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Biomedical subjects

G Fabietti

Publications and source records attributed to G Fabietti.

9 recordsLinked to original sources
PubMed1997

Soluble CD30 antigen in human colostrum.

It is now well established that the CD30 glycoprotein is a surface antigen expressed by activated T cells producing T-helper (Th)-2-type lymphokines. Mounting laboratory evidence, however, suggests that CD30 expression is not confined to a functionally restricted subset of T cells, but also identifies activated cells with a Th-1 and Th-0 pattern of cytokine secretion. CD30-bearing T lymphocytes release a soluble form of the molecule (sCD30), which can be detected both in vitro and in vivo. In the present study, very high levels of sCD30 were found in colostrum from 20 puerperal women, but not in autologous and heterologous (nonpregnant women) blood samples. These data strongly support an involvement of CD30+ T cells in the immune processes which take place at the level of the mammary gland during pregnancy and lactation. Passively transferred immune components such as immunoglobulins, cytokines, macrophages, natural killer cells, granulocytes and memory/activated T cells, all of which may help the baby to fight off infections, have been revealed in human breast milk. However, how Th-2-type cytokine-secreting T cells or other T-cell types help to endow the congenitally immunocompromised newborn infant with extrinsic immunological support remains an open question.

Colostrum↗
PubMed1990

Human breast milk T lymphocytes display the phenotype and functional characteristics of memory T cells.

Naive (unsensitized) and memory (antigen-primed) T cells can be phenotypically distinguished on the basis of the high or low intensity with which they express a number of immunologically relevant lymphocyte membrane antigens, including CD45R, CDw29, UCHL1, LFA-1, LFA-3, CD2 and Pgp-1. Here we report that in contrast to the two major T cell subsets found in the blood, milk T lymphocytes are almost exclusively composed of the one which exhibits the CD45Rlow, CDw29, UCHL1, LFA-1high memory T cell phenotype. In addition, while milk and autologous blood cells expressed similar levels of CD3 surface antigens, CD2 and ICAM-1 expression was approximately twofold greater on the milk T lymphocytes. This agrees with the finding that whereas colostrum T cells respond poorly to PHA, they proliferate and produce interferon-gamma normally when stimulated with either the anti-CD3 or anti-CD2 monoclonal antibodies. The selective colonization of the mammary gland during lactation by a population of T lymphocytes which displays the phenotype and functional characteristics of memory T cells may be one of the mechanisms whereby the suckling infant benefits form its mother's immunological experience.

Antibodies, Monoclonal↗
PubMed1990

Lymphocytes bearing the T cell receptor gamma delta in human breast milk.

Lymphocytes bearing the T cell receptor gamma delta (TCR-gamma delta) were searched for in human early milk lymphocyte suspensions by two colour cytofluorimetric analysis. It was found that the proportion of TCR-gamma delta+ cells was twofold greater in colostrum than in either autologous or heterologous blood samples. Additional studies are needed to determine whether this particular subset of lymphocytes is involved in the lactation transmission of cellular immunity.

Colostrum↗
PubMed1989

T-cell response to phorbol ester PMA and calcium ionophore A23187 in Down's syndrome.

The proliferative response of purified T cells to anti-CD2 monoclonal antibodies (T112 plus T113) was found to be markedly reduced in 12 subjects with Down's syndrome (DS). The addition of phorbol ester PMA, which activates Ca2+/phospholipid-dependent enzyme protein kinase C, or calcium ionophore A23187, which increases intracytosolic free Ca2+ concentration, enhanced, but did not normalize, the defective anti-CD2-mediated T-cell mitogenesis. In contrast, the proliferation of resting lymphocytes from trisomic patients was comparable to that of the control cells when PMA and A23187 were used as co-blastogenic reagents. Because PMA and A23187 together bypass the early activation pathways and promote T-cell growth through the direct induction of membrane interleukin 2 (IL-2) receptor expression and IL-2 synthesis and secretion, it could reasonably be hypothesized that the faulty DS T-cell activation induced by antigen or mitogen is due to a deranged transmembrane signal transduction, rather than a defect in the later intracellular events.

Adolescent↗
PubMed1986

Phenotypic heterogeneity within the circulating human neonatal T4-positive T cell subset.

An indirect immunofluorescence staining technique was employed to evaluate the TQ1 and 5/9 monoclonal antibody lymphocyte reactivity in 10 cord blood mononuclear cell (MC) preparations enriched of E-rosette-forming cells (E+). Ten adult E+ MC populations were used as controls. Unfractionated T4+ cord and adult MC positively selected by panning procedure were also assayed. The results of these experiments, taken together, suggest that there is an overexpanded neonatal T cell subset which displays a previously unrecognized immunophenotype (T4+, TQ1+, 5/9+). Whether these lymphocytes are involved in the wellknown fetal-maternal immunosuppressive mechanisms of whether they are a further example of neonatal phenotypic immaturity remains to be elucidated.

Adult↗
PubMed1985

Acute infectious lymphocytosis: phenotype of the proliferating cell.

A case of acute infectious lymphocytosis in an otherwise healthy 2-year-old child is reported. Marker analysis of the expanded blood lymphocytes showed that they were predominantly T cells and that there was a considerable increase in the helper/inducer phenotype (OKT4+) population. However, the lymphocyte response to polyclonal T-cell activators was low. This is the first report on T-cell subset distribution in acute infectious lymphocytosis.

Acute Disease↗