Figure 1.

In vitro validation of ⁸⁹Zr-hCD4-Mb and ⁸⁹Zr-mCD4-Mb. (A) ELISA assay of hCD4-Mb (top) and mCD4-Mb (bottom) with or without dfo conjugation to recombinant human CD4-his or mCD4-his protein. (B) HPLC chromatograms of dfo-h/mCD4-Mb after radiolabeling with ⁸⁹Zr. (C) Total binding of ⁸⁹Zr-h/mCD4-Mb under antigen excess conditions using HPB-ALL, DHL, or freshly isolated mCD4⁺ cells as indicated (40 x 10⁶ cells per well, triplicates). (D) Total binding of ⁸⁹Zr-h/mCD4-Mb to HPB-ALL cells, freshly isolated hCD4⁺ or mCD4⁺ cells as indicated (2 x 10⁶ cells per well, triplicates) with or without blocking with a 100-fold excess of unlabeled h/mCD4-Mb. P values were calculated by ordinary one-way and Tukey post-hoc (C) or unpaired t-test for pairwise comparisons (D). The data are presented as mean ± SD. *p < 0.05, **p < 0.01, ***p < 0.001; ****p < 0.0001.