Biomedical subjects

Wai-Keung Wong

Publications and source records attributed to Wai-Keung Wong.

3 recordsLinked to original sources

PubMed2005

HDL dysfunction in obstructive sleep apnea.

OBJECTIVE: HDL is anti-atherogenic and has antioxidant property. HDL dysfunction has been reported in patients with coronary heart disease and we hypothesize that HDL may also be dysfunctional in obstructive sleep apnea (OSA), a condition associated with increased oxidative stress. METHODS: 128 OSA patients and 82 controls were recruited. HDL dysfunction was determined by evaluating the ability of HDL to inhibit LDL oxidation ex vivo. Plasma HDL was incubated with native LDL in the presence of dichlorofluorescein which fluoresced upon interaction with lipid oxidation products. Plasma levels of oxidized LDL and 8-isoprostane were measured by ELISA and a specific enzyme immunoassay, respectively. RESULTS: Plasma total 8-isoprostane levels were elevated in OSA subjects (p<0.01). Despite having similar concentrations of plasma lipids and apolipoproteins as controls, OSA subjects had greater degree of HDL dysfunction (p<0.01) and increased oxidized LDL levels (p<0.05). The apnea-hypopnea index was the main determinant of HDL dysfunction in OSA, accounting for 30% of its variance, with oxidized LDL and apolipoprotein AI contributing to 8% and 5% of its variance respectively (p<0.001). CONCLUSION: HDL is dysfunctional in preventing the formation and inactivation of oxidized lipids in OSA subjects and may partly contribute to their increased cardiovascular risk.

Adult↗

PubMed2002

Bi-functional cytokine fusion proteins for gene therapy and antibody-targeted treatment of cancer.

Typically, multiple cytokines act in concert to mediate a desired immunological response, and thus more effective therapeutics may be achieved by combining several cytokines with potentially synergistic activities. We have developed a series of bi-functional cytokine fusion proteins which, when additionally linked to an intact antibody (or the Fc portion of an antibody) in a variety of configurations, can be specifically targeted. We focus here mainly on the synergizing cytokine combination interleukin-2/interleukin-12 (IL-2/IL-12), but also demonstrate the utility of this approach with interleukin-4/granulocyte-macrophage colony-stimulating factor (IL-4/GM-CSF). Cytokine activity was retained in constructs where the cytokines were fused in tandem at the carboxyl terminus of the Fc or antibody heavy (H) chain, as well as in constructs where one cytokine was fused at the carboxyl terminus of the H chain while the second cytokine was fused to the amino terminus of either the H or light (L) chain variable region. Even in such constructs, antigen binding of the antibody-cytokine fusion proteins could be maintained. In the context of bi-functional fusion proteins, hetero-dimeric IL-12 could be expressed either in a single-chain form, or maintained as a heterodimer in which the p40 subunit was fused to IL-2. These IL-12/IL-2 bi-functional fusion proteins were shown to induce extremely high levels of interferon-gamma (IFN-gamma), similar to the synergy normally seen with the combined application of the individual cytokines. In addition, these bifunctional molecules were shown to have striking anti-tumor activity as either gene therapy or as an antibody cytokine(s) fusion protein, and may provide a useful approach to the treatment of cancer.

Animals↗

PubMed2002

Improved circulating half-life and efficacy of an antibody-interleukin 2 immunocytokine based on reduced intracellular proteolysis.

PURPOSE: Previous studies showed that reducing the interaction of antibody-interleukin 2 immunocytokines with Fc receptors improved their circulating half-life in mice and increased their antitumor activity. We sought to modify sequences that would increase half-life but retain the ability to activate Fc receptor-mediated effector functions. EXPERIMENTAL DESIGN: Modified immunocytokines were assessed in vitro for effector function and protease sensitivity and in vivo for pharmacokinetic and antitumor activities in an syngeneic tumor regression model. RESULTS: Single amino acid changes in the junction sequence between the antibody and interleukin-2 components had dramatic effects on circulating half-life and antitumor activity. This effect was independent of Fc receptor binding to either Fcgamma receptors or the Fc protection receptor, but was associated with changes in susceptibility to intracellular proteases. CONCLUSIONS: We have identified modifications that dramatically improve the circulating half-life of immunocytokines based on increased resistance to intracellular degradation and thus have demonstrated how these molecules can be recycled in and out of an intracellular compartment. Use of these improved immunocytokines with highly favorable pharmacokinetic properties and retained effector functions should lead to more effective treatment of epithelial cancers.

Animals↗