PRODUCTION OF A GENETICALLY-ENGINEERED INHIBIN VACCINE

The goal of this research was to synthesize a chimeric ovalbumin/inhib in antigen using recombinant techniques. Antigenic epitopes of the tra nslated product from an ovalbumin cDNA were mapped using computer mode ling techniques. The corresponding nucleotide sequences of ovalbumin e pitopes were examined for unique restriction sites to allow insertion of a synthetic bovine inhibin a gene fragment which encoded the first 26 amino acids. A plasmid (pETOI-8) was synthesized which contained th e chimeric ovalbumin/inhibin alpha 1-26 gene. A 46 kDa recombinant pro tein (ovalin) was produced from BL21(DE3) Escherichia coli cells conta ining pETOI-8 that was identified with anti-ovalbumin and anti-inhibin alpha 1-26 antisera. Rabbits were immunized subcutaneously in four si tes along the back against ovalbumin (n=3), crude ovalin (n=3), or gel -purified ovalin (n=3) at week 0, 4, 7, and 18. Primary and booster im munizations contained ca 300 mu g of antigen emulsified in complete Fr eund's adjuvant and incomplete Freund's adjuvant, respectively. Blood samples collected at week 0, 6, 8, and 19 were evaluated for their abi lity to bind ovalbumin, 32 kDa bovine inhibin and bovine inhibin alpha 1-26 using ELISA. Mean anti-ovalbumin titers at week 19 were 1:100000 in rabbits immunized against ovalbumin or crude ovalin, and 1:23333 i n rabbits immunized against gel-purified ovalin. Anti-inhibin and anti -inhibin alpha 1-26 titers were nonexistent in antisera from pre-immun ized rabbits and rabbits immunized against ovalbumin. Mean anti-inhibi n titers at week 19 were 1:833 and 1:10000 in rabbits immunized agains t crude ovalin or gel-purified ovalin, respectively. Mean anti-inhibin alpha 1-26 titers at week 19 were 1:3333 and 1:6666 in rabbits immuni zed against crude or gel-purified ovalin, respectively We conclude tha t genetic engineering of inhibin alpha 1-26 into the antigenic epitope s of ovalbumin provides potential for the development of an anti-inhib in vaccine. Copyright (C) 1996 Elsevier Science Ltd.