Antigenic differences between strains of foot-and-mouth disease virus of type SAT 1

Abstract

Antigenic differences between the strains RV 11 and SA 13/61 of foot-and-mouth disease virus (type SAT 1) were studiedin vivoby cross-protection tests. Cattle inoculated with formolized antigen of either strain developed good immunity to experimental infection with the identical strain but little resistance to the other strain.In vitrothe results of complement fixation tests and of serum-virus neutralization tests in tissue culture were consistent with the observations madein vivo. The results of studies on the serological relationships between four strains of type SAT 1 are presented.The importance of strain differences in the epizootiology and control of the disease is discussed briefly.The authors wish to thank Dr I. A. Galloway and Dr J. B. Brooksby for their advice and criticism, and to acknowledge the valuable technical assistance of Mr K. Herniman, Mr R. L. G. King and Mr E. Scoates.

Isolation of variants during passage of a strain of foot-and-mouth disease virus in partly immunized cattle

“…For example, strains SA 13/61 and SWA 40/61, both isolated in the same year, though showing some antigenic resemblance were nevertheless demonstrably different from one another and differed to a much greater extent from the 'older' strain, RVII (Hyslop et al 1963), and also from the Middle East strain Isr. 4/62 (Hyslop, unpublished result).…”

“…Reports of effects of this diversity were reviewed briefly in a recent paper (Hyslop, Davie & Carter, 1963 passaged serially by inoculating clarified suspensions of epithelium into the mucosa of the tongues of partially immunized cattle. In the early passages a 1/10 suspension was employed, but later the dilution was increased to 1/1000, then to 1/10,000 and finally to 1/100,000.…”

“…Reports of effects of this diversity were reviewed briefly in a recent paper (Hyslop, Davie & Carter, 1963). Although it has been suspected that the antigenic changes leading to the appearance of new subtype strains may result from spread of the virus through a partially immune population, direct experimental evidence has been lacking.…”

A complement fixation technique for the quantitative measurement of antigenic differences between strains of the virus of foot-and-mouth disease

“…Subsequent work at this Institute was directed to the correlation of the results obtained by cross-vaccination, cross-serum neutralization and cross-complement fixation tests. In the first of these experiments Galloway, Davies & Smith, 1962;Hyslop, Davie & Carter, 1963; and unpublished work) has confirmed that there are strains of virus of the same immunological type which can be classified as antigenic variants or subtypes within the types and that in general there is good correlation between the results of the three tests. The results of the two serological tests and the cross-vaccination tests showed that three of the ten pairs were of the same subtype and that seven of them were dissimilar.…”

Isolation of a variant strain of foot-and-mouth disease virus (type O) during passage in partly immunized cattle

“…Evidence of the existence of different subtypes within the seven principal types of foot-and-mouth disease (FMD) virus was described by Hyslop, Davie & Carter (1963). Recently we reported the isolation of an immunologically distinct variant strain of virus of type SAT 1, which evolved when strain Tur.…”