A novel filtration method for cord blood processing using a polyester fabric filter

Cord blood processing by a novel filtration system

Objectives

Availability of cord blood (CB) processing has been limited by the need for electrically aided centrifugal techniques, which often produce only low final cell product yield. Here, we describe development and characterization of a novel filter device aimed at allowing CB processing, using gentle gravity‐led flow.

Materials and methods

CB was processed with a novel filter device (CellEffic CB, consisting of non‐woven fabric), without any centrifugation. Cells were harvested by flushing the filter with either HES or physiological saline solution (SALINE). Differential cell counts and viability analysis, combined with Fluorescence‐Activated Cell Sorting (FACS) (total nucleated cells [TNC], mononuclear cells [MNC], CD45+ CD34+ cells, hematopoietic precursor cells [HPCs]) and clonogenic assay, were employed for analysis of CB pre‐ and post‐processing, and after freeze/thawing.

Results

Processing using the novel filter yielded high quality RBC depletion while maintaining good recovery of TNC, MNC, CD34+, HPCs and colony forming unit (CFU) output. The filter performed equally well using HES or SALINE. Gravity‐led flow provided gentle cell movement and protection of the stem cell compartment. Post‐thaw CFU output was maintained particularly, an important indicator for CB banking.

Conclusions

Geographical limitations of CB transplantation and banking have required a non‐electrical, non‐centrifugal solution. This novel filter CellEffic CB device revealed rapid yet gentle cell processing while maintaining the stem/progenitor cell compartment required for both haematological and regenerative medicine therapies.

Human CD38hiCD138⁺ plasma cells can be generated in vitro from CD40-activated switched-memory B lymphocytes

B lymphocyte differentiation into long-lived plasma cells is the keystone event for the production of long-term protective antibodies. CD40-CD154 and CD27-CD70 interactions are involved in human B lymphocyte differentiation into CD38(hi)CD138(+) cells in vivo as well as in vitro. In this study, we have compared these interactions in their capacity to drive switched-memory B lymphocytes differentiation into CD38(hi)CD138(+) plasma cells. The targeted B lymphocytes were isolated from human peripheral blood, expanded for 19 days, and then submitted to CD70 or CD154 interactions for 14 days. The expanded B lymphocytes were constitutively expressing CD39, whereas CD31's expression was noticed only following the in vitro differentiation step (day 5) and was exclusively present on the CD38(hi) cell population. Furthermore, the generated CD38(hi)CD138(+) cells showed a higher proportion of CD31(+) cells than the CD38(hi)CD138(-) cells. Besides, analyses done with human blood and bone marrow plasma cells showed that in vivo and de novo generated CD38(hi)CD138(+) cells have a similar CD31 expression profile but are distinct according to their reduced CD39 expression level. Overall, we have evidences that in vitro generated plasma cells are heterogeneous and appear as CD39(+) precursors to the ones present in bone marrow niches.