Characterization of DNA-hyaluronan matrix for sustained gene transfer.

DNA-Hyaluronan (DNA-HA) matrix formulations intended for use as gene delivery systems have been developed and their potential for delivering DNA encoding a model therapeutic cytokine, platelet-derived growth factor (PDGF), has been evaluated. The results of enzyme-mediated release kinetics studies suggested that the rate of DNA release from the DNA-HA matrices could be modulated by changing the DNA loading or the degree of crosslinking. SEM imaging of the DNA-HA matrix showed that it was gradually eroded by enzymatic action.

Presentation of a viral peptide assembled on the carbohydrate moieties of immunoglobulin does not require processing.

We have previously demonstrated that an immunodominant CD4 T cell epitope, HA110-120 of the hemagglutinin (HA) of the A/PR/8/34 influenza virus, enzymatically assembled on the carbohydrate moieties of self immunoglobulins (Ig) primed the precursors of peptide-specific T cells and induced efficient proliferation in vivo of naive lymphocytes from transgenic mice expressing the peptide-specific T cell receptor. Here, we show that an immuno-galacto-peptide construct, IgG-gal-HA, does not require intracellular or extracellular processing to present the peptide to the specific T cells. The presentation occurs following the binding of the IgG-gal-HA construct to Fc gamma receptor on the surface of antigen-presenting cells (APC), with concurrent interaction of the peptides to their neighboring major histocompatibility complex class II molecules.

Immunopotency of a viral peptide assembled on the carbohydrate moieties of self immunoglobulins.

The T-cell receptor recognizes peptides bound to the major histocompatibility complex antigens. Synthetic peptides corresponding to microbial epitopes can efficiently stimulate the in vitro proliferation of T-cell hybridoma or in vivo primed T cells. However, the in vivo immune responses elicited by synthetic peptides are weak because of their short half-life and poor immunogenicity.

Engineering of doubly antigenized immunoglobulins expressing T and B viral epitopes.

Background: Concomitant with the advent of molecular biology techniques and the ability of immunoglobulins (Ig) to recognize proteins, carbohydrates, lipopeptides and nucleic acids, vaccinologists have taken advantage to develop a variety of prophylactic and therapeutic vaccine prototypes. Presentation of epitopes to the immune system by Ig molecules as a carrier platform offers several advantages: (i) long exposure of the antigen to antigen processing cells (APCs) by virtue of their long half life, (ii) lack of the immune response to self Ig, focusing the immune response to protective epitopes rather than irrelevant epitopes, (iii) it takes advantage of the properties of Fc fragment of various isotypes like crossing the placenta (IgG) or homing in epithelia (IgA), and (iv) targeting various antigens by virtue of their binding specificity.

Objectives: This study was aimed to genetically and enzymatically engineer immunoglobulins (Igs) able to express and to deliver concomitantly immunodominant T and B viral epitopes.

Enzymatically mediated, glycosidic conjugation of immunoglobulins with viral epitopes.

We developed a novel enzymatic procedure to couple a peptide to the sugar moieties of immunoglobulins (Igs). The synthesis of the conjugates consists in galactose (Gal) oxidation of desialylated Igs followed by covalent attachment of the peptides with concurrent stabilization of the Schiff bases upon mild reduction. The peptide used in this study, corresponds to the amino acid residues 110-120 of hemagglutinin (HA) of PR8 A virus and is recognized by CD4 T helper cells in association with I-Ed class II major histocompatibility complex (MHC).