Antigen-based vaccination and prevention of type 1 diabetes.

Insulin-dependent or type 1 diabetes (T1D) is a paradigm for prevention of autoimmune disease: Pancreatic β-cell autoantigens are defined, at-risk individuals can be identified before the onset of symptoms, and autoimmune diabetes is preventable in rodent models. Intervention in asymptomatic individuals before or after the onset of subclinical islet autoimmunity places a premium on safety, a requirement met only by lifestyle-dietary approaches or autoantigen-based vaccination to induce protective immune tolerance. Insulin is the key driver of autoimmune β-cell destruction in the nonobese diabetic (NOD) mouse model of T1D and is an early autoimmune target in children at risk for T1D.

T cell regulation mediated by interaction of soluble CD52 with the inhibitory receptor Siglec-10.

Functionally diverse T cell populations interact to maintain homeostasis of the immune system. We found that human and mouse antigen-activated T cells with high expression of the lymphocyte surface marker CD52 suppressed other T cells. CD52(hi)CD4(+) T cells were distinct from CD4(+)CD25(+)Foxp3(+) regulatory T cells.

Forward light scatter is a simple measure of T-cell activation and proliferation but is not universally suited for doublet discrimination.

Following activation by antigen, T cells enter the cell cycle in stages that can be defined with flow cytometric markers. We show that these markers include the increase of forward light scatter width (FSC-W) signal and the ratio of FSC area/peak. This change in light scatter precedes the first cell division and may reflect blast transformation.

Erythropoiesis from adult but not fetal blood-derived CD133+ stem cells depends strongly on interleukin-3.

We have shown previously that erythropoiesis in cultures from fetal blood depends less on interleukin-3 (IL3) than erythropoiesis from adult blood. This paper explores if this is due to different proportions of stem cell sub-populations with different IL3 requirement, or to different IL3 requirement on fetal and adult stem cells in general. The CD133 (AC133) antigen is found on half of all CD34+ cells with erythropoietic potential and is thought to mark a primitive stem cell sub-population.

IL-3-dependent early erythropoiesis is stimulated by autocrine transforming growth factor beta.

Autocrine/paracrine transforming growth factor beta (TGF-beta) is an important regulator of stem cell quiescence and generally suppresses stem cell proliferation. However, we show here that during the first few days of an erythroid cell culture from adult blood stem cells, the presence of neutralizing antibodies against TGF-beta had a suppressive effect on subsequent erythropoiesis, indicating a stimulatory action of autocrine TGF-beta. The suppression occured in the form of a delay in erythroblast proliferation rather than a reduction in final erythroid colony numbers.

Reactivation of fetal hemoglobin in adult stem cell erythropoiesis by transforming growth factor-beta.

Treatment of adult blood-derived stem cells with transforming growth factor (TGF-beta) during the first 3-4 days in culture increases the proportions and absolute numbers of erythroid cells subsequently expressing fetal hemoglobin (F+ cells). The change in F+ cell proportions may be due to globin switching or to selective effects on the expansion of stem cell subpopulations with different globin expression programs. To distinguish between the two mechanisms, we compared the effects of TGF-beta on proliferation and globin expression with the effects of well-researched agents known to increase fetal hemoglobin (HbF) in sickle cell patients.

A simple and sensitive erythroblast scoring system to identify fetal cells in maternal blood.

Objectives: Nucleated red blood cells (NRBCs) of fetal origin appear to have distinguishable characteristics from that of maternal NRBCs in both nuclear morphology and properties of hemoglobin staining. However, these differences have yet to be quantified. Our aim was to develop an erythroblast scoring system using four distinct phenotypic parameters (nuclear roundness, nuclear morphology, gamma hemoglobin staining intensity, and peripheral brightness of the stained cytoplasm) to address this issue.

Fetal cell isolation from maternal blood cultures by flow cytometric hemoglobin profiles. Results of a preliminary clinical trial.

Objective: We conducted a trial to test if the blood of pregnant women contains fetal clonogenic erythroid cells the progeny of which can be identified and isolated by a newly developed flow-sorting procedure.

Methods: We have previously demonstrated the identification of fetal nucleated red cells in cocultures of fetal and adult blood. The procedure is based on profiles of the correlated contents of fetal and adult hemoglobin (HbF and HbA, respectively), using antibodies specific for the different hemoglobin chains.