TABLE 3.

Population analysis of the appearance of BAP and HAP in three serial HM passages of TK/OR/71-delNS11-124 in MDCK cells starting from a single pool of LM-passage egg-derived virus

No. of HM passagesaParticle titer/ml (avg particle yield/cell)bRatio
PFP (iCKP)niCKPDIPHAPDIP/niCKPHAP/BAPHAP/PFP
06.9 × 108 (60)<0.1 × 108c<0.1 × 108 (<0.5)c205 × 108 (1,783)129.729.7
10.113 × 108 (9.4)d6.9 × 108 (580)15 × 108 (1,250)205 × 108 (17,083)c2.29.31,814.2
20.077 × 108 (6.4)4.1 × 108 (340)15 × 108 (1,250)51 × 108 (4,250)3.72.7662.3
30.002 × 108 (0.17)1.4 × 108 (120)15 × 108 (1,250)77 × 108 (6,417)10.44.738,500.0
  • a The “0-passage” virus is a pool of allantoic fluids from 9-day-old eggs infected with ∼103 PFP of an LM passage. Monolayers of 2.4 × 106 MDCK cells received 150 μl from the preceding passage.

  • b Values in parentheses were estimated from the total number of cells in the chorioallantoic membrane (6) and the amount of allantoic fluid in 9-day-old eggs.

  • c Less than the level of detection by the assay.

  • d Based on 2.0 ml of virus from 2.4 × 106 MDCK cells in a monolayer; e.g.,(0.113 × 108) × 2 = 0.226 × 106 PFP ÷ 2.4 × 106 = 9.4.

  • e Comparable yields have been reported from MDCK cells (35).