In one aspect, the invention relates to a method suitable for administering
protein therapeutic molecules orally, sublingually, topically, intravenously, subcutaneously, nasally, vaginally, rectally or by
inhalation so as to avoid inactivation, by using VHH polypeptides derived from Camelidae antibodies. The invention further relates to the said therapeutic molecules. The invention further a method for delivering therapeutic molecules to the interior of cells. The invention further relates to anti-IgE therapeutic molecules.In one aspect, the present invention relates to a method wherein an immunoglobulin
single variable domain (such as a Nanobody) and / or construct thereof are absorbed in pulmonary tissue. More particularly, the invention provides systemic delivery of an immunoglobulin
single variable domain and / or construct thereof via the pulmonary
route.