Seroprevalence of human respiratory syncytial virus and human metapneumovirus in healthy population analyzed by recombinant fusion protein-based enzyme linked immunosorbent assay

Abstract

Background: Human respiratory syncytial virus (hRSV) and human metapneumovirus (hMPV) are two of the most frequent respiratory pathogens that circulate worldwide. Infection with either virus can lead to hospitalization of young children, immunocompromised people and the elderly.A better understanding of the epidemiological aspects, such as prevalence of these viruses in the population will be of significant importance to the scientific community. The aim of this study was to gain some detailed knowledge on the humoral immune response to both viruses in different populations of individuals.

Findings: The fusion protein (F) of hRSV and hMPV was expressed in the baculovirus and Escherichia coli systems, respectively, and used as antigen in two independent enzyme-linked immunosorbent assays (ELISAs) for detection of specific antibodies in human sera. The seroprevalence of each virus in a large cohort of individuals with ages ranging from 0 to 89 years old was determined. Although the general distribution of the antibody response to each virus in the different age group was similar, the prevalence of hRSV appeared to be higher than that of hMPV in most of them. The group of children with ages between 0 and 2 showed the highest seronegative rates. After this age, an increase in the antibody response was observed, most likely as the result of new infections or even due to reinfections.

Conclusions: The use of these specific F-ELISAs in seroepidemiological studies might be helpful for a better understanding of the human antibody response to these viruses.

Figure 1

Western blot analysis of recombinant F protein of hRSV (A) and hMPV (B). A specific pool of positive human sera against the F protein of each virus was used to confirm the antigenicity of the recombinant proteins. Lanes 0 represent the molecular weight markers expressed in kDa and lanes 1 show the reactivity against the F protein of hRSV and hMPV, respectively. The location of the proteins is indicated with an arrow.

Figure 2

Distribution of anti-human hRSV and hMPV antibodies in different age groups tested by F-ELISA. Bars represent the mean optical density of the positive serum samples included in each age group plus the standard deviation.