Comparative analysis of B- and T-cell epitopes of Mycobacterium leprae and Mycobacterium tuberculosis culture filtrate protein 10.
Culture filtrate protein 10 (CFP-10) from Mycobacterium tuberculosis is a well-characterized immunodominant 10-kDa protein antigen known to elicit a very potent early gamma interferon response in T cells from M. tuberculosis-infected mice and humans. The sequence of the Mycobacterium leprae homologue of CFP-10 shows only 40% identity (60% homology) at the protein level with M. tuberculosis CFP-10 and thus has the potential for development as a T- or B-cell reactive antigen for specific diagnosis of leprosy. Antisera raised in mice or rabbits against recombinant M. leprae and M. tuberculosis CFP-10 proteins reacted only with homologous peptides from arrays of overlapping synthetic peptides, indicating that there was no detectable cross-reactivity at the antibody level. Sera from leprosy and tuberculosis patients were also specific for the homologous protein or peptides and showed distinct patterns of recognition for either M. leprae or M. tuberculosis CFP-10 peptides. At the cellular level, only 2 of 45 mouse T-cell hybridomas raised against either M. leprae or M. tuberculosis CFP-10 displayed a cross-reactive response against the N-terminal heterologous CFP-10 peptide, the region that exhibits the highest level of identity in the two proteins; however, the majority of peptide epitopes recognized by mouse T-cell hybridomas specific for each protein did not cross-react with heterologous peptides. Coupled with the human serology data, these results raise the possibility that peptides that could be used to differentiate infections caused by these two related microorganisms could be developed. Immunohistochemical staining of sections of M. leprae-infected nude mouse footpads resulted in strongly positive staining in macrophages and dendritic cells, as well as weaker staining in extracellular areas, suggesting that M. leprae CFP-10, like its homologue in M. tuberculosis, is a secreted protein.
Spencer
John S
JS
Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado 80523, USA. John.Spencer@colostate.edu
Kim
Hee Jin
HJ
Marques
Angela M
AM
Gonzalez-Juarerro
Mercedes
M
Lima
Monica C B S
MC
Vissa
Varalakshmi D
VD
Truman
Richard W
RW
Gennaro
Maria Laura
ML
Cho
Sang-Nae
SN
Cole
Stewart T
ST
Brennan
Patrick J
PJ
D000595:Amino Acid Sequence; D000818:Animals; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000276:immunology*; D018985:Epitopes, B-Lymphocyte / Q000276:immunology*; D018984:Epitopes, T-Lymphocyte / Q000276:immunology*; D006801:Humans; D006825:Hybridomas; D007106:Immune Sera / Q000276:immunology; D007918:Leprosy / Q000276:immunology / Q000382:microbiology; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D008969:Molecular Sequence Data; D009166:Mycobacterium leprae / Q000276:immunology*; D009169:Mycobacterium tuberculosis / Q000276:immunology*; D010455:Peptides / Q000138:chemical synthesis / Q000737:chemistry / Q000276:immunology; D011817:Rabbits; D011994:Recombinant Proteins / Q000235:genetics / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology; D014376:Tuberculosis / Q000276:immunology / Q000382:microbiology
D001426:Bacterial Proteins; C117940:CFP-10 protein, Mycobacterium tuberculosis; D018985:Epitopes, B-Lymphocyte; D018984:Epitopes, T-Lymphocyte; D007106:Immune Sera; D010455:Peptides; D011994:Recombinant Proteins