Method for enhancing an immune response

Abstract

Disclosed is a method for enhancing an immune response to a substance, such as an antigen or microbial pathogen. The immune response can be, for example, production of IgG2 antibodies. The method comprises administering an immunostimulatory nucleotide sequence (ISS) to a subject at least one hour prior to exposure to the substance by the subject. The subject may be exposed to the substance either naturally, as with an environmental pathogen, or by administration, as with a known antigen. The method can be used for protecting or immunizing a subject against an antigen or pathogen, providing more effective immunization than if the ISS were co-administered with the substance. The method can be used prophylactically or therapeutically. In preferred embodiments, the ISS comprises a CG, p(GC) or p(IC) DNA or RNA nucleotide sequence. Of these, a CG containing nucleotide sequence is preferred. The ISS can further comprise a pG nucleotide sequence. Examples of an ISS include sequences comprising 5′-rrcgyy-3′, 5′-rycgyy-3′, 5′-rrcgyycg-3′ or 5′-rycgyycg-3′. The ISS is preferably administered between about 6 hours and about 6 weeks prior to exposure to the substance, and more preferably between about 1 day and about 4 weeks prior. Most preferably, the ISS is administered between about 3 days and about 8 days prior to exposure to the substance. The ISS can be administered via a mucosal or systemic route. The substance can be an antigen or pathogen associated with an infectious disease, an allergen or a cancer.