The present invention provides an immunogenic composition comprising a T-cell antigen in association with a rhamnose monosaccharide and/or Forssman disaccharide, and corresponding methods for inducing immune response. The T-cell antigen may be for example, a tumor vaccine, such as a tumor cell or one or more tumor antigens. The invention takes advantage of the naturally high titers of anti-Rhamnose and/or anti-Forssman disaccharide in humans to target vaccine compositions to antigen presenting cells.