Immunoglobulin A¡]IgA¡^, the principal antibody class in secretions that bathe mucosal surfaces, acts as an important first line of defense. However, some pathogenic bacteria such as Haemophilus influenzae can produce IgA1 proteases to impair IgA1, especially in human mucosal immune system. IgA1 proteases are characterized by a polypeptide precursor containing four domains, the signal peptide, protease, linking region and the £]-domain. The function of the protease and the £]-domain (£] core) had been studied extensively, but the linking region is less defined, let alone its function. To complete the project, the DNA fragment for linking region was amplified by PCR from iga gene (Gene Bank DQ683353) spanning from NT3130 to NT4686, and then transferred to pGEX-2T for expression. Recombinant linking region-protein was purified using glutathione-Sepharose column. The proliferation assay showed that purified recombinant protein did not enhance cell growth significantly at the concentration of 1 £gg/ml compared to either the negative control or GST control; but when the concentration of the recombinant protein was increased to 5 £gg/ml or 10 £gg/ml, the cell proliferation was significantly stimulated. These results suggest that recombinant linking region-protein contains special element that stimulates the jurkat cell.

Thesis (Ph. D.)--University of Texas at Austin, 2003. / Vita. Includes bibliographical references. Available also from UMI Company.

Thesis (Ph. D.)--University of Missouri--Columbia, 2000. / Typescript. Vita. Includes bibliographical references (leaves 161-166). Also available on the Internet.

Not available / text

Following an outbreak of multi-resistant Haemophilus influenzae type b (Hib)infections in a tuberculosis hospital, this study was undertaken to determine carriage of Hib in 2 paediatric wards; to characterise all isolates of Hib, determine their antimicrobial susceptibility profile and the antibody response of the children to a conjugate vaccine. Prior to and one month after immunisation, oro- and nasopharyngeal swab specimens as well as venous blood were collected from each child. Isolates were tested for /3-lactamase and chloramphenicol acetyltransferase (CAT)production, their MIC's determined by the agar dilution method and characterisation of Hib isolates was performed by biotyping and analysis of outer membrane protein (OMP) profiles. An ELISA was also developed to determine serum antibody levels to polyribosyl-ribitol-phosphate (PRP), the capsular polysaccharide of Hib. The study population comprised a total of 135 children who had been hospitalised for treatment for tuberculosis. The patients were aged 4 months to 14 years with a median of 37,5 months. During the study period, none of the children developed invasive Hib disease. The overall carriage rate of Hib increased from 38% (51/135) before immunisation to 62% (84/135) after immunisation (P 0,15 /ig/ml. After immunisation, 34%(45) of patients increased their antibody levels to > 1,0 /xg/ml. There was no statistical difference between the mean antibody concentrations of patients who were colonised by Hib and those who were not (p = 0,58). The vaccine did not reduce carriage of Hib in this study population of children being treated for tuberculosis and the immune response to the vaccine was not optimal. Production of /3-lactamase and the prevalence of rifampicin resistance has implications for treatment and chemoprophylaxis in this population. OMP analysis showed a diversity of types. Multi-resistant strains causing invasive disease had the same OMP type as some multiresistant strains which colonised the children. / Thesis (M.Med.Sc.)-University of Natal, Durban, 1996.

Microbiological and molecular epidemiological studies were conducted on 36 multi-resistant Haemophilus influenzae strains, isolated from paediatric patients, over a 26 month period (April 1986 to May 1988). The majority of strains (80,5%) had been isolated from blood and cerebrospinal fluid. More than 80% of isolates tested belonged to biotype II and 90% were of serotype B. Minimal inhibitory concentrations against 6 antibiotics (ampicillin, chloramphenicol, tetracycline, rifampicin, streptomycin and cefotaxime) confirmed the presence of multi-resistant strains. Resistance to rifampicin was confirmed in 6 (16,7%) strains. All strains were susceptible to cefotaxime. Ten transconjugants analysed with respect to their plasmid content were shown to harbour an identical 41 MDa plasmid. Restriction endonuclease digests of these plasmids with Eco R1 and Sst1 revealed almost identical restriction patterns. Outer membrane protein profiles of 19 strains revealed the predominance of one particular subtype. By combining the microbiological and molecular epidemiological findings, it is concluded that one strain of H. influenzae type b is responsible for the nosocomial acquisition of infections amongst paediatric patients. The implifications of these findings are discussed. / Thesis (M.Med.)-University of Natal, Durban, 1988.

Proefschrift Universiteit van Amsterdam. / Met lit. opg. - Met samenvatting in het Nederlands.

Thesis (M.P.H.)--University of Adelaide, Dept. of Public Health, 1999? / Includes bibliographical references (leaves 123-135).

Thesis (M.S.)--University of Missouri-Columbia, 2006. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on April 17, 2009) Includes bibliographical references.

Thesis (M.S.)--University of Wisconsin--Madison, 1970. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.