Identification and nucleotide sequence ofBrucella melitensisL7/L12 ribosomal protein

Abstract

DNA sequencing of the gene encoding a Brucella melitensis 12-kDa protein revealed that this protein was the ribosomal protein L7/L12. The B. melitensis L7/L12 DNA sequence was identical to that of the corresponding B. abortus gene, showing the near identity of these two organisms. When comparing the sequence of this protein to that of other organisms some domains were highly conserved, especially the C-terminus, which contrasted with the lack of conservation of the sequences at the N-terminus. The finding that the ribosomal protein L7/L12 of Brucella is an immunodominant antigen provides a new rationale to explain the activity of ribosomal vaccines.

Identification of immunoreactive proteins ofChlamydia trachomatis by Western blot analysis of a two-dimensional electrophoresis map with patient sera

“…Therefore the scenario which postulates a role for immunological sensitization mechanisms in chlamydial pathology, as described for the hsp60 GroEL-like antigen [4,5] could in fact be extended to include several other common bacterial antigens, which are immunogenic in other bacterial infections. For instance the protein elongation factor EF-Tu is immunogenic during the acute phase of infection with Haemophilus influenzae (Marzocchi et al, unpublished), and both L7/L12 and the HtrA stress-induced protease homologs are immunogenic in Brucella infections [27,28]. In the case of EF-Tu, the abundance of this protein in the bacterial cell may favor its ªvisibilityº by the immune system; however, note that EF-Tu has been described as associated to outer membrane and periplasmic cell fractions [29], and recent data suggest that EF-Tu, in addition to its function in peptide elongation, also has a chaperone activity implicated protection from stress [30].…”

“…In Brucella melitensis infections, L7/L12 induces a DTH cell-mediated response [27], and vaccination of BALB/c mice with L7/L12 was shown to protect against infection by Brucella abortus [31]. Similarly, recombinant HtrA from H. influenzae was found to be very immunogenic and partially protective in both the passive infant rat model of bacteriemia and the active chinchilla model of otitis media [32] and is being considered as a candidate antigen for a vaccine against invasive H. influenzae type b.…”

The application of proteomics in defining the T cell antigens ofMycobacterium tuberculosis

“…Of note is RplL (Rv0652), a putative 50S ribosomal protein. The Brucella melitensis homologue of this protein has been shown to be a major delayed-type hypersensitivity antigen useful in diagnosis of brucellosis [34]. However, the T cell reactivity of the B. melitensis RplL homologue is dependent on post-translational modification of the protein.…”