Determination of critical factors causing cytotoxicity in the virus neutralization test.
The fluorescent antibody virus neutralization (FAVN) test, an international standard method for serological testing for rabies, has been adopted by many countries. However, some dog serum samples inhibit the formation of cell monolayers by BHK-21 cells used in the test, resulting in failures to determine antibody titers. This inhibition of cell monolayer formation was defined as cytotoxicity. In this study, critical factors that induce cytotoxicity of the dog serum in BHK-21 cells were determined, and the effective ways to prevent cytotoxicity were also established. Specifically, some anticoagulants, anti-BHK-21 cell IgG antibodies, and serum storage at temperatures of >25°C were found to induce cytotoxicity. On the other hand, several treatments of the dog serum, including the absorption by BHK-21 cells or kaolin, incubation with trypsin-EDTA, and the use of collagen- or gelatin-coated plates, were shown to reduce cytotoxicity. Based on these results, the FAVN test may be modified to enhance its performance.
Research Institute for Animal Science in Biochemistry & Toxicology, 3-7-11 Hashimotodai, Midori-ku, Sagamihara, Kanagawa 252-0132, Japan. Electronic address: r_shiraishi@riasbt.or.jp.
Rikiya
R
Shiraishi
Research Institute for Animal Science in Biochemistry & Toxicology, 3-7-11 Hashimotodai, Midori-ku, Sagamihara, Kanagawa 252-0132, Japan.
Masaaki
M
Nishimura
Research Institute for Animal Science in Biochemistry & Toxicology, 3-7-11 Hashimotodai, Midori-ku, Sagamihara, Kanagawa 252-0132, Japan.
Ryuji
R
Nakashima
Research Institute for Animal Science in Biochemistry & Toxicology, 3-7-11 Hashimotodai, Midori-ku, Sagamihara, Kanagawa 252-0132, Japan.
Chiho
C
Enta
Azabu University, 1-17-71 Fuchinobe, Chuo-ku, Sagamihara, Kanagawa 252-5201, Japan.
Norio
N
Hirayama
D000818:Animals; D057134:Antibodies, Neutralizing / Q000097:blood; D000914:Antibodies, Viral / Q000097:blood*; D002460:Cell Line; D006224:Cricetinae; D004283:Dog Diseases / Q000175:diagnosis*; D004285:Dogs; D005188:False Negative Reactions; D005260:Female; D006801:Humans; D008297:Male; D009500:Neutralization Tests / Q000379:methods*; D011818:Rabies / Q000175:diagnosis / Q000662:veterinary*; D011820:Rabies virus / Q000276:immunology*
D057134:Antibodies, Neutralizing; D000914:Antibodies, Viral
Cytotoxicity; Dog serum; Rabies; Virus neutralization test