Disclosed herein is the use of oxidatively transformed carotenoid for the preparation of a medicament for the enhancement of the adaptive immune response to an antigen in a subject being immunized, wherein said oxidatively transformed carotenoid is a mixture formed by reaction of 6 to 8 molar equivalents of oxygen with a carotenoid and contains a polymeric component, and wherein said infection is selected from the group consisting of community acquired pneumonia, upper and lower respiratory tract infection, skin and soft tissue infection, acute bacterial otitis media, bacterial pneumonia, pyelonephritis, intra-abdominal infection, bacterial sepsis, central nervous system infection, bacteremia, wound infection, peritonitis, meningitis, infections after burn, urogenital tract infection, pelvic inflammatory disease, endocarditis, and intravascular infection. . Also disclosed is a pharmaceutical composition comprising oxidatively transformed carotenoid and an antigen, wherein said oxidatively transformed carotenoid is a mixture formed by reaction of 6 to 8 molar equivalents of oxygen with a carotenoid and contains a polymeric component.
