Immune recognition of viral glycoproteins is probably influenced by their glycosylation. Gp120 of HIV-1, for example, consists of 50% carbohydrate and, together with many other glycoproteins, contains glycosylation sites within or close to both B- and T-cell determinants. It is highly likely that the glycosylation affects the recognition of both B- and T-cells by stabilizing the structures recognized. Immunogenic effects of carbohydrate moieties attached to protein fragments are difficult to address unless a method of preparing the appropriate tools is at hand. This proposal is focused on the synthesis of these tools (glycopeptides) and the assessment of glycosylation effects on the conformation of peptides involved in immune recognition. We propose to extend the solid-phase synthetic method, which we used to synthesize glycopeptides carrying Asn(GIcNAc) residue, to longer and branched carbohydrate chains with O-glycosydic bonds between the sugar moieties. These structures mimic the naturally occurring ones. We will use physical-chemical methods such as CD and NMR to measure the influence of incorporation of different carbohydrate chains to specific and non- specific positions on the conformation of epitopic peptides. The conformation data obtained will be compared with recognition of differentially glycosylated and parent non-glycosylated peptides by T- and B-cells. These studies will give clues to the minimal criteria of sequence and conformation necessary for glycopeptide structures to stimulate T cells and elicit neutralizing antibody production against viral glycoproteins.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM045011-03
Application #
3304394
Study Section
Special Emphasis Panel (SRC)
Project Start
1990-06-05
Project End
1993-11-30
Budget Start
1992-06-01
Budget End
1993-11-30
Support Year
3
Fiscal Year
1992
Total Cost
Indirect Cost
Name
Wistar Institute
Department
Type
DUNS #
042250712
City
Philadelphia
State
PA
Country
United States
Zip Code
19104
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Cudic, Mare; Ertl, Hildegund C J; Otvos Jr, Laszlo (2002) Synthesis, conformation and T-helper cell stimulation of an O-linked glycopeptide epitope containing extended carbohydrate side-chains. Bioorg Med Chem 10:3859-70
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Kragol, G; Lovas, S; Varadi, G et al. (2001) The antibacterial peptide pyrrhocoricin inhibits the ATPase actions of DnaK and prevents chaperone-assisted protein folding. Biochemistry 40:3016-26
Otvos Jr, L (2000) Antibacterial peptides isolated from insects. J Pept Sci 6:497-511
Otvos Jr, L; Pease, A M; Bokonyi, K et al. (2000) In situ stimulation of a T helper cell hybridoma with a cellulose-bound peptide antigen. J Immunol Methods 233:95-105
Otvos Jr, L; O, I; Rogers, M E et al. (2000) Interaction between heat shock proteins and antimicrobial peptides. Biochemistry 39:14150-9
Otvos Jr, L; Bokonyi, K; Varga, I et al. (2000) Insect peptides with improved protease-resistance protect mice against bacterial infection. Protein Sci 9:742-9
Horvat, S; Otvos Jr, L; Urge, L et al. (1999) Circular dichroism study of the carbohydrate-modified opioid peptides. Spectrochim Acta A Mol Biomol Spectrosc 55A:2347-52

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