Differential effects of respiratory syncytial virus and adenovirus on mononuclear ceil cytokine responses

Respiratory syncytial virus (RSV) and adenovirus (Advs) serotype 3 (Adv3) and 7h (Adv7h) are associated with mild to severe respiratory infection and are indistinguishable during the acute phases of the illnesses. However, outcome and long-term prognosis are different with both infections. RSV infection is associated with later development of asthma, and Adv, mainly Adv7h, with severe lung damage, bronchiectasis, and hyperlucent lung. We hypothesized that this difference could be partly due to different immune responses induced by these viruses. To test this hypothesis we quantified TCD4+, TCD8+, and BCD19+ expressing the interleukin-2 receptor-alpha chain (CD25) and interferon-γ (IFN-γ), interleukin (IL)-10, and IL-4 in the supernatant of peripheral blood mononuclear cells (PBMC) from school children infected in vitro with and without RSV, Adv7h, and Adv3 and after phytohemagglutinin (PHA) stimulation in the presence or absence of these viruses at a multiplicity of infection (MOI) of 1. PBMC from every child produced more IL-10 (p ≤ 0.05) when infected with RSV than with Advs and noninfected control, and Adv induced more (p ≤ 0.05) IFN-γ than did RSV and control. The IL-10/IFN-γ ratio was significantly higher (p ≤ 0.05) in RSV- infected and significantly lower (p ≤ 0.05) in Adv-infected PBMC, than in noninfected cells. PHA-stimulated BCD19+ RSV-infected cells expressed more (p ≤ 0.05) IL-2R than did Adv-infected cells. These results suggest that Advs induce a Th-1-type immune response that is not seen with RSV. These patterns persist despite intersubject variation in the absolute quantity of cytokine produced.