An Fcγ receptor I (CD64)-negative subpopulation of human peripheral blood monocytes is resistant to killing by antigen-activated CD4-positive cytotoxic T cells
✍ Scribed by Evelin Grage-Griebenow; Jaroslaw Baran; Harald Loppnow; Marek Los; Martin Ernst; Hans-Dieter Flad; Juliusz Pryjma
- Publisher
- John Wiley and Sons
- Year
- 1997
- Tongue
- English
- Weight
- 818 KB
- Volume
- 27
- Category
- Article
- ISSN
- 0014-2980
No coin nor oath required. For personal study only.
✦ Synopsis
An Fcy receptor I (CD64)aegative subpopulation of human peripheral blood monocytes is resistant to killing by antigen-activated CD4-positive cytotoxic T cells
It has been demonstrated that in monocyte/T cell co-cultures activated with recall antigens, cytotoxic T cells were generated which are able to reduce the number of antigen-presenting monocytes. In previous studies we could show that a minor subset of monocytes, the Fcy receptor I-negative (CD64-) monocytes, exhibits significantly higher antigen-presenting capacity than the main population of monocytes (> 90 'YO) which are Fcy receptor I-positive (CD64'). Therefore, we addressed the question whether they are also differentially susceptible to T cell-mediated killing. In the present study we demonstrate that the CD64-monocyte subset is more resistant to killing by antigen-activated T cells than CD64' monocytes, as indicated by a higher viability and recovery of CD64monocytes. This mechanism involves CD95 (Fas) antigen, since monocyte death in co-cultures with antigen-activated T cells could be partially reduced by blocking anti-Fas monoclonal antibodies (mAb). In agreement with this finding, although CD95 antigen was expressed on CD64+ and CD64-monocytes at comparable levels, killing of CD64-monocytes by activating anti-Fas mAb was lower than of CD64' monocytes.