Detection of Q Fever Specific Antibodies Using Recombinant Antigen in ELISA with Peroxidase Based Signal Amplification

Abstract

Currently, the accepted method for Q fever serodiagnosis is indirect immunofluorescent antibody assay (IFA) using the whole cell antigen. In this study, we prepared the recombinant antigen of the 27-kDa outer membrane protein (Com1) which has been shown to be recognized by Q fever patient sera. The performance of recombinant Com1 was evaluated in ELISA by IFA confirmed serum samples. Due to the low titers of IgG and IgM in Q fever patients, the standard ELISA signals were further amplified by using biotinylated anti-human IgG or IgM plus streptavidin-HRP polymer. The modified ELISA can detect 88% (29 out of 33) of Q fever patient sera collected from Marines deployed to Iraq. Less than 5% (5 out of 156) of the sera from patients with other febrile diseases reacted with the Com1. These results suggest that the modified ELISA using Com1 may have the potential to improve the detection of Q fever specific antibodies.

Com1 as a Promising Protein for the Differential Diagnosis of the Two Forms of Q Fever

“…Zhang and coworkers utilized Com1 and proposed that an ELISA with the 27-kDa recombinant antigen is sensitive and specific enough to detect antibodies against the pathogen in human sera [18]. In an additional study carried out by Chen et al (2014) [19], the authors evaluated the ability of the protein to detect the pathogen's antibodies in an ELISA with peroxidase-based signal amplification [19].…”

Development of loop-mediated isothermal amplification assays for rapid and easy detection of Coxiella Burnetii

“…It requires specially trained staff and has to be performed in a BSL-3 laboratory, confining C. burnetii culture to a limited number of laboratories. The current diagnosis of Q fever relies mainly on serological methods such as indirect immunofluorescent antibody assay (IFA) and ELISA (Chen et al, 2014). However, IFA or ELISA is not suitable for early diagnosis because high levels of antibody appear late in the disease.…”

An Observational Study of Sepsis in Takeo Province Cambodia: An in-depth examination of pathogens causing severe infections

“…japonica ) [ 25 ], evidence of murine typhus was detected via antibodies to purified whole cell antigens from R . typhi using ELISA [ 26 ], Leptospirosis was also detected by ELISA using four recombinant proteins (LipL32, LipL41, LigA and LigB) from the pathogenic strain of Leptospira interrogans [ 27 , 28 ], and ELISAs for evidence of Coxiella burnetii infection (causative agent of Q fever) employed a recombinant protein from a pathogenic strain (Henzerling) [ 29 ]. In all cases of laboratory-developed assays, cutoff values were derived from negative controls originating from neighboring Thailand that were previously confirmed to be antibody-negative as previously described [ 25 , 29 – 31 ].…”

“…Serological evidence of infection with Orientia tsutsugamushi was detected using an ELISA utilizing three recombinant proteins from four strains of O. tsutsugamushi (Karp, Kato, Gilliam and TA763) [25]. Spotted fever group rickettsia antibodies were detected by ELISA utilizing purified whole cell antigens from three species (R. conorii, R. siberica and R. japonica) [25], evidence of murine typhus was detected via antibodies to purified whole cell antigens from R. typhi using ELISA [26], Leptospirosis was also detected by ELISA using four recombinant proteins (LipL32, LipL41, LigA and LigB) from the pathogenic strain of Leptospira interrogans [27,28], and ELI-SAs for evidence of Coxiella burnetii infection (causative agent of Q fever) employed a recombinant protein from a pathogenic strain (Henzerling) [29]. In all cases of laboratory-developed assays, cutoff values were derived from negative controls originating from neighboring Thailand that were previously confirmed to be antibody-negative as previously described [25,[29][30][31].…”

“…For instance, the association of positive leptospirosis serology with culture-confirmed B. pseudomallei infection may reflect a common water source as a well-characterized risk factor for both. To improve accuracy, we followed CDC diagnostic guidelines for serum-only diagnoses and utilized recombinant antigens with no known cross-reactivity to other organisms [25,27,29]. Because background seropositivity for many pathogens we tested (spotted fever group rickettsia and Leptospira spp., for example) is high in this area, we applied high cutoff values and rigorous standards for our serum-only diagnoses.…”