Relationship of San Miguel sea lion virus to other members of the calicivirus group.

San Miguel sea lion virus (SMSV) is indistinguishable from vesicular exanthema virus (VEV) and feline calicivirus (FCV) in its morphology and in possessing a single capsid polypeptide with a molecular weight of approximately 65 X 10(3). Neutralization tests readily differentiate the three viruses, but immunodiffusion tests show that SMSV is closely related serologically to VEV but not to FCV. Although the RNAs of the three caliciviruses have similar base compositions, homology tests show that SMSV is closely related to VEV but is not related to FCV. Tryptic peptide maps of the single major polypeptide comprising the capsid of each virus also show that SMSV and VEV are more closely related to each other than to FCV.