Figure 1.
Principle of the IA-2A bridging LFIA.
Serum samples are mixed with HA-Tag- and biotin-labeled IA-2 and colloidal gold-conjugated streptavidin before migration along the strip. In the case of a positive test, serum IA-2As form a bridge between HA-Tag- and biotin-labeled IA-2 and this complex is captured by an anti-HA-Tag mAb in the test line. Biotin-labeled IA-2 bound to IA-2As is detected using colloidal gold-labeled streptavidin, producing a purple-colored band on the test line. In the case of a negative test, only the control line is observed. It is generated by the biotinylated IA-2/gold nanoparticle-conjugated streptavidin complex being captured by mAb anti-polyhistidine in the control line. Insert: detail of the formation of the bridging complex.
Figure 2.
Representative image of negative and positive results with the IA-2A LFIA.
A positive signal limited to the control line is obtained with buffer alone (A) and with an IA-2A-negative sample (B). A positive signal in both the test and control line is observed with a IA-2A-positive serum (C).
Figure 3.
Titer distribution of the serum samples analyzed using the IA-2A LFIA.
Sera were from 35 T1D patients and 44 age-matched controls. The dotted line indicates the cut-off value (1939 a.u.) based on the control samples.
Figure 4.
Comparison of IA-2A results detected by in-house IA-2A bridging ELISA and a commercial IA-2A ELISA.
Serum samples from 35 T1D patients and 44 control subjects were analyzed with both methods. Dotted lines indicate the cut-off values for both assay methods. mAU, milli-absorbance units.
Figure 5.
Comparison of IA-2A levels obtained by IA-2A LFIA and in-house IA-2A bridging ELISA.
Serum samples from 35 T1D patients and 44 control subjects were analyzed with both methods and the two assays were correlated. Dotted lines indicate the cut-off values for both assay methods. mAU, milli-absorbance units.