Murine T cell-stimulatory peptides from the 19-kDa antigen of Mycobacterium tuberculosis. Epitope-restricted homology with the 28-kDa protein of Mycobacterium leprae.
Fifteen overlapping synthetic peptides, spanning the entire amino acid sequence of the Mycobacterium tuberculosis 19-kDa protein, were used to identify epitopes recognized by murine T cells. Five of the 15 peptides tested were able to elicit in vitro lymph node T cell proliferative responses in C57BL/10 mice primed by footpad inoculation with homologous peptide. Analysis in congenic strains of mice revealed H-2 restriction in the response to four peptides. However, one peptide, 19.7 (residues 61 to 80), induced T cell responses in all four haplotypes tested. This peptide was also unique in being able to stimulate lymph node cells from C57BL/10 mice immunized with recombinant 19-kDa protein, killed M. tuberculosis, or live bacillus Calmette Guerin infection. T cell lines specific for peptide 19.7 were of the CD4 phenotype. Significantly, sequence analysis revealed that residues 61 to 80 of the 19-kDa protein exhibited considerable homology with a single 20-amino acid sequence (residues 120 to 140), but not with any other region of the 28-kDa protein expressed in Mycobacterium leprae. This finding is the first evidence of epitope-restricted homology between otherwise structurally unrelated microbial Ag.
Harris
D P
DP
MRC Tuberculosis and Related Infections Unit, Royal Postgraduate Medical School, London, UK.
Vordermeier
H M
HM
Roman
E
E
Lathigra
R
R
Brett
S J
SJ
Moreno
C
C
Ivanyi
J
J
D000595:Amino Acid Sequence; D000818:Animals; D000942:Antigens, Bacterial / Q000276:immunology*; D000939:Epitopes / Q000032:analysis*; D006183:H-2 Antigens / Q000235:genetics; D006239:Haplotypes; D007114:Immunization; D008213:Lymphocyte Activation; D051379:Mice; D008810:Mice, Inbred C57BL; D008969:Molecular Sequence Data; D009163:Mycobacterium bovis / Q000276:immunology; D009166:Mycobacterium leprae / Q000276:immunology*; D009169:Mycobacterium tuberculosis / Q000276:immunology*; D010446:Peptide Fragments / Q000276:immunology; D013329:Structure-Activity Relationship; D013601:T-Lymphocytes / Q000276:immunology*
D000942:Antigens, Bacterial; D000939:Epitopes; D006183:H-2 Antigens; D010446:Peptide Fragments