improvement of th1/th2 and th1/treg imbalances by adjutants cpg, mpla and bcg in a model of acute asthma induced by allergen derp2 in balb/c mice

background the imbalance in the t helper (th) 1/th2 and th1/t regulatory (treg) cells-related immune responses plays a key role in pathogenesis of allergic asthma. objectives the aim of this study was to evaluate the effects of cpg-oligodeoxynucleotide (cpg-odn), monophosphoryl lipid a (mpla) and bacillus calmette-guerin (bcg) on the ratio of th1/th2 and th1/treg cells-related parameters in an animal model of asthma. methods this was an experimental study in which female balb/c mice were divided to five groups and then immunized subcutaneously (sc) with the allergen dermatophagoides pteronyssinus 2 (derp2) on days 1, 15 and 22. three groups of mice were considered as test groups and pre-treated sc with cpg, cpg + mpla or cpg + bcg on days 0, 14 and 21. two groups were also considered as saline-control group and derp2-sensitized control group that were administrated only saline or allergen derp2, respectively. the mice (except saline-control group) were challenged intranasally with allergen derp2 for ten days, from days 28 to 37 of post immunization. blood samples were obtained from retro-orbital sinus, on days 0, 23 and 40. the serum interleukin (il)-4, interferon (ifn)-γ, immunoglobulin (ig) e and igg2a levels were measured using the enzyme linked immunosorbent assay (elisa) technique. the blood count of th1- and treg cells was detected using flow cytometry. conclusions these results showed that bcg, mpla and cpg improve the th1/th2- and th1/treg cells imbalances in a mouse model of asthma. results at sensitization phase, the serum ifn-γ/il4 ratio was significantly increased in derp2-sensitized group pre-treated with cpg plus mpla or cpg plus bcg as compared with derp2-sensitized control mice (p < 0.002 and p < 0.003). the ifn-γ/il4 ratio was also markedly elevated in derp2-sensitized group pre-treated with cpg as compared with derp2-sensitized control mice (p = 0.07). in the challenge phase, the ifn-γ/il4, igg2a/ige and th1/treg ratios in derp2-sensitized mice pre-treated with cpg plus mpla were significantly higher than in derp2-sensitized control mice (p < 0.003, p < 0.006 and p < 0.003, respectively). the ifn-γ/il4 and th1/treg ratios were also significantly raised in derp2-sensitized mice pre-treated with cpg plus bcg in comparison with derp2-sensitized control mice (p < 0.001 and p = 0.012, respectively). in the challenge phase the th1/treg ratio was significantly decreased in derp2-sensitized group pre-treated with cpg plus bcg in comparison with derp2-sensitized mice pre-treated with cpg (p = 0.011). the th1/treg ratio in derp2-sensitized group pre-treated with cpg plus mpla was significantly higher than in derp2-sensitized mice pre-treated with cpg plus bcg (p < 0.035).