Immunoglobulin synthesis by cord blood lymphocytes.

The IgG, IgA and IgM synthesis by adult peripheral blood and cord blood lymphocytes incubated alone and with pokeweed mitogen was quantitated. The cord blood lymphocytes produced no immunoglobulin even with mitogen stimulation while the adult peripheral blood lymphocytes responded to the mitogen with a significant (p less than 0.04) increase in immunoglobulin production.     

Early B lymphocytes in man

Summary We have confirmed in man the presence of a subpopulation of B lymphocytes which cannot reexpress their immunological receptors after challenge with antibodies. These early B lymphocytes were studied in peripheral blood, in cord blood and also, with anti-idiotypic sera, in the peripheral blood of a myeloma patient.Acknowledgments. This work was supported by CNR, Progetti finalizzati, Controllo della Crescita Neoplastica. We thank Prof. J. Urbain for helpful suggestions.     

Chromosome aberrations in in vitro irradiated lymphocytes from human cord blood.

An in vitro dose effect curve of dicentric chromosome aberrations in human cord blood lymphocytes has been obtained for 250-kV X-rays. This is compared with a curve prepared in an identical manner using blood from adults. The comparison shows a marginally higher dicentric yield in blood of newborns at doses above about 250 rads.     

I and i antigens of human erythrocytes : their detection by means of immunofluorescence technic and their changes during ontogenesis]

I and i antigens were detected by indirect immunofluorescence on human erythrocytes. 80% of the cord blood cells were brightly fluorescent with anti-i, 15% only with anti-I. In adult blood, this ratio is reversed, 2% only of the cells being intensively labelled with anti-i. The percentages characteristic of adult blood are established within the first 8 months of life.     

Erythrocyte catechol-0-methyltransferase and plasma dopamine-beta-hydroxylase in human umbilical cord blood

Plasma dopamine-beta-hydroxylase enzymatic activity and immunoreactive protein levels in human umbilical cord blood are only about 2% as great as values in the blood of older subjects. Erythrocyte catechol-0-methyltransferase activity levels in umbilical cord blood are very similar to those in the blood of adult subjects.     

Chromosome aberrations in in vitro irradiated lymphocytes from human cord blood

Summary An in vitro dose effect curve of dicentric chromosome aberrations in human cord blood lymphocytes has been obtained for 250-kV X-rays. This is compared with a curve prepared in an identical manner using blood from adults. The comparison shows a marginally higher dicentric yield in blood of newborns at doses above about 250 rads.Acknowledgment. We wish to thank Miss P. Orledge of the John Radcliffe Hospital, Oxford, for samples of cord blood, Mr M.J. Corp of the MRC Radiobiology Unit, Harwell, for irradiating the samples and Mr A.A. Edwards of NRPB, for help with statistics. The work was partly supported by Euratom Contract No. 171-76-1 BIO UK.     

Lymphopenia and lymphocyte transformation in alcoholics.

The basis of peripheral blood lymphopenia observed in patients with chronic alcoholism and liver disease was investigated by examining the effect of sera of these patients on in vitro transformation of normal human peripheral blood lymphocytes. A positive correlation was demonstrated between the serum inhibition of phytohaemagglutinin- and pokeweed mitogen-induced transformation and the degree of lymphopenia. Thus serum factors may contribute to the observed lymphopenia by inhibiting lymphocyte production in vivo.     

Inhibition of DNA biosynthesis in human lymphocytes by alpha 1-antitrypsin]

Incorporation of tritiated thymidine into human lymphocytes from tonsils is markedly inhibited by purified alpha1-antitrypsin-preparations. This inhibitory effect is observed in lymphocytes stimulated by a mitogen factor (phytohemagglutinin) as in non stimulated lymphocytes.     

Sensitivity of human lymphocytes to bleomycin increases with age.

The sensitivity of human peripheral blood lymphocytes to bleomycin and mitomycin-C was assessed by measuring the inhibition of phytohemagglutinin stimulated proliferation. The sensitivity to bleomycin, and not to mitomycin-C, increased with the age.     

Preparation of lymphocytes from small volumes of peripheral mouse blood.

A method was developed which allowed for the isolation of lymphocytes (95% of leukocytes in the final suspensions) from small volumes of peripheral mouse blood (38% recovery). The method proved of value for studies of murine lymphocytes which required biochemical analysis of samples from individual animals on a serial basis.     

Enhancement by caffeine of sister-chromatid exchange frequency induced by antineoplastic agents in human lymphocytes.

The SCE frequency induced by Thiotepa and the effect of this antineoplastic drug in combination with caffeine have been studied in cultures of human peripheral blood. Caffeine was found to enchance SCE and breakage frequencies induced by Thiotepa in human lymphocytes.     

Comparison of protein synthesis profiles in chronic lymphocytic leukaemia cells and B-lymphocytes from peripheral blood,cord blood and tonsil

2D-gel electrophoresis was used to investigate protein synthesis in leukaemic cells from a series of 15 chronic lymphocytic leukaemia (CLL) patients, and in non-malignant B-cell populations from different sources. The protein synthesis profiles of CD5+ B-cells from umbilical cord blood and from tonsil were determined, and the levels of expression of their proteins were observed to be similar to the CLL cells. The CD5-cells from cord blood resembled peripheral blood B-lymphocytes, and the protein synthesis profile of CD5-cells from tonsils was very complex. One protein was also identified which consistently appeared to be synthesised at a low level in CD5+ B-cells from tonsil but which was always more prominant in CLL cells and other non-malignant B-lymphocytes. On the basis of these data it is possible that the closest non-malignant counterpart to CLL is the CD5+ B-lymphocyte from cord blood.     

Stimulation of peripheral guinea pig blood lymphocytes by autologous epidermal cells]

Using a strictly autologous (and not syngeneic) mixed culture system in the guinea-pig, it was shown that Mitomycin C treated ear epidermal cells (E) were capable of stimulating peripheral blood lymphocytes (L) from the same animal. The proliferative response of the lymphocytes as measured by 3H thymidine incorporation, is optimal on the 5th day of culture, and when the ratio of the concentrations of the two cell populations (L : E) is 1 : 1. The autoreactivity of the lymphocytes varies with the animal.     

Isolation of a protease from the cell-free medium of in vitro cultured mammary carcinoma.

Trypsin-like protease with wide spectrum of enzymatic activities have been isolated from cell-free medium from in vivo cultured human mammary carcinoma cells, and from peripheral blood lymphocytes of patients with mammary carcinoma cultured in presence of cell-membrane carcinoma-associated glycoprotein.     

Mitogenic action of neuraminidase

Summary A new effect of NCV on lymphocytes is demonstrated. This property is the capacity to act as a mitogen in and of itself. The possible mechanisms of this phenomenon are discussed.     

Effect of a mitogenic concentration on membrane glycoconjugates of human lymphocytes

Periodate oxidation of human peripheral blood lymphocytes followed by reduction with 3H labelled sodium borohydride and acidic hydrolysis generates N-AN 7, glycerol and propane 1-2 diol. This indicates that sialyl, fucosyl and probably galactosyl residues are oxidized by periodate. Neuraminidase-treated lymphocytes exhibit decreased N-AN 7 levels, increased N-AN 8 levels and increased glycerol levels. Such results were neither found with mouse splenocytes nor with calf lymph node cells.     

Number of glucocorticoid receptors in lymphocytes and their sensitivity to hormone action

The study demonstrated a decreased level of glucocorticoid receptors (GR) in peripheral blood lymphocytes from hypercholesterolemic subjects, and an elevated level in patients with acute myocardial infarction. In the lymphocytes with a high GR number, dexamethasone inhibited [3H]-thymidine and [3H]-acetate incorporation into DNA and cholesterol, respectively, in the same manner as in the control cells. On the other hand, a decreased GR number resulted in a less efficient dexamethasone inhibition of the incorporation of labeled compounds. These data showed that the sensitivity of lymphocytes to glucocorticoids changed only with a decrease of GR level.