Immunoglobulin class switch induced by the interleukins IL-4,IL-6,IL-10,IL-11 and IL-13 in the CD40 B-cell system

The influence of the interleukins IL-4. IL-6. IL-10, IL-11 and IL-13 each s eparately and in various combinations, on the immunoglobulin production in B-cell cultures, should be investigated, B-cells from healthy individuals w ere cultured 14 days in the so-called CD40 system in co-incubation with Fc gamma-receptor expressing Ltk-fibroblasts and anti-human-CD40 IgG in functi on of CD40 ligand. In the supernatants the concentrations of IgM, IgA, IgG and IgE were analysed by using ELISA and the Pharmacia CAP system. Despite strong interindividual differences of values, after a-standardisation many statistically significant influences of interleukins were detected. ted. Th e strongest effects were the suppression of IgM, IgA and IgG production by IL-4 and the significant inversion by additional application of IL-10. Sing le IL-10 had few effects, but in combination with any other interleukin it increases generally the IgM, IgA and IgG production. IgE was only detectabl e in cultures supplemented with IL-4. This study demonstrates, that effects of single interleukins can be intensively modulated by other interleukins and therefore in vitro studies on isolated interleukins should be handled c ritically in respect to their signification in vivo.