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H-2-associated effects of flanking residues on the recognition of a permissive mycobacterial T-cell epitope.
- Source :
-
Immunology . Oct95, Vol. 86 Issue 2, p183-189. 7p. - Publication Year :
- 1995
-
Abstract
- Previously we have identified an immunodominant, eight-residue, epitope core sequence (TAAGNVNI) from the 19 000 MW protein of Mycobacterium tuberculosis, which is recognized in the context of multiple H-2 I-A molecules. In this study, the role of residues flanking this T-cell epitope core was examined, using a series of 20 mer analogue peptides in which the native flanking residues were progressively replaced with L-alanine. Analogue peptides were tested for their capacity to stimulate a CD4+ 19000 MW protein-specific T-cell line, revealing that all but one N-terminal flanking residue could be replaced collectively by alanine without significant loss of stimulatory activity. However, clear H-2-associated differences in the requirement for flanking residues were demonstrated with peptide-specific T-cell hybridomas. In particular, H-2d-derived hybridomas were much more stringent in their requirement for flanking residues than were hybridomas. All polyalanine-substituted peptides bound I-Ab molecules, with affinities similar to the native unsubstituted peptide. In contrast, significantly reduced binding to I-Ad was observed with several analogue peptides, although without a clear relationship to the degree of substitution. Furthermore, in H-2b mice, neither immunogenicity nor cross-reactivity with the native peptide showed a clear inverse relationship with respect to the degree of alanine substitution. The results presented in this paper indicate that flanking residues can influence T-cell specificity and that these effects may be controlled by major histocompatibility complex (MHC) haplotype. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 00192805
- Volume :
- 86
- Issue :
- 2
- Database :
- Academic Search Index
- Journal :
- Immunology
- Publication Type :
- Academic Journal
- Accession number :
- 14075403