25-OH Vitamin D3/KLH is an antigen-adjuvant conjugate of 25-OH Vitamin D3 and Keyhole Limpet Hemocyanin (KLH). By conjugating the antigen with the protein adjuvant , the production of antigen-specific antibodies in vaccine models can be enhanced. The conjugate does not affect protein folding or disrupt major epitopes, and it can enhance cross-presentation and the generation of antigen-specific T cells.