Microfilariae of Brugia pahangi in the blood of cats have variable levels of feline IgG on their sheaths.

Feline IgG was found on the sheath of microfilariae (mf) of Brugia pahangi isolated from the blood of cats. Gamma heavy chains, both light chains, and the Fc and F(ab')2 portions of IgG were present, suggesting that the molecule is intact. The amount of IgG on the sheath was variable and the younger the mf the less IgG was present on their sheaths. Possible functions of this adherent layer of host protein are considered.