Ultrastructure of white spot syndrome virus development in primary lymphoid organ cell cultures

Primary cell cultures from the lymphoid organ of Penaeus monodon were used to investigate in vitro propagation and morphogenesis of white spot syndrom e virus (WSSV). Double-strength Leibovitz's L15 supplemented with 20% fetal bovine serum, pH 7.5, with a final osmolarity of 530 +/- 5 mOsm kg(-1) was identified as the most suitable culture medium. In this medium, the lympho id cells remained viable for more than 1 wk. Migrating cells were inoculate d with WSSV, and the consequent cytopathic effects documented by Light and electron microscopy. WSSV appears capable of following 2 alternative assemb ly sequences, one similar to the morphogenesis of the Oryctes rhinocerus vi rus and another which is more typical of baculoviral assembly. Possible rel ationships between WSSV, Oryctes virus, and baculoviruses are discussed.