purified exotoxins

Can Be Converted Into Toxoid? Toxoid vaccines (e.g. vaccines for diphtheria and tetanus) are made by purifying the bacterial exotoxin (Flow Chart 26.3). Toxicity of purified exotoxins is then suppressed or inactivated either by heat or with formaldehyde (while maintaining immunogenicity) to form toxoids. Which toxins can be converted into toxoid by formaldehyde? Diphtheria toxoid