Thymic function and T cell parameters in a natural human experimental model of seasonal infectious diseases and nutritional burden
<p>Abstract</p> <p>Background</p> <p>The study exploits a natural human experimental model of subsistence farmers experiencing chronic and seasonally modified food shortages and infectious burden. Two seasons existed, one of increased deprivation and infections (Jul-Dec...
| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
BMC
2011-06-01
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| Series: | Journal of Biomedical Science |
| Online Access: | http://www.jbiomedsci.com/content/18/1/41 |
| Summary: | <p>Abstract</p> <p>Background</p> <p>The study exploits a natural human experimental model of subsistence farmers experiencing chronic and seasonally modified food shortages and infectious burden. Two seasons existed, one of increased deprivation and infections (Jul-Dec), another of abundance and low infections (Jan-Jun); referred to as the hungry/high infection and harvest/low infection seasons respectively. Prior analysis showed a 10-fold excess in infectious disease associated mortality in young adults born in the hungry/high infection versus harvest/low infection season, and reduced thymic output and T cell counts in infancy. Here we report findings on the role of early life stressors as contributors to the onset of T cell immunological defects in later life.</p> <p>Methods</p> <p>We hypothesised that season of birth effects on thymic function and T cell immunity would be detectable in young adults since Kaplan-Meier survival curves indicated this to be the time of greatest mortality divergence. T cell subset analyses by flow-cytometry, sjTRECs, TCRVβ repertoire and telomere length by PCR, were performed on samples from 60 males (18-23 y) selected to represent births in the hungry/high infection and harvest/low infection</p> <p>Results</p> <p>Total lymphocyte counts were normal and did not differ by birth season. CD3<sup>+ </sup>and CD4<sup>+ </sup>but not CD8<sup>+ </sup>counts were lower for those born during the hungry/high infection season. CD8<sup>+ </sup>telomere length also tended to be shorter. Overall, CD8<sup>+ </sup>TCRVβ repertoire skewing was observed with 'public' expressions and deletions seen in TCRVβ12/22 and TCRVβ24, respectively but no apparent effect of birth season.</p> <p>Conclusions</p> <p>We conclude that, although thymic function was unchanged, the CD4<sup>+ </sup>and CD3<sup>+ </sup>counts, and CD8<sup>+ </sup>telomere length results suggested that aspects of adult T cell immunity were under the influence of early life stressors. The endemicity of CMV and HBV suggested that chronic infections may modulate immunity through T cell repertoire development. The overall implications being that, this population is at an elevated risk of premature immunosenescence possibly driven by a combination of nutritional and infectious burden.</p> |
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| ISSN: | 1021-7770 1423-0127 |