Aging Aging

Dendritic Cells in Old Age 30512. DC precursors are only weakly adherent. Therefore it is important to avoid strongwashing after the initial 2 h of adherence lest the adherent fraction is depleted ofDC progenitors. If done correctly, control cultures of the nonadherent fraction,which is normally discarded, should not show aggregates.4.5. Generation of DCs from Human Blood CD34 + Progenitors13. The percentage of proliferating CD34 + precursors is extremely low (0.06% in theperipheral blood of healthy adults).4.6. Generation of DCsfrom Murine Bone Marrow CD34 + Progenitors14. It is essential to proceed quickly with the procedure. Avoid delays and interruptions.Initially, do not try to handle more than three mice at one time.15. Cell yields: Generally, we obtain up to 20–30 × 10 6 MHC class II-negative cellsfrom one mouse (two femurs and two tibias), of which most are washed away atd 2 of culture. By d 7, the yield of DCs is about 5 × 10 6 per mouse (60).Cell yields are dependent on the age of the mice. Five to six weeks is optimal.DC yields decline substantially at an age of more than 10 wk. It is preferable touse male mice. One usually obtains 30–50% more cells from male than fromfemale mice.References1. Steinman, R. M. (1991) The dendritic cell system and its role in immunogenicity.Annu. Rev. Immunol. 9, 271–296.2. Hart, D. N. J. (1997) Dendritic cells: unique leukocyte populations which controlthe primary immune response. Blood 90, 3245–3287.3. Süss, G. and Shortman, K. (1996) A subclass of dendritic cells kills CD4 T cells viaFas/Fas-ligand-induced apoptosis. J. Exp. Med. 183, 1789–1796.4. Steinman, R. M., Pack, M., and Inaba, K. (1997) Dendritic cells in the T-cell areasof lymphoid organs. Immunol. Rev. 156, 25–37.5. Kronin, V., Vremec, D., Winkel, K., Classon, B. J., Miller, R. G., Mak, T. W.,Shortman, K., and Süss, G. (1997) Are CD8 + dendritic cells (DC) veto cells? Therole of CD8 on DC in DC development and in the regulation of CD4 and CD8 T cellresponses. Int. Immunol. 9, 1061–1064.6. Banchereau, J. and Steinman, R. M. (1998) Dendritic cells and the control of immunity.Nature 392, 245–252.7. Schuler, G., Thurner, B., and Romani, N. (1997) Dendritic cells: from ignored cellsto major players in T-cell mediated immunity. Int. Arch. Allergy Immunol. 112,317–322.8. Stingl, G. and Bergstresser, P. R. (1995) Dendritic cells: a major story unfolds.Immunol. Today 16, 330–333.9. Caux, C., Liu, Y. J., and Banchereau, J. (1995) Recent advances in the study ofdendritic cells and follicular dendritic cells. Immunol. Today 16, 2–4.