Immunoblot analysis of SSL vesivirus VP1 proteins expressed in the baculovirus expression system. The panels are the same as described above for Fig. 1. The viral proteins were detected using a 1:2,000 dilution of a mixture of type specific antibodies to San Miguel sea lion virus (SMSV) serotypes 4, 6, 9, 10, 11, and 13. A 60 kDa protein consistent with the positive control vesiviruses V810 and V1415 (panel D, lanes 5 and 6) was detected from the daily samples and from VLPs purified in cesium chloride gradients.