Evaluation of Recombinant Dense Granule Antigen 7 (GRA7) ofToxoplasma gondiifor Detection of Immunoglobulin G Antibodies and Analysis of a Major Antigenic Domain

• DOI: 10.1128/cdli.6.1.24-29.1999
• Publication Date: 2019-12-31T19:21:56Z
• Authors: Dirk Jacobs; Martine Vercammen; Eric Saman
• Keywords: 0301 basic medicine; Base Sequence; toxoplasma gondii; Recombinant Fusion Proteins; DNA, Recombinant; Protozoan Proteins; Antibodies, Monoclonal; Antibodies, Protozoan; Antigens, Protozoan; Enzyme-Linked Immunosorbent Assay; Sensitivity and Specificity; Peptide Fragments; 3. Good health; Epitopes; Mice; 03 medical and health sciences; Immunoglobulin M; Evaluation Studies as Topic; Immunoglobulin G; Animals; Humans; Toxoplasma; Toxoplasmosis

ABSTRACT Dense granule protein 7 (GRA7) of Toxoplasma gondii was expressed in Escherichia coli as a fusion protein. The leader peptide contained 25-amino-acid mouse tumor necrosis factor fragment and six histidyl residues. After purification by metal chelate affinity chromatography, the antigen evaluated an enzyme-linked immunosorbent assay for detection immunoglobulin G (IgG). For two sets IgG-positive human serum samples, obtained from routine screening, overall sensitivity 81% obtained. chronic-phase sera, 79%, but sera with low titers were more difficult to detect (65% immunofluorescence titer 1/64). When GRA7 combined Tg34AR (rhoptry 2 C-terminal fragment), rose 96%. set acute-phase samples tested on GRA7, 94%, high-titer IgM-positive detected at especially high rate. In contrast, when used, only 85% this latter samples. Three truncated fragments containing same that recombinant produced. shortest (97 N-terminal amino acids) not reactive or specific anti-GRA7 monoclonal antibody, while larger reactive. most important antigenic domain localized between residues 97 146. epitope antibody could be further narrowed down use synthetic peptides, is recognized T. -infected humans. These results indicate may considered additional tool studying immune response .