The immune response in humans and rabbits to monomeric and polymeric grass allergens

The antigenicity of polymerized grass (PG) and monomer grass (MG) was studied. As compared with MG, PG produces a similar immunologic response in rabbits as demonstrated by a tanned red blood cell (TRBC) passive hemagglutination assay or by total serum binding of perennial rye grass Group I antigens (RGGI). Six patients with allergic rhinitis sensitive to several grass pollens received an average of 60,000 protein nitrogen units (PNU) or PG. The initial dose was 100 PNU ans a maintenance dosage of 8500 PNU was obtained after six injections without systemic reactions in any of the patients. Serum binding of RGGI increased significantly in the PG-treated patients and this increase was quantitatively similar to that measured in a second group of six atopic patients previously treated for 1 year with a total of 100,000 PNU of a standard grass extract mixture. PG, like polymerized ragweed (PRW), has a reduced allergenicity while retaining immunogenicity. These data suggest that PG as compared to standard aqueous grass extract mixtures represents an improved form of immunotherapy for the atopic patients.