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 £12 months of age (39 males and 26 females, 28 cases <3 months and 37 cases ³3 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, whose acute-phase PBMC were mostly T lymphocytes (63.0 ± 9.0%). In contrast, a higher rate of seroconversion was observed in children >3 months of age, with predominance of B lymphocytes (71.0 ± 17.7%). Stimulation of PBMC with RSV (2 x 10 5 TCID 50 ) for 48 h did not induce a detectable increase in intracellular cytokines and only a few showed a detectable increase in RSVspecific secreted cytokines. These data suggest that age is an important factor affecting the infants' ability to develop an immune response to RSV.

Respiratory syncytial virus and human metapneumovirus in severe lower respiratory tract infections in children under two

“…This finding is consistent with data showing that hMPV has both seasonal and annual distribution; in a study conducted in Italy by Caracciolo et al [30], the incidence of hMPV infection was 25 There are several limitations to our study. The seasonality of infection with RSV or hMPV could bias our results, as our study took place over 6 months only, whereas a study of a full 12 months may have given a more accurate representation of the incidence of infection with RSV or hMPV.…”

“…Young age is a known vulnerability for severe RSV infection, and that was demonstrated in many studies [17,[21][22][23]. This can be attributed to lower cellular immunity [24], as in infants younger than six months of age, the maternally acquired antibodies are decreasing, with a half-life of about one month associated with lower magnitude of the humoral immune response to RSV in children younger than three months of age [25].…”

Epidemiology of Respiratory Pathogens in Children with Lower Respiratory Tract Infections in Shanghai, China, from 2013 to 2015

“…Thus, the incidence of CT infection primarily occurred in infants younger than 6 months. RSV was the most common viral cause of LRTIs in children, especially children younger than 6 months, and the prevalence of this pathogen decreased with age owing to the maturation of the immune system (19). PIV and other type 2 pathogens showed a peak detection rate in the ~24 mo or ~5 yr groups.…”

Molecular characterization of adenoviruses from children presenting with acute respiratory disease in Uberlândia, Minas Gerais, Brazil, and detection of an isolate genetically related to feline adenovirus

“…This kit was used for the detection of respiratory syncytial virus (RSV), parainfluenza viruses 1, 2 and 3 (PIV 1, 2 and 3), influenza viruses A and B (Flu A and B) and HAdV. We followed the classification of results (positive, negative or inconclusive) established by Queiróz et al (2002). RNA was extracted from IFnegative/inconclusive samples with Trizol ® (Invitrogen Corp, Carlsbad, CA), following the manufacturer's instructions.…”