FIG. 1.

Identification of newly developed serum IgG antibodies to the LOS of the homologous M. catarrhalis isolate. ELISAs were used to test the level of serum IgG antibody (abs) in response to LOS obtained from the exacerbating strain of bacterium. COPD patients are indicated in addition to the LOS serotype of the exacerbating strain of M. catarrhalis isolated from that patient. Serum samples obtained preacquisition and postclearance of the infecting M. catarrhalis strain were incubated in a 96-well plate coated with 20 to 30 μg of the homologous LOS per well. The bars represent the mean differences in absorbance for data from at least three independent ELISAs of serum samples taken after clearance of the exacerbating strain to preacquisition of that strain, with the error bars representing the standard errors of the means. Asterisks indicate a P value of ≤0.05 as determined by a one-sided paired t test.