Improvement in the therapeutic efficacy of an asthma-inducing sea squirt antigen termed DIIIa by its polymerization in hyposensitization of sea squirt allergy.

Polymerization using glutaraldehyde markedly improved the apparently low efficacy of an asthma-inducing sea squirt antigen, DIIa (MW 9,980), in hyposensitization therapy on patients with sea squirt allergy. A product (poly-DIIa-G) comparable to Gi-rep (MW 106,000) in MW-distribution showed high therapeutic efficacy comparable to the most effective therapeutic antigen, Ei-M, which was paralleled by a significant increase in the allergen-specific IgG titer in most of the successfully hyposensitized patients as assayed using Ei-M as the target antigen. Another product (poly-DIIa-E) comparable to Ei-M (MW 22,800) in MW also showed a high but slightly lower therapeutic efficacy relative to poly-DIIIa-G with an apparent increase in the specific IgG titer in some patients. However, no significant change in the IgG titer was detected in most patients unsuccessfully treated with intact DIIIa. On the other hand, no significant change was detected in the IgE titer specific to the target antigen in the patients, except in a few cases where the change was independent of the therapeutic effect. The apparent correlation between the increase in the specific IgG titer and the enhancement of the therapeutic effect suggested that polymerization enhanced the immunogenicity of DIIIa and resulted in a significant improvement in the therapeutic efficacy through an additional induction of the specific IgG capable of competing, as a blocking antibody, with the specific IgE for an asthma-inducing antigen, like DIIIa, in patients treated with the polymerized antigens.