Evaluation of a di‐ O ‐methylated glycan as a potential antigenic target for the serodiagnosis of human toxocariasis

Summary Serodiagnosis of human toxocariasis is based on the detection of specific IgG antibodies by the enzyme‐linked immunosorbent assay ( ELISA ) using Toxocara larvae excretory–secretory ( TES ) antigens, but its production is a laborious and time‐consuming process being also limited by the availability of adult females of T. canis as source for ova to obtain larvae. Chemical synthesis of the di‐ O ‐methylated (DiM) glycan structure found in the TES antigens has provided material for studying the antibody reactivity in a range of mammalian hosts, showing reactivity with human IgM and IgG. In this study, we have evaluated the performance of the DiM glycan against a panel of sera including patients with toxocariasis ( n  = 60), patients with other helminth infections ( n  = 75) and healthy individuals ( n  = 94), showing that DiM is able to detect IgG antibodies with a sensitivity and specificity of 91·7% and 94·7%, respectively, with a very good agreement with the TES antigens (kappa = 0·825). However, cross‐reactivity was observed in some sera from patients with ascariasis, hymenolepiasis and fascioliasis. These results show that the DiM glycan could be a promising antigenic tool for the serodiagnosis of human toxocariasis.