Intramuscular injection of DNA vaccines elicits potent humoral and cellular immune responses in mice. However, DNA vaccines are less efficient in larger animal models and humans. To gain a better understanding of the factors limiting the efficacy of DNA vaccines, we used fluorescence-labeled plasmid DNA in mice to 1) define the macroscopic and microscopic distribution of DNA after injection into the tibialis anterior muscle, 2) characterize cellular uptake and expression of DNA in muscle and draining lymph nodes, and 3) determine the effect of modifying DNA distribution and cellular uptake by volume changes or electroporation on the magnitude of the immune response. Injection of a standard 50-μl dose resulted in the rapid dispersion of labeled DNA throughout the muscle. DNA was internalized within 5 min by muscle cells near the injection site and over several hours by cells that were located along muscle fibers and in the draining lymph nodes. Histochemical staining and analysis of mRNA expression in isolated cells by RT-PCR showed that the transgene was detectably expressed only by muscle cells, despite substantial DNA uptake by non-muscle cells. Reduction of the injection volume to 5 μl resulted in substantially less uptake and expression of DNA by muscle cells, and correspondingly lower immune responses against the transgene product. However, expression and immunogenicity were restored when the 5-μl injection was followed by electroporation in vivo. These findings indicate that distribution and cellular uptake significantly affect the immunogenicity of DNA vaccines.

Purpose: Expansion and activation of natural killer (NK) cells with interleukin-2 (IL-2) may enhance antibodydependent cellular cytotoxicity (ADCC), an important mechanism of rituximab activity. Two parallel Phase I studies evaluated combination therapy with rituximab and IL-2 in relapsed or refractory B-cell non-Hodgkin's lymphoma (NHL).Experimental Design: Thirty-four patients with advanced NHL received rituximab (375 mg/m 2 i.v. weekly, weeks 1-4) and escalating doses of s.c. IL-2 [2-7.5 MIU daily (n ‫؍‬ 19) or 4.5-14 million international units three times weekly (n ‫؍‬ 15), weeks 2-5]. Safety, tolerability, clinical responses, NK cell counts, and ADCC activity were evaluated.Results: Maximally tolerated doses (MTD) of IL-2 were 6 MIU daily and 14 million international units thrice weekly. The most common adverse events were fever, chills, and injection site reactions. Dose-limiting toxicities were fatigue and reversible liver enzyme test elevations. Of the 9 patients enrolled at the daily schedule MTD, 5 showed clinical response. On the thrice-weekly schedule at the MTD, 4 of 5 patients responded. Responders showed median time to progression of 14.9 and 16.1 months, respectively, for the two studies. For the same total weekly dose, thrice-weekly IL-2 administration induced greater increases in NK cell counts than daily dosing, and NK cells correlated with clinical response on the thrice-weekly regimen. ADCC activity was increased and maintained after IL-2 therapy in responding and stable disease patients.Conclusions: Addition of IL-2 to rituximab therapy is safe and, using thrice-weekly IL-2 dosing, results in NK cell expansion that correlates with response. This combination treatment regimen merits additional evaluation in a randomized clinical trial.

Adding a long-acting beta(2)-agonist (LABA) by dry powder inhaler (DPI) to tiotropium provides significantly increased and sustained bronchodilation in chronic obstructive pulmonary disease (COPD) patients over either product alone. To demonstrate similar benefits with a nebulized LABA, a placebo-controlled trial was conducted to evaluate the efficacy and safety of formoterol fumarate inhalation solution in subjects receiving tiotropium as a maintenance treatment for COPD. After a 7-14-day screening period using tiotropium 18 microg once daily, subjects with diagnosed COPD (> or = 25% to <65% predicted FEV(1)) were randomized to receive 20 microg formoterol fumarate inhalation solution twice daily for nebulization plus tiotropium (FFIS/TIO) or nebulized placebo twice daily plus tiotropium (PLA/TIO) for 6 weeks. Efficacy was assessed with spirometry at each visit (Day 1, Week 1, 3, 6), the transition dyspnea index (TDI), and St. George's Respiratory Questionnaire (SGRQ). Baseline characteristics were comparable, including mean FEV(1)% predicted. At Week 6, FEV(1) AUC(0-3) was 1.52 L for FFIS/TIO-treated subjects vs. 1.34 L for PLA/TIO-treated subjects (p<0.0001). The mean TDI scores in the FFIS/TIO and PLA/TIO groups were 2.30 and 0.16, respectively (p=0.0002). SGRQ did not change significantly with 6 weeks treatment, with the exception of FFIS/TIO improvements in symptom score vs. PLA/TIO (p=0.04). More PLA/TIO- than FFIS/TIO-treated subjects experienced AEs (39.7% vs. 22.9%), COPD exacerbations (7.9% vs. 4.5%), and serious AEs (3.2% vs. 1.5%). Nebulized formoterol fumarate in combination with tiotropium provided statistically and clinically significant improvements in bronchodilation and symptom control over tiotropium alone and demonstrated good tolerability.

Dendritic cells (DC) play a key role in antigen presentation and activation of specific immunity. Much current research focuses on harnessing the potency of DC for vaccines, gene therapy, and cancer immunotherapy applications. However, DC are not readily transfected in vitro by traditional nonviral techniques. A novel DNA vaccine formulation was used to determine if DC are transfected in vitro. The formulation consists of plasmid DNA adsorbed on to cationic microparticles composed of the biodegradable polymer polylactide-co-glycolide (PLG) and the cationic surfactant, cetyltrimethylammonium bromide (CTAB). Using preparations of fluorescentlabeled plasmid DNA formulated on PLG-CTAB microparticles to study internalization by macrophages and dendritic cells in vitro and in vivo, we found that most, but not all, of