A comparison of New World alphaviruses in the Western equine encephalomyelitis complex by immunochemical nd oligonucleotide fingerprint echniques

We have examined the molecular basis for the observed antigenic differences between isolates of western equine encephalomyelitis (WEE) virus and those of a serologically related aIphavirus from the eastern United States designated High-lands J (HJ). The structural proteins of WEE virus isolates have tool. wt. of 55 × IO3 (El), 47 × ~o 3 (E~) and 33 × 1o3 for the nucleocapsid. The E1 glycoprotein had an isoelectric point (pI) of 6"4 and induced haemagglutination-inhibiting (HI) antibody which was specific for WEE virus. The E 2 glycoprotein of WEE virus had a pI of 8"4 and induced antibody which was virus specific by neutralization (PRNT) but cross-reacted with HJ virus in the radioimmune precipitation (RIP) test. Envelope glycoproteins of HJ virus isolates had tool. wt. of 58 x io ~ (El) and 49 x ~o 3 (E2) respectively. The E 1 glycoprotein from HJ virus had a pI of 6.8 and induced antibody which reacted specifically in the HI, PRNT and RIP tests. Isolated E2 protein of HJ virus had a pI of 9"I and induced antibodies which were reactive at equal titre with both WEE and HJ viruses by RIP. Two-dimensional gel electrophoresis of RNase T ~ oligonucleotides of WEE virus and HJ virus genome RNase T ~ oligonucleotides revealed that the primary structures of the RNAs of these two serologically related alphaviruses were very distant. The fingerprints of the oligonucleotides from I6 WEE viruses from western and central North America, Mexico and South America were similar to each other and easily distinguished from those of the eight HJ viruses isolated in the eastern United States from Massachusetts o Louisiana