Immunologic response of patients with legionellosis against major protein-containing antigens of Legionella pneumophila serogroup 1 as shown by immunoblot analysis

Abstract

Major protein-containing antigens of Legionella pneumophila serogroup 1 were identified by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblot analysis with rabbit antisera to 14 different Legionella species or serogroups. Fourteen bands were observed in immunoelectropherograms of whole-cell, sonicated cell, and heated cell preparations, seven of which appeared in the supernatant fluid from the heated cells and three of which were shown in an outer membrane fraction. Immunoblots of whole-cell antigen preparations of 14 Legionella species or serogroups revealed seven major Legionella proteins: antigens with molecular weights of 58,000, 79,000, and 154,000 were present in all Legionella sp. strains, antigens with molecular weights of 44,000 and 97,000 occurred in multiple species, and antigens with molecular weights of 14,000 and 25,000 were present only in L. pneumophila strains. All sera from 15 patients with cultureconfirmed L. pneumophila serogroup 1 disease and 14 of 18 (78%) sera from serologicaily diagnosed patients reacted with the 58-kilodalton (kDa) common antigen. In contrast, less than one-half of the sera reacted with the L. pneumophia-specific proteins (14 and 25 kDa). Absorption of sera with Escherichia coli cells had no effect on their reactivity with the 58-kDa antigen, whereas absorption with L. pneumophila serogroup 1 cells removed reactivity. These data suggest that the 58-kDa antigen may prove useful in serodiagnostic tests for legionellosis.

Immunoblot studies in the differential diagnosis of porcine brucellosis: an immunodominant 62 kDa protein is related to the mycobacterial 65 kDa heat shock protein (HSP-65)

“…The experiment reported here with monoclonals to the M. leprae HSP-65 demonstrates that the 62 kDa protein is the Brucella homologue of the mycobacterial antigen. This family of proteins is immunodominant in infections due to Mycobacteria (Thole and Van der Zee, 1990) and Legionella (Sampson et al, 1986;Plikaytis et al, 1987) and the results reported here confirm its immunodominance in porcine brucellosis. In addition, this group of proteins is known to be cross-reactive, demonstrating sequence homology and serological cross-reactions with a wide range of prokaryotic and eukaryotic organisms (Hoiby, 1975;Shinnick et al, 1988;Thole et al, 1988;Waldinger et al, 1988;Sampson et al, 1990).…”

Nucleotide sequence of htpB, the Legionella pneumophila gene encoding the 58-kilodalton (kDa) common antigen, formerly designated the 60-kDa common antigen

“…The deduced amino acid sequence was 547 amino acids long with a computed molecular mass of 57,952 daltons. This compares favorably with the previously reported molecular masses of 58 and 60 kDa (determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis [19,20]) and 63 kDa (chromatographically determined [18]). Hydrophobicity analysis as described by Hopp and Woods (12) revealed no significant areas of hydrophobicity within the sequence.…”

“…In an earlier study, we identified a genus-wide 58-kilodalton (kDa) protein in Legionella pneumophila which reacted with convalescent-phase sera from culture-positive patients with active L. pneumophila infections (20). Data reported here suggest that the molecular mass of this protein is 58 kDa, not 60 kDa as previously reported (19).…”

Cloning and sequencing of the genes coding for the 10- and 60-kDa heat shock proteins from Pseudomonas aeruginosa and mapping of a species-specific epitope

“…The hsp60 family comprises highly immunodominant molecules which have been found to represent the major stress protein antigen recognized by antibodies in bacterial infections (37). In a study of the 58-kDa common antigen of L. pneumophila, this antigen was found to be the only antigen which was recognized by all sera from patients with cultureconfirmed legionellosis (25). All of these findings suggest that species-specific hsp60 epitopes may be prime candidates for the development of serological tests.…”