Phosphotyrosine-BSA is an antigen-adjuvant conjugate of Phosphotyrosine and bovine serum albumin (BSA). This conjugation enhances the production of antigen-specific antibodies in vaccine models by linking the antigen with a protein adjuvant. The conjugate does not alter protein folding or damage primary epitopes, and it also improves cross-presentation and the production of antigen-specific T cells.