scholarly journals Comparison of major antigenic proteins of six strains of the human granulocytic ehrlichiosis agent by Western immunoblot analysis.

1997 ◽  
Vol 35 (10) ◽  
pp. 2606-2611 ◽  
Author(s):  
N Zhi ◽  
Y Rikihisa ◽  
H Y Kim ◽  
G P Wormser ◽  
H W Horowitz
1998 ◽  
Vol 36 (6) ◽  
pp. 1666-1673 ◽  
Author(s):  
N. Zhi ◽  
N. Ohashi ◽  
Y. Rikihisa ◽  
H. W. Horowitz ◽  
G. P. Wormser ◽  
...  

A 44-kDa major outer membrane protein of the human granulocytic ehrlichiosis (HGE) agent is an immunodominant antigen in human infection. A gene encoding this protein was cloned and sequenced. Southern blot results revealed the existence of multigenes homologous to the P44 gene in the genome of the HGE agent. The recombinant 44-kDa protein (rP44) was expressed by using expression vector pET30a. The reactivity of the affinity-purified rP44 was evaluated by Western immunoblot analysis and dot blot immunoassay. Western immunoblot analysis showed that mouse anti-rP44 serum reacted with 44- to 42-kDa proteins in six different HGE agent strains tested except strain 2, in which three proteins of 42, 40, and 38 kDa were recognized. Eleven HGE patient serum samples, a horse anti-HGE serum, and a horse anti-Ehrlichia equi serum recognized the rP44 protein. This suggests that rP44 is an HGE-E. equi group-specific antigen. Neither human anti-Ehrlichia chaffeensis serum nor rabbit anti-Borrelia burgdorferi serum reacted with rP44. Sera from two patients coinfected with the HGE agent and B. burgdorferi reacted positively with rP44 and the HGE agent. Sera from 20 HGE patients with indirect fluorescent-antibody (IFA) titers ranging from 1:20 to 1:2,560 gave distinct positive reactions in a dot immunoblot assay. There was a positive correlation between the color densities of the dot reactions and the IFA titers when greater than 50 ng of recombinant antigen per dot was used. The use of the affinity-purified rP44 protein as antigen would provide a more specific, consistent, and simpler serodiagnosis for HGE than the use of whole infected cells or purified HGE agents.


1993 ◽  
Vol 122 (4) ◽  
pp. 877-886 ◽  
Author(s):  
JD Harper ◽  
MA Sanders ◽  
JL Salisbury

The antiphosphoprotein monoclonal antibody MPM-2 was used to investigate protein phosphorylation during flagellar regeneration in Chlamydomonas reinhardtii. MPM-2 recognizes a phosphorylated epitope and detects several Chlamydomonas proteins by Western immunoblot analysis. Two MPM-2 reactive proteins (34 and 90 kD) increase in Western immunoblot intensity after flagellar excision and decrease in intensity during flagellar regeneration. Immunofluorescence and immunogold labeling revealed MPM-2 staining within the nucleus, especially towards the nuclear periphery, the flagellar basal apparatus, and the nucleus-basal body connector after flagellar excision. Comparison of MPM-2 reactivity in wild-type cells and in the mutant bald-2, which lacks functional basal bodies, demonstrates that the 34-kD protein is localized in the nucleus and the 90-kD protein is localized in the flagellar basal region. MPM-2 reactivity is observed in cells competent for flagellar regeneration. However, when cells were treated with the kinase inhibitor, staurosporine, MPM-2 reactivity did not increase after flagellar excision and flagellar regeneration was impaired. These observations suggest that phosphorylation of the 34- and 90-kD proteins may be important for flagellar regrowth. Possible roles for phosphorylation in flagellar regeneration include transcriptional activation and transport of flagellar precursors to the base of the growing flagella.


2003 ◽  
Vol 15 (4) ◽  
pp. 349-354 ◽  
Author(s):  
Edward B. Breitschwerdt ◽  
Jiraporn Suksawat ◽  
Bruno Chomel ◽  
Barbara C. Hegarty

Bartonella vinsonii subspecies berkhoffii is a recently recognized zoonotic pathogen that causes endocarditis, granulomatous rhinitis, and granulomatous lymphadenitis in dogs. Isolation of B. vinsonii ( berkhoffii) from blood or tissue samples is frequently unsuccessful; therefore, diagnosis is primarily dependent on serologic or molecular testing modalities. Because previous canine serologic studies have used an indirect immunofluorescence assay (IFA), without Western immunoblot (WI) confirmation, the overall objective of this study was to examine the diagnostic use of WI for confirmation of B. vinsonii ( berkhoffii) infection in dogs. To confirm that agar-grown and cell culture–grown organisms yielded similar patterns of WI antigenic protein recognition, the 2 preparations were compared using IFA-reactive sera obtained from dogs experimentally infected with B. vinsonii ( berkhoffii). Temporal changes in the pattern of antigenic protein recognition were characterized using sera obtained from dogs at various time points after experimental B. vinsonii ( berkhoffii) infection. The specificity of B. vinsonii ( berkhoffii) WI was examined by testing canine sera that were reactive to B. henselae, B. clarridgeiae, Ehrlichia canis, Rickettsia rickettsii, Babesia canis, Anaplasma phagocytophilum (previously E. equi), or Brucella canis antigens. Clinical accessions including serum samples obtained from B. vinsonii ( berkhoffii) culture–positive dogs and B. vinsonii ( berkhoffii) culture–negative dogs that were IFA seroreactive to B. vinsonii ( berkhoffii) antigens were examined by WI. The results of this study indicate that WI using agar-grown or cell culture–grown B. vinsonii ( berkhoffii) antigens produce identical patterns of antigenic protein recognition. After experimental infection, there is a progressive increase in the number of antigenic proteins that are recognized by WI, with the 33-kD antigen representing the first and the most persistent antigen recognized by B. vinsonii ( berkhoffii)–infected dogs. Regarding specificity, sera from dogs that were reactive to various heterologous antigens did not recognize B. vinsonii ( berkhoffii) antigens by IFA or WI, and sera from dogs experimentally infected with B. henselae did not recognize B. vinsonii ( berkhoffii) antigens by WI. Regarding clinical accessions, there was good agreement between B. vinsonii ( berkhoffii) IFA test results and WI analysis. Western immunoblot analysis can be used to detect or confirm exposure to B. vinsonii ( berkhoffii) in dogs.


1999 ◽  
Vol 37 (11) ◽  
pp. 3540-3544 ◽  
Author(s):  
Jacob W. Ijdo ◽  
Caiyun Wu ◽  
Louis A. Magnarelli ◽  
Erol Fikrig

Current antibody testing for human granulocytic ehrlichiosis relies predominantly on indirect fluorescent-antibody assays and immunoblot analysis. Shortcomings of these techniques include high cost and variability of test results associated with the use of different strains of antigens derived from either horses or cultured HL-60 cells. We used recombinant protein HGE-44, expressed and purified as a maltose-binding protein (MBP) fusion peptide, as an antigen in a polyvalent enzyme-linked immunosorbent assay (ELISA). Fifty-five normal serum samples from healthy humans served as a reference to establish cutoff levels. Thirty-three of 38 HGE patient serum samples (87%), previously confirmed by positive whole-cell immunoblotting, reacted positively in the recombinant ELISA. In specificity analyses, serum samples from patients with Lyme disease, syphilis, rheumatoid arthritis, and human monocytic ehrlichiosis (HME) did not react with HGE-44–MBP antigen, except for one sample (specificity, 98%). We conclude that recombinant HGE-44 antigen is a suitable antigen in an ELISA for the laboratory diagnosis and epidemiological study of HGE.


1998 ◽  
Vol 5 (1) ◽  
pp. 118-120 ◽  
Author(s):  
Jacob W. Ijdo ◽  
Yan Zhang ◽  
Matthew L. Anderson ◽  
David Goldberg ◽  
Erol Fikrig

ABSTRACT We describe a patient with human granulocytic ehrlichiosis (HGE), a diagnosis confirmed by PCR and immunoblot analysis. Unexpectedly, immunoglobulin G (IgG) directed towards an 80-kDa ehrlichial antigen (without detectable IgM) was present in the patient’s serum in the first week of illness. Lyme disease immunoblots were reactive for IgG (but not IgM), a result indicative of prior exposure to the Lyme disease spirochete. Amino-terminal sequencing revealed that the 80-kDa ehrlichial antigen was an HSP-70 homolog similar to Borrelia burgdorferi HSP-70. We conclude that antibodies against B. burgdorferi HSP-70 may cross-react with the ehrlichial heat shock protein and that this possibility must be considered when serologic test results for HGE and Lyme disease are interpreted.


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