Localisation and characterisation of ovine immunglobulin within the sheep scab mite, Psoroptes ovis

Ovine IgG was detected in homogenates of repeatedly washed Psoroptes ovis. Some of the immunoglobulin in the homogenates was fragmented although the h ost IgG present in mite washings was largely intact. The host immunoglobuli n was immuno-localised to the surface or cytoplasm of the gut cells of feed ing stages of freshly harvested P. ovis examined by cryosectioning. A simil ar distribution of rabbit IgG was detected in P. cuniculi. The IgG demonstr ated in the mite gut represented partially digested as well as intact immun oglobulin. The presence of intact host immunoglobulin suggests that P. ovis may be susceptible to vaccination by the gut antigen approach, a method us ed successfully for blood-feeding ectoparasites like Boophilus microplus. ( C) 2000 Elsevier Science B.V. All rights reserved.