Figure 1

G-CSF/anti-G-CSF mAb complexes exhibit enhanced biological activity in comparison with G-CSF. (A) B6 mice were injected i.p. once with G-CSF/anti-G-CSF mAb complexes (0.5 μg G-CSF plus 2.5 μg anti-G-CSF mAb), cytokine alone (0.5 μg G-CSF), antibody alone (2.5 μg anti-G-CSF mAb), or vehicle alone. CD11b⁺Gr-1⁺ myeloid cells were identified by FACS analysis of spleens cells at 48 hours. (B) B6 mice were injected i.p. three times (on days 1, 3, and 5) with G-CSF/anti-G-CSF mAb complexes (1.5 μg G-CSF plus 7.5 μg anti-G-CSF mAb) or controls. Spleens were harvested on day 7. Shown are the number of CD11b⁺Gr-1⁺ myeloid cells identified by FACS. Each triangle represents an individual mouse and the bar indicates the mean. *P-values ≤ 0.05 were generated by Wilcoxon Rank-Sum test. (C) B6 mice were injected once with G-CSF only (1.5 μg) or with G-CSF/anti-G-CSF mAb complexes (1.5 μg G-CSF plus 7.5 μg anti-G-CSF mAb). For the 1/10 condition, mice were injected with 0.15 μg G-CSF plus 0.75 μg anti-G-CSF mAb, and for the 1/100 condition, an additional 10-fold dose reduction. The percent of CD11b⁺Gr-1⁺ myeloid cells in the spleen was determined by FACS analysis at 36 hours. Each triangle represents an individual mouse and the bar indicates the mean. *P-values ≤ 0.05 were generated by Wilcoxon Rank-Sum test. (D) B6 mice (n = 4/group) were injected once i.p. with G-CSF/anti-G-CSF mAb complexes (1.5 μg G-CSF plus 7.5 μg anti-G-CSF mAb), cytokine alone (1.5 μg G-CSF), pegylated G-CSF (3.1 μg PEG-G-CSF), or vehicle alone. Peripheral blood was harvested prior to injection and on days 1, 2, 4, and 6. The percentage of CD11b⁺Gr-1⁺ myeloid cells was determined by FACS analysis. The error bars indicate standard deviation. *P-values < 0.01 were generated by a repeated measures design with group-time interactions tested at each timepoint.