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Generation and Assembly of Virus-Specific Nucleocapsids of the Respiratory Syncytial Virus
Published on: July 27, 2021
Dampening of IL-2 Function in Infants With Severe Respiratory Syncytial Virus Disease
Inés Sananez1, Silvina Raiden2, Fernando Erra-Díaz1
1Instituto de Investigaciones Biomédicas en Retrovirus y Sida (INBIRS), Facultad de Medicina, Universidad de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina.
Background:
FOXP3+ regulatory T cells (Tregs) restrain the destructive potential of the immune system. We have previously reported a pronounced reduction in circulating Tregs in infants with severe respiratory syncytial virus (RSV) disease. Because interleukin-2 (IL-2) is critical for Treg growth, survival, and activity, we here analyzed IL-2 production and function in RSV-infected infants.
Methods:
Phenotype, proliferation, IL-2 production, and IL-2 signaling in CD4+ T cells were analyzed by flow cytometry. Serum soluble CD25 levels were quantified by ELISA.
Results:
CD4+ T cells from RSV-infected infants produced lower amounts of IL-2 and showed a reduced proliferative response compared with healthy infants. IL-2 increased CD4+ T-cell proliferation and FOXP3 expression in both healthy and RSV-infected infants. However, although IL-2 induced a similar pattern of STAT5 phosphorylation, the proliferative response of CD4+ T cells and the expression of FOXP3+ remained significantly lower in RSV-infected infants. Interestingly, we found a negative correlation between disease severity and both the production of IL-2 by CD4+ T cells and the ability of exogenous IL-2 to restore the pool of FOXP3+CD4+ T cells.
Conclusions:
A reduced ability to produce IL-2 and a limited response to this cytokine may affect the function of CD4+ T cells in RSV-infected infants.
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