Streptococcus pneumoniae (pneumococcus) is a Gram positive opportunistic bacterium that is a primary cause of pneumonia in young children and immunocompromised individuals. This microorganism colonizes the nasopharynx of all age groups and health levels and is easily transmitted through respiratory droplets or aerosols. While capsule-based vaccines are available, these are becoming more obsolete as S. pneumoniae strains are undergoing serotype replacement, thus evading detection, and antibiotic resistant strains are increasing in prevalence. This study has taken a different approach by identifying immunogenic proteins that elicit antibodies which block attachment of bacteria to host epithelial cells. Proteins with the most potential were assessed by analyzing the reactivities of human sera with varying degrees of colonization blockage. Proteins which reacted with the primary protective antibody in mucosal sites, IgA, were prioritized. Identification of those proteins through mass spectrometry will be crucial in creating more effective, long-term protection against S. pneumoniae infections.

published_or_final_version / Community Medicine / Doctoral / Doctor of Philosophy

published_or_final_version / Surgery / Master / Master of Philosophy

published_or_final_version / Dentistry / Doctoral / Doctor of Philosophy

published_or_final_version / Medicine / Master / Doctor of Medicine

Nasopharyngeal Carcinoma (NPC) as a typical malignancy that occurs in high-incidence areas, e.g. southern China region, including Hong Kong, and it has aroused wide interests for local researchers to study. The Epstein-Barr virus (EBV) was reported as a vital herpes virus for the growth of NPC. Two significant proteins in EBV, namely Epstein-Barr Nuclear Antigen 1 (EBNA1) and latent infection membrane protein 1 (LMP1) are crucial for virus maintenance and EBV-infected cell development, and essential for cell proliferation and differentiation of EBV latent life cycle, respectively. Thus, inhibition of EBNA1 and LMP1 can be regarded as effective and potent therapy on EBV-associated cancers. In this thesis, the conjugation of core-shell structured upconversion nanoparticles (UCNPs) with distinct EBV-specific peptides including EBNA1 and LMP1 targeting peptides to achieve both impressive inhibition on EBV-positive cancers in vitro/in vivo and visualization on EBV-positive cells with responsive upconversion emission signals were investigated. Taking advantage of lanthanide-based UCNPs, their unique photophysical properties offer deep tissue penetration depth, negligible photobleaching and photocytotoxicity, and therefore provides a solid foundation for convincible theranostic studies. Furthermore, desired inhibitory performance was achieved, it was shown that ~50 mg/mL of nanoprobes can inhibit half of EBV-infected cell viability and only 0.25 mg/tumor of nanoprobes dosage via intravenous injection can prohibit 64.7% of growth inhibition of an EBV-positive tumor

published_or_final_version / Anatomy / Doctoral / Doctor of Philosophy

published_or_final_version / abstract / Surgery / Master / Master of Philosophy

published_or_final_version / abstract / Pathology / Master / Master of Philosophy

published_or_final_version / abstract / Anatomy / Doctoral / Doctor of Philosophy