Antonella Vitiello

Lymphocyte subpopulations in the neonate: a subset of HNK-1−, OKT3−, OKT8+ lymphocytes displays natural killer activity

It has been recently reported that cord blood lymphocytes (CBL) contain a subpopulation of OKT8+, sheep erythrocyte-rosetting negative (E-) cells not detectable in adult peripheral blood lymphocytes (a-PBL). The present studies were undertaken to characterize this subset of lymphocytes functionally and phenotypically. OKT8+ cells were purified from E-depleted CBL by negative selection on nylon-wool columns as well as by positive selection on plates coated with rabbit antibody to murine IgG (panning). The purified CBL displayed natural killer (NK) activity against K562 erythroleukemic cells. Although most of these CBL were large granular lymphocytes, they lacked typical NK markers such as HNK-1 and OKM1 surface antigens. Most OKT8+, OKT3- cells were also OKT10+, Ia+ and had the receptor for peanut agglutinin. These CBL may represent a stage along the differentiation pathway leading to mature NK or T cells.

Plaque Assay with Protein A‐coated Erythrocytes for the Evaluation of Human Immunoglobulin‐secreting Cells Induced by Pokeweed Mitogen

Cells secreting IgM, IgG and IgA were evaluated in cultures of human peripheral blood lymphocytes stimulated in vitro with pokeweed mitogen by a haemolytic plaque assay using protein A‐coated erythrocytes in the presence of class‐specifie antisera. Kinetic study revealed that immunoglobulin‐secreting cells appeared after 3 days of culture and peaked between days 5 and 7. IgM‐secreting cells predominated throughout the culture period. This plaque assay is a useful and sensitive in vitro test for the evaluation of polyclonal B‐cell activation in humans and may provide a good approach to the study of disturbances in the synthesis of the various classes of immunoglobulins.

Cell-mediated immunity in children with chronic cholestasis

Cell-mediated immune response was evaluated in 14 children with long-lasting intra- or extrahepatic cholestasis. Cell-mediated immunity was clearly depressed in children with intrahepatic cholestasis while children with extrahepatic biliary obstruction had a more modest and variable degree of impairment. This finding may be related to the longer duration of cholestasis and the higher total bile acid level in the intrahepatic compared to the extrahepatic group. In particular, in children with Byler disease, long-lasting, severe intrahepatic cholestasis was associated with depressed cell-mediated immunity and recurrent severe infections.

Polyclonal Activation of Human B Lymphocytes in Vitro by Pokeweed Mitogen: a Simple Technique for the Simultaneous Assessment of Cell Proliferation, Generation of Plasma Cells, Plaque‐forming Cells and Immunoglobulin Production

A simple technique has been worked out for the simultaneous assessment of cell proliferation, generation of plasma cells, plaque‐forming cells and immunoglobulin production from single cultures of 1 × 104 human peripheral blood lymphocytes stimulated with pokeweed mitogen (PWM). Kinetic studies showed that number of cells, thymidine incorporation rate, number of plaque‐forming cells against fluorescein‐isothiocyanate‐haptenated sheep erythrocytes and concentration of IgM and IgG in the supernatant peaked on the average between day 5 and 7 of culture. This technique is particularly suitable for the analysis of hypogammaglobulinaemias in infancy.

Effect of in vitro treatment with reducing drugs on structure and function of human secretory immunoglobulin as

SummarySamples of unstimulated whole saliva from 15 healthy children with 0.5–6 mg/100 ml of secretory IgA and from 10 healthy adults with 4–18 mg/100 ml of secretory IgA were pooled and treated in vitro with dithiothreitol andα-mercaptopropionylglycine. The effect of these reducing drugs on the immunochemical properties of secretory IgA was evaluated. Dithiothreitol induced depolymerization of secretory IgA and splitting of the secretory piece from the IgA molecule; furthermore it strongly reduced the titer of secretory antibodies toEscherichia coli antigens. The drugα-mercaptopropionylglycine apparently did not affect either the polymeric structure of secretory IgA or the titer of secretory anti-E. coli antibodies; however it induced splitting of the secretory piece. On the whole it appears that drugs with reducing properties, currently employed for liquifying mucous secretions in clinical practice, should be carefully evaluated for possible depressive side-effects on local immunity.ZusammenfassungProben von nicht stimuliertem komplettem Speichel von 15 gesunden Kindern mit 0,5–6 mg/100 ml sekretorischem IgA und von zehn gesunden Erwachsenen mit 4–18 mg/100 ml sekretorischem IgA wurden gesammelt und in vitro mit Dithiothreitol und Alpha-Mercaptopropionylglycin behandelt, und die Wirkung dieser reduzierenden Medikamente auf die immunchemischen Eigenschaften des sekretorischen IgA wurde untersucht. Dithiothreitol führte zu einer Depolymerisation des sekretorischen IgA und einer Abspaltung des sekretorischen Stücks vom IgA Molekül; darüber hinaus verminderte es stark den Titer der sekretorischen Antikörper gegenEscherichia coli-Antigene. Die Substanz Alpha-Mercaptopropionylglycin veränderte offensichtlich weder die polymere Struktur des sekretorischen IgA noch den Titer der sekretorischen anti-E. coli-Antikörper, jedoch bewirkte es eine Abspaltung des sekretorischen Stücks. Insgesamt scheint es, daß Medikamente mit reduzierenden Eigenschaften, die derzeit zur Verflüssigung von schleimigen Sekreten in der klinischen Praxis verwendet werden, sorgfältig auf ihre mögliche Nebenwirkung einer Verminderung der lokalen Immunität untersucht werden sollten.

Ascaris Suum Extract: Polyclonal Activator Properties as Possible Tools for Investigating in Vitro IgE Production in Humans

Intestinal infestation by parasites such as Nypponstrongylus brasiliensis and Ascaris suum is usually associated with high levels of serum IgE in animals and humans [1, 2].