1. Effect of HL60 cell age (expressed in cell passage) on opsonophagocytic activity.
Effect of HL60 cell age (expressed in cell passage) on opsonophagocytic activity. Dilutions of a serum specimen from a nonvaccinated adult were tested in the pneumococcal serotype 6B OPA with day 3 HL60 cells (400:1) from postdifferentiated passage 51 (p51; solid line) and 111 (p111; dotted line). Incomplete opsonophagocytic activity (i.e., high baseline numbers of CFU [>20]) was observed when high-passage-number (>80) differentiated HL60 cells were used. However, the OPA titer assigned to the serum specimen remained the same when qualified HL60 cells from a different passage were used.
Branda T. Hu et al. Clin. Diagn. Lab. Immunol. 2005; doi: /CDLI