A novel method for assaying human regulatory T cell direct suppression of B cell effector function.

We have established a highly reproducible and reliable protocol for testing human regulatory T cell function in suppressing IgM production from an immature human B cell line. The autoreactive Ramos B cell line provides a stable reporter of B cell effector function that can be tested by a straight-forward IgM ELISA. Tregs from healthy volunteers display a range of ability for suppressing baseline IgM production in a contact- and death-independent manner. Having established the normal range for human Treg direct suppression of B cell effector function, it will now be possible to efficiently test Tregs from various autoimmune conditions in which B cell hyperactivity and secretion of auto-antibodies are a hallmark of disease.