Evaluación de la especificidad de anticuerpos policlonales aviarios y mamíferos anti-Factor Precoz de Preñez porcino

Early Pregnancy Factor (EPF) is a secreted protein with known functions as immunomodulator and growth factor, released very early in mammalian gestation. EPF represents an early marker of gestation and a very useful tool to supervise embryonic viability during the peri-implantational period. Obtaining anti-EPF antibodies (Abs) would mean having a valuable tool to investigate the biological functions of this factor, but it has failed so far due to EPF's function as an autocrine growth factor for hibridomas. The phylogenetic distance between birds and mammals is potentially advantageous for the efficient production of specific Abs against mammalian antigens. Thus, the objective of this work was to obtain avian and mammalian polyclonal anti-porcine EPF Abs and to evaluate the protein yield and the specificity of each batch of antibodies. Hens and rabbits were immunized with a synthetic EPF peptide, or with EPF isolated and purified from porcine serum of 7 days of gestation by SDS-PAGE (29 kDa band). IgY anti-EPF antibodies from hens were purified by combined caprylic acid and polyethylene glycol 6000 precipitation, and rabbit anti-EPF IgG by sulphate ammonium precipitation. Protein yield was evaluated by Bradford, and Ab specificity by Dot Blot and Immunoblot. The protein yield was satisfactory in all batches of Abs. The specificity of Abs obtained from rabbits immunized with the synthetic EPF peptide was satisfactory. Batches of immunoglobulins obtained from rabbits and hens immunized with the SDS-PAGE 29 kDa band displayed low specificity, whereas the batch obtained from hens immunized with the synthetic peptide presented null specificity. The synthetic peptide induced the production of more specific Abs when they were raised in rabbits. In contrast, the SDS-PAGE 29 kDa band is not useful to obtain specific Abs against this factor, since in addition to EPF it recognizes other proteins present in the serum.