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Techniques

Improvements in the Passive Hemagglutination Technique for Serological Detection of Plant Viruses. R. Rajeshwari, International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), ICRISAT Patancheru Post Office, 502324, A. P. India; D. V. R. Reddy(2), and N. Iizuka(3). (2)International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), ICRISAT Patancheru Post Office, 502324, A. P. India; (3)Hokkaido National Agriculture Experiment Station, Hitsujigaoka, Sapporo, Japan. Phytopathology 71:306-308. Accepted for publication 23 July 1980. Copyright 1981 The American Phytopathological Society. DOI: 10.1094/Phyto-71-306.

The use of some samples of normal rabbit serum for diluting antigen in passive hemagglutination (PHA) resulted in nonspecific agglutination. Bovine serum albumin at 0.5% concentration prevented such nonspecific agglutination. The sensitivity of sheep red blood cells (RBC) treated with glutaraldehyde before they were tanned and sensitized, was comparable to that of fresh RBC. Glutaraldehyde-treated cells could be preserved at 4–6 C for 2 mo without detectable loss in sensitivity. Better agglutination was obtained when sensitization of glutaraldehyde-treated cells with globulins was done at pH 7.0 rather than at 6.4 or 5.2. In comparative experiments, the sensitivity of PHA with purified peanut green mosaic virus was 40–80 times that of agar gel diffusion and precipitin ring tests, respectively. The minimum concentration of peanut green mosaic virus detected by PHA was 0.75 μg/ml.