A decaepitope polypeptide primes for multiple CD8+ IFN-gamma and Th lymphocyte responses: evaluation of multiepitope polypeptides as a mode for vaccine delivery.
Proteins are generally regarded as ineffective immunogens for CTL responses. We synthesized a 100-mer decaepitope polypeptide and tested its capacity to induce multiple CD8(+) IFN-gamma and Th lymphocyte (HTL) responses in HLA transgenic mice. Following a single immunization in the absence of adjuvant, significant IFN-gamma in vitro recall responses were detected for all epitopes included in the construct (six A2.1-, three A11-restricted CTL epitopes, and one universal HTL epitope). Immunization with truncated forms of the decaepitope polypeptide was used to demonstrate that optimal immunogenicity was associated with a size of at least 30-40 residues (3-4 epitopes). Solubility analyses of the truncated constructs were used to identify a correlation between immunogenicity for IFN-gamma responses and the propensity of these constructs to form particulate aggregates. Although the decaepitope polypeptide and a pool of epitopes emulsified in IFA elicited similar levels of CD8(+) responses using fresh splenocytes, we found that the decaepitope polypeptide more effectively primed for in vitro recall CD8(+) T cell responses. Finally, immunogenicity comparisons were also made between the decaepitope polypeptide and a corresponding gene encoding the same polypeptide delivered by naked DNA immunization. Although naked DNA immunization induced somewhat greater direct ex vivo and in vitro recall responses 2 wk after a single immunization, only the polypeptide induced significant in vitro recall responses 6 wk following the priming immunization. These studies support further evaluation of multiepitope polypeptide vaccines for induction of CD8(+) IFN-gamma and HTL responses.
Alexander
Jeff
J
Epimmune, San Diego, CA 92121, USA. jalexander@epimmune.com
Oseroff
Carla
C
Dahlberg
Carol
C
Qin
Mingsheng
M
Ishioka
Glenn
G
Beebe
Melanie
M
Fikes
John
J
Newman
Mark
M
Chesnut
Robert W
RW
Morton
Phillip A
PA
Fok
Kam
K
Appella
Ettore
E
Sette
Alessandro
A
D000818:Animals; D002021:Buffers; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology* / Q000378:metabolism; D004247:DNA / Q000008:administration & dosage / Q000276:immunology; D004340:Drug Contamination; D004655:Emulsions; D018984:Epitopes, T-Lymphocyte / Q000008:administration & dosage / Q000737:chemistry / Q000276:immunology*; D005620:Freund's Adjuvant / Q000276:immunology; D006680:HLA Antigens / Q000235:genetics / Q000276:immunology; D006801:Humans; D007273:Injections, Intramuscular; D007279:Injections, Subcutaneous; D007371:Interferon-gamma / Q000096:biosynthesis*; D019169:Jurkat Cells; D008213:Lymphocyte Activation; D051379:Mice; D008807:Mice, Inbred BALB C; D008822:Mice, Transgenic; D010446:Peptide Fragments / Q000008:administration & dosage / Q000138:chemical synthesis / Q000276:immunology*; D012995:Solubility; D006377:T-Lymphocytes, Helper-Inducer / Q000276:immunology* / Q000378:metabolism; D019076:Transgenes / Q000276:immunology; D014611:Vaccination / Q000379:methods*; D014614:Vaccines, Synthetic / Q000008:administration & dosage / Q000276:immunology*
D002021:Buffers; D004655:Emulsions; D018984:Epitopes, T-Lymphocyte; D006680:HLA Antigens; D010446:Peptide Fragments; D014614:Vaccines, Synthetic; D007371:Interferon-gamma; D004247:DNA; D005620:Freund's Adjuvant