Adenovirus serotypes differ in their natural tropism. The adenovirus serotypes
2, 4, 5, and 7 all have a natural affiliation towards lung epithelia and other
respiratory tissues. In contrast, serotypes 40 and 41 have a natural affiliation
towards the gastrointestinal tract. The serotypes described, differ in at least
capsid proteins (penton-base, hexon), proteins responsible for cell binding (fiber
protein), and proteins involved in adenovirus replication. This difference in tropism
and capsid protein among serotypes has led to the many research efforts aimed at
redirecting the adenovirus tropism by modification of the capsid proteins.
