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Biomedical subjects

J Duchateau

Publications and source records attributed to J Duchateau.

At least 181 records · Page 10Linked to original sources
PubMed1982

Characterization of immunoregulatory T cells during pregnancy by monoclonal antibodies.

T Lymphocyte subpopulations were characterized by means of monoclonal antibodies in 44 pregnant women at different stages of gestation, and in 45 healthy controls. In the pregnant subjects, there is a small but significant reduction of the whole circulating T Lymphocytes and of their T helper subset identified respectively by OKT3 and OKT4 monoclonal antibodies. There is no influence of pregnancy on the proportions of T cytotoxic-suppressor cells (OKT8 positive) nor of lymphocytes bearing Ia antigen. Low counts of circulating cells with a thymocyte phenotype (OKT6 positive) are found in the two groups of subjects. It is concluded that pregnancy has a marginal effect on maternal immunocompetence.

Antibodies, Monoclonal↗
PubMed1981

Beneficial effects of oral zinc supplementation on the immune response of old people.

Zinc is known to have beneficial effects on the immune response. In an attempt to modify age-associated immune dysfunction, supplemental zinc was administered to 15 subjects over 70 years of age (220 mg zinc sulfate twice daily for a month). As compared to 15 controls, matched for age and sex, there was a significant improvement in the following immune parameters in the treated group: (1) number of circulating T lymphocytes; (2) delayed cutaneous hypersensitivity reactions to purified protein derivative, Candidin and streptokinase-streptodornase; (3) immunoglobulin G (IgG) antibody response to tetanus vaccine. Zinc treatment had no influence on the number of total circulating leukocytes or lymphocytes, or on the in vitro lymphocyte response to three mitogens: phytohemagglutinin (PHA), concanavalin A (Con A) and pokeweed mitogen (PWM). The data suggest that the addition of zinc to the diet of old persons could be an effective and simple way to improve their immune function.

Adult↗
PubMed1981

Influence of oral zinc supplementation on the lymphocyte response to mitogens of normal subjects.

Oral zinc sulfate was given for 1 month to 83 normal subjects distributed in four groups according to age (20 to 40; 40 to 60), sex, and oral contraception. Their in vitro lymphocyte response to phytohemagglutinin and Concanavalin A, and their serum zinc and copper levels were measured before and after treatment. They were compared in 20 untreated subjects. Zinc treatment significantly increased the lymphocyte response to phytohemagglutinin and Concanavalin A. In the group of women aged 40 to 60, this resulted in a normalisation of the response to Concanavalin A. The response to zinc was related to the starting value of lymphocyte stimulation obtained by phytohemagglutinin, i.e., in low responders this was enhanced whereas in high responders it tended to be reduced. Treatment increased serum zinc and had no effect on serum copper. There was no correlation between serum zinc or copper and the lymphocyte response. The beneficial effect of zinc supplementation on the lymphocyte response does not result from a correction of latent zinc deficiency.

Adult↗
PubMed1980

Differential responses to mitogen stimulation in lymphocytes from normal individuals and Lesch-Nyhan patients: influence of the bicarbonate buffer system.

Three patients affected with the Lesch-Nyhan syndrome were found to have normal levels of immunoglobulins, normal numbers of circulating B and T cells and normal IgG secretion in vitro in response to polyclonal activators. However, when cultures were performed in the absence of a bicarbonate buffer system, the proliferative response to several T cell stimulants (phytohaemagglutinin, concanavalin A and streptokinase-streptodornase) was impaired in Lesch-Nyhan cells as judged from the incorporation of labelled thymidine, uridine and leucine. This situation could be abolished by incubation in a 5% CO2 atmosphere and even reversed by supplementation of bicarbonate to the culture medium. Blocking the de novo purine synthesis by Methotrexate resulted in a more pronounced inhibition of the mitogenic response in Lesch-Nyhan lymphocytes than in normal cells. The differences in proliferative response between normal and Lesch-Nyhan lymphocytes with regard to culture conditions point to the critical role of the de novo pathway in lymphocyte stimulation.

Adolescent↗
PubMed1980

In vitro response of human peripheral blood lymphocytes of protein A. DNA synthesis and generation of cells synthesizing the three major classes of Ig.

Increased DNA synthesis and immunoglobulin secretion was observed in human peripheral blood lymphocytes (PBL) cultured in vitro with soluble protein A from Staphylococcus aureus (Sp-A). Optimal Ig secretion was obtained in 6 day cultures containing 1 x 10(6) cells/ml and 10 microgram/ml Sp-A. The presence of 5 x 10(-5) M 2-mercaptoethanol in the culture medium as well as careful selection of foetal calf serum were needed for optimal results. In response to Sp-A stimulation, the three main classes of immunoglobulins were secreted by PBL. In some individuals, concentration of Sp-A optimal for IgG and IgM secretion inhibited IgA production. Immunoglobulin-containing cells were less abundant (0.5--5% of total cells) and smaller in Sp-A than in PWM-stimulated cultures (5--15%). The data suggest that Sp-A and PWM stimulated different subsets of circulating lymphocytes.

Cells, Cultured↗
PubMed1976

In vitro response of subpopulations of human tonsil lymphocytes. I. Cellular collaboration in the proliferative response to PHA and Con A.

Human tonsil lymphocytes have been separated into three subpopulations of cells: purified B cells and two subsets of purified T cells (F1 and F2). B cells were obtained by rosetting with neuraminidase treated SRBC. F1 and F2 were separated by filtration on a nylon wool column using different speeds of elution. Purified B cells contained less than 5% T cells, the T cells preparations contained less than 5% B cells for F1 and 10 to 15% for F2, respectively. A significant contamination in cells not identified by any B or T marker was observed in purified B cells and in F1. Adherent cells enhanced the response of each lymphochte population to PHA and Con A. This explained the paradoxically low responsiveness of the purified T cells. Purified B cells did not respond to these mitogens in different culture conditions. However, a small B cell response was observed when they were cultured in the presence of mitomycin-treated T cells. Striking was the enhancing effect of B cells on the T cell response to PHA and Con A. This enhancing effect was observed even when B cells were treated with mitomycin or depleted in adherent cells. The comparison of the F1 and F2 response suggested that they contained distinct types of T cells.

B-Lymphocytes↗
PubMed1976

Cellular interactions in the proliferative response of human circulating lymphocytes to PHA-analysis of the impaired response in old age.

Peripheral blood lymphocytes (PBL) from old subjects were less responsive to PHA than those from young controls, in both groups the PBL content of macrophages, T and B cells were comparable. Macrophages were identified as peroxydase containing cells, rosette formation with sheep red blood cell was used as a T cell marker and immunoglobulin bearing lymphocytes were considered to be B cells. PBL were separated in two subpopulations of purified T cells (F1 and F2) differing in their responsiveness to PHA and in their ability to cooperate with B cells. Purified B cells had a synergistic effect on the F1 response to PHA whereas they were often suppressive for the corresponding F2 response. Peroxydase containing cells enhanced the response of unfractionated total PBL and of purified T cells in the young subjects. The depressed response of the old age group could be related mainly to a suppressive effect of monocytes and a decreased circulating pool of F1 T cells.

Adult↗