Proteomic and immunoblot analyses of Bartonella quintana total membrane proteins identify antigens recognized by sera from infected patients.
Bartonella quintana is a fastidious, gram-negative, rod-shaped bacterium that causes prolonged bacteremia in immunocompetent humans and severe infections in immunocompromised individuals. We sought to define the outer membrane subproteome of B. quintana in order to obtain insight into the biology and pathogenesis of this emerging pathogen and to identify the predominant B. quintana antigens targeted by the human immune system during infection. We isolated the total membrane proteins of B. quintana and identified 60 proteins by two-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis and peptide mass fingerprinting. Using the newly constructed proteome map, we then utilized two-dimensional immunoblotting with sera from 21 B. quintana-infected patients to identify 24 consistently recognized, immunoreactive B. quintana antigens that have potential relevance for pathogenesis and diagnosis. Among the outer membrane proteins, the variably expressed outer membrane protein adhesins (VompA and VompB), peptidyl-prolyl cis-trans-isomerase (PpI), and hemin-binding protein E (HbpE) were recognized most frequently by sera from patients, which is consistent with surface expression of these virulence factors during human infection.
Boonjakuakul
Jenni K
JK
Division of Infectious Diseases, 521 Parnassus Ave., Room C-443, University of California at San Francisco, San Francisco, CA 94143-0654, USA.
Gerns
Helen L
HL
Chen
Yu-Ting
YT
Hicks
Linda D
LD
Minnick
Michael F
MF
Dixon
Scott E
SE
Hall
Steven C
SC
Koehler
Jane E
JE
D000907:Antibodies, Bacterial / Q000276:immunology; D000942:Antigens, Bacterial / Q000276:immunology* / Q000378:metabolism; D001426:Bacterial Proteins / Q000276:immunology / Q000302:isolation & purification / Q000378:metabolism; D018413:Bartonella quintana / Q000276:immunology* / Q000378:metabolism; D015180:Electrophoresis, Gel, Two-Dimensional; D006801:Humans; D007106:Immune Sera / Q000276:immunology*; D015151:Immunoblotting / Q000379:methods*; D008565:Membrane Proteins / Q000276:immunology / Q000302:isolation & purification / Q000378:metabolism; D010449:Peptide Mapping; D020543:Proteome; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D014205:Trench Fever / Q000382:microbiology*
D000907:Antibodies, Bacterial; D000942:Antigens, Bacterial; D001426:Bacterial Proteins; D007106:Immune Sera; D008565:Membrane Proteins; D020543:Proteome