Respiratory syncytial virus specific serum antibodies in infants under six months of age: Limited serological response upon infection

Abstract

The decline of maternal respiratory syncytial virus (RSV) specific serum antibodies was studied in 45 children during the first 6 months of life, using a virus neutralization assay and competition ELISAs measuring fusion protein and glycoprotein specific antibodies. In all children RSV neutralizing antibodies were demonstrated at birth, with titers ranging from 33 to 1382. The calculated mean half life of these antibodies was 26 days. Furthermore, in a group of 38 children with suspected RSV infection, all younger than 6 months of age on admission, the diagnostic value of serological assays was evaluated. In 32 children RSV infection was confirmed by virus isolation, direct immune fluorescence and RT-PCR. In 7 patients of this group a significant titer rise in virus neutralization assay was demonstrated. Six additional RSV infected children could be identified by showing the presence of RSV-specific IgM or IgA serum antibodies or by showing an increase in fusion protein or glycoprotein specific antibodies. All serological tests together identified 13 (41%) of the 32 RSV infected patients. It is concluded that in children of this age group, which represent the majority of patients hospitalized with RSV infections, serological assays not only have a limited diagnostic value but are of limited value for sero-epidemiological studies.

Immune response to respiratory syncytial virus in young Brazilian children

“…The lower magnitude of the humoral immune response to RSV in children <3 months may suggest that: i) maternal antibodies may interfere with IgG-producing cells and mediate a temporary immunosuppression in infants; ii) most of the children <3 months are not able to produce sufficiently high antibody titers to be protected; iii) in most cases maternal antibodies did not have enough neutralizing activity against the RSV strains which caused the infections. Brandenburg et al (18) found variable titers of neutralizing antibodies (33 to 1382) in infants at birth, a fact that could explain, at least in part, why some children produce RSV-specific antibodies and others do not.…”

“…The decrease in RSV-specific antibodies detected in infants <1 month to 6 months of age is consistent with the loss of maternal antibodies, as reported previously (5,18). In the present study, examination of sera from RSV-infected children revealed that the total IgG levels were higher than IgG1 levels.…”

“…Tsutsumi et al (38) did not detect RSV-specific IgG seroconversion in nasopharyngeal secretions of children <2 months of age and observed that the titer of RSV-specific IgG was significantly lower in children <8 months than in children 8-17 months. Brandenburg et al (18) showed that only 7/32 RSV-infected children <6 months of age produced significantly increased neutralizing antibodies. The lower magnitude of the humoral immune response to RSV in children <3 months may suggest that: i) maternal antibodies may interfere with IgG-producing cells and mediate a temporary immunosuppression in infants; ii) most of the children <3 months are not able to produce sufficiently high antibody titers to be protected; iii) in most cases maternal antibodies did not have enough neutralizing activity against the RSV strains which caused the infections.…”

“…The peak age for hospitalization associated with RSV infection occurs in infants less than 6 months of age (1,10), an age when maternally acquired antibodies are decreasing with a half life of about one month (18). The presence of these antibodies may not protect children against RSV infection (19,20) and may even contribute to the disease process, as hypothesized by some investigators (4,21).…”

The transmission dynamics of groups A and B human respiratory syncytial virus (hRSV) in England & Wales and Finland: seasonality and cross-protection

“…The role of maternal antibodies in the transmission of hRSV at the population level is uncertain. It has been shown that higher levels of maternal antibodies are associated with increased protection from clinical infection [24], but this association is partial and probably short term (maternal antibodies are only present for 3-6 months [25]). For the purposes of the model presented, it is assumed that maternal antibodies have negligible effect on the transmission of the virus in the whole population.…”