MSc (Med), Faculty of Health Sciences, University of the Witwatersrand / The hepatitis B virus remains a major public health problem even after decades of its discovery. Horizontal transmission during early childhood is the predominant mode of transmission in highly endemic regions such as sub-Saharan Africa. Infection exhibits a wide spectrum of clinical manifestations, from an asymptomatic stage to severe liver disease which may result in hepatocellular carcinoma (HCC). The HBV X protein (HBx) has been implicated in carcinogenesis, which often has a poor prognosis, consequently the use of highly specific monoclonal antibodies (mAbs) directed against HBx in an enzyme-linked immunosorbent assay (ELISA) could lead to early identification of HBV carriers at risk of developing liver cancer. A variety of mixed hybridoma cell cultures secreting anti-HBx antibodies were cloned and sub-cloned by “limiting dilution”. Clonal supernatants were assessed for anti-HBx antibody production by Indirect ELISA and Western/Immunoblotting. Monoclonal antibodies were then characterized according to their relative binding affinity (Indirect ELISA) and relative epitope specificity (Competitive ELISA). One of our monoclonal antibodies was found to bind to the same epitope on HBx as the commercial anti-HBx antibody and with the same high affinity. In the developed Sandwich ELISA, our monoclonal antibody proved effective as the „detecting‟ antibody when the commercial anti-HBx antibody was deployed as the „capture‟ antibody. This Sandwich ELISA will be further developed in our laboratory with the object of applying it to patient sera.

by Michael Yiu-kwong Leung. / Thesis (Ph.D.)--Chinese University of Hong Kong, 1998. / Includes bibliographical references (p. 158-168). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Mode of access: World Wide Web. / Abstracts in English and Chinese.

Kwok Leung Wong. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1996. / Includes bibliographical references (leaves 149-170). / Acknowledgments --- p.i / Abstract --- p.ii -v / Abbreviations --- p.vi-vii / Chapter Chapter 1 : --- General Introduction --- p.1 / Chapter Chapter 2 : --- Development of Polyclonal Antibodies Against 6-B-hydroxycortisol （6-B-OHC) And Its Applications / Chapter 2.1 : --- Introduction --- p.40 / Chapter 2.2 : --- Materials and methods --- p.43 / Chapter 2.3: --- Results --- p.55 / Chapter 2.4: --- Discussion --- p.73 / Chapter Chapter 3 : --- Development of Monoclonal Antibody-Based ELISA Against 6-B-hydroxycortisol (6-B-OHC) And Its Applications / Chapter 3.1 : --- Introduction --- p.76 / Chapter 3.2 : --- Materials and methods --- p.89 / Chapter 3.3: --- Results --- p.108 / Chapter 3.4: --- Discussion --- p.135 / Chapter Chapter 4 --- : General Conclusion --- p.141 / References --- p.149

Graduation date: 1996

An enzyme-linked immunosorbent assay was developed to measure specific antibody response in bovine sera to bovine adenovirus type 3 (BA3), an etiologic agent of respiratory disease causing economic losses annualy to the cattle industry. Observed endpoint titers were determined using the intersection point from optical density values of serially diluted sera with a positive-negative threshold. Regression equations were determined from standards with titers ranging from low to high and used to predict ELISA titers from a single-serum dilution. A near-linear relationship existed between the observed and predicted ELISA titers of 118 bovine sera (r=0.9261). Predicted ELISA titers were determined using the single-dilution method for another 76 bovine sera and the correlation between the ELISA titers and serum-virus neutralization titers for these sera indicated a strong linear trend (r=0.8172). Both the ELISA and serum-virus neutralization titers on the bovine sera tested indicated widespread exposure to several types of bovine adenovirus. Although detection of active infection would still require examination of sera over time for evidence of a rising titer, the single-dilution ELISA devised should provide a rapid and sensitive method for detection of antibody response to bovine adenovirus type 3. / Graduation date: 1992

Thesis (Ph. D.)--University of Texas at Austin, 2000. / Vita. Includes bibliographical references (leaves 220-243). Available also in a digital version from Dissertation Abstracts.

Thesis (M.S.)--Florida State University, 2003. / Advisor: Dr. Shridhar K. Sather, Florida State University, College of Human Sciences, Dept. of Nutriton, Food and Excercise Sciences. Title and description from dissertation home page (viewed 5/4/04). Includes bibliographical references.

Thesis (doctoral)--Universität, Giessen, 1999.

Thesis (doctoral)--Universität, Hohenheim, 2000.

 The emergence of the pandemic H1N1 2009 virus of swine-origin and its transmission back to swine highlighted the need for global surveillance of swine influenza. Serology can help to address the epidemiological situation of influenza infection. Since typical serology tests such as hemagglutination inhibition or microneutralization assays are subtype and partially virus-lineage specific, it is important to select appropriate viral antigens for such studies. A poorly chosen panel of antigens will lead to underestimation of the seroprevalence. The choice of well-matched antigen is difficult if there is no prior virological surveillance in that area and even if there was virological surveillance data, transient infections may go undetected. Hence an universal influenza A type reactive serological test is needed. While such tests are available for poultry, there is little published data on the performance of these commercial influenza ELISA assays for serology on swine sera. In this study we evaluated 3 commercially available competitive ELISA assays, IDEXX? Influenza A Ab test, IDEXX? AI MultiS-Screen Ab Test and IDVet ID Screen? Influenza A Antibody Competition ELISA kit for detecting influenza type A reactive antibodies in swine. The virus antigens and the serum samples were obtained from a 14-year systematic abattoir-based virological and serological surveillance for swine influenza in southern China. The performance was evaluated by ROC curve and scatter plot, together with other statistical parameters including the Youden index to optimize the cut-off levels. Using the optimized cut-off levels, sensitivity and specificity of the IDEXX? Influenza A Ab test was 86% and 89% respectively; for IDEXX? AI MultiS-Screen Ab Test was 91% and 87% and for IDVet ID Screen? Influenza A was 95% and 79%, respectively. These findings help to provide different cut-off levels to maximize the sensitivity or specificity to suit different purposes. We found that the ELISA assay was useful in detecting serum samples that may be positive for influenza antibody but missed in the serology screening tests due to limitations in the chosen antigen panel. The ELISA assay maybe helpful in global swine influenza surveillance programs. / published_or_final_version / Microbiology / Master / Master of Medical Sciences