Immune response to respiratory syncytial virus in young Brazilian children

Abstract

We have evaluated the cellular and humoral immune response to primary respiratory syncytial virus (RSV) infection in young infants. Serum specimens from 65 patients or = 3 months; median 3 ± 3.9 months) were tested for anti-RSV IgG and IgG subclass antibodies by EIA. Flow cytometry was used to characterize cell surface markers expressed on peripheral blood mononuclear cells (PBMC) from 29 RSV-infected children. There was a low rate of seroconversion in children 3 months of age, with predominance of B lymphocytes (71.0 ± 17.7%). Stimulation of PBMC with RSV (2 x 10(5) TCID50) for 48 h did not induce a detectable increase in intracellular cytokines and only a few showed a detectable increase in RSV-specific secreted cytokines. These data suggest that age is an important factor affecting the infants' ability to develop an immune response to RSV.

Keywords

• Respiratory syncytial virus
• Peripheral blood mononuclear cells
• Young children
• Surface antigens
• Cytokines