Anti-horseradish peroxidase associated with tubular structures in the endoplasmic reticulum of plasma cells in stimulated lymph nodes of mice.

Tubular structures are described in dilated cisternae of the endoplasmic reticulum in plasma cells of lymph nodes stimulated with horseradish peroxidase (HRP). A positive reaction for anti-HRP antibody suggests that they are formed of immunoglobulins or are at least closely associated with them.