A proprietary oligonucleotide with immunostimulatory activity. Immunostimulatory phosphorothiolate oligodeoxyribonucleotide SD-101 targets Toll-Like Receptor 9 (TLR9) found on a specialized subset of dendritic cells. The interaction of TLR9 with SD-101, in conjunction with an allergen or antigen, induces activation of memory T helper cells 1 (Th1) against a specific pathogen or allergen, thereby leading to long-lasting therapeutic effects. Furthermore, this agent does not cause a generalized activation of the immune system.