Antibodies elicited by naked DNA vaccination against the complementary-determining region 3 hypervariable region of immunoglobulin heavy chain idiotypic determinants of B-lymphoproliferative disorders specifically react with patients' tumor cells.
Several reports have suggested that the mechanism of protection induced by antiidiotypic vaccination against low-grade lymphoproliferative disorders is likely to be antibody mediated. Here we test the hypothesis that DNA vaccination with the short peptide encompassing the complementary-determining region 3 hypervariable region of immunoglobulin heavy chain (VH-CDR3) may elicit a specific antibody immune response able to recognize the native antigens in the form required for therapy. As a test system, we used the VH-CDR3 sequences derived from two patients with non-Hodgkin's B lymphomas (PA, AS) and one patient with hairy cell leukemia (BA) to immunize outbred Swiss mice. This experimental model could mimic a clinical setting in which different patients present distinct HLA haplotypes. Individual tumor-specific VH-CDR3 sequences were amplified by a two-step procedure and directly cloned into multigenic plasmid vectors (pRC100 and derived) with and without mouse interleukin 2 (mIL-2). Each tumor-specific sequence was characterized by sequencing. Female Swiss mice were vaccinated i.m. with plasmids expressing the tumor-specific VH-CDR3 sequence alone (pRC101-PA), mIL-2 plus the VH-CDR3 sequence (pRC111-PA), or a different unrelated antigen (NS3 of hepatitis C virus; pRC112), the sole mIL-2 (pRC110), and the empty plasmid (pRC100). Boost injections were performed at 3 and 16 weeks from the first vaccination, and sera were drawn before each vaccination and at 6, 9, and 19 weeks. Induction of anti-VH-CDR3s antibodies in the sera and their ability to recognize native antigens on patients' tumor cells were evaluated by FACS analysis. Up to 56% (n = 25) of mice vaccinated with pRC111-PA plasmid and 20% (n = 15) of mice vaccinated with pRC101-PA developed a specific immune response that was maintained throughout 19 weeks of observation in 40% of pRC111-PA-vaccinated mice. No response was detected in sera obtained from mice vaccinated with the other plasmids (n = 45). pRC111-PA injection s.c. was less effective (13%, n = 15) than i.m. injection (53%, n = 15). Indeed, we demonstrated that antibodies elicited by naked DNA vaccination against three different patient-derived VH-CDR3 peptides (pRC111-PA or BA or AS) readily reacted with binding epitopes on the idiotypic proteins expressed on the surface of tumor cells derived from each patient; 60, 40, and 40% of, respectively, PA-, BA-, and AS-vaccinated mice developed specific antibodies. No cross-reactivity was detected among the three different CDR3s against tumor cells derived from the other two patients. The outbred mouse strategy confirmed the significant matching potential of three different VH-CDR3 peptides to be efficaciously presented through different MHCs. We conclude that individual VH-CDR3 DNA vaccination can result in a potentially effective specific immune response against non-Hodgkin's B lymphoma cells by a rapid and low-cost therapeutic approach.
Laboratory for Molecular and Biotechnology, Università Campus Bio-Medico, Rome, Italy.
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M
Rinaldi
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Ria
P
P
Parrella
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E
Signori
A
A
Serra
S A
SA
Ciafrè
I
I
Vespignani
M
M
Lazzari
M G
MG
Farace
G
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Saglio
V M
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Fazio
D000595:Amino Acid Sequence; D000818:Animals; D000888:Antibodies, Anti-Idiotypic / Q000096:biosynthesis / Q000276:immunology; D000912:Antibodies, Neoplasm / Q000096:biosynthesis / Q000097:blood / Q000276:immunology*; D001483:Base Sequence; D019496:Cancer Vaccines / Q000276:immunology*; D002461:Cell Line, Transformed; D022801:Complementarity Determining Regions / Q000276:immunology*; D000939:Epitopes / Q000276:immunology; D005434:Flow Cytometry; D005822:Genetic Vectors / Q000008:administration & dosage / Q000276:immunology; D006801:Humans; D007143:Immunoglobulin Heavy Chains / Q000276:immunology; D007130:Immunoglobulin Idiotypes / Q000276:immunology; D007135:Immunoglobulin Variable Region / Q000276:immunology; D007376:Interleukin-2 / Q000096:biosynthesis; D015448:Leukemia, B-Cell / Q000276:immunology*; D007943:Leukemia, Hairy Cell / Q000276:immunology; D016393:Lymphoma, B-Cell / Q000276:immunology*; D051379:Mice; D008969:Molecular Sequence Data; D019444:Vaccines, DNA / Q000276:immunology*
D000888:Antibodies, Anti-Idiotypic; D000912:Antibodies, Neoplasm; D019496:Cancer Vaccines; D022801:Complementarity Determining Regions; D000939:Epitopes; D007143:Immunoglobulin Heavy Chains; D007130:Immunoglobulin Idiotypes; D007135:Immunoglobulin Variable Region; D007376:Interleukin-2; D019444:Vaccines, DNA