The ability of a peptide vaccine derived from the human T-lymphotropic virus type 1 (HTLV-1) surface envelope glycoprotein protein (gp46) to mimic the native protein and elicit a protective immune response has been examined. This peptide construct, designated MVFMF2, comprises amino acids (aa) 175-218 of gp46 linked by a four residue turn (GPSL) to a promiscuous T-cell epitope from the measles virus fusion protein (MVF, aa 288-302). The peptide was structurally characterized by circular dichroism (CD) spectroscopy and was found to contain α-helical secondary structure. The immunogenicity of MVFMF2 in rabbits and mice was evaluated by direct ELISA and competitive ELISA using peptide constructs and the recombinant protein ACH-RE3 (aa 165-306). This peptide, when administered with adjuvant (N-acetyl-glucosamine-3yl-acetyl-L-alanyl-D-isoglutamine, nor-MDP) was immunogenic in an outbred population of both rabbits and mice. Furthermore, the peptide construct was encapsulated in biodegradable microspheres of poly(D,L-lactide-co-glycolide) to eliminate booster immunization and to examine adjuvant requirements. The data indicate that MVFMF2 shows enhanced immunogenicity when encapsulated in biodegradable microspheres. Inoculation of the encapsulated peptide produced a similar humoral response to that of the free peptide, but did not require the use of adjuvant. Elicited anti-rabbit and anti-mouse antibodies recognized whole viral preparations and the recombinant protein ACH-RE3 in ELISA assays. Additionally, inoculated rabbits exhibited enhanced reactivity to viral antigens by western blot compared to non-vaccinated controls. Although anti-rabbit and anti-mouse antibodies were capable of inhibiting syncytium formation at low dilutions, rabbits were not protected from cell-associated viral challenge. Future development of vaccines to HTLV-1 may need to incorporate the ability to elicit cell-mediated immune responses in order to protect against cell-associated viral infection.

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The immune system often recognises tumour cells and infectious agents from the unique peptides found on their surfaces therefore, synthetic peptides of similar structure can be used as vaccines to stimulate the immune system. Despite the problems associated with proteolysis and delivery to the immune system, peptide-based vaccines have enormous potential due to their ease of synthesis and purification. The aim of this research was to synthesise ligands for mannose receptors (MRs) that are found on human Antigen Presenting Cells (APCs), for use in synthetic vaccines. Carbohydrate bearing antigens are recognised by MRs which play an important role in binding antigens, migration of dendritic cells (DCs) and interaction of DCs with lymphocytes. Hence, incorporation of a sugar residue into a peptide chain can be used to enhance antigen presentation. This thesis describes the synthesis of fluorescein labelled O-mannosylated peptides using either manual or microwave assisted solid phase glycopeptide synthesis (SPGS) on pre-loaded WANG resin. The mannosylated peptides thus prepared can be tested for their ability to bind mannose receptors on human APCs in vitro. In order to prepare compounds that could be analysed in biological screens, a fluorescent label (5(6)-carboxyfluorescein) was introduced into the glycopeptides via the Nα- or the Nε-amino group of the lysine residue. It was found that preparation of the glycopeptide was more facile when the peptide chain was built onto the Nε of Lys (label into Nα) rather than onto the Nα of Lys (label into Nε). In order to overcome problems experienced when introducing more than one glycosylated building block into the peptide chain, a polyethylene glycol (PEG) linker was employed as a sugar carrier. It was found that mono- and dimannosylated building blocks attached to PEG carrier were incorporated more easily into the peptide chain compared to mono- and dimannosylated serine units. Importantly, microwave technology (CEM Liberty microwave peptide synthesiser) was used for SPGS which resulted in improved purity and yields of the glycopeptides thus prepared with a significant reduction in reaction times. The first fifteen glycopeptides prepared in the present study were tested for binding to mannose receptors. Several compounds have shown improved binding to monocytes (bear MRs) in comparison to lymphocytes (do not bear MRs), in the presence of calcium ions. Calcium dependent binding is specific for C type lectin receptor family that MRs belong to. Five remaining glycopeptides are currently undergoing biological evaluation.

The immune system often recognises tumour cells and infectious agents from the unique peptides found on their surfaces therefore, synthetic peptides of similar structure can be used as vaccines to stimulate the immune system. Despite the problems associated with proteolysis and delivery to the immune system, peptide-based vaccines have enormous potential due to their ease of synthesis and purification. The aim of this research was to synthesise ligands for mannose receptors (MRs) that are found on human Antigen Presenting Cells (APCs), for use in synthetic vaccines. Carbohydrate bearing antigens are recognised by MRs which play an important role in binding antigens, migration of dendritic cells (DCs) and interaction of DCs with lymphocytes. Hence, incorporation of a sugar residue into a peptide chain can be used to enhance antigen presentation. This thesis describes the synthesis of fluorescein labelled O-mannosylated peptides using either manual or microwave assisted solid phase glycopeptide synthesis (SPGS) on pre-loaded WANG resin. The mannosylated peptides thus prepared can be tested for their ability to bind mannose receptors on human APCs in vitro. In order to prepare compounds that could be analysed in biological screens, a fluorescent label (5(6)-carboxyfluorescein) was introduced into the glycopeptides via the Nα- or the Nε-amino group of the lysine residue. It was found that preparation of the glycopeptide was more facile when the peptide chain was built onto the Nε of Lys (label into Nα) rather than onto the Nα of Lys (label into Nε). In order to overcome problems experienced when introducing more than one glycosylated building block into the peptide chain, a polyethylene glycol (PEG) linker was employed as a sugar carrier. It was found that mono- and dimannosylated building blocks attached to PEG carrier were incorporated more easily into the peptide chain compared to mono- and dimannosylated serine units. Importantly, microwave technology (CEM Liberty microwave peptide synthesiser) was used for SPGS which resulted in improved purity and yields of the glycopeptides thus prepared with a significant reduction in reaction times. The first fifteen glycopeptides prepared in the present study were tested for binding to mannose receptors. Several compounds have shown improved binding to monocytes (bear MRs) in comparison to lymphocytes (do not bear MRs), in the presence of calcium ions. Calcium dependent binding is specific for C type lectin receptor family that MRs belong to. Five remaining glycopeptides are currently undergoing biological evaluation.

The immune system often recognises tumour cells and infectious agents from the unique peptides found on their surfaces therefore, synthetic peptides of similar structure can be used as vaccines to stimulate the immune system. Despite the problems associated with proteolysis and delivery to the immune system, peptide-based vaccines have enormous potential due to their ease of synthesis and purification. The aim of this research was to synthesise ligands for mannose receptors (MRs) that are found on human Antigen Presenting Cells (APCs), for use in synthetic vaccines. Carbohydrate bearing antigens are recognised by MRs which play an important role in binding antigens, migration of dendritic cells (DCs) and interaction of DCs with lymphocytes. Hence, incorporation of a sugar residue into a peptide chain can be used to enhance antigen presentation. This thesis describes the synthesis of fluorescein labelled O-mannosylated peptides using either manual or microwave assisted solid phase glycopeptide synthesis (SPGS) on pre-loaded WANG resin. The mannosylated peptides thus prepared can be tested for their ability to bind mannose receptors on human APCs in vitro. In order to prepare compounds that could be analysed in biological screens, a fluorescent label (5(6)-carboxyfluorescein) was introduced into the glycopeptides via the Nα- or the Nε-amino group of the lysine residue. It was found that preparation of the glycopeptide was more facile when the peptide chain was built onto the Nε of Lys (label into Nα) rather than onto the Nα of Lys (label into Nε). In order to overcome problems experienced when introducing more than one glycosylated building block into the peptide chain, a polyethylene glycol (PEG) linker was employed as a sugar carrier. It was found that mono- and dimannosylated building blocks attached to PEG carrier were incorporated more easily into the peptide chain compared to mono- and dimannosylated serine units. Importantly, microwave technology (CEM Liberty microwave peptide synthesiser) was used for SPGS which resulted in improved purity and yields of the glycopeptides thus prepared with a significant reduction in reaction times. The first fifteen glycopeptides prepared in the present study were tested for binding to mannose receptors. Several compounds have shown improved binding to monocytes (bear MRs) in comparison to lymphocytes (do not bear MRs), in the presence of calcium ions. Calcium dependent binding is specific for C type lectin receptor family that MRs belong to. Five remaining glycopeptides are currently undergoing biological evaluation.

The immune system often recognises tumour cells and infectious agents from the unique peptides found on their surfaces therefore, synthetic peptides of similar structure can be used as vaccines to stimulate the immune system. Despite the problems associated with proteolysis and delivery to the immune system, peptide-based vaccines have enormous potential due to their ease of synthesis and purification. The aim of this research was to synthesise ligands for mannose receptors (MRs) that are found on human Antigen Presenting Cells (APCs), for use in synthetic vaccines. Carbohydrate bearing antigens are recognised by MRs which play an important role in binding antigens, migration of dendritic cells (DCs) and interaction of DCs with lymphocytes. Hence, incorporation of a sugar residue into a peptide chain can be used to enhance antigen presentation. This thesis describes the synthesis of fluorescein labelled O-mannosylated peptides using either manual or microwave assisted solid phase glycopeptide synthesis (SPGS) on pre-loaded WANG resin. The mannosylated peptides thus prepared can be tested for their ability to bind mannose receptors on human APCs in vitro. In order to prepare compounds that could be analysed in biological screens, a fluorescent label (5(6)-carboxyfluorescein) was introduced into the glycopeptides via the Nα- or the Nε-amino group of the lysine residue. It was found that preparation of the glycopeptide was more facile when the peptide chain was built onto the Nε of Lys (label into Nα) rather than onto the Nα of Lys (label into Nε). In order to overcome problems experienced when introducing more than one glycosylated building block into the peptide chain, a polyethylene glycol (PEG) linker was employed as a sugar carrier. It was found that mono- and dimannosylated building blocks attached to PEG carrier were incorporated more easily into the peptide chain compared to mono- and dimannosylated serine units. Importantly, microwave technology (CEM Liberty microwave peptide synthesiser) was used for SPGS which resulted in improved purity and yields of the glycopeptides thus prepared with a significant reduction in reaction times. The first fifteen glycopeptides prepared in the present study were tested for binding to mannose receptors. Several compounds have shown improved binding to monocytes (bear MRs) in comparison to lymphocytes (do not bear MRs), in the presence of calcium ions. Calcium dependent binding is specific for C type lectin receptor family that MRs belong to. Five remaining glycopeptides are currently undergoing biological evaluation.