Unique antigens on neoplastic cells of the soft shell clam Mya arenaria.

Soft shell clams (Mya arenaria) are commonly found in coastal waters of both the eastern and western United States. These invertebrates, which have an open circulatory system, may develop neoplasms of the haemolymph which ultimately kill the host. In this study we have 1) recorded the prevalence of hematopoietic neoplasms (HN) in Mya arenaria within a 50 mile radius of Woods Hole, Massachusetts and 2) utilized cells from one HN bearing clam to generate a series of monoclonal antibodies. Our data show that determinants are expressed on HN cells which are not detected on normal clam haemocytes, suggesting separate ontogenetic pathways of cell differentiation.