Multiplex rapid lateral flow assays for respiratory infections such as the flu, COVID and RSV offer an efficient testing solution. However, due to differences in the viral strains, viral loads, and sample types, balancing high assay sensitivity and specificity can be complex, especially if the viruses share genetic or antigenic similarities, leading to potential cross-reactivity.

Meridian’s monoclonal antibodies for Flu A, Flu B, COVID, and RSV are designed for low cross-reactivity and high sensitivity, ideal for lateral flow rapid multiplex tests for COVID/FLU/RSV.

Binding affinity is a critical factor in lateral flow assays because it directly influences the sensitivity, specificity, and overall performance of the assay. Specifically, a high antibody on-rate is desirable as the analyte has only a short amount of time to be in contact with the immobilized capture antibody as the sample solution moves down the membrane. A fast on-rate and a slow off-rate will enhance the analyte binding to antibody which correlates to enhanced performance in assay sensitivity, specificity, signal intensity, dynamic range and limit of detection. 

INFLUENZA ANTIBODIES

The kinetics of influenza A antibodies BN1069, BN1070, BN1223, BN1223 and BN1224 were measured (Table 1).  Specifically, the association (kon) and dissociation rate (koff) constants as well as the equilibrium dissociation constant (KD) were determined by fitting to sensorgrams via the 1:1 binding model with a correlation coefficient (R2) value greater than 0.99. The KD values of each of anti-influenza A BN1069 and BN1070 and anti-influenza B BN1223 were 2.60x10-11, 6.10x10-11, and 2.23x10-11 M..

Table 1. Binding kinetics of interactions between soluble Influenza A/B and immobilized anti-Influenza antibodies, as measured by bio-layer interferometry.

Table 2. Limit of detection of RIDTs with recommended mAb pairs.