The sheath of the microfilaria of Brugia malayi from human infections has IgG on its surface.

Microfilariae (mf) of Brugia malayi from microfilaraemic people had human IgG on their sheath. Fluorescent antibody studies showed that the predominant IgG isotype was IgG3, with IgG4 and IgG1 being present in lower quantities. Human albumin could not be detected. The sera of patients with chronic disease contained high levels of an IgG2 antibody that reacted with the sheath of mf taken from other people.