Acquisition of susceptibility to coxsackievirus A2 by the rat L8 cell line during myogenic differentiation.

Coxsackievirus A2 was propagated to high titres in the established rat L8 myogenic cell line during the stage of differentiation characterized by fusion of myoblasts into multinucleated myotubes (192 h post-plating cultures). In contrast, pre-fusion mononucleated L8 cultured infected 24 h after plating were refractory to Coxsackievirus A2 infection, as was a non-fusing clonal variant of the L8 line (L8CL3-U) regardless of the age of the latter cultures. The development of virus susceptibility in the older L8 cultures correlated with a marked virus-specific c.p.e. as evidenced by vacuolated degenerating myotubes with disrupted cytoplasm, whereas no c.p.e. was seen following infection of the young L8 or variant L8CL3-U cultures. The restriction of Coxsackievirus A2 replication in young L8 and L8CL3-U cultures occurred after virus attachment.