Importance of the CD3 marker for evaluating changes in rhesus macaque CD4/CD8 T-cell ratios
✍ Scribed by Marta Dykhuizen; Jennifer Ceman; Jacque Mitchen; Maria Zayas; Alex MacDougall; Jody Helgeland; Eva Rakasz; C. David Pauza
- Publisher
- John Wiley and Sons
- Year
- 2000
- Tongue
- English
- Weight
- 184 KB
- Volume
- 40
- Category
- Article
- ISSN
- 0196-4763
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✦ Synopsis
Background: Until recently, there were no CD3 antibodies that crossreacted with rhesus macaque T cells. Consequently, studies relying on CD8 counts or CD4/CD8 ratios enumerated this subpopulation on the basis of CD8ϩ or CD8brightϩ staining. We used a rhesus-specific, anti-CD3 antibody to better define the CD8ϩ T-cell population, and to show the effects of better measurements on CD4/CD8 ratios and changes in T cells as macaques age. Methods: We used three-color flow cytometry to measure CD4 and CD8 populations with and without CD3 costaining. Venous blood samples were obtained from 52 colonybred macaques between 2 months and 9 years of age. Results: The CD8ϩ T cells defined by CD3 and CD8 double staining were approximately 60% of all cells that were stained by CD8 alone. Improved detection of this lymphocyte subset showed that CD4/CD8 ratios were close to the range of 1.5-2.0. Declining CD4/CD8 ratios during aging are predominantly due to decreasing CD4ϩ T-cell counts. Conclusions: Better quantitation of the CD8ϩ T-cell population showed that the CD4/CD8 ratio was not inverted as had been reported, but is actually very similar to the values observed in human beings. Although the two species differ in the pattern of CD8 expression, the general immune system characteristics are very similar.