Sialic acid-modified der p 2 allergen exerts immunomodulatory effects on human PBMCs.

BACKGROUND: House dust mite extract-based allergen immunotherapy (AIT) to treat house dust mite allergy is substantially effective but still presents some safety and efficacy concerns that warrant improvement. Several major allergen-based approaches to increase safety and efficacy of AIT have been proposed. One of them is the use of the group 2 allergen, Der p 2.

OBJECTIVE: We sought to investigate the immunomodulatory effects of sialic acid-modified major allergen recombinant Der p 2 (sia-rDer p 2) on PBMCs from healthy volunteers.

METHODS: We activated PBMCs with anti-CD3/CD28 antibodies and incubated them at 37°C for 6 days in the presence or absence of either native rDer p 2 or α2-3 sialic acid-modified rDer p 2 (sia-rDer p 2). We assessed the changes in CD4+ T-cell activation and proliferation by flow cytometry and changes in T-lymphocyte cytokine production in cell culture supernatant by ELISA.

RESULTS: We observed that PBMCs treated with sia-rDer p 2 presented with a markedly decreased expression of CD69 and an increased abundance of LAG-3+ lymphocytes compared with cells treated with rDer p 2. Moreover, PBMCs treated with sia-rDer p 2 showed a reduced production of IL-4, IL-13, and IL-5 and displayed a higher IL-10/IL-5 ratio compared with rDer p 2-treated PBMCs.

CONCLUSIONS: We demonstrate that sia-rDer p 2 might be a safer option than native rDer p 2 for Der p 2-specific AIT. This is most relevant in the early phase of AIT that is often characterized by heightened TH 2 responses, because sia-rDer p 2 does not enhance the production of TH 2 cytokines.