Results and Discussion
We were unable to find any reports of whole virus being conjugated to beads for use in this type of multiplex assay. While our approach using SDS-disrupted whole virus did work, it resulted in multiple fragmented beads. Comparing all three approaches, undisrupted, SDS-disrupted, and Triton X-100-disrupted virus, the Triton X-100 treatment gave lower background (as determined by the negative plasma) and a higher signal to the positive plasma than either the SDSdisrupted or undisrupted virus, and with no bead fragmentation (Figure 2).
The results of the virus/plasma titration studies are shown in Figure 3.
Correlation With ELISA
The results we obtained showed a strong correlation between the Bio-Plex and ELISA assays of positive and negative control plasma (Table 1).
When control plasma was incubated with the bead mixture and then analyzed for each separate bead type, there was no cross-reactivity between the different bead types (Table 2).
Single-Bead vs. Multiplex Assays
Because we were concerned that sensitivity might be lost when multiplex assays were compared to a single-bead assay, both single- and multiple-bead assays were performed; however, as shown in Table 3, we found no loss of sensitivity.
Sensitivity and Specificity
We determined the sensitivity and specificity of the assays by evaluating the number of true and false readings (Table 4).