Assessment of immunobiological effects induced by chemicals, drugs or food additives. I. Tier testing and screening approach.

The indications of immunologic dysfunction following low level exposure of rodents or even man to certain chemicals and drugs have raised concern regarding methodology and approaches for routine assessment of immunobiological effects. The immunogiological effect observed may either indicate impaired immunopotentiation or hypersensitization. The assays selected for testing should be relevant to the human experience and adaptable to certain practical considerations such as cost, reproducibility of data, ease of performance and application to routine toxicology studies. Using these considerations, a tier approach was proposed consisting of assays for screening for immunologic effects (Tier I) and assays to help define the mechanisms responsible for the immunobiological effects observed (Tier II). A tier of assays was also proposed for measuring the sensitization potential of certain compounds. Certain assays from the screening tier were assembled into a hypothetical and practical test battery to screen for immunological effects of a chemical with potential immunosuppressive properties. Information provided by this test battery should provide a reasonable and sensitive data base from which a standard of evaluation could be made regarding the safety of the test (1) compound.