Phenotypic characterization of immature lymphoid cells in human umbilical cord blood

Abstract

SummaryThe antigenic phenotype of neonatal lymphoid cells isolated from umbilical cord blood was investigated using monoclonal antibodies and flow cytometry. Although the majority ofcells expressed mature T or B cell differentiation antigens, small subpopulations of phenotypically immature lymphocytes were detected. A small proportion (mean 2-8%) ofcells expressed the common acute lymphoblastic leukaemia antigen (CD-10), a significantly higher figure than that detected on adult peripheral blood lymphocytes. The cortical thymocyte antigen (CD-I) was detected on a very small subset of eord lymphoid eells, but was also present on adult lymphocytes at approximately the same frequency. The nuclear enzyme terminal deoxynucleotidyl transferase (TdT). a marker of early lymphoid differentiation, was detected by immunofluoreseenee on 0 031% of mononuclear cells in cytocentrifuge preparations, representing an approximate 10-fold increase in frequency over expression in childhood or adult blood. These circulating TdT+ cells were shown in double labelling experiments to predominantly express markers of B eell differentiation (CD-24, CD-10. MHC Class 2), although occasional cells co-expressing the T lineage marker CD-2 were also seen. These findings are consistent with the circulation of B cell precursors in neonatal blood. The nature ofthe CD-I + cells is unclear, although the absence of CD-1 ^ TdT"*" double labelled cells mitigates against the possible presenee of immature thymus-processed lymphocytes in these samples.

Fetal T-Lymphocyte Subpopulations in Normal Pregnancies

“…Furthermore, data derived from analysis of cord blood ob tained at term or premature delivery may have been affected by the stress of delivery or the underlying reason for premature birth, such as infection or hypoxia [9-1 1 ]. Addition ally, most previous studies have used tech niques to enumerate lymphocytes that may result in inaccurate estimations or selective loss of cellular populations [9][10][11][12][13]. Two stud ies which used direct whole blood staining techniques to examine T lymphocyte subpop ulations in large numbers of patients at 18-20 weeks and at term, respectively, demon strated results consistent with the data of the present study [8.…”

Immune Responses During Human Schistosomiasis Mansoni. XVIII. Immunologic Status of Pregnant Women and Their Neonates

“…Cord blood totals and differentials for neonates of infeeted mothers did not differ appreciably from literature values [22]. Our results with cord blood T-eell CD4 • and CDS ' subsets from seven neonates of Infected mothers apparently eontlict with most [27][28][29][30][31][32], but not all [33], studies on this topic. Generally, the CDS ' pereentage is ritthcr low in CBMC.…”

Immunological Characteristics of Umbilical Cord Blood Cells: Phenotypic and Functional Analysis

“…The variable number of contaminating immature nonlymphoid mononuclear cells remaining in cord cell suspensions after Ficoll may account for these differences. In our study, as in that of Bradstock (1988), the use of a flow cytometer may make it possible to select a small lymphoid window, thereby eliminating nonlymphoid cells.…”

“…(Bradstock et al, 1988) found, or significantly lower (Deacock et al, 1992;Foa et al, 1984;Hannet et al, 1992). The variable number of contaminating immature nonlymphoid mononuclear cells remaining in cord cell suspensions after Ficoll may account for these differences.…”