Jh. Pruett, PROTEOLYTIC CLEAVAGE OF BOVINE IGG BY HYPODERMIN-A, A SERINE-PROTEASEOF HYPODERMA-LINEATUM (DIPTERA, OESTRIDAE), The Journal of parasitology, 79(6), 1993, pp. 829-833
Cattle grub larvae are able to survive a lengthy 8%-mo internal migrat
ion within the naive bovine host connective tissues. Larval survival i
s observed even in the presence of host immunological responses to pri
ncipal parasite proteins. In this study, data are presented that sugge
st that a digestive enzyme, hypodermin A, of the first-instar larvae e
ffectively cleaves bovine immunoglobulin G in vitro. A (fab)'(2) fragm
ent is produced, and the heavy-chain fragments associated with the cle
aved fc piece remain intact. Hypodermin A is not specific for bovine I
gG as other species' IgGs are also degraded as are other bovine protei
ns. Destruction of the biological activity of bovine immunoglobulin G
by hypodermin A suggests a potential parasite escape mechanism that ma
y contribute to the survival of first-instar larvae within the bovine
host.