Kv1.3 channel expression in RA and OA T cells. (A) Kv1.3 number per cell in RA-SF-T cells, RA-PB-T cells, and OA-SF-T cells. Most RA-SF-T cells were CD4⁺ cells (Fig. 5B). (B) Confocal images of Kv1.3 (green) and Kvβ2 (red) staining in RA and OA T cells. (C) CCR7 expression in RA and OA T cells by FACS. (D) Synovial tissue from RA patients stained with anti-CD3, anti-Kv1.3, or anti-CCR7 Abs and counterstained with hematoxylin/eosin. Data are from five patients studied.

Kv1.3 expression in T cells specific for GAD65 (red), INS (black), or myelin antigens (blue) from patients with T1DM, type-2 diabetes mellitus, or MS or healthy controls. (A) Kv1.3 currents (Upper) and channel number per cell (Lower) in activated INS-, GAD65-, and myelin-specific CD4⁺ TCLs from new-onset T1DM patients, healthy controls, and MS patients (10). Each data point represents the mean ± SEM from 20–50 cells from two to four TCLs from a single donor. (B) Immunostaining for Kv1.3. (C) CCR7 expression in TCLs by FACS. (D) Kv1.3 number per cell in TCLs from a patient with both T1DM and MS and from patients with longstanding T1DM or type-2 diabetes mellitus. (E) Kv1.3 channel numbers per cell and CCR7, CD45R, and Kv1.3 protein expression in CD4⁺ T cells FACS-sorted with MHC class II tetramers loaded with GAD65 557I peptide or HA 306–318 peptide from T1DM patients.

Specific Kv1.3 blockers preferentially suppress human T_EM cells. (A) Kv1.3-containing signaling complex: Kv1.3, Kvβ2, SAP97 (synapse-associated protein 97), ZIP (PKC ζ-interacting protein, p56^lck-associated p62 protein), p56^lck, and CD4 (37). (B) Cocapping of Kv1.3 (green) with CD4 (red) in human T_EM cells. (C and D) CD4 (red) and Kv1.3 (green) staining in human GAD65-specific T_EM cells exposed to APCs loaded with GAD65 557I (C) or MBP (D). (E) SL5 100 nM does not prevent IS formation. (F) Ca²⁺ signaling in GAD-specific CD4⁺ T_EM clones triggered by anti-CD3 plus cross-linking secondary Ab (arrow) in the absence (black) or presence of SL5 at 0.1 nM (blue), 1 nM (green), or 100 nM (red). (G) SL5 suppression of cytokine production by RA-SF-T cells, RA-PB-T cells, and tetramer-sorted GAD65-specific T_EM clones from T1DM patients. Amounts of cytokines produced are in Fig. 9. (H Left) Anti-CD3 Ab-stimulated [³H]thymidine incorporation by RA-PB-T cells versus RA-SF-T cells from three RA patients. (H Right) [³H]Thymidine incorporation by same two populations after they were stimulated for 48 h with anti-CD3 Ab, rested overnight in medium, and then rechallenged with anti-CD3-Ab. (I) GAD65-specific T_EM cells escape from Kv1.3 blockade as the amount of GAD65 557I peptide increases from 10 (green) to 30 (red) to 90 (blue) μg/ml. (J) Effect of 4-AP on T_EM proliferation induced by anti-CD3 Ab. Each point represents mean ± SD of triplicates. Dotted line shows previously published data (17) on PB-T cells from healthy donors.

Kv1.3 blockers ameliorate PIA and EAD in rats. (A) SL5 treatment of PIA in which vehicle-treated animals have periostitis and joint deformation. (B) X-rays of paws. (C) Staining of joints from vehicle-treated (n = 5) and SL5-treated (n = 5) rats with PIA. (D) Cumulative incidence of EAD. (E) Islets immunostained for INS (first column), CD3 (second column), CD8 (third column), and CD68 (fourth column) in vehicle-treated (Upper) and PAP1-treated (Lower) rats. (F) PAP1 reduces β cell destruction and intraislet infiltration by T cells and macrophages on day 70. Destruction/infiltration: none, white; moderate, gray; severe, black.