Epitope specificity of IgE antibodies to a major allergen (Cry j 1) of Japanese cedar pollen in sera of humans and monkeys with pollinosis

Abstract

Japanese cedar (Cryptomeria japonica) pollinosis has been reported to occur naturally in Japanese monkeys (Macaca fuscata) as well as humans. Using monoclonal antibodies (mAb) specific to Cry j 1, a major allergen in Japanese cedar pollen, we identified five independent epitopes (EP‐1 to EP‐5) on the molecule. The epitopes recognized by IgE antibodies in the sera of humans and monkeys with the pollinosis were analysed by an IgE enzyme‐linked immunosorbent assay inhibition method with these mAb. In human patients, the mAb to EP‐1 strongly blocked the binding of IgE antibodies in all patients’ sera to Cry j 1. The reaction patterns of IgE antibodies in monkeys, however, varied among the troops of monkeys. In some troops, the mAb to EP‐1 showed a blocking pattern similar to that for human patients. In other troops, mAb to EP‐4 and EP‐5 blocked binding of IgE. These results indicate that some, but not all, monkeys have antibody responses to the major allergen similar to those of humans.

Structural basis for epitope sharing between group 1 allergens of cedar pollen

“…However, since none of the five known allergenic homologues of Cry j 1 share this glycosylation site (Midoro-Horiuti et al, 2001;Aceituno et al, 2000;Suzuki et al, 1996;Sone et al, 1994), this epitope cannot be shared with the other known cedar allergens (Midoro-Horiuti et al, 1992;Schwietz et al, 2000). The presence of additional IgE epitopes on Cry j 1 was demonstrated by the finding that three unique groups of anti-Cry j 1 mAbs inhibited the binding to Cry j 1 of IgE from the sera of patients with Japanese cedar hypersensitivity (Sakaguchi et al, 1997). However, these epitopes have not been localized to specific structural elements or regions of Cry j 1.…”

“…Six monoclonal antibodies (mAbs) against native Cry j 1 (S14, S36, S84, S91, S95 and S131) were described previously (Sakaguchi et al, 1997). These antibodies represent four of the five antibody groups defined by Sakaguchi et al, including the three mAbs groups that competed with the IgE in the sera of Japanese cedar-sensitive patient for binding to Cry j 1.…”

“…One of these mAbs (S95) inhibits the binding of IgE antibodies in sera from 10 of 21 Japanese cedar-sensitive patients (Sakaguchi et al, 1997) to Cry j 1. In the experiments described here, S95 also interfered with the binding of IgE antibodies from sera of mountain cedar-sensitive patients to Jun a 1.…”

“…However, S131 did not react with any of the synthetic peptides representing Jun a 1, suggesting that S131 identifies a conformational or discontinuous epitope shared by Cry j 1 and Jun a 1. Finally, one group of mouse mAbs that identify EP-1 (Sakaguchi et al, 1997) only reacts with Cry j 1. It is possible that this epitope is formed by the glycopeptide structure described by Taniai et al (1993).…”

Determination of Human Linear IgE Epitopes of Japanese Cedar Allergen Cry j 1

“…4) Based on the inhibition of human IgE binding to Cry j 1 by murine monoclonal antibodies, the presence of five independent epitopes was suggested. 5,6) IgE-binding sites on pollen allergens are generally reported to be conformational. 7,8) Taniai et al reported that the inhibitoriest monoclonal antibody (mAb 046) recognized a conformational epitope on Cry j 1.…”