Use of an invasive snail as a novel model for comparative studies of immunology and haematopoiesis

VEGA, ISRAEL A; CASTRO-VAZQUEZ, ALFREDO; RODRÍGUEZ, CRISTIAN

Mendoza

Simposio; II Simposio Internacional Medicina Traslacional; 2019

Universidad Nacional de Cuyo

Tropical diseases caused by gastropod-borne parasites affect millions of people worldwide and cause the loss of billions of dollars in developing countries every year. In this context, the immune system of the apple snail Pomacea canaliculata has become the focus of international research because of this species? role as an intermediate host of the parasitic nematode Angiostrongylus cantonensis, the aetiologic agent of eosinophilic meningitis. Over the past few years, our projects have been aimed at characterising the internal defence system of P. canaliculata, using both in vitro and in vivo approaches. Specifically, our studies concerned the identification and characterisation of (1) the immunocompetent cells (i.e., the haemocytes), (2) the organs that act as immune barriers, and (3) the haematopoietic cells and tissues. We found three haemocyte populations with distinct properties that give them different roles during an immune response. A surprising finding was their ability to form spheroids in aseptic cultures. The intrinsic ability to form spheroids parallels that of many mammalian cancer cells, thus this evolutionary conserved behaviour may be significant in a much wider context. Also, we characterised the kidney and the lung as immune barriers and haematopoietic sites. Using non-pathogenic (baker?s yeast) and pathogenic (Mycobacterium marinum) immune challenges we found that haemocyte nodules occurred in both organs as a conspicuous reaction. That and other responses (hypertrophy, multinucleate cell formation) are analogous to those of tuberculous granulomas, but lacking lymphocytes. P. canaliculata lacks an acquired immunity and, in this context, zebrafish has been used as a model for tuberculosis only during a temporal window of development, when the adaptive system has not formed yet. Therefore, a potential development of a model for the experimental infection with M. marinum, in an animal that lacks an adaptive system, may be of high significance.