Increased gene expression of a cytokine-related molecule and profilin after activation of Suberites domuncula cells with xenogeneic sponge molecule(s)

Porifera (sponges) constitute the lowest metazoan phylum, Experiments exami ned whether sponges can recognize self/nonself molecules. Cells from the ma rine sponge Suberites domuncula were incubated with membranes from either S . domuncula or another marine sponge, Geodia cydonium, as well as with reco mbinant alpha-integrin from G. cydonium. The cells responded immediately wi th a rise of intracellular Ca2+ ([Ca-i(2+)]) if they were treated with memb ranes from G. cydonium but not after treatment by those from S. domuncula. This change of [Ca-i(2+)] was also recorded with G. cydonium alpha-integrin . In parallel, the expression of two genes was strongly upregulated; one co des for a cytokine-related molecule, pre-B-cell colony-enhancing factor, an d the other for profilin. These genes have previously been found to be high ly expressed in human or echinoderm cells in the presence of xenogeneic pro teins. Our data support the hypothesis that a primordial immune response sy stem is present in sponges.