Changes in the plasma membrane surface of lymphocytes stimulated in vivo with DNCB

Summary Stereological principles have been used to evaluate ultrastructural changes which accompany the transformation of lymphocytes stimulated in vivo with dinitrochlorobenzene (DNCB). Whereas unstimulated lymphocytes and blast cells have slightly more than the minimal containing plasmalemmal surface for their volume, stimulated (blast-derived) lymphocytes have an excess surface area in the order of 30%. This observation is discussed in the context of altered cell function and the biosynthesis of additional membrane components.We wish to thank Prof. R. Barer for his continued support and encouragement. The work was undertaken by M.M. A.-H. in part fulfilment of requirements for the degree of Ph. D. in this department. M.M. A-H. was supported by the Ministry of Higher Education and Scientific Research, Government of Iraq.     

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.     

alpha-Mercaptopropionyl-glycine influence on the in vitro proliferative response of human lymphocytes.

The effect of alpha-mercaptopropinyl-glycine on the in vitro proliferative response of healthy subjects' lymphocytes was studied. Low doses of the drug enhanced spontaneous lymphocyte blastigenesis but had no effect on the PHA-induced blastic response. With increasing concentrations of alpha-mercaptopropionyl-glycine inhibition of 3H-thymidine incorporation was found in unstimulated as well as in PHA stimulated lymphocytes.     

Receptors for cytomegaloviruses on the surface of human lymphocytes]

The relationships between cytomegalovirus (CMV) and lymphocytes have already been noted because of: (a) the immunological abnormalities induced by this virus, and (b) activation of latent CMV in the course of lymphocyte reactions associated with anti-histocompatibility antigen immune response. The present work shows that the lymphocyte surface may have specific receptors for CMV. Cultured fibroblasts infected with DMV were incubated with lymphocytes isolated from the blood of human immune subjects. Rosettes defined by the adherence of three or more lymphocytes around a fibroblast were formed in infected preparation while no rosettes were seen with normal control fibroblasts. Approximately 1.2 per cent of lymphocytes were involved in the formation of these rosettes. Rosette formation is inhibited when infected fibroblasts have been incubated with anti-CMV antibodies prior to the addition of lymphocytes.     

Differences in in vitro incorporation of tritiated deoxycytidine and tritiated thymidine into human lymphocytes.

Human lymphocytes stimulated in vitro by PHA or PWM incorporate 3H-CdR into DNA, but less well than 3H-TdR. More 3H-CdR is incorporated in populations enriched for T cells. No 3H-CdR is used by cells stimulated by lipopolysaccharides under circumstances in which 3H-TdR is incorporated. We conclude that human T cells and B cells differ in their ability to use 3H-CdR.     

Evaluation of cellular immunity after rabies vaccination in man]

The peripheral lymphocytes of vaccinated men were stimulated by homologous antigen or its subunits (nucleocapsid and glycoprotein) or by some parent viruses (Mokola and Lagos). All subjects produced a high level of antibody. A difference was noted between the two types of immunity. A lack of cell-mediated immunity could explain the very few failures in Pasteur antirabies treatment.     

Chronic overcrowding decreases cytoplasmic free calcium levels in T lymphocytes of aged CBA/CA mice

Intracellular calcium concentration is a sensitive marker of the homeostasis of living cells, and its increase is an essential step of T lymphocyte activation. Changes in the environment provoke an adaptive stress-response of the organism. In our present work we have investigated the effect of chronic overcrowding on resting and lectin-stimulated cytoplasmic free calcium concentration of splenic T lymphocytes from young and aged CBA/CA mice (50 animals total). The animals were kept under ‘normal’ (68 cm²/animal) or ‘overcrowded’ (22 cm²/animal) conditions for 3 months. Young animals showed no change in resting and stimulated calcium after overcrowding. T cells from aged mice, however, displayed significantly smaller levels of both resting and lectin-stimulated intracellular calcium concentration (p<0.01 each), as compared to those of the non-stressed, aged animals. This inadequate adaptation in the calcium metabolism of T lymphocytes may significantly contribute to the diminished immune response of the aged in stress.     

Differential binding of conA and WGA on the cell surface, the role of sialic acid in their expression and the increased activity of sialidase after cis-Platin treatment

It is reported that concanavalin A (conA) and wheat germ agglutinin (WGA) have a differential binding pattern on normal mouse spleen lymphocytes and the surface of Dalton's lymphoma cells. It is suggested that sialic acid on the cell surface controls the expression of lectin binding sites. Further, it has been observed that the increased release of sialic acid from cell surfaces after cis-dichlorodiammine platinum (II) (cis-Platin) treatment is due to the increased activity of sialidase.     

Effect of high doses of somatostatin on adenylate cyclase activity in peripheral mononuclear leukocytes from normal subjects and from acute leukemia patients

In normal lymphocytes somatostatin non-competitively inhibited basal (ID50 5 x 10(-4) M) and isoproterenol- and forskolin-stimulated adenylate cyclase activity (Ac). In acute leukemia blasts, non-responsive to isoproterenol, forskolin, which activates the catalytic subunit, stimulated and somatostatin inhibited Ac, thus indicating the leukemic enzyme, though defective, retains the inhibitory pathway and catalyst function.     

Differences in in vitro incorporation of tritiated deoxycytidine and tritiated thymidine into human lymphocytes

Summary Human lymphocytes stimulated in vitro by PHA or PWM incorporate³H-CdR into DNA, but less well than³H-TdR. More³H-CdR is incorporated in populations enriched for T cells. No³H-CdR is used by cells stimulated by lipopolysaccharides under circumstances in which³H-TdR is incorporated. We conclude that human T cells and B cells differ in their ability to use³H-CdR.     

Decrease of mast cells in regional lymph nodes in response to allogeneic antigens and syngeneic tumor antigens

Summary The absolute number of mast cells in regional lymph nodes decreases on the 5th day after stimulation by allogeneic lymphocytes and semisyngeneic leukaemic cells, despite the enlargement of stimulated lymph nodes. It is postulated that the reaction of lymphatic mast cells could be a sensitive test for tissue incompatibility, and probably also for the presence of tumor associated antigens.     

Differences in utilization of tritiated thymidine and tritiated deoxycytidine by rat lymph node cells.

Large lymphoid cells and plasma cells in antigenically stimulated rat lymph nodes retain less label after injection of 3H-CdR than after injection of 3H-TdR. There is no difference amongst small lymphocytes. The data are consistent with a defect in the utilization of 3H-CdR in the late stages of B cell maturation in the rat.     

A simple technique for testing the in vitro response of rabbit lymphocytes to PHA and allogeneic cells.

Lymphocytes of rabbits can be separated from small quantities of heparinized whole blood using a simple density gradient of Ficoll-Ronpacon 1.09. This separation technique yields a pure suspension of viable cells allowing reproducible results from cultures stimulated either with PHA or allogeneic lymphocytes isolated by the same technique.     

Differential binding of conA and WGA on the cell surface,the role of sialic acid in their expression and the increased activity of sialidase after cis-Platin treatment

Summary It is reported that concanavalin A (conA) and wheat germ agglutinin (WGA) have a differential binding pattern on normal mouse spleen lymphocytes and the surface of Dalton's lymphoma cells. It is suggested that sialic acid on the cell surface controls the expression of lectin binding sites. Further, it has been observed that the increased release of sialic acid from cell surfaces aftercis-dichlorodiammine platinum (II) (cis-Platin) treatment is due to the increased activity of sialidase.To whom reprint requests should be addressed.     

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.     

A simple technique for testing the in vitro response of rabbit lymphocytes to PHA and allogeneic cells

Summary Lymphocytes of rabbits can be separated from small quantities of heparinized whole blood using a simple density gradient of Ficoll-Ronpacon 1.09. This separation technique yields a pure suspension of viable cells allowing reproducible results from cultures stimulated either with PHA or allogeneic lymphocytes isolated by the same technique.Supported by the Swiss Science Foundation No. 3.890-0.77.     

C-type virus particles in lymphocytes cultured from cows with persistant lymphocytosis. Preliminary results on French cattle stock]

C type virus particles were shown in cultures of lymphocytes originating from cows with persistent lymphocytosis. These observations on French cattle are in complete accordance with data previously obtained in the USA. Viral replication is highly stimulated by the addition of phytohemagglutinin in the culture medium. Several morphological and biological properties, specific to the bovine virus differentiate this virus from C type viruses of other species.     

A mouse system for demonstrating the presence of inflammatory factors from human peripheral blood lymphocytes

Summary An assay system is described that allows the presence of inflammatory factors in supernatants from stimulated tuberculin-sensitive human peripheral blood lymphocytes to be demonstrated, by the induction of an inflammatory exudate in the peritoneal cavity of normal C57 BL mice.     

Effect of high doses of somatostatin on adenylate cyclase activity in peripheral mononuclear leukocytes from normal subjects and from acute leukemia patients

Summary In normal lymphocytes somatostatin non-competitively inhibited basal (ID₅₀ 5×10^–4 M) and isoproterenol- and forskolin-stimulated adenylate cyclase activity (Ac). In acute leukemia blasts, non-responsive to isoproterenol, forskolin, which activates the catalytic subunit, stimulated and somatostatin inhibited Ac, thus indicating the leukemic enzyme, though defective, retains the inhibitory pathway and catalyst function.     

Detection, by direct lymphocyte immunocytotoxicity, of antigens in cells transformed by Rous virus]

The hamster cells transformed by the Rous Sarcoma Virus (V.S.R.) evidenced surface antigenic alterations that were detected by a method of cellular mediated immunocytotoxicity. Immune hamster lymphocytes were added to tritiated proline prelabeled target cells. These lymphocytes were able to lyse specifically the V.S.R. transformed cells.