Development of a Luminex Bead Based Assay for Diagnosis of Toxocariasis Using Recombinant Antigens Tc-CTL-1 and Tc-TES-26.
The clinical spectrum of human disease caused by the roundworms Toxocara canis and Toxocara cati ranges from visceral and ocular larva migrans to covert toxocariasis. The parasite is not typically recovered in affected tissues, so detection of parasite-specific antibodies is usually necessary for establishing a diagnosis. The most reliable immunodiagnostic methods use the Toxocara excretory-secretory antigens (TES-Ag) in ELISA formats to detect Toxocara-specific antibodies. To eliminate the need for native parasite materials, we identified and purified immunodiagnostic antigens using 2D gel electrophoresis followed by electrospray ionization mass spectrometry. Three predominant immunoreactive proteins were found in the TES; all three had been previously described in the literature: Tc-CTL-1, Tc-TES-26, and Tc-MUC-3. We generated Escherichia coli expressed recombinant proteins for evaluation in Luminex based immunoassays. We were unable to produce a functional assay with the Tc-MUC-3 recombinant protein. Tc-CTL-1 and Tc-TES-26 were successfully coupled and tested using defined serum batteries. The use of both proteins together generated better results than if the proteins were used individually. The sensitivity and specificity of the assay for detecting visceral larval migrans using Tc-CTL-1 plus Tc-TES-26 was 99% and 94%, respectively; the sensitivity for detecting ocular larval migrans was 64%. The combined performance of the new assay was superior to the currently available EIA and could potentially be employed to replace current assays that rely on native TES-Ag.
Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America.
John P
JP
Anderson
Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America.
Lisa N
LN
Rascoe
Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America.
Keith
K
Levert
Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America.
Holly M
HM
Chastain
National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America.
Matthew S
MS
Reed
Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America.
Hilda N
HN
Rivera
Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America.
Isabel
I
McAuliffe
National School of Tropical Medicine, Baylor College of Medicine, Houston, Texas, United States of America.
Bin
B
Zhan
Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America.
Ryan E
RE
Wiegand
National School of Tropical Medicine, Baylor College of Medicine, Houston, Texas, United States of America.
Peter J
PJ
Hotez
Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America.
Patricia P
PP
Wilkins
National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America.
Jan
J
Pohl
Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America.
Sukwan
S
Handali
D000909:Antibodies, Helminth / Q000097:blood*; D000947:Antigens, Helminth / Q000235:genetics / Q000276:immunology* / Q000302:isolation & purification; D004926:Escherichia coli / Q000235:genetics; D015870:Gene Expression; D006801:Humans; D011994:Recombinant Proteins / Q000235:genetics / Q000276:immunology / Q000302:isolation & purification; D012680:Sensitivity and Specificity; D012698:Serologic Tests / Q000379:methods*; D014120:Toxocariasis / Q000175:diagnosis*
D000909:Antibodies, Helminth; D000947:Antigens, Helminth; D011994:Recombinant Proteins