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Cytotoxic T lymphocyte activity in children infected with HIV
K S Froebel1, M C Aldhous, J Y Mok
1Department of Medicine, University of Edinburgh, United Kingdom.
Insights
Cytotoxic T lymphocyte (CTL) activity against HIV proteins was studied in infected children. CTL specificity varied with age, and while children with CTLs appeared well, long-term study is needed to link CTLs to HIV disease progression.
Area of Science:
- Immunology
- Virology
- Pediatrics
Background:
- HIV infection in children born to infected mothers presents unique challenges.
- Understanding the immune response, specifically cytotoxic T lymphocyte (CTL) activity, is crucial for managing pediatric HIV.
- Natural history studies provide vital insights into disease progression and immune dynamics.
Purpose of the Study:
- To investigate the development and specificity of CD8 T cell-mediated cytotoxicity against HIV proteins in infected children.
- To correlate CTL activity over time with clinical progression and viral activity.
- To explore the implications of CTL responses for HIV vaccine design.
Main Methods:
- Studied a cohort of children born to HIV-infected mothers, including those infected and uninfected.
- Assessed CTL activity against HIV proteins (Gag, Tat, Pol, Env) using autologous EBV cell lines and peripheral blood mononuclear cells.
- Analyzed clinical data and viral activity in relation to CTL responses.
Main Results:
- Six of nine HIV-infected children exhibited CTL activity against one or more HIV proteins.
- CTL specificity shifted from Tat in younger children to Pol, Gag, or Env in older children.
- Preliminary data showed no clear association between CTL activity and viral load, but children with CTLs tended to be clinically stable.
Conclusions:
- CTL responses against HIV proteins are present in infected children and exhibit age-dependent specificity.
- Further long-term follow-up is required to establish a definitive link between CTL activity and HIV disease progression.
- Understanding CTL specificity is important for designing effective HIV vaccines.
Abstract:
Of the Edinburgh cohort of approximately 130 children born to HIV-infected women, 9 are infected and alive. This article describes results from the first 18 months of a natural history study of seven of these, and two adopted children, studying the CD8 T cell-mediated cytotoxicity against HIV proteins (Gag, Tat, Pol, and Env), over time, and relating it to clinical progression and viral activity. Autologous EBV cell lines infected with vaccinia-HIV constructs were used as target cells, and bulk-cultured peripheral blood mononuclear cells as effector cells. The children ranged in age from 0 to 93 months, with six of the nine showing CTL activity to one or more HIV proteins. The specificity of the response was directed against Tat in the younger children, switching to Pol, then Gag or Env. Preliminary analysis of virological data showed no association between CTL and virus activity. The children with CTLs tended to be well clinically, but the cohort needs to be studied longer before conclusions can be made about CTL activity and HIV disease progression. Cytotoxic T lymphocyte activity has also been observed in two children diagnosed as HIV uninfected. These results show the importance of looking at CTL specificity, and may have implications in vaccine design.