ANTIBODY DEGRADATION IN WOUND EXUDATES FROM BLOWFLY INFECTIONS ON SHEEP

Sheep were immunised with ovalbumin and then infected with the sheep b lowfly, Lacilia cuprina in order to study immunoglobulin and specific antibody degradation at the wound site, Serum and wound exudates were collected over the infection period and the dry weight and protein con tent of the exudates were determined. Exudates were analysed by SOS-PA GE and immunoblotting for IgG degradation, Levels of IgG and specific anti-ovalbumin antibodies in the exudates were measured by ELISA, The total weight of exudates increased over the whole period of the infect ion, while protein content increased in the first 24 h and then remain ed relatively constant, Immunoglobulin was present 6 h after infection and levels increased with protein content, However, the levels of IBG measured were quite different depending on the secondary antibody use d in the ELISA, A monoclonal antibody measured mainly intact IgG while a polyclonal anti-IgG measured intact and degraded IgG, This allowed an estimation that approximately 60% of the IgG in exudates was degrad ed from 6 h after infection, Assays in vitro showed that L, cuprina la rval enzymes degraded sheep antibody. However, measurement of specific anti-ovalbumin levels in exudates suggested that although high levels of antibody were degraded this did not necessarily decrease the level of antigen binding. As a result, IgG degradation may assist and not h inder vaccine development by allowing antibody fragments to penetrate the peritrophic membrane and access gut cell antigens