Studies on the immunoglobulin-E system of the common marmoset in comparison with human data

In the common marmoset (Callithrix jacchus jacchus) immunoglobulin E (IgE) serum levels and IgE synthesis of peripheral blood mononuclear cells (PBMC) in vitro were investigated in order to look for homologies to the human system. While IgE was not found in marmoset blood plasma with three commercial antihuman IgE-kits with monoclonal antibodies (mAbs), two other kits using polyclonal antibodies against human IgE revealed detectable IgE concentrations of up to 10 kU/liter in plasma samples of 19 out of 21 marmosets. In accord with human data, rhIL-4 showed biological functions under in vitro conditions in PBMC of the New World monkey. Proliferation, measured by 3H-thymidine incorporation, of isolated PBMC of marmosets could be induced by rhIL-4. FACScan analysis showed an enhanced expression of the low affinity IgE receptor CD23 (Fc epsilon RII) on CD20+ B lymphocytes after incubation with rhIL-4. Furthermore, PBMC from marmosets could be stimulated by IL-4 alone or in combination with dexamethasone as well as with lipopolysaccharide (E. coli) to produce IgE in culture. The results indicate that Callithrix jacchus is using an IgE system that is rather similar to that of humans, although not completely identical. Antihuman mAbs and rhIL-4 can be used to investigate IgE regulation in vitro of marmoset PBMC. These data encourage the development of a primate animal model for studying possible modifications of the IgE system under pathological conditions to find new therapeutic strategies in atopic diseases.