Recombinant protein-44-based class-specific enzyme-linked immunosorbent assays for serologic diagnosis of human granulocytic ehrlichiosis.
Recombinant protein 44, expressed and purified as a maltose-binding protein fusion peptide of the human granulocytic ehrlichiosis (HGE) agent (Ehrlichia phagocytophila genogroup), was used as antigen in enzyme-linked immunosorbent assays (ELISAs) to detect total antibodies, immunoglobulin (Ig) M antibodies, and IgG antibodies. Of the 67 human sera obtained from 64 HGE patients 3-5 weeks after the onset of illness and confirmed as having total immunoglobulins to whole-cell antigen by indirect fluorescent antibody analyses, 63 were positive in a polyvalent ELISA. Fifty-six and 61 sera had IgM or IgG antibodies, respectively. Fifty sera had both IgM and IgG antibodies. In specificity tests of 110 sera, one serum sample from a patient who had Lyme borreliosis reacted to the protein 44 antigen in the analysis for IgM antibody (specificity, 99%). There were no false-positive results in an ELISA for IgG antibodies. With their high sensitivity and specificity, class-specific ELISAs can be used in conjunction with indirect fluorescent antibody analyses or immunoblotting methods to help diagnose human granulocytic ehrlichiosis.
Magnarelli
L
L
Department of Entomology, Connecticut Agricultural Experiment Station, New Haven 06504, USA. louis.magnarelli@po.state.ct.us
Ijdo
J
J
Wu
C
C
Fikrig
E
E
D000907:Antibodies, Bacterial / Q000097:blood*; D001426:Bacterial Proteins / Q000097:blood / Q000276:immunology; D015153:Blotting, Western; D004536:Ehrlichia / Q000302:isolation & purification*; D016873:Ehrlichiosis / Q000097:blood / Q000175:diagnosis*; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods*; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood / Q000276:immunology; D007075:Immunoglobulin M / Q000097:blood / Q000276:immunology; D008297:Male; D011336:Probability; D011446:Prospective Studies; D011993:Recombinant Fusion Proteins / Q000097:blood / Q000276:immunology; D012680:Sensitivity and Specificity; D012698:Serologic Tests / Q000379:methods
D000907:Antibodies, Bacterial; D001426:Bacterial Proteins; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D011993:Recombinant Fusion Proteins