CD40LG and meningococcal infection: Conjugation of the polysaccharide to carrier proteins such as tetanus toxoid and diphtheria toxin or its genetic mutant CRM197 improved the immunological response in terms of isotype antibody switching from IgM to IgG, which is more protective against meningococcal infection and the anamnestic response [36], [37], [38], [39].