title: Decreased capacity of recombinant 45/47-kDa molecules (Apa) of Mycobacterium tuberculosis to stimulate T lymphocyte responses related to changes in their mannosylation pattern.
abstract: The Apa molecules secreted by Mycobacterium tuberculosis, Mycobacterium bovis, or BCG have been identified as major immunodominant antigens. Mass spectrometry analysis indicated similar mannosylation, a complete pattern from 1 up to 9 hexose residues/mole of protein, of the native species from the 3 reference strains. The recombinant antigen expressed in M. smegmatis revealed a different mannosylation pattern: species containing 7 to 9 sugar residues/mole of protein were in the highest proportion, whereas species bearing a low number of sugar residues were almost absent. The 45/47-kDa recombinant antigen expressed in E. coli was devoid of sugar residues. The proteins purified from M. tuberculosis, M. bovis, or BCG have a high capacity to elicit in vivo potent delayed-type hypersensitivity (DTH) reactions and to stimulate in vitro sensitized T lymphocytes of guinea pigs immunized with living BCG. The recombinant Apa expressed in Mycobacterium smegmatis was 4-fold less potent in vivo in the DTH assay and 10-fold less active in vitro to stimulate sensitized T lymphocytes than the native proteins. The recombinant protein expressed in Escherichia coli was nearly unable to elicit DTH reactions in vivo or to stimulate T lymphocytes in vitro. Thus the observed biological effects were related to the extent of glycosylation of the antigen.
authors.affiliation: Unité de Physiopathologie de l'Infection, Institut Pasteur, 25 rue du Dr. Roux, 75724 Paris Cedex 15, France.
authors.forename: C
authors.initials: C
authors.lastname: Horn
authors.forename: A
authors.initials: A
authors.lastname: Namane
authors.forename: P
authors.initials: P
authors.lastname: Pescher
authors.forename: M
authors.initials: M
authors.lastname: Rivière
authors.forename: F
authors.initials: F
authors.lastname: Romain
authors.forename: G
authors.initials: G
authors.lastname: Puzo
authors.forename: O
authors.initials: O
authors.lastname: Bârzu
authors.forename: G
authors.initials: G
authors.lastname: Marchal
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000942:Antigens, Bacterial / Q000235:genetics / Q000494:pharmacology*; D001426:Bacterial Proteins / Q000235:genetics / Q000494:pharmacology*; D006023:Glycoproteins / Q000235:genetics / Q000494:pharmacology*; D006031:Glycosylation; D006168:Guinea Pigs; D006968:Hypersensitivity, Delayed; D008213:Lymphocyte Activation / Q000187:drug effects; D008358:Mannose / Q000378:metabolism*; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009169:Mycobacterium tuberculosis; D011994:Recombinant Proteins / Q000494:pharmacology; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013601:T-Lymphocytes / Q000187:drug effects / Q000276:immunology*
chemical_list: C095715:45-47 kDa antigen complex, Mycobacterium; D000942:Antigens, Bacterial; D001426:Bacterial Proteins; D006023:Glycoproteins; D011994:Recombinant Proteins; D008358:Mannose