Immunodiagnosis of Strongyloides stercoralis infection: a method for increasing the specificity of the indirect ELISA

Trans R Soc Trop Med Hyg. 1993 Mar-Apr;87(2):173-6. doi: 10.1016/0035-9203(93)90477-8.

Abstract

Indirect enzyme-linked immunosorbent assay (ELISA) allows sensitive detection of serum immunoglobulin (Ig) G against a soluble extract of Strongyloides stercoralis infective larvae. In this study, 40/40 (100%) human strongyloidiasis sera had high levels of anti-S. stercoralis IgG, but 30/40 (75%) filariasis sera, and 12/40 (30%) necatoriasis sera also had higher levels than control sera from UK residents. In attempts to increase the assay specificity by absorption of cross-reactive IgG, the effectiveness of pre-incubation of sera with extracts of different parasitic nematodes was investigated. One hour of incubation with 20 micrograms/ml aqueous extract of Onchocerca gutturosa absorbed cross-reactive IgG in most filariasis and necatoriasis sera, reducing the proportion with IgG levels above the positivity threshold by more than one-half. Preliminary results suggest that absorption with extracts of other filarial nematodes is equally effective, and that some of the cross-reactive IgG is directed against phosphorylcholine. Cross-reactive IgG in most necatoriasis sera was effectively absorbed with 20 micrograms/ml extract of Necator americanus. Cross-reactive IgG was not effectively absorbed with an extract of Ascaris lumbricoides. Absorption of cross-reactive IgG is an effective means of increasing the specificity of the indirect ELISA, for use in the immunodiagnosis and immuno-epidemiology of S. stercoralis infection.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Absorption
  • Animals
  • Antibodies, Helminth / analysis
  • Cross Reactions
  • Enzyme-Linked Immunosorbent Assay / methods
  • Humans
  • Immunoglobulin G / analysis
  • Nematoda / immunology
  • Sensitivity and Specificity
  • Strongyloides stercoralis* / immunology
  • Strongyloidiasis / diagnosis*

Substances

  • Antibodies, Helminth
  • Immunoglobulin G