Institute of Experimental Immunology, Universitätsspital Zürich, Schmelzbergstrasse 12, CH8091 Zürich, Switzerland. amacpher@pathol.unizh.ch
T cell help is not obligatory for B cell Ig class switching. Instead, DC expression of BLyS and APRIL can provide the signals to induce T-independent B cell production of IgG and IgA.