Downloaded from www.microbiologyresearch.org by IP: 23.22.6.154 On: Fri, 05 Feb 2016 01:28:30 J. gen. Virol. (1986), 67, 549-556. Printed in Great Brita#1 Key words: B YD V/monoehmal antibodies~serological groups 549 Characterization of Monoclonal Antibodies to a U.K. Isolate of Barley Yellow Dwarf Virus By L. TORRANCE, 1. M. T. PEAD, 1 A. P. LARKINS 2 AND G. W. BUTCHER 2 1MAFF Harpenden Laboratorl,, Hatching Green, Harpenden, Herts. AL5 2BD and 2The Monoclonal Antibody Centre, AFRC Institute of Animal Physiology, Babraham, Cambridge CB2 4AT, U.K. (Accepted 14 November 1985) SUMMARY Five rat monoclonal antibodies (MAbs) specific for U.K. isolate B of barley yellow dwarf virus (BYDV) have been produced and tested. The reactions of the MAbs against a range of isolates of known vector specificity from the U.K., U.S.A. and Sweden were compared and a provisional serological correlation suggested. A survey of 90 U.K. field isolates showed that they were of the same serological groupings as the typed isolates, and that the panel of MAbs could be used to characterize field isolates of BYDV. Two of the MAbs were produced in large quantities in ascitic fluids; antibody partially purified from them and conjugated to alkaline phosphatase was used successfully in direct ELISA. INTRODUCTION The luteovirus barley yellow dwarf virus (BYDV) causes a widespread and economically damaging disease in cereals and grasses in the U.K. and other cereal-growing areas world-wide (Plumb, 1983; Burnett, 1984). There are many strains of BYDV which are usually differentiated by their aphid vector(s). For example, five groups have been identified in North America (Rochow, 1969; Johnson & Rochow, 1972); these are serologically distinct and can be distinguished readily in ELISA (Rochow & Carmichael, 1979). Three vector aphid species occur commonly in the U.K., Sitobion (Maerosiphum) avenae, Rhopalosiphum padi and Metopolophium dirhodum, and at least two different BYDV groups have been identified (Plumb, 1974; R. T. Plumb, personal communication). However, the serological relationships between the isolates of these groups have not been well studied. Antisera have been prepared against only two of them, B and F. B, which is transmitted mainly by R. padi, but also by S. avenae, causes severe symptoms in oats, and may be similar to the PAV isolate found in the U.S.A.; F, which is transmitted predominantly by S. avenae, causes mild symptoms in oats and may be similar to the North American MAV isolate. Direct ELISA using antiserum against F (Plumb el al., 1980) detected B, but more weakly than F ; in the reciprocal test with antiserum against B, F was not detected. The relative incidence of the different BYDV types in the U.K. is also unclear. Previous work has suggested that isolates which cause more severe symptoms in cereals (usually B strains) are more prevalent in the south and west of England whereas those which cause mild symptoms (usually F strains) are more prevalent in the north and east (Plumb, 1974). However, changes in the prevalence of isolates are known to occur over long periods (t0 years) (Rochow, 1979; Plumb, 1974) and in 1984 there were reports of a greater incidence of isolates causing severe symptoms in cereals in the north of England (S. A. Hill, personal communication). Because the isolates cause different symptoms in their cereal hosts, it is important to be able to identify which strains are prevalent for example in grass reservoir hosts, or in vector aphids, in order to assist the forecasting of disease incidence. 0000-6850@1986 SGM