Adaptive Immune Response to Model Antigens Is Impaired in Murine Leukocyte-Adhesion Deficiency-1 Revealing Elevated Activation Thresholds In Vivo
Figure 4
High NP/CG ratios are critical for elicitation of hapten- and protein-specific IgG titers in CD18−/− mice. Eight- to twelve-week-old CD18−/− (open symbols) and WT (filled symbols) mice were immunized intraperitoneally with 100 μg of NP21-CG/aluM (squares), 10 μg NP21-CG/alum (circles), 100 μg NP4-CG/alum (triangles), or 100 μg CG/alum (diamonds). (a) Serum levels of anti-NP specific IgG1 were subsequently detected by ELISA on NP4-BSA coated ELISA plates and calculated in μg/mL by comparison to IgG1 standards, as described above. (b) For detection of CG-specific IgG1, sera obtained by bleeding from tail veins were diluted 1 : 10, and then plated out on CG-coated plates in 1 : 5 dilution steps. Serum titers of anti-CG-specific IgG1 were determined from the last dilution step where the optical density was still above the background level of the assay. For assessment of the primary immune response, results from sera collected at days 7 and 28 are displayed. Besides, measurements for day 49 are shown, and depict IgG1 titers representative also for further time points assessed during secondary immune responses. Bars represent the median of each group. *; **. Asterisks used in the key box indicate significant differences for the marked cohorts at all times points shown.
