Immunogenicity/hypersensitivity of biologics

Area of Science:

• Immunology
• Toxicology
• Pharmacology

Background:

• Biologics can elicit immunologic responses, including hypersensitivity reactions.
• Understanding these reactions is crucial for interpreting nonclinical toxicity studies.

Purpose of the Study:

• To provide an overview of immunologic mechanisms in biologic-induced hypersensitivity.
• To describe methods for detecting hypersensitivity reactions in nonclinical studies.
• To outline associated clinical and anatomic pathology findings.

Main Methods:

• Antemortem diagnostics: hematology, antibody detection, complement assays, and erythrocyte-bound complement receptor 1 evaluation.
• Postmortem diagnostics: light and electron microscopy for tissue changes.
• Immunohistochemistry for detecting immune complexes and the test article in tissues.

Main Results:

• Type I and Type III hypersensitivity reactions are most common with biologics.
• A combination of antemortem and postmortem methods aids in detection.
• Histopathology and immunohistochemistry reveal characteristic immune complex-mediated damage.

Conclusions:

• Accurate assessment of hypersensitivity requires a weight-of-evidence approach.
• Findings may not be consistent across all animals in a study.
• Distinguishing true hypersensitivity from other findings is critical for safety evaluation.