Table 6.

Summary of variations made to traditional allergen-specific immunotherapy (table adapted from Valenta et al. [195].

Target	Type of Modification	Advantage
Antigen	Chemically modified allergen extracts (allergoids, haptens, PEG)	Allergenic activity is reduced, inducing tolerance and Th1 responses [163,166,196,197]
	Recombinant allergens and recombinant hypoallergens	Allergen specificity; induces blocking of antibodies and increases safety Immunomodulation occurs with the induction of T-cell tolerance [160,198,199]
	T cell peptides	Induction of T-cell tolerance increases allergen specificity and increases safety [200,201,202]
	B cell peptides	Induction of blocking antibodies increases allergen specificity and increases safety [150,186]
	Mimotopes	Allergen specificity induces the blocking of antibodies in DNA vaccines [203,204,205]
	DNA Vaccines	Induction of Th1 response leads to allergen specificity [150,206,207]
Route/mode of administration	Oral/sublingual administration	Safety. The induction of T-cell anergy makes the treatment easy to perform and convenient for patients [208,209,210]
	Nasal administration	Safe and convenient for patients [211,212]
Adjuvant	Al(OH)3	Reduces anaphylactic side effects [213,214]
	CpG, MPL liposomes	CpG reduces allergen activity Overall induces Th1 [215,216]
	Chitosan-nanoparticles	Induction of T-cell tolerance [215,217]
	Carbohydrate based particles	Ease of production and reduced tissue damage [206,218]
	Live vaccines	Induces Th1 response [219,220,221]
	Surface layers	Induces Th1 response [222,223]