Development of LAMP-based vaccine for cashew allergy immunotherapy

Abstract

Abstract Tree nut allergy is the second most common triggers of anaphylaxis behind peanut in children and adults. Proactive therapies to decrease reaction severity are currently not available. Here, we utilized Lysosomal-associated membrane protein-1 (LAMP-1) as a targeting signal to make novel DNA vaccines against three major cashew allergens (Ana O1, Ana O2, Ana O3). Briefly, the chimeric constructs encoding the DNA sequences of Ana O1 or Ana O2 or Ana O3 or multivalent plasmid fused to LAMP-1 were synthesized and administrated to BALB/c mice through a needle-free delivery method (Biojector). By ELISA analysis, it showed that LAMP-Ana O 1/Ana O 2/Ana O 3 immunized mice produced high titers of IgG2a and moderate titers of IgG1 antibodies against each antigen. In contrast, IgE response was reduced in the vaccine immunized mice. Moreover, induction of IFN-γ and reduction of allergen-stimulated Th2 cytokine IL-4 were observed in vitro in splenocyte cells of LAMP-Ana O1/Ana O2/Ana O 3 treated mice after antigen stimulation, suggesting a predominant Th1 type immune response was elicited via DNA immunization. To further explore the therapeutic effect of this vaccine, we pre-sensitized the C3H/HeJ mice by oral gavage of protein of cashew extracts, and then immunized the mice with either single LAMP-Ana O plasmids or multivalent plasmid. LAMP-Ana O 1/Ana O 2/Ana O 3 treated mice exhibited strong IgG2a response and decreased IgE level, while control LAMP-vector treated mice demonstrated low IgG2a titer and higher IgE level accompanied by elevation of plasma histamine and IL-4 producing basophils in the blood. These results indicate that immunotherapy with LAMP-Ana O1/Ana O 2/Ana O 3 is effective, and may be a potential approach for treating cashew allergy.