Molecular context of a viral T cell determinant within a chimeric bacterial protein alters the diversity of its T cell recognition.
We genetically introduced two different viral CD4+ T cell epitopes within two internal sites of the Escherichia coli maltose-binding (MalE) protein. Affinity-purified hybrid MalE proteins were used to analyze the influence of the molecular environment on the presentation of inserted epitope to T cells. In the first model, the 120 to 132 PreS T cell epitope was inserted alone or with its C-terminal B cell epitope (132-145) at site 133 or 303 of MalE. The maltose-binding protein with PreS peptide inserts expressing the 120 to 132 sequence were able to induce in vivo and in vitro peptide-specific T cell response, whatever the length and the position of the insert. In the second model, the 103 to 115 T cell epitope from the C3 region of poliovirus type 1 (PV1) was inserted, with various flanking sequences, either at site 133 or 303 of MalE protein. The longer C3:86 to 115 insert induced poliovirus-specific T cell responses at both sites of MalE, whereas the C3:93 to 115 insert did it only at site 303 but not at site 133. Moreover, C3:103 to 115 specific T cell hybridomas discriminated between the processed peptides generated from the different chimeric proteins, as a result of differences in the length and the position of the inserted sequence. Therefore, in this experimental model the loss of in vivo immunogenicity of an antigenic determinant within a chimeric protein is related to the activation of a reduced T cell repertoire. These observations involve important consequences for the engineering of recombinant vaccines.
Lo-Man
R
R
Unit on Biology of Immune Regulation, Pasteur Institute, Paris, France.
Martineau
P
P
Betton
J M
JM
Hofnung
M
M
Leclerc
C
C
D018528:ATP-Binding Cassette Transporters; D000595:Amino Acid Sequence; D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics / Q000276:immunology; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D002213:Capsid / Q000235:genetics / Q000276:immunology; D036022:Capsid Proteins; D002352:Carrier Proteins / Q000235:genetics / Q000276:immunology; D000939:Epitopes / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics / Q000276:immunology; D029968:Escherichia coli Proteins; D006514:Hepatitis B Surface Antigens / Q000235:genetics; D006515:Hepatitis B virus / Q000235:genetics / Q000276:immunology; D006825:Hybridomas / Q000276:immunology; D008213:Lymphocyte Activation; D058619:Maltose-Binding Proteins; D051379:Mice; D008807:Mice, Inbred BALB C; D008811:Mice, Inbred DBA; D008969:Molecular Sequence Data; D009004:Monosaccharide Transport Proteins; D033902:Periplasmic Binding Proteins; D017955:Poliovirus / Q000235:genetics / Q000276:immunology; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000276:immunology; D014764:Viral Proteins / Q000235:genetics / Q000276:immunology*
D018528:ATP-Binding Cassette Transporters; D001426:Bacterial Proteins; D036022:Capsid Proteins; D002352:Carrier Proteins; D000939:Epitopes; D029968:Escherichia coli Proteins; D006514:Hepatitis B Surface Antigens; C461619:MalE protein, E coli; D058619:Maltose-Binding Proteins; D009004:Monosaccharide Transport Proteins; D033902:Periplasmic Binding Proteins; D011993:Recombinant Fusion Proteins; C442540:VP1 protein, Poliovirus; D014764:Viral Proteins; C461599:maltose transport system, E coli