Antigen of Setaria digitata: cross-reaction with surface antigens of Wuchereria bancrofti microfilariae and serum antibodies of W. bancrofti-infected subjects.

Extracts of Setaria digitata have been fractionated by DEAE-Sephadex A50 chromatography and the fractions obtained were used in the inhibition of indirect immunofluorescence of Wuchereria bancrofti microfilariae. The fractions were also tested by an enzyme-linked immunosorbent assay (ELISA) technique for reactivity against antibodies in the serum of patients with W. bancrofti infections. The results indicate that S. digitata contains several antigenic fractions that show cross-reactivity against filariasis sera; two of these fractions cross-reacted with surface antigens of W. bancrofti microfilariae but, when tested by the ELISA technique, these antigens did not show the highest reactivity against serum antibodies.