Predominant recognition of species-specific determinants of the GroES homologues from Mycobacterium leprae and M. tuberculosis

The Mycobacterium leprae and M. tuberculosis 10,000 MW heat-shock protein homologues of GroES have previously been identified as major immunogens for human T cells. We used synthetic peptides to characterize the determinants recognized by murine T cells. The findings suggest that, despite 90% sequence identity between these two proteins, T cells recognize prominently the species-specific determinants localized within amino acid residues 21-40 and 49-72. Analysis of the molecular determinants of species-specificity for the M. leprae GroES sequence 25-40, using T-cell hybridomas and major histocompatibility complex (MHC)-binding assays, led to the identification of epitope cores and critical residues. Interestingly, closely overlapping epitope cores were found to be restricted by either H-2Ad (24-34) or H-2Ed (28-34). Furthermore, the site recognized by the M. leprae-specific monoclonal antibodies ML06 and ML10 was also localized in the overlapping sequences 25-31 and 25-29. In conclusion, we demonstrated that immunodominant species-specific T- and B-cell epitopes can be found in a mycobacterial heat-shock protein despite its highly conserved amino acid sequence. This finding suggests the feasibility of identifying a sufficient number of M. leprae-specific determinants for a composite T-cell immunodiagnostic reagent for tuberculoid leprosy

Immune profiling of leprosy and tuberculosis patients to 15-mer peptides of Mycobacterium leprae and M. tuberculosis GroES in a BCG vaccinated area: implications for development of vaccine and diagnostic reagents

Mycobacterium leprae (ML) GroES has been shown to induce strong T cell responses in tuberculoid as well as in exposed healthy contacts of leprosy patients, and therefore this antigen has been the focus of study as a potential vaccine candidate. Paradoxically, we have shown that ML GroES also induces extremely high titres of IgG1 antibody in leprosy patients across the disease spectrum, a response associated with disease progression. IgG1 antibodies in leprosy also show a negative association with interferon-γ, a critical T cell cytokine responsible for macrophage activation and intracellular killing of mycobacteria. We therefore queried if antibody and T cell responses were being evoked by different epitopes in ML GroES proteins. To address the issue of epitope recognition in mycobacterial diseases, we have analysed 16 peptides (15-mer peptides) spanning the entire ML and M. tuberculosis GroES protein in leprosy (n = 19) and tuberculosis (n = 9) patients and healthy endemic controls (n = 8). Our analysis demonstrates clearly that the dominant peptides evokingT cell and IgG subclass antibodies were different. The target of both T and B cell responses were cross-reactive epitopes in all groups. Differences in disease and healthy states related to the strength (mean intensity) of the T cell and antibody response. IgG1 and IgG3 antibodies were associated with disseminated disease and IgG 2 and IgG4 with disease limitation. Such comprehensive immune profiling of antigen-specific responses is critical to understanding the disease pathogenesis and also if these reagents are to be exploited for either diagnostic or vaccine purposes

T-Cell Recognition of Mycobacterial GroES Peptides in Thai Leprosy Patients and Contacts

We report here the mapping of T-cell-stimulatory determinants of the GroES 10-kDa heat shock protein homologues from Mycobacterium leprae and Mycobacterium tuberculosis, which are known as major immunogens in mycobacterial infections. Peripheral blood mononuclear cells (PBMC) from treated tuberculoid leprosy or lepromatous leprosy patients and from healthy household or hospital staff contacts of the patients were cultured with 20 16-mer peptides covering the entire sequences of both M. leprae and M. tuberculosis GroES. The total number of recognized peptides was found to be the largest in family contacts, while responder frequencies to the individual tested peptides varied (5 to 80%) with specificity between the patient and contact groups. Proliferative responses to some peptides showed positive or negative associations of low statistical significance with DR and DQ alleles, though responses to most GroES peptides were genetically permissive. Notably, the sequence of the 25–40 peptide of M. leprae, but not that of M. tuberculosis, was more frequently stimulatory in tuberculoid leprosy patients than in either group of sensitized healthy contacts. This peptide bound to a number of HLA-DR molecules, of which HLA-DRB5*0101 had the strongest affinity. The epitope core binding to this allele was localized to the 29-to-37 sequence, and its key residue was localized to the M. leprae-specific glutamic acid at position 32. This epitope may be of interest for the development of a blood test- or skin test-based diagnostic reagent for tuberculoid leprosy, subject to further clinical evaluation in untreated patients

Influence of composition of the surface layer of strip on the protective properties of tinplate

Translated from Russian (Stal' 1989 (1) p. 90-92)Available from British Library Document Supply Centre- DSC:9022.06(BISI-Trans--27294)T / BLDSC - British Library Document Supply CentreSIGLEGBUnited Kingdo