Mapping of a protective helper T cell epitope of human influenza A virus hemagglutinin.
The synthetic peptide comprising the 317-341 region of human influenza A virus (H1N1 subtype) hemagglutinin elicits peptide-specific antibody and helper T cell responses and confers protection against lethal virus infection. Molecular mapping of the 317-329 region, which encompasses the epitope recognized by peptide-specific T cells, revealed that the minimal size required for T cell activation was the 317-326 segment. The most likely peptide alignment, which placed 320Leu to pocket 1 of the I-E(d) peptide binding groove, was predicted by molecular mechanics calculations performed with the parental and with the Ala-substituted analogs. In line with the prediction data, the results of the peptide binding assay, where the relative binding efficiency to I-E(d) molecules expressed on the surface of antigen-presenting cells was monitored, identified the 320-326 core sequence interacting with the major histocompatibility class II peptide binding groove. Functional analysis of Ala-substituted variants by functional assays and by calculating the surface-accessible areas of the single peptidic amino acids in the I-E(d)-peptide complexes demonstrated that 324Pro is a primary contact residue for the T cell receptor. Our results show that this type of analysis offers a suitable tool for molecular mapping of helper T cell epitopes and thus provides valuable data for subunit vaccine design.
Gogolák
P
P
Department of Immunology, L. Eötvös University, Göd, Hungary.
Simon
A
A
Horváth
A
A
Réthi
B
B
Simon
I
I
Berkics
K
K
Rajnavölgyi
E
E
Tóth
G K
GK
D000409:Alanine / Q000235:genetics; D003198:Computer Simulation; D018604:Epitope Mapping; D000939:Epitopes; D019267:Hemagglutinin Glycoproteins, Influenza Virus / Q000235:genetics / Q000276:immunology*; D000949:Histocompatibility Antigens Class II / Q000737:chemistry / Q000276:immunology; D009980:Influenza A virus / Q000235:genetics / Q000276:immunology*; D007376:Interleukin-2 / Q000096:biosynthesis; D008213:Lymphocyte Activation; D016297:Mutagenesis, Site-Directed; D010446:Peptide Fragments / Q000235:genetics / Q000276:immunology; D011485:Protein Binding; D011948:Receptors, Antigen, T-Cell; D006377:T-Lymphocytes, Helper-Inducer / Q000276:immunology*
D000939:Epitopes; D019267:Hemagglutinin Glycoproteins, Influenza Virus; D000949:Histocompatibility Antigens Class II; C024138:I-E-antigen; D007376:Interleukin-2; D010446:Peptide Fragments; D011948:Receptors, Antigen, T-Cell; D000409:Alanine