Michel Leclerc
We have discovered, in the past, the sea star lymphocytes (Figure 1); these cells of 4-5 µm in diameter are smaller than Vertebrate lymphocytes and we discovered recently the IPA (Invertebrate Primitive Antibody) with the sea star IGKAPPA gene with IG sites. Therefore genomic data assert the evidence of primitive antibody in Echinodermata. Furthermore, we find MHC genes class I and class II and Fab gene, Fc receptor gene in these invertebrates. The sea star Igkappa gene is clearly the oldest IgKappa gene of the immune system of animals