Normal Immune Responses to Ingested Foods

Abstract

This is a short review of the literature with a bias toward the author's work. Small amounts of dietary antigens are taken up into the circulation. B‐cell responses to foods (antibodies and antibody‐secreting cells) occur as a physiological event locally and in the circulation in all three major immunoglobulin classes. A low levels of IgE is also a normal phenomenon. IgA anti‐gliadin antibodies represent an exception. Antibody titers in general tend to decline with age. T‐cell responses specific for foods are low in the circulation of healthy subjects. T‐cell cytokines are more frequently produced in the gastrointestinal mucosa compared with the circulation. Results indicate that the phenomenon of oral tolerance takes place in humans. Oral tolerance within the T cell system may represent an important regulatory mechanism for normal immunity.