Thymosin induces helper function in OKT3-positive, E-rosette-negative human cord blood T cells

Impaired late suppression of Epstein-Barr virus (EBV)-induced immunoglobulin synthesis: a common feature of autoimmune disease

We examined regulation of Epstein-Barr virus-induced plaque-forming cell generation in peripheral blood mononuclear cells from several autoimmune and seronegative diseases and correlated these results with Epstein-Barr virus-induced proliferation. We confirmed the defective regulation of Epstein-Barr virus-induced plaque-forming cells in peripheral blood mononuclear cells of patients with rheumatoid arthritis and scleroderma. Peripheral blood mononuclear cells from patients with seronegative arthropathies and chronic infective inflammation (cystic fibrosis) had normal regulation of Epstein-Barr virus-induced plaque-forming cells. Peripheral blood mononuclear cells from rheumatoid arthritis had excessive plaque-forming cell generation in the face of a normally regulated decrease in Epstein-Barr virus-induced proliferation. In contrast, peripheral blood mononuclear cells from scleroderma had defective suppression of both Epstein-Barr virus-induced proliferation and plaque-forming cell generation. Thus, impaired regulation of Epstein-Barr virus-induced plaque-forming cell generation is a common feature of autoimmune disease and demonstrates some specificity for these disorders.

Phenotypic characterization of immature lymphoid cells in human umbilical cord blood

The antigenic phenotype of neonatal lymphoid cells isolated from umbilical cord blood was investigated using monoclonal antibodies and flow cytometry. Although the majority of cells expressed mature T or B cell differentiation antigens, small subpopulations of phenotypically immature lymphocytes were detected. A small proportion (mean 2.8%) of cells 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-1) was detected on a very small subset of cord lymphoid cells, 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 immunofluorescence 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 cell 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 of the CD-1+ cells is unclear, although the absence of CD-1+ TdT+ double labelled cells mitigates against the possible presence of immature thymus-processed lymphocytes in these samples.

Age-related changes in human lymphocyte subsets: progressive reduction of the CD4 CD45R (suppressor inducer) population

The purpose of this study was to investigate, by double-labeling immunofluorescence, lymphocyte subsets in the peripheral blood of healthy children, adults, and aged individuals. The absolute number of T and B lymphocytes decreases with age. The decline in T cells was attributed to a decrease in CD4 lymphocytes. We also found that the composition of the CD4 subset changes with age: in children the CD45R molecule is expressed on the majority of CD4 cells, whereas in aged subjects the absolute number of these lymphocytes is greatly reduced. The reciprocal CD4 CD29 population is not modified during the life span. Aging is also associated with the appearance of CD8 Leu 7 lymphocytes. Putative contrasuppressor cells, identified by Vicia villosa binding, represent a very small population in peripheral blood and are not subject to age-dependent variations.

Thymic hormone modulation of CD38 (T10) antigen on human cord blood lymphocytes

We studied the in vitro effect of three different thymic factors on the expression of CD38 (T10) antigen on cord T-lymphoid cell surface. The results showed that cord mononuclear cell populations contain variable percentages of CD38+ cells. The CD38 molecule was expressed on cord T and B lymphocyte and monocyte surfaces. Incubation with thymic agents induced a significant increases in the CD38+ cell percentage only in the samples with low CD38 antigen expression, and this modulation was mainly attributable to the T-cell subset. The effect seems to be specific and not correlated with the known high spontaneous DNA synthesis rate of cord mononuclear cells.

Phenotypic dissection of cord blood immunoregulatory T-cell subsets by using a two-color immunofluorescence study

Expression of TQ1(Leu8) and 2H4 antigens on human cord blood T-cell subsets was evaluated by a double immunofluorescence analysis. In normal adult blood all of the helper function for B-cell differentiation is confined to the smaller OKT4+TQ1-(Leu8-) cell subset, while the OKT4+TQ1+(Leu8+) cell subpopulation includes a subset of suppressor inducer 2H4+(JRA+) cells. Our results indicated that the OKT4+TQ1-(Leu8-) cell subpopulation was decreased and the reciprocal OKT4+TQ1+(Leu8+) cell subset was markedly increased in cord blood E-rosetting OKT3+ cell population. A rise in the number of cord OKT4+2H4+ cells was also found. In addition, TQ1 antigen was present on OKT3+E-, a less mature, cord T-cell subset, not present in adult blood. These findings may not only be of help in understanding lymphoid cell development during ontogeny, but also may agree with the reported strong-suppressor and weak-helper activities exerted by the T-cell subsets circulating in human cord blood.

Comparison of accessory cell functions of endothelial cells and monocytes: IL-2 production by T cells and PFC generation

It has been previously shown that endothelial cells (EC) can modulate T-cell responsiveness by mimicking monocyte (AC) function in several different in vitro systems. We now report that EC and AC differ quantitatively in their ability to provide help for IL-2 generation and T-cell induced B-cell differentiation into immunoglobulin secreting cells (ISC). Equal numbers of EC were deficient when compared to AC for promoting ISC generation, but exceeded AC for IL-2 production. Adding optimal numbers of EC drive non-adherent cell cultures to produce more than twice as much IL-2 as adding any number of AC. Furthermore, small numbers of EC were capable of modulating ongoing immune responses when added to cultures containing AC. IL-2 production by PBM was doubled by the addition of enough EC to comprise only 3% of the total culture. EC do not just mimic monocytes in immune responses, but modulate these responses in unique ways.