Fig. 4: Typical plate layout of the MNA and the PNA.

a, MNA. b, PNA. In this example layout, the reference serum (R1) is prediluted 1/6.25 such that the initial in-plate dilution of 1/250 is achieved. Test sera (S1 to S6) are all tested with no predilution. In the PNA, a second reference (R2) is run without predilution. VOC and PC contain no test serum and are used to determine the foci count and maximum luminance (100% unneutralized) for the analysis, respectively. NVC and cell control (CC) contain no serum or virus and are used to ensure that cell monolayers are of good quality and that no virus cross-contamination has occurred during assay setup.