These agreed with previous findings that human influenza viruses are adapted to replicate in the upper respiratory tract at 33 37°C, whereas avian influenza viruses prefer to replicate in the gut at around 41°C [61], [62].
These results suggest that adaptation of avian influenza viruses in land-based birds such as quail and chickens, not only can result in the selection of strains better adapted to replicate in mice but also in the selection of strains that can rapidly acquire mutations that favor replication in mammals.
One hypothesis could be that HIV-1 is still an emerging viral pathogen that is not yet totally adapted to replicate in its different host cells i.e. it has not "achieved" the control of autophagy in both infected and uninfected cells, essentially macrophages and CD4 T lymphocytes, respectively.
Anyone who has spent much time examining the molecular structure of DNA soon realizes that it is adapted to replicate.
Sheep pox virus initially adapted to replicate in primary lamb kidney cells was adapted to Vero cells by serial passages in monolayer cultures.
The prevailing notion is that avian influenza viruses must undergo molecular changes before they become better adapted to replicate in mammals [37], [38].
Thus, we were interested in determining whether the adaptation of a duck H9N2 virus in quail and chickens would result in strains better adapted to replicate in mammals, particularly mice.
While GBV-B infects small New World primates like tamarins, marmosets and owl monkeys, but not chimpanzees [34], hence probably not humans either, neo-RepD replicon RNA is adapted to replicate in human hepatoma, Huh7-derived cells [30].
This could be interpreted as HIV-1 being better adapted to replicate in macrophages than in T cells.
Current influenza vaccines are trivalent or quadrivalent inactivated split or subunit vaccines administered intramuscularly, or live attenuated influenza vaccines (LAIV) adapted to replicate at temperatures below body temperature and administered intranasally.
