylactic reactions in sensitized individuals.

    METHODS: A protein of 58 kd with an isoelectric point of 8.45 was purified from raw latex and from latex gloves and identified as the major allergen, completely blocking specific IgE antibodies in the serum of latex-sensitized subjects. The allergen is a noncovalent homotetramer molecule, in which the 14.6 kd monomer was identified, by amino acid composition and sequence homologies of tryptic peptides, to be the rubber elongation factor found in natural latex of the Malaysian rubber tree.

    RESULTS: Competitive immunoinhibition tests showed that the starch powder covering the finished gloves is the airborne carrier of the allergen, resulting in bronchial asthma on inhalation. The purified allergen can induce allergic reactions in the nanogram range.

    CONCLUSION: The identification of the allergen (Hev b I) may help to eliminate it during the production of latex-based articles in the future.

    Matched MeSH terms: Proteins/immunology*
  13. Kurup VP, Kumar A, Kelly KJ, Fink JN
    J Allergy Clin Immunol, 1993 Nov;92(5):638-43.
    PMID: 8227854 DOI: 10.1016/0091-6749(93)90005-z
    Several hybridomas were produced against antigens extracted from the latex sap of Hevea brasiliensis. One of the monoclonal antibodies (LA-E3) reacted with antigens demonstrating binding to patient sera on crossed enzyme immunoelectrophoresis. This monoclonal antibody reacted with 2 of 10 glove extracts studied and with both Malaysian and Indian latex plant extracts. The antigens purified with monoclonal antibody affinity chromatography demonstrated specific IgE in the sera of patients with latex allergy as determined by ELISA. This monoclonal antibody can thus be utilized to obtain reliable antigens useful in the diagnosis of latex sensitivity, although additional antigens will likely be necessary to enhance sensitivity and specificity.
    Matched MeSH terms: Plant Proteins/immunology*
  14. Mathew A, Cheng HM, Sam CK, Joab I, Prasad U, Cochet C
    Cancer Immunol Immunother, 1994 Jan;38(1):68-70.
    PMID: 8299121
    The BamHI Z EBV replication activator (ZEBRA) protein is involved in the switch from latency to productive cycle of Epstein-Barr virus. A recombinant ZEBRA protein was synthesized and assessed in enzyme-linked immunosorbent assay (ELISA) for serum IgG response in nasopharyngeal carcinoma (NPC) patients. In 100 NPC serum samples that were positive for IgA to the EBV viral capsid antigen (VCA), 75% had IgG anti-ZEBRA antibodies. In contrast, only 3/83 (3.6%) serum samples from healthy donors and 2/50 (4%) from other cancers were positive for IgG to ZEBRA. Interestingly, in a selected group of 100 NPC sera negative for IgA to VCA, 25% contained IgG anti-ZEBRA antibodies. This suggests that the ELISA for IgG anti-ZEBRA may also identify earlier cases of NPC not detected by the conventional immunofluorescence test for IgA to VCA.
    Matched MeSH terms: DNA-Binding Proteins/immunology*; Recombinant Proteins/immunology; Viral Proteins/immunology
  15. Hashim OH, Gendeh GS, Cheong CN, Jaafar MI
    Immunol Invest, 1994 Mar;23(2):153-60.
    PMID: 8194855
    The effect of Artocarpus integer lectin (lectin C) on the functional activity of guinea-pig complement was investigated. Purified and crude extract of lectin C from six cultivars of Artocarpus integer seeds were found to consume complement and thus decreased the complement-induced haemolytic activity of sensitized sheep erythrocytes. The change in the complement-mediated haemolytic activity was significantly decreased when incubation of the lectins was performed in the presence of melibiose. The reversal effect of the carbohydrate, which is a potent inhibitor of the lectin's binding to O-linked oligosaccharides of glycoprotein, demonstrate involvement of the lectins interaction with O-glycans of glycoproteins in the consumption of guinea-pig complement.
    Matched MeSH terms: Complement System Proteins/immunology*
  16. Mathew A, Cheng HM, Sam CK, Prasad U
    Clin. Immunol. Immunopathol., 1994 May;71(2):164-8.
    PMID: 7514112
    Inhibition studies were carried out to study possible cross-reactivity between a peptide fragment of the Epstein-Barr virus nuclear antigen, EBNA-1, and keratin/collagen. The 20-amino acid peptide (pAG), derived from a glycine-alanine repeat region of EBNA-1, uniquely makes up about one-third of the viral protein and is a dominant IgA antigenic epitope in patients with nasopharyngeal carcinoma (NPC). A small percentage of normal human sera (NHS) also binds pAG and this reactivity is examined in this study. Ten percent (2/20) and 13.4% (2/15) of IgA-pAG-positive NPC sera and NHS, respectively, were significantly inhibited by keratin in a competitive ELISA system. Conversely, 31.6% (6/19) and 30.8% (4/13) of IgA-keratin-positive NPC sera and NHS, respectively, were significantly inhibited by pAG. This indicated minimum cross-reactivity between IgA serum antibodies to EBNA-1 and keratin. Using collagen as inhibitor, none of 18 and only 2/13 IgA-pAG-positive NPC sera and NHS, respectively, were inhibited. In the collagen ELISA system, only 2/19 (10.5%) and 4/25 (16%) of IgA-collagen-positive NPC sera and NHS, respectively, were inhibited with pAG. Therefore, cross-reactivity with collagen was also low. IgA-pAG-positive NHS may therefore not be a false positive phenomenon, but whether it may represent an early serological profile related to NPC carcinogenesis remains to be determined.
    Matched MeSH terms: DNA-Binding Proteins/immunology*
  17. Choo KE, Oppenheimer SJ, Ismail AB, Ong KH
    Clin Infect Dis, 1994 Jul;19(1):172-6.
    PMID: 7948526
    A dot enzyme immunoassay (EIA) using 50-kD outer-membrane proteins (OMPs) of Salmonella typhi was compared with the Widal test for the serodiagnosis of typhoid fever in 109 febrile children admitted to a hospital in an endemic area. In the culture-positive typhoid group, the initial dot EIA was positive in 40 of 42 cases and the initial Widal test was positive in 41. In the culture-negative clinical typhoid group, both the dot EIA and the Widal test were positive in 17 of 18 cases. In the nontyphoidal fever group, the dot EIA was negative in all of 49 cases and the Widal test was negative in 44. With culture used as the gold standard, the dot EIA is as sensitive as the Widal test (95% vs. 98%), has a similar high negative predictive value (96% vs. 98%), and is more specific (75% vs. 67%). In addition, the dot EIA offers the advantages of simplicity, speed, early diagnosis, economy, and flexibility (i.e., other diagnostic tests can be conducted simultaneously).
    Matched MeSH terms: Bacterial Outer Membrane Proteins/immunology*
  18. Teh LS, Doherty DG, Williams BD
    Br J Rheumatol, 1994 Dec;33(12):1125-6.
    PMID: 8000739
    Antibodies to the ribosomal P protein are specific for SLE but their prevalence varies in different ethnic groups. In a group of Chinese SLE patients from Malaysia who have a high prevalence of this antibody, we have found an increased frequency of an uncharacterized HLA-DRB gene allele, DR16X, in patients who are positive for anti-P antibodies compared to antibody negative patients (31.3% vs 3.2%, P < 0.01, Pcorr not significant, relative risk = 13.6). DR16X has only been found in south east Asian populations and may be a genetic factor which influences the high prevalence of anti-P antibodies in Chinese.
    Matched MeSH terms: Ribosomal Proteins/immunology*
  19. Adams SC, Broom AK, Sammels LM, Hartnett AC, Howard MJ, Coelen RJ, et al.
    Virology, 1995 Jan 10;206(1):49-56.
    PMID: 7530394
    Previous studies have found Kunjin (KUN) virus isolates from within Australia to be genetically homogenous and that the envelope protein of the type strain (MRM61C) was unglycosylated and lacked a potential glycosylation site. We investigated the extent of antigenic variation between KUN virus isolates from Australia and Sarawak using an immunoperoxidase assay and a panel of six monoclonal antibodies. The glycosylation status of the E protein of each virus was also determined by N glycosidase F (PNGase F) digestion and limited sequence analysis. The results showed that KUN viruses isolated within Australia oscillated between three antigenic types defined by two epitopes whose expression was influenced by passage history and host cell type. In contrast an isolate from Sarawak formed a stable antigenic type that was not influenced by passage history and was distinct from all Australian isolates. PNGase F digestions of KUN isolates indicated that 19 of the 33 viruses possessed a glycosylated E protein. Nucleotide sequence of the 5' third of the E gene of selected KUN isolates revealed that a single base change in PNGase F sensitive strains changed the tripeptide N-Y-F (amino acids 154-156 of the published sequence) to the potential glycosylation site N-Y-S. Further analysis revealed that passage history also had a significant influence on glycosylation.
    Matched MeSH terms: Viral Envelope Proteins/immunology
  20. Cheng HM, Foong YT, AbuSamah AJ, Dillner J, Sam CK, Prasad U
    Cancer Immunol Immunother, 1995 Apr;40(4):251-6.
    PMID: 7750123
    The linear antigenic epitopes of the Epstein-Barr virus replication activator protein (ZEBRA), recognised by specific serum IgG in nasopharyngeal carcinoma (NPC), were determined. This was achieved by synthesizing the entire amino acid sequence of ZEBRA as a set of 29, 22-residue peptides with an overlap of 14 amino acids. The ZEBRA peptides were tested in enzyme-linked immunosorbent assay (ELISA) for IgG binding in sera from 37 selected NPC patients who had IgG antibodies to the native ZEBRA protein. The most immunogenic epitope was peptide 1 at the amino-terminal end with 36 of the sera reactive against it. Further analysis of peptide 1, using the multipin peptide-scanning technique, defined a 10-amino-acid sequence FTPDPYQVPF, which was strongly bound by IgG. Two other regions of ZEBRA were also identified as immunodominant IgG epitopes, namely peptide 11 (amino acids 82-103) and peptide 19/20 (amino acids 146-175) with 8-13 of the NPC sera reactive against the peptides. The number of peptides reactive with individual NPC serum varies from 1 to 6 or more and there is some correlation between a greater number of peptide (at least 4) bound and a higher (at least 1:40) titre of serum IgA to viral capsid antigen. The immunodominant ZEBRA peptide 1 could be utilised in IgG ELISA for the detection of NPC.
    Matched MeSH terms: DNA-Binding Proteins/immunology*; Viral Proteins/immunology*
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