In mice, HMPV and RSV infections induced age-dependent and virus-specific differences in TNF-α and NF-κB elevation, with young mice showing elevated NF-κB after HMPV infection and aged mice showing elevated NF-κB solely after RSV infection.
Does infection with RSV and/or HMPV induce different host responses in young versus aged BALB/c-mice?
Young and old mice exhibit different immunological responses (TNF-α and NF-κB levels) to RSV and HMPV infections despite similar clinical appearances.
BACKGROUND: Human metapneumovirus and respiratory syncytial virus can cause severe respiratory diseases, especially in infants, young children, and the elderly. So far it remains unclear why infections in the elderly become life threatening despite the presence of neutralizing antibodies in the serum, and to which extent double infections worsen the clinical course. METHODS: Young and aged BALB/c-mice were infected with RSV or/and HMPV. Appearance of the mice was observed during course of infection. On day 5 p.i. animals were dispatched by cervical dislocation and levels of TNF-α and NF-κB were determined. RESULTS: The observation of activity, weight and appearance of the different mice showed no differences among the tested groups. Despite this, the immunologic response depends on the animals' age and the virus they were infected with. In young animals, NF-κB levels were elevated if infected with HMPV and HMPV/RSV but remained low in RSV infections, whereas in aged animals the opposite was observed: solely RSV-infected animals showed elevated levels of NF-κB. TNF-α was slightly elevated in HMPV-infected young and old animals, but only in young animals this elevation was significant. CONCLUSIONS: Contrary to other studies, no weight loss or change in activity despite productive lung infection with the different viruses were observed. This may be due to the weaker anaesthesia or the lesser volume of virus solution used, leading to less stress in the animals. The observed differences in TNF-α and NF-κB elevation lead to the assumption that young and old individuals have different mechanisms to react against the viruses.
Ditt et al. (Wed,) conducted a other in Respiratory Infections by HMPV and RSV. HMPV and/or RSV infection vs. Mock infection, PBS, or anesthesia only was evaluated on TNF-α and NF-κB levels. In mice, HMPV and RSV infections induced age-dependent and virus-specific differences in TNF-α and NF-κB elevation, with young mice showing elevated NF-κB after HMPV infection and aged mice showing elevated NF-κB solely after RSV infection.