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Published on: January 26, 2019
Age-Specific Profiles of Antibody Responses against Respiratory Syncytial Virus Infection
Nao Jounai1, Megumi Yoshioka2, Miyuki Tozuka1
1Kitasato Daiichi Sankyo Vaccine Co., Ltd., 1-16-13 Kitakasai, Edogawa-ku, Tokyo 134-8630, Japan; Laboratory of Adjuvant Innovation, National Institutes of Biomedical Innovation, Health and Nutrition, 7-6-8 Saito-Asagi, Ibaraki City, Osaka 567-0085, Japan.
Insights
Infant immune responses to respiratory syncytial virus (RSV) mature over time, showing distinct stages in antibody development against the F protein. This research clarifies age-specific immunity crucial for understanding RSV protection in children.
Area of Science:
- Immunology
- Virology
- Pediatrics
Background:
- Respiratory syncytial virus (RSV) is a major cause of infant respiratory infections.
- Infants have passive immunity but immature active immune systems against RSV.
- Understanding age-specific immune responses is vital for RSV prevention.
Purpose of the Study:
- To investigate age-specific antibody profiles against RSV.
- To elucidate the maturation stages of immune responses in children.
- To analyze antibody characteristics related to RSV protection.
Main Methods:
- Examined blood samples from pediatric and adult RSV patients (acute and convalescent phases).
- Assessed serum neutralization activity and antibody responses to the RSV fusion (F) protein.
- Analyzed total IgG, IgG subclasses, binding stability, and neutralization epitope-specific antibodies.
Main Results:
- Identified at least 5 stages of antibody maturation against RSV in children.
- Stages are characterized by neutralization titers, IgG subclass levels (IgG1, IgG2, IgG3), and F protein-specific responses.
- Observed affinity maturation, cross-reactivity with RSV glycoproteins, and epitope-specific IgG levels.
Conclusions:
- Children's antibody responses to RSV mature over months and years.
- Repetitive RSV infections may augment overall antibody responses.
- Findings provide insights into developing effective RSV immunotherapies and vaccines.
Abstract:
Respiratory syncytial virus (RSV) is one of the most prevalent causative agents of lower respiratory tract infections worldwide, especially in infants around 3 to 4months old. Infants at such a young age have maternally-transferred passive antibodies against RSV but do not have active immune systems efficient enough for the control of RSV infection. In order to elucidate age-specific profiles of immune responses against RSV protection, antibody responses were examined by using blood samples in both acute and convalescent phases obtained from child patients and adult patients. In addition to the serum neutralization activity, antibody responses to the RSV fusion protein (F protein) were dissected by analyzing levels of total IgG, IgG subclasses, the binding stability, and the levels of antibody for the neutralization epitopes. It was suggested that children's antibody responses against RSV are matured over months and years in at least 5 stages based on 1) levels of the neutralization titer and IgG3 for F protein in the convalescent phase, 2) geometric mean ratios of the neutralization titers and levels of IgG1 and IgG2 for F protein in the convalescent phase compared to those levels in the acute phase, 3) the affinity maturation of IgG for F protein and the cross reactivity of IgG for RSV glycoproteins of groups A and B, 4) levels of neutralization epitope-specific IgG, and 5) augmentation of overall antibody responses due to repetitive RSV infection.
