Table 1. Methods for analysis of NA-specific antibodies.
Listed in this table are methods currently in use for serological evaluation of NA-specific antibodies, and practical considerations associated with each.
| Assay format | Main advantage | Main drawback |
|---|---|---|
| NA protein binding (e.g. ELISA) [25,27,88] | Efficient | Does not demonstrate inhibition of NA function |
| Inhibition of NA enzymatic activity on sialic acid substrates | Detection of functional antibodies | In all formats, viral reagent with antigenically matched HA may confound results |
| Specific format: | ||
| Microplate TBA method with fetuin substrate and colorimetric readout [19] | Large molecule mimics natural substrate | Hazardous chemicals |
| Lectin-HRP detection of cleaved sialic acid on plate- bound fetuin [20,21] | Large molecule mimics natural substrate | Long procedure1 |
| Cleavage of muNANA with fluorescence readout [25,26] | Rapid procedure | Small molecule an imperfect mimic of natural substrate2 |
1
As with the microplate TBA method, an overnight incubation for enzyme digestion is typical.
2
Some NA inhibitory antibodies may not inhibit cleavage of small sialic acid substrates [23].