Expression of HLA‐DR, CAM and co‐stimulatory molecules on cord blood monocytes

Abstract

Umbilical cord blood (CB) transplantations are associated with a lower risk of severe graft‐versus‐host disease (GVHD) compared to BMT. GVHD is an immune reaction that involves interaction between cell surface molecules resulting in cell activation and release of many cytokines. Monocytes are known to be an important source of cell adhesion (CAM) and co‐stimulatory molecules which play a crucial role in the efficient activation of T and B cells. We analyzed the phenotype of CB monocytes in the presence or absence of an inflammatory signal (rIFN‐γ) and compared them to adult blood (AB); the expression of HLA‐DR and 17 different markers (CD11a, CD11b, CD11c, CD18, CD29, CD40, CD44, CD49a, CD49d, CD49e, CD49f, CD54, CD58, CD62L, CD80, CD86 and CD102) was measured by flow cytometry. Statistical analysis showed that, compared to AB, CB monocytes did not express CD11b, CD11c, CD49d and after stimulation with rIFNγ, they lost the expression of CD58 and CD102, whereas CD80 and CD86 expression was induced. The analysis of fluorescence intensity (MFI) revealed that CB monocytes expressed some CAM (CD29, CD54, CD102) with a lower intensity than AB monocytes except CD44. In conclusion, absence and reduced expression of some markers argue for a different phenotypic profile of CB monocytes compared to AB monocytes, which might partly contribute to their impaired immune response and to the low incidence of GVHD observed after CB transplantations. However, CB monocytes expressed CD80 and CD86 co‐stimulatory molecules, but this expression did not prove a normal co‐stimulatory function.

ORIGINAL ARTICLE: Isolation of Non‐Activated Monocytes from Human Umbilical Cord Blood

“…The present protocol yields 23–90 × 10 6 monocytes with a purity of 70–90% (average 83%) by adherence or 90–98% by flow cytometric analysis. The method is easy to apply with standard laboratory equipment, inexpensive with regard to necessary chemicals and compares well with the hyperosmolar isolation of cord blood monocytes using NycoPrep 1068 15 but does not subject the cells to hyperosmotic shock.…”