Evaluation of IgG₄ response in ascariasis by ELISA for serodiagnosis

Abstract

The excretory/secretory (ES) antigen(s) of Ascaris lumbricoides was fractionated into i o fractions by gel chromatography on a Suparose 12 column in FPLC. Of these, the third fraction (A1 111), showing binding activity with both IgE and IgG antibodies of A. lumbricoides infected patients' sera, was further resolved into z fractions (A1 Illa and A1 IIIb) on passage through a Mono Q column. A1 IIIb was found to be the most potent antigen due to its high binding affinity with IgE and IgG antibodies o f Ascaris infected patients as evidenced by ELISA inhibition. Although a two to five-fold increase of serum IgE level was ohserved in all helminthic parasite infected patients studied compared to control subjects, Al IIIb specific IgE was detected in sera of all Ascaris infected and only 40%) o f hookworm infected patients. When Al IIIb was tested by ELISA with sera of control subjects, Ascaris, hookworm, Strongyloides and Trichuris infected patients, strong binding was observed with the IgE and also IgG of all the Ascaris infected patients; however, it crossreacted with IgG in 50% of hookworm, 28.6% of Trichuris trichura and 22.2% of Strongyloides infected patients' sera; but with IgE only in 40% of hookworm infected patients' sera. Further study showed specific detection of IgG, in all the serum samples o f 6 s Ascaris infected patients when Al IIlb antigen was allowed to react with different subclasses of IgG by ELISA, giving a sensitivity of 100%. Reacrivities of A1 Illb with IgG, and IgG3 were only 47.6 and r r . 8 % respectively and there was no reactivity with lgCL subclass. No IgG, reactivity against A1 IIIb was observed in the sera of hookworm, Trichuris or Strongyloides infected patients and was similar to that observed with control subjects showing the 100% specificity of the test system. This study may therefore be regarded as a novel technique for serodiagnosis of ascariasis by measuring Ascaris specific IgG,.

Patterns and Risk Factors of Helminthiasis and Anemia in a Rural and a Peri-urban Community in Zanzibar, in the Context of Helminth Control Programs

“…First, whilst the prevalences and intensity of helminth infections have significantly decreased as a result of large-scale deworming programs in Zanzibar [21], antibodies from past infections can persist for a prolonged period of time after successful treatment, and hence be detected with ELISA [62], [63]. Second, it is known that unspecific cross-reactions (e.g., from antibodies against antigen from Ascaris or filarial worms) can occur [64], [65]. Third, widely used parasitological techniques such as the K-K thick smear lack sensitivity for detecting low-intensity helminth infections [30], [66].…”

Community Rates of IgG4 Antibodies to Ascaris Haemoglobin Reflect Changes in Community Egg Loads Following Mass Drug Administration

“…Previous serological experiments performed by Santra et al, 2001 [ 13 ] and Chatterjee et al, 1996 [ 14 ] showed that human IgG4 responses to a fractionated adult E/S antigen of Ascaris were superior in reactivity and also showed less cross reactivity than IgG1, IgG2 and IgG3 subclass antibodies in sera from patients infected with hookworm, Trichuris and Strongyloides . This, in combination with the results from earlier experiments performed in the lab, led to the decision to use the IgG4 subclass antibody as detecting antibody in the immunological assays described in this study.…”

Characterization of the Humoral Immune Response against Gnathostoma binucleatum in Patients Clinically Diagnosed with Gnathostomiasis

“…The IgG subclasses have been shown to provide improved specificity over the total IgG antibody array for the diagnosis of many parasitic infections, such as ascariasis, 16 echinococcosis, 17 leishmaniasis, 18 filariasis, 19,20 and gnathostomiasis caused by species of Gnathostoma other than G. binucleatum. 21,22 Therefore, the purpose of this study was to characterize the humoral immune response to a crude extract of G. binucleatum in patients with clinical diagnoses of gnathostomiasis to detect a possible antibody class or subclass that could be used in the diagnosis of gnathostomiasis.…”