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Impaired gamma interferon responses against parvovirus B19 by recently infected children
A Corcoran1, S Doyle, D Waldron
1Mucosal Immunology Laboratory, National University of Ireland, Maynooth, County Kildare, Ireland.
Insights
Immunity to parvovirus B19 is complex. While adults develop a robust T-cell response, children show a deficit in interferon-gamma production, suggesting vaccine strategies must focus on conformational epitopes and Th1 adjuvants.
Area of Science:
- Virology
- Immunology
- Vaccinology
Background:
- Parvovirus B19 causes fifth disease and is linked to pregnancy complications and rheumatoid arthritis.
- The precise nature of protective immune responses to parvovirus B19 remains unclear.
- Understanding B19 immunity is crucial for developing effective vaccines and managing associated conditions.
Purpose of the Study:
- To investigate and compare humoral and cell-mediated immune responses to parvovirus B19 capsid proteins (VP1 and VP2).
- To analyze immune responses in recently infected children and long-term convalescent adults.
- To inform the design of future parvovirus B19 vaccines.
Main Methods:
- Examined immune responses to purified VP1 and VP2 proteins.
- Compared antibody reactivity and T-cell cytokine production in children and adults.
- Assessed immunoglobulin subclasses and cytokine profiles (IL-4, IL-5, IL-2, IFN-gamma).
Main Results:
- Antibody responses primarily target conformational epitopes on VP1 and VP2.
- The unique VP1 region is a key target for cell-mediated immunity in recent infections.
- Children showed a significant deficit in IFN-gamma production compared to adults.
Conclusions:
- Future parvovirus B19 vaccines should use conformationally preserved capsid proteins and Th1-driving adjuvants, especially for pediatric use.
- The findings suggest potential mechanisms linking B19 infection to rheumatoid arthritis and pregnancy failure.
- Immune response differences between children and adults highlight the need for tailored vaccine approaches.
Abstract:
Parvovirus B19 is the causative agent of "fifth disease" of childhood. It has been implicated in a variety of conditions, including unsuccessful pregnancy and rheumatoid arthritis, and is a potential contaminant of blood products. There has been little study of immunity to parvovirus B19, and the exact nature of the protective humoral and cell-mediated immune response is unclear. Immune responses to purified virus capsid proteins, VP1 and VP2, were examined from a cohort of recently infected children and compared with responses from long-term convalescent volunteers. The results demonstrate that antibody reactivity is primarily maintained against conformational epitopes in VP1 and VP2. The unique region of VP1 appears to be a major target for cell-mediated immune responses, particularly in recently infected individuals. We confirm that antibody reactivity against linear epitopes of VP2 is lost shortly after infection but find no evidence of the proposed phenotypic switch in either the subclass of parvovirus B19-specific antibody or the pattern of cytokine production by antigen-specific T cells. The dominant subclass of specific antibody detected from both children and adults was immunoglobulin G1. No evidence was found for interleukin 4 (IL-4) or IL-5 production by isolated lymphocytes from children or adults. In contrast, lymphocytes from convalescent adults produced a typical type 1 response associated with high levels of IL-2 and gamma interferon (IFN-gamma). However, we observed a significant (P<0.001) deficit in the production of IFN-gamma in response to VP1 or VP2 from lymphocytes isolated from children. Taken together, these results imply that future parvovirus B19 vaccines designed for children will require the use of conformationally preserved capsid proteins incorporating Th1 driving adjuvants. Furthermore, these data suggest novel mechanisms whereby parvovirus B19 infection may contribute to rheumatoid arthritis and unsuccessful pregnancy.