Immunological relatedness of chicken and human riboflavin carrier protein

Polyclonal antibodies (pAbs) to riboflavin carrier protein (RCP) purified f rom human amniotic fluid were raised in two rabbits, These pAbs apart from recognizing the parent antigen, reacted significantly with chicken RCP as w ell. When all the 212 octapeptides overlapping by one amino acid residue an d covering the entire primary amino acid sequence of chicken RCP immobilize d on polyethylene rods mere probed with rabbit anti-human RCP antibodies, i t was found that these antibodies recognize five epitopic sequences (residu es 37-42, 73-76, 133-140, 174-176 and 200-207) in chicken RCP primary struc ture common to both the rabbits. In addition, the antisera from the two ind ividual animals also recognized additional epitopes characteristic to that particular animal. The reactivities of these antigenic determinants have be en confirmed with polyclonal anti-human RCP sera by using synthetic peptide s harbouring these chicken RCP sequences in inhibition ELISA. This high lev el of immunological similarities among linear epitopes observed may reflect the degree of conservation of local conformations among linear antigenic d eterminants shared by the two evolutionarily distant homologous proteins, ( C) 1999 Academic Press.