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.