MUMPS-VIRUS ALTERS AGGREGATION OF ACETYLCHOLINE-RECEPTORS IN CULTUREDRAT SKELETAL-MUSCLE CELLS

Cultured myoblasts, but not myotubes, from rat skeletal muscles were i nfected with the RW strain of mumps virus. Such myoblasts then fused t o form myotubes containing viral antigen. The infected myotubes showed a significant decrease in the number of dorsal, linear acetylcholine receptor (AChR) aggregates as determined by FITC-conjugated alfa-bunga rotoxin. Infected myotubes cocultivated with spinal cord cells showed no increase in the number of dorsal, linear AChR aggregates, compared to normal, uninfected myotubes. In addition, an increased proliferatio n of the myoblasts, which remained uninfected in the infected cultures , was noted. This may indicate a release of a growth stimulating facto r from the virus containing cells. This study shows that mumps virus i nfection can lead to an altered receptor organization in a morphologic ally preserved cell.