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

Immunocytochemistry of Psoroptes cuniculi stained by sera from naive and infested rabbits: preliminary results

“…On the contrary, it was observed that the sera from chronically infested and resistant rabbits react with the ventriculum, the two diverticula, the colon and also with the postcolon in the case of the resistant rabbit. The observation of only a faint stain of the gut contents, and of only a weak cuticle reaction in the absence of gut cells stain of the mites incubated with pooled sera from naive un-infected rabbits, indicated that P. cuniculi ingested rabbit IgG, confirming results obtained in previous studies (Pettit et al 2000;Beetham 1997). The absence of host IgG detection in gut cells surface and/or cytoplasm or inter-cellular spaces observed in mites incubated with sera from naive and acutely infested rabbits and its observation in mites incubated with sera from chronically infested and resistant rabbits suggests the presence of IgG direct to cellular antigens of mite digestive tract only in sera from chronically infested and resistant rabbits.…”

“…In her study, Beetham (1997), using immunocytochemistry, observed the presence of different antibodies to P. ovis gut antigens both in the sera from infested naive steers and in multiply infested animals. Pettit et al (2000) demonstrated the presence of host IgG localised at the surface or cytoplasm of the gut lumen of P. ovis taken from infested sheep and of P. cuniculi collected from infested rabbits, thus indicating that the mites ingest host immunoglobulin. Beetham (1997) observed that all infested animals, naive and resistant, produced antibodies to antigens throughout the digestive tract.…”

“…Effectively, nowadays, the search for a vaccination strategy for the control of psoroptic mange represents one of the main subject of the studies on this mite genus (Nuttall et al 2006). In previous studies, sera from infested and resistant steers demonstrated antibody specificity towards Psoroptes ovis digestive system (Beetham 1997), while ovine and rabbit immunoglobulins (IgG) were found immuno-localised to the surface or cytoplasm of the gut cells of P. ovis and P. cuniculi respectively, (Pettit et al 2000). These findings suggest that P. ovis and P. cuniculi may be susceptible to vaccination by the gut antigen approach, a method used successfully for blood-feeding ectoparasites like Boophilus microplus (Willadsen et al 1988(Willadsen et al , 1989Wikel et al 1996;Boué et al 1999;de la Fuente et al 1999;van den Broek and Huntley 2003).…”

Stimulation of the In Vitro Migration of Ovine Eosinophils by Factors Derived from the Sheep Scab Mite, Psoroptes ovis

“…Indeed, the response appears to benefit the parasite by providing the serous exudate on which the mites feed and thrive (Mathieson, 1995;Beetham, 1997;Pettit et al, 2000). The present study provides in vitro evidence suggesting that mites actively produce factor(s) that induce eosinophil chemokinesis.…”

“…A feature of the infection site is the rapid (within 24 h) and massive infiltration of eosinophils, which form the predominant cellular component of the characteristic scab lesion (van den Broek et al, 2000;van den Broek and Huntley, 2003). The rapid onset of the tissue eosinophilic response, allied to observations that the mites appear to rely on ingestion of serous exudate from the advancing lesion as a primary nutrient source (Mathieson, 1995;Beetham, 1997;Pettit et al, 2000), and the fact that the presence of large numbers of eosinophils does not prevent expansion of the lesion or the increase in mite numbers, has led to speculation in this laboratory that P. ovis may be directly involved in the recruitment and/or function of these cells as a means to promote their own maintenance and survival. Support for this hypothesis emerged from a study in which administration of an anti-inflammatory corticosteroid (dexamethasone) transiently impaired development of the lesion and depressed mite numbers (Bellworthy et al, 1997).…”