The need for alternative control strategies for sheep scab is critical. One
approach is to develop vaccines based on 'concealed' antigens derived from
Psoroptes ovis. This strategy requires the identification and characterisa
tion of potential target antigens, which has been hampered by the problem o
f limited biological material for isolation of protein antigens. To aid the
discovery of P. ovis antigens and to provide a resource for generating rec
ombinant protein, we constructed a P. ovis cDNA expression library, using t
otal RNA isolated from 250 mg of mixed-stage P. ovis and the Clontech SMART
(TM) cDNA synthesis kit. The presence of P. ovis-specific sequences was con
firmed using PCR amplification and sequencing of actin. The sequences of cD
NA inserts from six random clones included one with high homology to the De
rmatophagoides pteronyssinus (house dust mite) antigen p Dp15. This is a gl
utathione S-transferase known to be an important house dust mite antigen. W
e conclude that this library will be a useful tool for the identification o
f potential target antigens for the immunological control of P. ovis and to
further our understanding of the pathology of sheep scab. (C)1999 Elsevier
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