SEROLOGICAL RESPONSES INDUCED IN MICE BY IMMUNOGENIC PROTEINS AND BY PROTEIN RESPIRATORY ALLERGENS

It is known that a variety of materials, including both low molecular weight chemicals and proteins, is able to induce occupational respirat ory allergy. We have shown previously that exposure of mice to chemica l respiratory sensitizers results in both a marked increase in the ser um concentration of IgE and the appearance of specific IgE antibody. I n the present study we have examined the characteristics of immune res ponses induced in mice following intraperitoneal exposure to 3 protein respiratory allergens, ovalbumin (OVA), a lipase from Aspergillus ory zae (LP) and an amylase from Bacillus subtilis (AM) and to a fourth pr otein, bovine serum albumin (BSA), which is considered usually not to cause respiratory sensitization. Under conditions where all proteins p rovoked IgE antibody responses, only OVA, LP and AM elicited specific IgE antibody. As judged by passive cutaneous anaphylaxis (PCA) assay, BSA failed to induce an IgE response. In contrast to chemical respirat ory sensitizers, the protein allergens examined here failed to cause a substantial increase in the serum concentration of IgE; OVA and AM in duced no increase in serum IgE and LP only a comparatively modest incr ease relative to control values. In conclusion, these data demonstrate that while protein respiratory allergens are able to provoke specific IgE antibody, they fail to cause a marked increase in the concentrati on of this immunoglobulin in the sera of treated mice. It would appear , therefore, that the mouse IgE test, which seeks to evaluate chemical respiratory sensitization potential as a function of induced changes in the concentration of serum IgE, will be inappropriate for the ident ification of protein respiratory allergens. Nevertheless, identificati on of protein allergens may be possible by exploiting the observations reported here that such proteins induce in mice specific IgE antibody responses.