Disease relevance of Ehrlichiosis

• Major surface protein 2 (MSP2) is an immunodominant outer membrane protein of Anaplasma marginale and Anaplasma phagocytophilum pathogens that cause bovine anaplasmosis and human granulocytic ehrlichiosis, respectively [1].
• Sera from 35 patients diagnosed with human granulocytic ehrlichiosis in Connecticut were tested by indirect IFA staining methods with 5 strains of Ehrlichia equi or the human granulocytic ehrlichiosis agent to assess the suitability of different strains in laboratory analyses [2].
• The early antibody response in patients with human granulocytic ehrlichiosis (HGE) and in mice infected with the HGE agent was characterized by using sera to probe lysates of HL-60 cells infected with HGE organisms [3].
• As the first report of gram-negative bacteria incorporating cholesterol for survival, these findings offer insight into the unique nature of their parasitism and imply that cholesterol is important in the control of human ehrlichioses [4].
• 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%) [5].

High impact information on Ehrlichiosis

• Intracellular parasitism by the human granulocytic ehrlichiosis bacterium through the P-selectin ligand, PSGL-1 [6].
• Leukocyte infection by the granulocytic ehrlichiosis agent is linked to expression of a selectin ligand [7].
• Human ehrlichiosis in adults after tick exposure. Diagnosis using polymerase chain reaction [8].
• Immunopathology and ehrlichial propagation are regulated by interferon-gamma and interleukin-10 in a murine model of human granulocytic ehrlichiosis [9].
• Multiple p44 genes encoding major outer membrane proteins are expressed in the human granulocytic ehrlichiosis agent [10].

Chemical compound and disease context of Ehrlichiosis

• These observations are consistent with the finding that human ehrlichiosis appears to respond to tetracycline therapy, which has been the therapy of first choice [11].
• Taken together, these results suggest that human ehrlichiosis agents became cholesterol dependent due to the loss of these genes [4].
• Human ehrlichiosis appears to be tickborne and is prevalent primarily in the southern Atlantic and south-central states [12].
• Conserved serine-rich motifs identified in the repeat units of P120 and P140 were also found in the repeat units of the human granulocytotropic ehrlichiosis agent 130-kDa protein and of the fimbria-associated adhesin protein Fap1 of Streptococcus parasanguis [13].
• Therapeutic effect of doxycycline in experimental subclinical canine monocytic ehrlichiosis: evaluation of a 6-week course [14].

Biological context of Ehrlichiosis

• Immunodominant 44 kDa major outer membrane proteins of Anaplasma phagocytophila (human granulocytic ehrlichiosis agent) are encoded by the p44 multigene family [15].
• The assay amplifies the 16S rRNA gene and was used to examine acute-phase EDTA-blood and serum samples obtained from seven humans with clinical presentations compatible with human granulocytic ehrlichiosis [16].
• Knowledge of characteristic complete blood count patterns that occur during active ehrlichiosis may help clinicians to identify patients who should be evaluated specifically for ehrlichiosis and who should receive empiric antibiotic treatment with doxycycline [17].
• A gene that is homologous to the Ehrlichia chaffeensis groEL operon was recovered and characterized by broad-range PCR amplification of whole blood from patients with human granulocytic ehrlichiosis (HGE) and from infected HL60 cell cultures [18].
• The purpose of this work was to study the association of positive serological titers to Ehrlichia risticii, the causative agent of equine monocytic ehrlichiosis (EME) with gastro-intestinal disorders in hospitalized horses referred to The Ohio State University College of Veterinary Medicine Teaching Hospital (OSU VMTH) [19].

Anatomical context of Ehrlichiosis

• Second, severe and fatal murine ehrlichiosis in immunocompetent animals, which mimics human disease, is associated with a low bacterial burden in different organs and late systemic and local overproduction of TNF-alpha by T cells [20].

Gene context of Ehrlichiosis

• Our data suggest that fatal ehrlichiosis could be a multistep process, where TNF-alpha is not solely responsible for mortality [21].
• The cytokine response to the agent of human granulocytic ehrlichiosis (HGE) was assessed in a murine infection model and the role of gamma interferon (IFN-gamma), a cytokine that is crucial for host defenses against intracellular pathogens, was investigated by using IFN-gamma-deficient mice [22].
• Ehrlichia chaffeensis and E. sennetsu, but not the human granulocytic ehrlichiosis agent, colocalize with transferrin receptor and up-regulate transferrin receptor mRNA by activating iron-responsive protein 1 [23].
• The objectives of this study were (i) to determine if MAP2 is conserved among five geographically divergent strains of C. ruminantium and (ii) to determine if MAP2 homologs are present in Ehrlichia canis, the causative agent of canine ehrlichiosis, and Ehrlichia chaffeensis, the organism responsible for human monocytic ehrlichiosis [24].
• Antibodies in the sera of patients with human granulocytic ehrlichiosis (HGE) commonly recognize a 44-kDa antigen [25].

Analytical, diagnostic and therapeutic context of Ehrlichiosis

• These results indicate that the recombinant p120 is a potential antigen for the serodiagnosis of canine ehrlichiosis [26].
• Western blot analysis of sera reactive to human monocytic ehrlichiosis and human granulocytic ehrlichiosis agents [27].
• Protein immunoblotting demonstrated that the recombinant E. canis p120 reacted with convalescent sera from dogs with canine ehrlichiosis [26].
• Tissue diagnosis of Ehrlichia chaffeensis in patients with fatal ehrlichiosis by use of immunohistochemistry, in situ hybridization, and polymerase chain reaction [28].
• Validation of chemoprevention of canine monocytic ehrlichiosis with doxycycline [29].

References