Genetic and Antigenic Variations among Geographical Isolates of Sindbis Virus

Abstract

SUMMARYThe genetic and antigenic variation in 12 Sindbis (SIN) virus isolates from four zoogeographic regions (Paleoarctic, Ethiopian, Oriental and Australian) has been examined at a molecular level. RNase T1 oligonucleotide fingerprinting of genomic RNA from SIN isolates revealed that the primary structure of the RNA from viruses from each zoogeographic region was unique. The E1 and E2 glycoproteins and the capsid protein of two isolates from each zoogeographic region were compared by tryptic peptide mapping with the Egyptian prototype strain AR-339. Tryptic peptide maps of viruses from Sicily and the Ethiopian region were similar to those of the prototype; maps of isolates from the Oriental and Australia regions were different from each other and from those of the prototype strain. Viruses from each of the four zoogeographic regions were analysed antigenically by neutralization with polyclonal serum to AR-339 and by enzyme-linked immunosorbent assay with an anti-E2 monoclonal AR-339 antibody. Clear antigenic divergence of SIN isolates into two groups, representing the Paleoarctic-Ethiopian and Oriental-Australian regions were demonstrated. These results support a hypothesis which proposes that ancestral SIN virus diverged into two distinct groups. The genetic changes have resulted in further phenotypic divergence within the geographic varieties.

Geographic distribution and evolution of Sindbis virus in Australia.

“…The results confirm earlier reports that significant genetic diversity exists between isolates of SIN virus from the Paleoarctic\Ethiopian and Oriental\Australian zoogeographic regions (Norder et al, 1996 ;Olson & Trent, 1985 ;Rentier-HEF Delrue & Young, 1980). The isolates contained within each of the two genotypes were closely related genetically.…”

“…Rentier-Delrue & Young (1980) and Olson & Trent (1985), using a different Malaysian isolate of SIN virus, have also demonstrated that the Malaysian isolate was more closely related to Australian isolates than to other isolates from the Oriental zoogeographic region. The Oriental and Australasian zoogeographic regions are separated by the Wallace Line in the Indo-Australian archipelago, and seroepidemiological studies have indicated that the alphavirus Chikungunya virus and the flavivirus Japanese encephalitis (JE) virus may be restricted to the Oriental zoogeographic region, whereas the alphavirus RR virus and flavivirus Murray Valley encephalitis (MVE) virus are restricted to the Australian zoogeographic region (Mackenzie et al, 1994).…”

“…These authors suggested that divergent evolution had occurred between European\African and Indian\Far Eastern\Australian types. A subsequent study of antigenic variation among SIN virus isolates from Paleoarctic, Ethiopian, Oriental and Australian areas demonstrated antigenic diversion between viruses from the Paleoarctic\ Ethiopian and Oriental\Australian regions (Olson & Trent, 1985). Genetic studies, by RNase T1 mapping, indicated that the primary structures of RNA from viruses isolated in the four zoogeographic regions were distinct from one another (Olson & Trent, 1985).…”

“…A subsequent study of antigenic variation among SIN virus isolates from Paleoarctic, Ethiopian, Oriental and Australian areas demonstrated antigenic diversion between viruses from the Paleoarctic\ Ethiopian and Oriental\Australian regions (Olson & Trent, 1985). Genetic studies, by RNase T1 mapping, indicated that the primary structures of RNA from viruses isolated in the four zoogeographic regions were distinct from one another (Olson & Trent, 1985). An RNase T1 mapping study of a limited number of Australian SIN virus isolates indicated that the virus may exist throughout Australia as a single topotype (Brand, 1989).…”

Effect of Alternating Passage on Adaptation of Sindbis Virus to Vertebrate and Invertebrate Cells

“…Alphaviruses and other arthropod-borne viruses also appear to undergo lower rates of evolution than many other animal RNA viruses that replicate solely in vertebrates (6,33,35). Rates of SINV nucleotide substitution, deduced from oligonucleotide fingerprinting, are approximately 4 ϫ 10 Ϫ4 substitutions per nucleotide per year (18,36), similar to estimates for other alphaviruses and other arboviruses and approximately 10-fold lower than rates reported for many single-host RNA viruses (25).…”