US EPA

5194152 

Journal Article 

Antigens of Powdered Pearl-Oyster Shell Causing Hypersensitivity Pneumonitis 

Weiss, W; Bauer, X 

1987 

Yes 

Chest
ISSN: 0012-3692
EISSN: 1931-3543 

91 

1 

The identification and characterization of antigens causing hypersensitivity pneumonitis in a worker exposed to pearl oyster dust is described. Powdered pearl oyster shell whole extract was prepared by decalcification with acetic acid and dialysis against water for three days. A portion of this was lyophilized without further treatment as total extract. The remaining portion of the extract was centrifuged and the supernatant was lyophilized as soluble extract. Antigen coated discs were prepared by binding both protein extracts to cyanogen bromide activated paper discs. Antibodies against proteins in the extracts were measured by the protein-A radioallergosorbent test (PA-RAST). Proteins were further characterized using polyacrylamide gel electrophoresis. Proteins isolated by this technique were electrophoretically transferred to nitrocellulose sheets for immunoblotting. Precipitating antibodies were measured using a double immunodiffusion technique. In the clinical case described, a 42 year old male worker was exposed for five years to pearl oyster shell dust and then began to develop flu like symptoms on working days. After another ten years, his symptoms gradually worsened and he lost 6 kilograms of weight. His clinical signs improved after several days away from the workplace. Physical examination, lung function tests including vital capacity, FEV1, and diffusing capacity for carbon monoxide, blood gas analyses, and radiographs were all normal. An inhalation challenge test using pearl oyster shell dust was performed and produced a pulmonary and systemic reaction typical for hypersensitivity pneumonitis. Results of the immunologic tests included high titers of IgG-antibodies suggestive of underlying type-III immune reaction. Results also indicated that the causative antigens were contained in the soluble portion, and were probably glycoproteins. Significantly higher PA-RAST results were obtained with the patient's serum compared to control serum. The authors suggest that there may be IgG-antibodies against oyster components in most people, possibly due to widespread consumption of oyster meat. They also suggest that some of the reactions seen may be due to components similar to lectin which bind human immunoglobulins in a nonimmunologic manner.