RECOMBINANT ALLERGEN LOL-P-II - EXPRESSION, PURIFICATION AND CHARACTERIZATION

Pollen from perennial rye grass (Lolium perenne) is a major cause of t ype I allergies worldwide. It contains complex mixtures of proteins, a mong which Lol p II is a major allergen. Previously, we have reported the cloning and sequencing of Lol p II and its expression in fusion wi th the heavy chain of human ferritin as carrier polypeptide (Sidoli et al., 1993, J. biol. Chem. 268, 21819-21825.). Here, we describe the e xpression, purification and characterization of a recombinant Lol p II overproduced as a non-fusion protein in the periplasm off. coli. The recombinant allergen was expressed in high yields and was easily purif ied in milligram amounts. It competed with the natural Lol p II for bi nding to specific IgE, and it induced allergic responses in skin prick tests, indicating to be immunologically analogous to the natural prot ein. Biochemical analyses indicate that recombinant Lol p II is a high ly stable and soluble monomeric molecule which behaves like a small gl obular protein.