title: Identification of an I-Ad restricted peptide on the 65-kilodalton heat shock protein of Mycobacterium avium.
abstract: The 65 kilodalton heat shock protein (Hsp65) from mycobacterial species elicits immune responses and in some cases protective immunity. Here we have used a DNA sublibrary approach to identify antigenic fragments of Mycobacterium avium Hsp65 and a synthetic peptide approach to delineate CD4+ T cell determinants. A panel of Hsp65 reactive CD4+ T cell clones was established from lymph node cells obtained from BALB/c mice immunized with recombinant Hsp65. The clones were tested for proliferative reactivity against the products of the DNA sublibrary of the hsp65 gene. A T cell epitope, restricted by the I-Ad molecule, was identified within the C-terminal region of Hsp65 and the minimal epitope (amino acid residues 489-503) delineated using overlapping peptides spanning the C-terminal fragment. Additionally, the CD4+ T cell clone recognizing this epitope also responded to native Hsp65 present in M. avium lysates by both proliferation and cytokine production, indicating that the epitope was present and processed similarly both in the native and the recombinant forms of Hsp65. This sequence identified in BALB/c mice (Hsp65 489-503) is identical in other mycobacteria, notably M. tuberculosis, M. bovis and M. leprae, suggesting the epitope may have wider application in murine models of other mycobacterial infections.
authors.affiliation: Division of Infectious Diseases, University of California, Rosalind Russell Arthritis Research Laboratory and Loewenstein Laboratory for Mycobacterial Research, San Francisco General Hospital, 94110, USA. vnagabh@itsa.ucsf.edu
authors.forename: Vijaya
authors.initials: V
authors.lastname: Nagabhushanam
authors.forename: Anthony W
authors.initials: AW
authors.lastname: Purcell
authors.forename: Stuart
authors.initials: S
authors.lastname: Mannering
authors.forename: Susie
authors.initials: S
authors.lastname: Germano
authors.forename: Judyta
authors.initials: J
authors.lastname: Praszkier
authors.forename: Christina
authors.initials: C
authors.lastname: Cheers
mesh_terms: D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D001426:Bacterial Proteins; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D018834:Chaperonin 60; D018833:Chaperonins / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D000939:Epitopes; D000949:Histocompatibility Antigens Class II / Q000378:metabolism*; D008969:Molecular Sequence Data; D009162:Mycobacterium avium / Q000378:metabolism*; D010455:Peptides / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000276:immunology
chemical_list: D001426:Bacterial Proteins; D018834:Chaperonin 60; D000939:Epitopes; D000949:Histocompatibility Antigens Class II; C111389:I-Ad antigen; D010455:Peptides; D011993:Recombinant Fusion Proteins; C074119:heat-shock protein 65, Mycobacterium; D018833:Chaperonins