Displaying publications 81 - 100 of 1061 in total

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  1. Organization of a blood transfusion service in tropical areas
    Lopez CG
    Southeast Asian J. Trop. Med. Public Health, 1979 Jun;10(2):177-83.
    PMID: 524138
    Matched MeSH terms: Blood Group Antigens; Hepatitis B Core Antigens/analysis; Hepatitis B Surface Antigens/analysis
  2. Fulltext Genetic polymorphisms in the CD14 gene are associated with monocyte activation and carotid intima-media thickness in HIV-infected patients on antiretroviral therapy
    Yong YK, Shankar EM, Westhorpe CL, Maisa A, Spelman T, Kamarulzaman A, et al.
    Medicine (Baltimore), 2016 Aug;95(31):e4477.
    PMID: 27495090 DOI: 10.1097/MD.0000000000004477
    HIV-infected individuals on antiretroviral therapy (ART) are at increased risk of cardiovascular disease (CVD). Given the relationship between innate immune activation and CVD, we investigated the association of single-nucleotide polymorphisms (SNPs) in TLR4 and CD14 and carotid intima-media thickness (cIMT), a surrogate measurement for CVD, in HIV-infected individuals on ART and HIV-uninfected controls as a cross-sectional, case-control study. We quantified the frequency of monocyte subsets (CD14, CD16), markers of monocyte activation (CD38, HLA-DR), and endothelial adhesion (CCR2, CX3CR1, CD11b) by flow cytometry. Plasma levels of lipopolysaccharide, sCD163, sCD14, sCX3CL1, and sCCL2, were measured by ELISA. Genotyping of TLR4 and CD14 SNPs was also performed. The TT genotype for CD14/-260SNP but not the CC/CT genotype was associated with elevated plasma sCD14, and increased frequency of CD11b+CD14+ monocytes in HIV-infected individuals. The TT genotype was associated with lower cIMT in HIV-infected patients (n = 47) but not in HIV-uninfected controls (n = 37). The AG genotype for TLR4/+896 was associated with increased CX3CR1 expression on total monocytes among HIV-infected individuals and increased sCCL2 and fibrinogen levels in HIV-uninfected controls. SNPs in CD14/-260 and TLR4/+896 were significantly associated with different markers of systemic and monocyte activation and cIMT that differed between HIV-infected participants on ART and HIV-uninfected controls. Further investigation on the relationship of these SNPs with a clinical endpoint of CVD is warranted in HIV-infected patients on ART.
    Matched MeSH terms: Antigens, Differentiation, Myelomonocytic/blood; Antigens, CD/blood; Antigens, CD14/genetics*; Antigens, CD14/metabolism; Antigens, CD11b/metabolism
  3. Fulltext Evaluation of the dried blood spot (DBS) collection method as a tool for detection of HIV Ag/Ab, HBsAg, anti-HBs and anti-HCV in a Malaysian tertiary referral hospital
    Lee CE, Sri Ponnampalavanar S, Syed Omar SF, Mahadeva S, Ong LY, Kamarulzaman A
    Ann Acad Med Singap, 2011 Oct;40(10):448-53.
    PMID: 22206053 DOI: 10.47102/annals-acadmedsg.V40N10p448
    INTRODUCTION: Dried blood spot (DBS) collection is an appealing alternative to whole blood or plasma sampling, as it has technical and economic advantages over the latter.

    MATERIALS AND METHODS: A prospective cross-sectional study was conducted at a Malaysian tertiary referral hospital from November 2009 to March 2010. One hundred and fifty paired specimens of DBS and plasma were analysed by the standard assays for HIV Ag/Ab, HBsAg, anti-HBS and anti-HCV, separately (total 600 paired specimens). DBS sample titres were then compared to the results of plasma testing, which was used as the gold standard.

    RESULTS: For the HIV Ag/Ab assay with a cut-off point of 0.35 Relative Light Units (RLUs), the sensitivity and specificity were both 100%. For the HBsAg assay, the sensitivity was 96.5% and the specificity was 97.8%, with a cut-off point of 1.72 RLUs. Sensitivity for the anti-HBs test was 74.2% and the specificity was 86.9%, using a cut-off point of 0.635 RLUs. For the anti-HCV assay, the sensitivity was 97.3% and the specificity was 100%, with a cut-off point of 0.10 RLUs.

    CONCLUSION: DBS is an ideal choice to be used as a screening tool for the detection of HIV, Hepatitis B and Hepatitis C virus infections. However, different cut-off values need to be used for the validation of test positivity in DBS samples because the small amount of blood in the DBS specimens leads to lower assay titres.
    Matched MeSH terms: Hepatitis B Surface Antigens/blood*; Hepatitis B Surface Antigens/immunology; HIV Antigens/blood*; HIV Antigens/immunology; Hepatitis C Antigens/blood*; Hepatitis C Antigens/immunology
  4. Lineage-related cytotoxicity and clonogenic profile of 1,4-benzoquinone-exposed hematopoietic stem and progenitor cells
    Chow PW, Abdul Hamid Z, Chan KM, Inayat-Hussain SH, Rajab NF
    Toxicol Appl Pharmacol, 2015 Apr 1;284(1):8-15.
    PMID: 25645895 DOI: 10.1016/j.taap.2015.01.016
    Hematopoietic stem cells (HSCs) and hematopoietic progenitor cells (HPCs) are sensitive targets for benzene-induced hematotoxicity and leukemogenesis. The impact of benzene exposure on the complex microenvironment of HSCs and HPCs remains elusive. This study aims to investigate the mechanism linking benzene exposure to targeting HSCs and HPCs using phenotypic and clonogenic analyses. Mouse bone marrow (BM) cells were exposed ex vivo to the benzene metabolite, 1,4-benzoquinone (1,4-BQ), for 24h. Expression of cellular surface antigens for HSC (Sca-1), myeloid (Gr-1, CD11b), and lymphoid (CD45, CD3e) populations were confirmed by flow cytometry. The clonogenicity of cells was studied using the colony-forming unit (CFU) assay for multilineage (CFU-GM and CFU-GEMM) and single-lineage (CFU-E, BFU-E, CFU-G, and CFU-M) progenitors. 1,4-BQ demonstrated concentration-dependent cytotoxicity in mouse BM cells. The percentage of apoptotic cells increased (p < 0.05) following 1,4-BQ exposure. Exposure to 1,4-BQ showed no significant effect on CD3e(+) cells but reduced the total counts of Sca-1(+), CD11b(+), Gr-1(+), and CD45(+) cells at 7 and 12 μM (p < 0.05). Furthermore, the CFU assay showed reduced (p < 0.05) clonogenicity in 1,4-BQ-treated cells. 1,4-BQ induced CFU-dependent cytotoxicity by significantly inhibiting colony growth for CFU-E, BFU-E, CFU-G, and CFU-M starting at a low concentration of exposure (5μM); whereas for the CFU-GM and CFU-GEMM, the inhibition of colony growth was remarkable only at 7 and 12μM of 1,4-BQ, respectively. Taken together, 1,4-BQ caused lineage-related cytotoxicity in mouse HPCs, demonstrating greater toxicity in single-lineage progenitors than in those of multi-lineage.
    Matched MeSH terms: Antigens, Ly/metabolism; Antigens, CD45/metabolism; Antigens, CD11b/metabolism
  5. Fulltext Heterogeneity of osteosarcoma cell lines led to variable responses in reprogramming
    Choong PF, Teh HX, Teoh HK, Ong HK, Choo KB, Sugii S, et al.
    Int J Med Sci, 2014;11(11):1154-60.
    PMID: 25170299 DOI: 10.7150/ijms.8281
    Four osteosarcoma cell lines, Saos-2, MG-63, G-292 and U-2 OS, were reprogrammed to pluripotent state using Yamanaka factors retroviral transduction method. Embryonic stem cell (ESC)-like clusters started to appear between 15 to 20 days post transduction. Morphology of the colonies resembled that of ESC colonies with defined border and tightly-packed cells. The reprogrammed sarcomas expressed alkaline phosphatase and pluripotency markers, OCT4, SSEA4, TRA-1-60 and TRA-1-81, as in ESC up to Passage 15. All reprogrammed sarcomas could form embryoid body-like spheres when cultured in suspension in a low attachment dish for up to 10 days. Further testing on the directed differentiation capacity of the reprogrammed sarcomas showed all four reprogrammed sarcoma lines could differentiate into adipocytes while reprogrammed Saos-2-REP, MG-63-REP and G-292-REP could differentiate into osteocytes. Among the 4 osteosarcoma cell lines, U-2 OS reported the highest transduction efficiency but recorded the lowest reprogramming stability under long term culture. Thus, there may be intrinsic differences governing the variable responses of osteosarcoma cell lines towards reprogramming and long term culture effect of the reprogrammed cells. This is a first report to associate intrinsic factors in different osteosarcoma cell lines with variable reprogramming responses and effects on the reprogrammed cells after prolonged culture.
    Matched MeSH terms: Antigens, Surface/genetics; Antigens, Surface/metabolism; Stage-Specific Embryonic Antigens/genetics; Stage-Specific Embryonic Antigens/metabolism
  6. Fulltext The pattern of CD15, CD30 and Bcl-2 expression in diffuse large B-cell lymphoma
    Eow GI, Kim LH, Peh SC
    Med J Malaysia, 2006 Oct;61(4):416-21.
    PMID: 17243518 MyJurnal
    Diffuse large B-cell lymphoma (DLBCL) is a heterogenous entity. The pattern of CD15, CD30 and Bcl-2 expression is not well documented, especially in local population. We investigated 67 consecutive cases of DLBCL by immunohistochemistry on paraffin-embedded tissue. The male to female ratio was 1.2:1 with median age of 55 years, and more common nodal than extranodal in presentation. Only 3 of 67 cases expressed CD15. In addition, three cases showed weak membrane staining for CD30. Only one of these three cases was noted to have co-expression of CD15 and with occasional tumour cells showing weak CD30 expression. Bcl-2 protein was expressed in 43 of 67 (64%), more frequently in nodal than in extranodal tumours. In conclusion, CD15 and CD30 expressions are infrequent in DLBCL, and co-expression is rare. Bcl-2 protein expression is common in DLBCL.
    Matched MeSH terms: Antigens, CD15/biosynthesis*; Antigens, CD15/genetics; Antigens, CD30/biosynthesis*; Antigens, CD30/genetics
  7. Fulltext Hepatitis B markers in heterosexuals involved in promiscuous sexual activity
    Rajakumar MK, Ton SH, Lim KF, Oorloff KH
    Med J Malaysia, 1984 Mar;39(1):65-8.
    PMID: 6513842
    179 heterosexuals, selected for VDRL testing on the basis of a history of involvement in promiscuous sexual activity, mainly prostitution, had their serum also tested for hepatitis B infection markers, HBsAg, HBeAg and anti-HBe. 51 samples (29%) were found to be positive for at least one of the three markers, at levels higher than the already high levels in voluntary random blood donors in Malaysia.
    Matched MeSH terms: Hepatitis B Antigens/analysis*; Hepatitis B e Antigens/analysis*; Hepatitis B Surface Antigens/analysis*
  8. Inhibition of hepatitis B virus assembly with synthetic peptides derived from the viral surface and core antigens
    Tan WS
    J Gen Appl Microbiol, 2002 Apr;48(2):103-7.
    PMID: 12469306
    The long surface antigen (L-HBsAg) of hepatitis B virus (HBV) plays a central role in the production of infectious virions. During HBV morphogenesis, both the PreS and S domains of L-HBsAg form docking sites for the viral nucleocapsids. Thus, a compound that disrupts the interaction between the L-HBsAg and nucleocapsids could serve as a therapeutic agent against the virus based upon inhibition of morphogenesis. Synthetic peptides correspond to the binding sites in L-HBsAg inhibited the association of L-HBsAg with core antigen (HBcAg). A synthetic peptide carrying the epitope for a monoclonal antibody to the PreS1 domain competed weakly with L-HBsAg for HBcAg, but peptides corresponding to a linear sequence at the tip of the nucleocapsid spike did not, showing that the competing peptide does not resemble the tip of the spike.
    Matched MeSH terms: Hepatitis B Core Antigens/metabolism; Hepatitis B Core Antigens/pharmacology*; Hepatitis B Surface Antigens/metabolism; Hepatitis B Surface Antigens/pharmacology*
  9. Interdigitating dendritic reticulum cell sarcoma: cytologic, histologic and immunocytochemical features
    Jayaram G, Mun KS, Elsayed EM, Sangkar JV
    Diagn Cytopathol, 2005 Jul;33(1):43-8.
    PMID: 15945093
    Tumors of dendritic reticulum cells are rare neoplasms that exhibit significant morphologic overlap with other malignancies. Fine-needle aspiration cytologic appearances of this neoplasm are not well understood. A 33-yr-old woman presented with a rapidly growing nodular mass in the right upper cervical region and right-sided ptosis. Fine-needle aspiration cytology of the mass showed dissociated as well as clustered, large, polygonal cells that showed high nuclear-cytoplasmic ratio. Nuclei were round, oval, or irregular in shape. Large and small blastoid forms with prominent nucleoli and chromatin clumping as well as binucleated cells and cells with lobulated nuclei were seen. Numerous mitoses were observed. The tumor cells expressed focal immunocytochemical reactivity to CD45 and CD68, but were negative for CD2, CD3, CD4, CD8, CD20, CD30, CD45RO, epithelial membrane antigen (EMA), cytokeratin, and HMB45. Histologic sections of the biopsy from the growth showed nodal tissue effaced by a tumor composed of large, pleomorphic neoplastic cells with some binucleate and multinucleate forms resembling Reed-Sternberg cells. The intervening stroma contained numerous small lymphocytes. Tumor cells expressed vimentin, S-100 protein, CD68, and MAC387, but were negative for LCA, CD1a, CD3, CD15, CD20, CD21, CD23, CD30, CD35, carcino-embryonic antigen, HMB45, cytokeratin AE1/3, EMA, myeloperoxidase, lysozyme, smooth-muscle actin, and desmin. The combined histologic and immunohistologic features suggested a histiocytic/dendritic reticulum cell neoplasm and a diagnosis of interdigitating dendritic reticulum cell sarcoma was made.
    Matched MeSH terms: Antigens, Differentiation, Myelomonocytic/analysis; Antigens, CD/analysis; Antigens, CD45/analysis
  10. HLA-DR2 haplotypic diversity in populations of South-East Asia, northern China, Melanesia and Australian aborigines using PCR-RFLP for DRB1, DRB5, DQA1 and DQB1. A novel DRB1 allele: DRB1*16022
    Trejaut J, Bhatia K, Greville WD, Hu KR, Duraisamy G, Nuchprayoon C, et al.
    Eur. J. Immunogenet., 1996 Dec;23(6):437-49.
    PMID: 8971541
    The polymorphism of the human leucocyte antigen HLA-DR2 and the heterogeneity of HLA-DR2 class II-related haplotypes (HLA-DRB1-DRB5-DQA1-DQB1) were investigated in four populations of east and south-east Asia (SEA) and five Melanesian populations using TaqI restriction fragment length polymorphism (RFLP) analysis, and the polymerase chain reaction (PCR) amplification-based techniques PCR-RFLP and sequence-specific oligonucleotide (SSO) typing. The haplotype DRB1*1502-DRB5*0101-DQA1*0102-DQB1*0601 was common in Malaysians, Javanese, Thursday Islanders, Madang, Goroka and the Australian Aborigines, while DRB1*16021-DRB5*0101-DQA1*0102-DQB1*0502 was common in the Thai and Thursday Islanders. DRB1*1501-DRB5*0101-DQA1*0102-DQB1*0602 was present at a high frequency in Northern Chinese, Goroka, Watut and Australian Aborigines. The study describes four rare or unusual haplotypes: HLA-DRB1*1501-DRB5*0101-DQA1*0101-DQB1*0601, DRB1*1502-DRB5*0101-DQA1*0101-DQB1*0502, DRB1*1502-DRB5*0102-DQA1* 0102-DQB1*0502 and DRB1*1501-DRB5*0101-DQA1*0101/2-DQB1*0503; the latter two were confirmed by segregation in two Javanese families. A new DR2 allele, initially detected by PCR-RFLP and confirmed by DNA sequencing as DRB1*16022 (previously designated DRB1*16Madang), was seen in a Madang individual. A new HLA-DR2 TaqI RFLP subtype, locally designated as DR15U, is also described. This RFLP subtype segregated in a Javanese family and correlated with a typically SEA haplotype, DRB1*1502-DRB5*0102-DQA1*0101-DQB1*0501. The allele HLA-DR16Thai, determined by TaqI DRB RFLP, was found by PCR-RFLP and SSO typing to correlate with a unique SEA haplotype, HLA-DRB1*16021-DRB5*0101-DQA1*0102-DQB1*0502, and was observed in the Thai, Malaysian, Thursday Islander, Javanese and Northern Chinese populations.
    Matched MeSH terms: HLA-DQ Antigens/classification*; HLA-DQ Antigens/genetics; HLA-DR Antigens/classification*; HLA-DR Antigens/genetics
  11. Angiogenic squamous dysplasia-like phenomenon in oral epithelial precursor lesions
    Siar CH, Oo VP, Nagatsuka H, Nakano K, Ng KH, Kawakami T
    Eur J Med Res, 2009 Jul 22;14(7):315-9.
    PMID: 19661015
    STATEMENT OF THE PROBLEM: Dysplasia, the morphological yardstick of epithelial precursor lesions, is the collective term for a variety of architectural and cytological changes within the altered oral epithelium. Angiogenic squamous dysplasia (ASD), a distinct morphological characteristic in pre-invasive bronchial lesions, describes the presence of capillary tufts that are closely juxtaposed to and projecting into the dysplastic bronchial epithelium.

    OBJECTIVE: To determine whether ASD-like phenomenon occurs in oral epithelial precursor lesions, and to speculate on its relevance.

    METHODS: Twenty cases each of mild, moderate and severe oral dysplasia (inclusive of carcinoma-in-situ), and 10 normal oral mucosa (normal controls) were serial sectioned for H and E staining, and for microvessel density (MVD) scoring with CD31, CD34 and CD105. Microcapillary pattern images were digitally captured for 3-D reconstruction.

    RESULTS: Oral ASD foci consisting of CD31- and CD34-positive capillary loops abutting onto the overlying dysplastic oral epithelium (and causing it to assume an irregular or papillary surface configuration) were identified in moderate (3/20; 15%) and severe dysplasia (13/20; 65%), but not in normal oral mucosa and mild dysplasia. MVD score demonstrated increasing vascularity as epithelium progressed from normal to severe dysplasia (p<0.05). CD105 demonstrated increase neovascularization in all dysplasia grades (p<0.05).

    CONCLUSIONS: These preliminary findings taken together suggest that: 1. ASD-like phenomenon may be an important intermediary biomarker in oral precursor lesions; and 2. architectural alterations of the entire disturbed mucosa may be a more useful pre-malignancy index.

    Matched MeSH terms: Antigens, CD/analysis; Antigens, CD34/analysis; Antigens, CD31/analysis
  12. Fulltext CD24, CD44 and EpCAM enrich for tumour-initiating cells in a newly established patient-derived xenograft of nasopharyngeal carcinoma
    Hoe SLL, Tan LP, Abdul Aziz N, Liew K, Teow SY, Abdul Razak FR, et al.
    Sci Rep, 2017 09 28;7(1):12372.
    PMID: 28959019 DOI: 10.1038/s41598-017-12045-8
    Subpopulations of nasopharyngeal carcinoma (NPC) contain cells with differential tumourigenic properties. Our study evaluates the tumourigenic potential of CD24, CD44, EpCAM and combination of EpCAM/CD44 cells in NPC. CD44br and EpCAMbr cells enriched for higher S-phase cell content, faster-growing tumourigenic cells leading to tumours with larger volume and higher mitotic figures. Although CD44br and EpCAMbr cells significantly enriched for tumour-initiating cells (TICs), all cells could retain self-renewal property for at least four generations. Compared to CD44 marker alone, EpCAM/CD44dbr marker did not enhance for cells with faster-growing ability or higher TIC frequency. Cells expressing high CD44 or EpCAM had lower KLF4 and p21 in NPC subpopulations. KLF4-overexpressed EpCAMbr cells had slower growth while Kenpaullone inhibition of KLF4 transcription increased in vitro cell proliferation. Compared to non-NPC, NPC specimens had increased expression of EPCAM, of which tumours from advanced stage of NPC had higher expression. Together, our study provides evidence that EpCAM is a potentially important marker in NPC.
    Matched MeSH terms: Antigens, CD44/genetics; Antigens, CD44/metabolism*; Antigens, CD24/genetics; Antigens, CD24/metabolism*
  13. Fulltext Preventing Mother-to-child Transmission of Hepatitis B Virus - A Success Story Which Can Be Enhanced
    Tan SS, Chua A
    Med J Malaysia, 2013 Apr;68(2):103-4.
    PMID: 23629552
    Matched MeSH terms: Hepatitis B Surface Antigens*
  14. An assay for selection of sera with circulating Toxoplasma gondii antigens
    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: Antigens, Protozoan/blood*
  15. Extrinsic allergic alveolitis
    Ismail T, McSharry C, Boyd G
    Respirology, 2006 May;11(3):262-8.
    PMID: 16635083
    Extrinsic allergic alveolitis (also known as hypersensitivity pneumonitis) is caused by repeated inhalation of mainly organic antigens by sensitized subjects. This induces a hypersensitivity response in the distal bronchioles and alveoli and subjects may present clinically with a variety of symptoms. The aims of this review are to describe the current concepts of the immunological response, the diverse clinical presentation of this disease, the relevant investigations and management, and areas for future studies.
    Matched MeSH terms: HLA Antigens/immunology*
  16. Letter regarding "CD95 rs1800682 polymorphism and cervical cancer risk: evidence from a meta-analysis" by Zhang et al
    Tan SC
    Tumour Biol., 2015 Nov;36(11):8275-6.
    PMID: 26515334 DOI: 10.1007/s13277-015-4330-1
    Matched MeSH terms: Antigens, CD95/genetics*
  17. Fulltext Comparison of Abtectcell III and Diamed red cell antibody screening kit for detection of clinically significant red cells alloantibody
    Syed Azim SM, Muhamad NA, Leong CF, Hussin NH
    Malays J Pathol, 2015 Aug;37(2):109-14.
    PMID: 26277667 MyJurnal
    Antibody screening is important for the antenatal screening and pre-transfusion tests. This study aimed to compare the MUT/Mur kodecytesAbtectcell III (CSL Abtectcell III) red cell antibody screening kit with DiaMed ID-Dia Cell I-II-III Asia that was then used in our laboratory. In this study, 125 samples were randomly chosen, with 67 samples of known antibody specificities and 58 samples identified as negative for antibody, as the negative control. Concordant negative results were obtained in 57 out of 58 antibody negative samples. Concordant antibody positive results with both reagents were seen in 49 out of 67 samples. There were 18 discrepant results of antibody screening with CSL Abtetcell III (16/18 for vMNS antibodies). The sensitivity and specificity for CSL Abtectcell III were 73.0% and 98.3% respectively. In conclusion, the CSL Abtectcell III reagent would be an acceptable alternative for screening of red cell alloantibodies. It was able to detect all the clinically significant alloantibodies.
    Matched MeSH terms: Blood Group Antigens/immunology*
  18. Detection of rickettsial antibodies using Weil-Felix (OXK and OX19) antigens and the indirect immunoperoxidase assay
    Tay ST, Kamalanathan M, Rohani MY
    Southeast Asian J. Trop. Med. Public Health, 2003 Mar;34(1):171-4.
    PMID: 12971531
    Matched MeSH terms: O Antigens/immunology*
  19. Selection of high affinity ligands to hepatitis B core antigen from a phage-displayed cyclic peptide library
    Ho KL, Yusoff K, Seow HF, Tan WS
    J Med Virol, 2003 Jan;69(1):27-32.
    PMID: 12436474
    M13 phages that display random disulfide constrained heptapeptides on their gpIII proteins were used to select for high affinity ligands to hepatitis B core antigen (HBcAg). Phages bearing the amino acid sequences C-WSFFSNI-C and C-WPFWGPW-C were isolated, and a binding assay in solution showed that these phages bind tightly to full-length and truncated HBcAg with K D rel values less than 25 nM, which is at least 10 orders of magnitude higher than phage carrying the peptide sequence LLGRMK selected from a linear peptide library. Both the phages that display the constrained peptides were inhibited from binding to HBcAg particles by a monoclonal antibody that binds specifically to the immunodominant region of the particles. A synthetic heptapeptide with the amino acid sequence WSFFSNI derived from one of the fusion peptides inhibits the binding of large surface antigen (L-HBsAg) to core particles with an IC50 value of 12 +/- 2 microM. This study has identified a smaller peptide with a greater inhibitory effect on L-HBsAg-HBcAg association.
    Matched MeSH terms: Hepatitis B Core Antigens/biosynthesis; Hepatitis B Core Antigens/metabolism*; Hepatitis B Core Antigens/chemistry; Hepatitis B Surface Antigens/biosynthesis; Hepatitis B Surface Antigens/metabolism; Hepatitis B Surface Antigens/chemistry
  20. Development of a slide latex agglutination test for rotavirus antigen detection
    Yap KL
    Malays J Pathol, 1994 Jun;16(1):49-56.
    PMID: 16329576
    The aim of this study was to optimize the conditions for the passive adsorption of polyclonal antibody onto plain surface polystyrene latex particles and its performance in a slide latex agglutination test for rotavirus antigen detection. Cleaning of latex particles by washing through repetitive centrifuging, decanting and resuspending in distilled water was adequate in removing surfactants from the particles' surfaces to enable coating. A study of antibody concentration, incubation temperature and buffer pH revealed that optimum coating was achieved with a 3-fold excess of antibody to the calculated total particle surface capacity for the antibody in a glycine-saline buffer of pH 9.2 at 40 degrees C for 4 hours. The ionic strength and pH of the latex suspending buffer and the sample buffer were critical factors determining the sensitivity of the test and the appearance of non-specific agglutination. Ultrasonication, addition of glycerol and Tween 20, either individually or in combination, were able to suppress non-specific agglutination in some batches of latex reagents. Polyethylene glycol 6000 enhanced the quality of agglutination as well as reduced the time of its appearance, especially in reagents that produced poor agglutination.
    Matched MeSH terms: Antigens, Viral/immunology
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