title: Interferon-Gamma Release Assay: An Effective Tool to Detect Early Toxoplasma gondii Infection in Mice.
abstract: Early diagnosis of Toxoplasma gondii infection before the formation of tissue cysts is vital for treatment, as drugs available for toxoplasmosis cannot kill bradyzoites contained in the cysts. However, current methods, such as antibody-based ELISA, are ineffective for detection of early infection. Here, we developed an interferon-gamma release assay (IGRA), measuring the IFN-γ released by T lymphocytes stimulated by Toxoplasma antigen peptides in vitro, for the detection of T. gondii infection in mice. Splenocytes isolated from infected mice were stimulated by peptides derived from dense granule proteins GRA4 and GRA6 and rhoptry protein ROP7, and released IFN-γ was measured by ELISA. Results showed that both acute and chronic infection could be detected by IGRA. More importantly, IGRA detected infection as early as the third day post infection; while serum IgM and IgG were detected 9 days and 13 days post infection, respectively. Our findings demonstrated that an IGRA-positive and ELISA-negative sample revealed an early infection, indicating the combination of IGRA and ELISA can be employed for the early diagnosis of T. gondii infection in human beings, cats and livestock.
authors.affiliation: State Key Laboratory for Agrobiotechnology, China Agricultural University, Beijing, 100193, China; National Animal Protozoa Laboratory & College of Veterinary Medicine, China Agricultural University, Beijing, 100193, China.
authors.forename: Qing
authors.initials: Q
authors.lastname: Yin
authors.affiliation: State Key Laboratory for Agrobiotechnology, China Agricultural University, Beijing, 100193, China; National Animal Protozoa Laboratory & College of Veterinary Medicine, China Agricultural University, Beijing, 100193, China; Faculty of Science, Kafr El-Sheikh University, Kafr El-Sheikh, Egypt.
authors.forename: Saeed
authors.initials: S
authors.lastname: El-Ashram
authors.affiliation: Department of Pharmacology, Hebei North University, Zhangjiakou, 075000, China.
authors.forename: Hongbin
authors.initials: H
authors.lastname: Liu
authors.affiliation: Department of Parasitology, Capital Medical University, Beijing, 100069, China.
authors.forename: Ximeng
authors.initials: X
authors.lastname: Sun
authors.affiliation: State Key Laboratory for Agrobiotechnology, China Agricultural University, Beijing, 100193, China; National Animal Protozoa Laboratory & College of Veterinary Medicine, China Agricultural University, Beijing, 100193, China.
authors.forename: Xinxin
authors.initials: X
authors.lastname: Zhao
authors.affiliation: State Key Laboratory for Agrobiotechnology, China Agricultural University, Beijing, 100193, China; National Animal Protozoa Laboratory & College of Veterinary Medicine, China Agricultural University, Beijing, 100193, China.
authors.forename: Xianyong
authors.initials: X
authors.lastname: Liu
authors.affiliation: State Key Laboratory for Agrobiotechnology, China Agricultural University, Beijing, 100193, China; National Animal Protozoa Laboratory & College of Veterinary Medicine, China Agricultural University, Beijing, 100193, China; Key Laboratory of Animal Epidemiology and Zoonosis of Ministry of Agriculture, Beijing, 100193, China.
authors.forename: Xun
authors.initials: X
authors.lastname: Suo
mesh_terms: D000818:Animals; D000913:Antibodies, Protozoan / Q000097:blood*; D000953:Antigens, Protozoan / Q000276:immunology*; D002415:Cats; D002478:Cells, Cultured; D042241:Early Diagnosis; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood; D007075:Immunoglobulin M / Q000097:blood; D007371:Interferon-gamma / Q000032:analysis* / Q000276:immunology; D059425:Interferon-gamma Release Tests / Q000379:methods*; D058751:Livestock; D051379:Mice; D008807:Mice, Inbred BALB C; D015800:Protozoan Proteins / Q000276:immunology; D013154:Spleen / Q000166:cytology / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology; D014122:Toxoplasma / Q000302:isolation & purification; D014124:Toxoplasmosis, Animal / Q000175:diagnosis*
chemical_list: D000913:Antibodies, Protozoan; D000953:Antigens, Protozoan; C079248:GRA4 protein, Toxoplasma gondii; C095047:GRA6 protein, Toxoplasma gondii; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D015800:Protozoan Proteins; D007371:Interferon-gamma