Antibody isotype (IgG and IgM) levels to a high molecular weight antig
en (1.56 x 10(5) kDa) isolated from water-insoluble components of Seta
ria digitata were determined to be highly elevated in microfilariae-ne
gative individuals of a Wuchereria bancrofti endemic area of Orissa, I
ndia. The highest IgM response was found in endemic normals. The preva
lence of antibodies was minimum in microfilaraemic group and maximum i
n endemic normals of the population.