Linear and branched glyco-lipopeptide vaccines follow distinct cross-presentation pathways and generate different magnitudes of antitumor immunity.
BACKGROUND
Glyco-lipopeptides, a form of lipid-tailed glyco-peptide, are currently under intense investigation as B- and T-cell based vaccine immunotherapy for many cancers. However, the cellular and molecular mechanisms of glyco-lipopeptides (GLPs) immunogenicity and the position of the lipid moiety on immunogenicity and protective efficacy of GLPs remain to be determined.


RESULTS
We have constructed two structural analogues of HER-2 glyco-lipopeptide (HER-GLP) by synthesizing a chimeric peptide made of one universal CD4(+) epitope (PADRE) and one HER-2 CD8(+) T-cell epitope (HER(420-429)). The C-terminal end of the resulting CD4-CD8 chimeric peptide was coupled to a tumor carbohydrate B-cell epitope, based on a regioselectively addressable functionalized templates (RAFT), made of four alpha-GalNAc molecules. The resulting HER glyco-peptide (HER-GP) was then linked to a palmitic acid moiety, attached either at the N-terminal end (linear HER-GLP-1) or in the middle between the CD4+ and CD8+ T cell epitopes (branched HER-GLP-2). We have investigated the uptake, processing and cross-presentation pathways of the two HER-GLP vaccine constructs, and assessed whether the position of linkage of the lipid moiety would affect the B- and T-cell immunogenicity and protective efficacy. Immunization of mice revealed that the linear HER-GLP-1 induced a stronger and longer lasting HER(420-429)-specific IFN-gamma producing CD8(+) T cell response, while the branched HER-GLP-2 induced a stronger tumor-specific IgG response. The linear HER-GLP-1 was taken up easily by dendritic cells (DCs), induced stronger DCs maturation and produced a potent TLR- 2-dependent T-cell activation. The linear and branched HER-GLP molecules appeared to follow two different cross-presentation pathways. While regression of established tumors was induced by both linear HER-GLP-1 and branched HER-GLP-2, the inhibition of tumor growth was significantly higher in HER-GLP-1 immunized mice (p<0.005).


CONCLUSIONS
These findings have important implications for the development of effective GLP based immunotherapeutic strategies against cancers.
Renaudet
Olivier
O
Laboratory of Cellular and Molecular Immunology, The Gavin Herbert Eye Institute, School of Medicine, University of California Irvine, Irvine, California, USA.
Dasgupta
Gargi
G
Bettahi
Ilham
I
Shi
Alda
A
Nesburn
Anthony B
AB
Dumy
Pascal
P
BenMohamed
Lbachir
L
D000818:Animals; D000918:Antibody Specificity; D001402:B-Lymphocytes / Q000276:immunology; D001692:Biological Transport; D015704:CD4 Antigens / Q000378:metabolism; D016827:CD8 Antigens / Q000378:metabolism; D045744:Cell Line, Tumor; D045142:Cross-Priming / Q000276:immunology*; D003593:Cytoplasm / Q000378:metabolism; D003713:Dendritic Cells / Q000166:cytology / Q000276:immunology / Q000378:metabolism; D018985:Epitopes, B-Lymphocyte / Q000276:immunology; D005260:Female; D006023:Glycoproteins / Q000737:chemistry*; D006801:Humans; D007114:Immunization; D007074:Immunoglobulin G / Q000276:immunology; D007371:Interferon-gamma / Q000096:biosynthesis; D055666:Lipopeptides / Q000737:chemistry* / Q000276:immunology* / Q000378:metabolism; D051379:Mice; D009369:Neoplasms / Q000276:immunology* / Q000628:therapy; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000737:chemistry; D013237:Stereoisomerism; D013601:T-Lymphocytes / Q000276:immunology / Q000378:metabolism; D013997:Time Factors; D051195:Toll-Like Receptor 2 / Q000378:metabolism; D022223:Vaccines, Subunit / Q000737:chemistry / Q000276:immunology / Q000378:metabolism
D015704:CD4 Antigens; D016827:CD8 Antigens; D018985:Epitopes, B-Lymphocyte; D006023:Glycoproteins; D007074:Immunoglobulin G; D007371:Interferon-gamma; D055666:Lipopeptides; D018719:Erb-b2 Receptor Tyrosine Kinases; D051195:Toll-Like Receptor 2; D022223:Vaccines, Subunit