The immune response of the sheep popliteal lymph node to a purified phenoloxidase from larval cuticle of the sheep ectoparasite, Lucilia cuprina

The popliteal lymph node of the sheep can mount a strong immune response to a phenoloxidase, enzyme A, purified from larval cuticle of a major sheep ectoparasite, the sheep blowfly, Lucilia cuprina. Continuous sampling from a cannulated efferent lymphatic allowed monitoring of changes in both cellular output (total cells and large blast cells) and specific antibody production (by ELISA) following primary and secondary challenge with antigen. Anti-enzyme A antibodies in lymph selectively precipitated enzyme A but not a second cuticular phenoloxidase, enzyme B, a finding that will prove useful in immunolocalization of the enzymes and in elucidating their origins. The implications for immunization of sheep against L. cuprina are discussed.