Specific cross-reactivity of antibodies raised against two major stress proteins, stress 70 and chaperonin 60, in diverse species

Immunoblot analysis using several antibodies raised against two major families of stress proteins, stress 70 and chaperomn 60 (cpn60), which are highly conserved in mammals, was carried out in diverse species often used in environmental research, including molluscs, annelids, crustaceans, echinoderms, and fish The study revealed surprisingly different patterns of antibody cross reactivity among species The monoclonal anti-stress 70 antibody (mAb) C92 was the least cross reactive for all species tested The mAbs anti-stress 70 N27, BRM-22, and 3a3 were more broadly cross reactive, but their binding specificities to stress 70 isoforms in the diverse species tested did not correlate with one another or follow taxonomic lines The polyclonal anti-stress 70 antibody reacted to proteins in the 70 to 74 kDa range in all fish examined and in most invertebrates When a polyclonal antibody (pAb) raised against cpn60 from a moth was used as a probe, specific binding was observed with proteins in the 60 to 64 kDa range in all fish examined and in most invertebrates However, the size and number of isoforms that reacted with the pAb were species specific These data suggest that these two major stress protein families are less highly conserved in invertebrates and fish than in mammals Therefore, to minimize misinterpretation when using antibodies in heterologous assays with species in which the stress response has not been well characterized, it is important to determine which isoforms of stress 70 react with a particular antibody and to take into account the differential regulation of each member of this multigene family