Use of acute-stage-specific antigens of Toxoplasma gondii for serodiagnosis of acute toxoplasmosis.
Antisera to acetone-fixed tachyzoites were prepared by immunizing rabbits intravenously with the fixed organisms. Immunoblots in which purified immunoglobulin G (IgG) of the antisera was used recognized four antigens of a supernatant (after centrifugation at 10,000 x g for 30 min) fraction of sonicated tachyzoites. A purified toxoplasma antigen fraction, referred to as acute-stage-specific (AC) antigen, that contained mainly three antigens was obtained by affinity chromatography by using the purified IgG. One antigen had a molecular weight of approximately 52,000, and two antigens had molecular weights of approximately 6,000. An enzyme-linked immunosorbent assay (AC-ELISA) in which this purified antigen fraction, obtained by affinity chromatography, was used for detection of IgG antibody detected early acute infection in sera of patients with toxoplasmic lymphadenopathy. Ninety-two percent of sera obtained within 2 months after onset of lymphadenopathy were positive in the AC-ELISA, whereas only 9% of sera obtained later than 5 months after onset of the clinical illness were positive. The AC-ELISA appears highly sensitive and specific for diagnosis of acute toxoplasmosis.
Department of Immunology and Infectious Diseases, Palo Alto Medical Foundation, California 94301.
Y
Y
Suzuki
P
P
Thulliez
J S
JS
Remington
D000208:Acute Disease; D000209:Acute-Phase Proteins / Q000276:immunology*; D000818:Animals; D000913:Antibodies, Protozoan / Q000032:analysis*; D000953:Antigens, Protozoan / Q000302:isolation & purification; D002846:Chromatography, Affinity; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D007074:Immunoglobulin G / Q000032:analysis*; D011817:Rabbits; D012698:Serologic Tests; D014122:Toxoplasma / Q000276:immunology*; D014123:Toxoplasmosis / Q000175:diagnosis*
D000209:Acute-Phase Proteins; D000913:Antibodies, Protozoan; D000953:Antigens, Protozoan; D007074:Immunoglobulin G