3.2 IgG1 and IgG4 similarly neutralize allergen and prevent primed basophils from degranulation
To test the ability of IgG1 and IgG4 to block basophil activation by neutralization (Figure 1B), basophils from non-allergic individuals were loaded with each of one of the IgE antibodies (G078, A044, F127) and challenged with Fel d 1 complexed with IgG antibodies of the same specificity. Figure 3A shows that neutralizing inhibition occurred independent of the IgG subclass, as both IgG1 and IgG4 inhibited basophil activation in a similar manner. This may also have been expected as both IgG1 and IgG4 antibodies share the same variable region for each of the 3 mAb types. Differences in neutralizing capacity therefore would have been somewhat unexpected.