4-Hydroxynonenal/BSA is an antigen-adjuvant conjugate composed of 4-Hydroxynonenal and bovine serum albumin (BSA). This conjugation enhances the production of antigen-specific antibodies in vaccine models by coupling the antigen with a protein adjuvant. The conjugate maintains proper protein folding and does not disrupt major epitopes, while also improving cross-presentation and the generation of antigen-specific T cells.