Effects of Caryota mitis profilin-loaded PLGA nanoparticles in a murine model of allergic asthma

BACKGROUND Pollen allergy is the most common allergic disease. However, tropical pollens, such as those of Palmae, have seldom been investigated compared with the specific immunotherapy studies done on hyperallergenic birch, olive, and ragweed pollens. Although poly(lactic-co-glycolic acid) (PLGA) has been extensively applied as a biodegradable polymer in medical devices, it has rarely been utilized as a vaccine adjuvant to prevent and treat allergic disease. In this study, we investigated the immunotherapeutic effects of recombinant Caryota mitis profilin (rCmP)-loaded PLGA nanoparticles and the underlying mechanisms involved. METHODS A mouse model of allergenic asthma was established for specific immunotherapy using rCmP-loaded PLGA nanoparticles as the adjuvant. The model was evaluated by determining airway hyperresponsiveness and levels of serum-specific antibodies (IgE, IgG, and IgG2a) and cytokines, and observing histologic sections of lung tissue. RESULTS The rCmP-loaded PLGA nanoparticles effectively inhibited generation of specific IgE and secretion of the Th2 cytokine interleukin-4, facilitated generation of specific IgG2a and secretion of the Th1 cytokine interferon-gamma, converted the Th2 response to Th1, and evidently alleviated allergic symptoms. CONCLUSION PLGA functions more appropriately as a specific immunotherapy adjuvant for allergen vaccines than does conventional Al(OH)3 due to its superior efficacy, longer potency, and markedly fewer side effects. The rCmP-loaded PLGA nanoparticles developed herein offer a promising avenue for specific immunotherapy in allergic asthma.