Antigen-induced histamine release from guinea pig basophils

Area of Science:

• Immunology
• Hematology

Background:

• Histamine is a key mediator in allergic and immune responses.
• Basophils are critical immune cells involved in hypersensitivity reactions.
• Quantifying basophil histamine release is essential for understanding immune sensitization.

Purpose of the Study:

• To quantify histamine levels in guinea pig blood.
• To investigate histamine release from basophils induced by Concanavalin A and specific antigens.
• To establish an assay for evaluating basophil sensitization over time.

Main Methods:

• Blood histamine levels were measured in guinea pigs.
• Basophil histamine release was induced using Concanavalin A and specific antigens (ovalbumin, keyhole limpet hemocyanin) in sensitized animals.
• Repeated blood sampling was used to monitor basophil sensitization longitudinally.

Main Results:

• Guinea pig blood contains an average of 106 ng/ml histamine, with 85-90% originating from platelets and the remainder from basophils.
• Concanavalin A induced approximately 65% histamine release from basophils.
• Specific antigens triggered histamine release from sensitized basophils at low concentrations (≤0.01 µg/ml).
• Basophil sensitization persisted for at least 17 weeks post-sensitization, with a minimum of 7 days required for detectable release.

Conclusions:

• A reliable assay for assessing basophil sensitization and histamine release in guinea pigs was developed.
• This assay allows for longitudinal studies of basophil sensitization following immunization.
• The findings facilitate further investigation into the mechanisms, timing, and role of basophil sensitization in immune and hypersensitivity reactions.