Colonial ascidians as model organisms for the study of the invertebrate/vertebrate transition in immunity


Loriano Ballarin , Francesca Cima, Nicola Franchi, Francesca Baldin

Laboratory web site


Botryllus schlosseri is a colonial ascidian introduced as a model organism for biological studies 60 years ago, in Padova. It represents a reliable model for the study of innate immunity and for the comparison of immune responses of protochordates with those of vertebrates. In this species we are studying the role of haemocytes in immune defense and stress responses.
Immunocytes are represented by phagocytes and cytotoxic morula cells. The former can eliminate non-self cells or particles by phagocytosis; the latter are the first cells to sense the presence of non-self molecules and release cytokines as a consequence of the recognition.
We are focusing on the following issues: i) identification and role of secreted molecules (cytokines) in immunocyte communication; ii) role of secreted lectins in immune responses; iii) complement activation and its role in tunicate immune defense; iv) identification of immune receptors and of the codifying genes in immunocytes; v) immunotoxicity of xenobiotics; vi) role of haemocytes in stress responses.

Collaborations

Prof. K. Kawamura. Kochi University, Kochi, Japan
Prof. M. de Eguileor, Università dell’Insubria, Varese, Italia
Dr. B. Rinkevich, National Institut of Oceanography, Haifa, Israel

Selected publications

Ballarin L., 2008. Immunobiology of compound ascidians, with particular reference to Botryllus schlosseri: state of art. ISJ-Invert. Survival J. 5: 54-74.

Ballarin L., Franchi N., Schiavon F., Tosatto S.C., Mičetić I., Kawamura K., 2012. Looking for putative phenoloxidases of compound ascidians: haemocyanin-like proteins in Polyandrocarpa misakiensis and Botryllus schlosseri. Dev. Comp. Immunol. 38: 232-242.

Cima F., Ballarin L., 2012. Immunotoxicity in ascidians: Antifouling compounds alternative to organotins - III. The case of Copper(I) and Irgarol 1051. Chemosphere 89: 19-29.

Franchi N., Ballarin L., 2014. Preliminary characterization of complement in a colonial tunicate: C3, Bf and inhibition of C3 opsonic activity by compstatin. Dev. Comp. Immunol. 46: 430-438.

Franchi N., Schiavon F., Carletto M., Gasparini F., Bertoloni G., Tosatto S.C.E., Ballarin L., 2011. Immune roles of a rhamnose-binding lectin in the colonial ascidian Botryllus schlosseri. Immunobiology 216: 725-736.