3.3.66
ASSAYS OF CUCUMBER MOSAIC VIRUS CUCUMOVIRUS WITH VIRUS-SPECIFIC AND SEROGROUP-SPECIFIC MURINE MONOCLONAL ANTIBODIES

FIT HSUl, CL SUTULA2, W BLISS 2, YH HSU3 and KL PERRY4

lUS Dept. Of Agriculture, Agricultural Research Service, Beltsville, MD, USA; 2Agdia, Inc., Elkhart, IN, USA; 3National Chung Hsing University, Agricultural Biotechnology Laboratory, Taichung, ROC and 4Purdue University, Botany and Plant Pathology Department, West Lafayette, IN, USA

Background and objectives
Cucumber mosaic virus (CMV) is the type member of the genus Cucumovirus. It is one of the most widespread viruses in the world, having a very broad natural host range in both wild and cultivated plants. The virus causes many diseases resulting in economic loss in cereals, fruits, vegetables and ornamentals. Symptoms incited by CMV include mosaic, blight, fan leaf, ringspot, fruit woodiness; necrosis of bulbs, and the death of host plants. CMV infection, however, is not always obvious. Many diseases caused by CMV have been attributed to other viruses.

Immunological comparisons of CMV isolates show that strains of the virus are antigenically heterogenous [1]. Strains of CMV have been grouped into two major serogroups (subgroups). A quick and reliable method of identification of CMV in the early stage of infection is an essential measure for better control of the disease caused by the virus. Further more, serological differentiation of strains of CMV provides important information in studying the epidemiology of the diseases caused by CMV and developing effective programs for breeding CMV resistance. We have established somatic cell hybrids that secrete monoclonal antibodies to CMV. Monoclonal antibodies were characterized and their potential for use in the detection of CMV and the diagnosis of the diseases caused by the virus were investigated.

Results and conclusions
Antibody-secreting hybridomas were produced by tusing mouse FOX-NY myeloma cells with splenocytes prepared from mice in'munized with a mixture of S, D, Price's 6, NT6 (from tomato), BCM (from banana), GC 1 and GCM (from gladiolus), CRM- 1 (from melon), and CRP- 1 (from plantain) CMV cultures. A total of 20 hybrid cell lines were established by the limiting dilution technique. Their antibody specificities were investigated by testing with 18 thoroughly characterized isolates of CMV. Group-specific antibodies were identified; three reacted exclusively with members m serogroup I, and four only with members in serogroup II. Results also showed that four antibodies reacted with every isolate of CMV tested. The remaining 10 monoclonal antibodies reacted with at least one, but not all, of the isolates from each serogroup. Nearly 120 CMV cultures obtained from various parts of the "Plant Virus Collection of the American Type Culture Collection". The majority (75%) of the cultures tested were identified as serogroup II. Six cultures (5%) did not react with group-specific recognized all CMV cultures.

References
1. Kaper JM, Waterworth HE, 1981. Handbook of Plant Virus Infection and Comparative Diagnosis. pp.257-332.
2. McDaniel LL, Cox RL, Maratos ML, 1993. American Type Culture Collection: Catalogue of Plant Viruses and Antisera. pp.1-84