Plaque Formation Assay for Human Parainfluenza Virus Type 1

• Published in: Biological & Pharmaceutical Bulletin Vol. 34; no. 7; pp. 996 - 1000
• Main Authors: Fukushima, Keijo, Takahashi, Tadanobu, Takaguchi, Masahiro, Ueyama, Hiroo, Ito, Seigo, Kurebayashi, Yuuki, Kawanishi, Tomohiro, McKimm-Breschkin, Jennifer Lois, Takimoto, Toru, Minami, Akira, Suzuki, Takashi
• Format: Journal Article
• Language: English
• Published: Japan The Pharmaceutical Society of Japan 2011; Pharmaceutical Society of Japan; Japan Science and Technology Agency
• Subjects: Animals; antiviral reagent; Cell Line; Culture Media; human parainfluenza virus type 1; isolation; Lewis lung carcinoma-monkey kidney cell; Parainfluenza Virus 1, Human - growth & development; plaque assay; Viral Plaque Assay
• ISSN: 0918-6158; 1347-5215
• DOI: 10.1248/bpb.34.996

Human parainfluenza virus type 1 (hPIV1) generally does not show visible plaques in common cell lines, including Lewis lung carcinoma-monkey kidney (LLC-MK2) cells, by plaque formation assays for human parainfluenza virus type 3 (hPIV3) and Sendai virus. In several conditions of the plaque formation assay, complete elimination of serum proteins in the overlay medium was necessary for visualization of hPIV1-induced plaque formation in LLC-MK2 cells. We developed a plaque formation assay for hPIV1 isolation and titration in LLC-MK2 cells using an initial overlay medium of bovine serum albumin-free Eagle's minimum essential medium containing agarose and acetylated trypsin for 4—6 d followed by a second overlay staining medium containing agarose and neutral red. The assay allowed both laboratory and clinical hPIV1 strains to form large plaques. The plaque reduction assay was also performed with rabbit anti-hPIV1 antibody as a general evaluation model of viral inhibitors to decrease both the plaque number and size. The results indicate that the plaque formation assay is useful for hPIV1 isolation, titration, evaluation of antiviral reagents and epidemiologic research.