Differences between T cell epitopes recognized after immunization and after infection.
Evidence suggests that cellular immune responses play a crucial role in the control of HIV and SIV replication in infected individuals. Several vaccine strategies have therefore targeted these CD8(+) and CD4(+) responses. Whether vaccination induces the same repertoire of responses seen after infection is, however, a key unanswered question in HIV vaccine development. We therefore compared the epitope specificity induced by vaccination to that present postchallenge in the peripheral blood. Intracellular cytokine staining of PBMC stimulated with overlapping 15/20-mer peptides spanning the proteins of SIV were measured after DNA/modified vaccinia Ankara vaccination of eight rhesus macaques. Lymphocytes from 8 animals recognized a total of 39 CD8 epitopes and 41 CD4 epitopes encoded by the vaccine. T cell responses were again monitored after challenge with SIVmac239 to investigate the evolution of these responses. Only 57% of all CD8(+) T cell responses and 19% of all CD4(+) T cell responses present after vaccination were recalled after infection as measured in the peripheral blood. Interestingly, 29 new CD8 epitopes and 5 new CD4 epitopes were recognized by PBMC in the acute phase. These new epitopes were not detected after vaccination, and only some of them were maintained in the chronic phase (33% of CD8 and no CD4 responses). Additionally, 24 new CD8 epitopes and 7 new CD4 epitopes were recognized by PBMC in the chronic phase of infection. The repertoire of the immune response detected in the peripheral blood after immunization substantially differed from the immune response detected in the peripheral blood after infection.
Vogel
Thorsten U
TU
Wisconsin National Primate Research Center, University of Wisconsin, 1220 Capital Court, Madison, WI 53715, USA.
Horton
Helen
H
Fuller
Deborah H
DH
Carter
Donald K
DK
Vielhuber
Kathy
K
O'Connor
David H
DH
Shipley
Tim
T
Fuller
Jim
J
Sutter
Gerd
G
Erfle
Volker
V
Wilson
Nancy
N
Picker
Louis J
LJ
Watkins
David I
DI
D000285:Administration, Rectal; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology / Q000378:metabolism / Q000821:virology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology / Q000378:metabolism / Q000821:virology; D002461:Cell Line, Transformed; D018984:Epitopes, T-Lymphocyte / Q000032:analysis* / Q000235:genetics / Q000276:immunology*; D007111:Immunity, Cellular / Q000235:genetics; D007117:Immunization, Secondary; D007271:Injections, Intradermal; D007963:Leukocytes, Mononuclear / Q000276:immunology / Q000821:virology; D008221:Lymphoid Tissue / Q000276:immunology / Q000378:metabolism / Q000821:virology; D008253:Macaca mulatta; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000032:analysis / Q000235:genetics / Q000276:immunology; D010449:Peptide Mapping; D018449:SAIDS Vaccines / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology*; D016097:Simian Acquired Immunodeficiency Syndrome / Q000276:immunology*; D015302:Simian Immunodeficiency Virus / Q000276:immunology; D014614:Vaccines, Synthetic / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology; D014616:Vaccinia virus / Q000235:genetics / Q000276:immunology*; D014764:Viral Proteins / Q000032:analysis / Q000235:genetics / Q000276:immunology
D018984:Epitopes, T-Lymphocyte; D010446:Peptide Fragments; D018449:SAIDS Vaccines; D014614:Vaccines, Synthetic; D014764:Viral Proteins