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

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.     

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.     

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.     

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.     

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.     

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.     

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.     

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.     

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

Summary 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 enhance SCE and breakage frequencies induced by Thiotepa in human lymphocytes.Acknowledgment. I am deeply grateful to Dr M.J.W. Faed, for stimulating discussions, guidance and constructive criticism. This paper is a part of my Ph.D. thesis submitted to Dundee University.     

Isoenzymes of creatine phosphokinase in white blood cells

Summary Creatine phosphokinase activity was found in human lymphocytes. Only MM type of the enzyme was detected in lymphocytes and polymorphonuclear leukocytes.Supported by U.S.P.H.S. MH 16 127. H.Y.M. is recipient of RCSA MH 47 808.     

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.     

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.     

The action of the cholecystokinin-A receptor antagonist,devazepide, on the digestive system of the chicken

The influence of the cholecystokinin (CCK)-A receptor antagonist, devazepide (DVZ), on the chicken digestive tract was investigated. The passage of food from the crops of birds treated with DVZ was not significantly different from that of the control. DVZ treatment did not inhibit the biliary flow stimulated by the CCK analogue, caerulein. Dispersed chicken pancreatic acini stimulated with CCK were treated with various concentrations of DVZ. At 10^–5 M, DVZ completely inhibited amylase release; this concentration was much higher than those reported to have similar effects in mammals. The results suggest that the action DVZ as a CCK antagonist in the chicken is very weak.     

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.     

Sensitivity of human lymphocytes to bleomycin increases with age

Summary 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.We thank Miss L. Bailey for excellent technical assistance and the Bristol-Myers Company for supply of bleomycin. This work was supported by the National Health and Medical Research Council of Australia and the Anti-Cancer Council of Adelaide University, South Australia.     

Dialyzable serum factors alter cellular immunity in pregnancy

Summary Lymphocyte responsiveness was found to be decreased in pregnant and increased in habitually aborting women. This is attributed to a dialyzable serum factor(s), that can be removed from the surface of lymphocytes by repeated washing.     

Tubuloreticular structures in chicken bursa Fabricii lymphocytes

Summary Tubuloreticular structures were observed in bursal lymphocytes of a 12-day-old male chicken. These structures are often observed in mammalian lymphocytes and endothelial cells. Their presence in bursal lymphocytes confirm their association with B-lymphocytes.We are grateful to Dr. J.L.F. Cristina Afonso for material support, to Mrs M. Lapão and J.P. Cristina Afonso for thier technical help, and to the Freixial Poultry Industry for providing the chickens.     

Suramin stimulates renal growth in the rat

Summary Suramin given to rats in a single high dose (20 mg/100 g i.v.) stimulated renal growth. Maximum changes are taking place after 6–9 days of treatment.Suramin (Bayer 205) was generously provided by bayer (Leverkusen, Federal Republic of Germany).The authors thank Miss J. Telegdy and Mrs I. Harmos for technical assistance and Mrs M. Herczeg for the preparation of the sections.     

Enzymatic characteristics of the catalytic subunit of the protein kinase complex of human lymphocytes]

In earlier reports we have shown the existence in human lymphocytes homogenate, of a cyclic-AMP dependent protein-kinase activity. We demonstrate by affinity chromatography that two subunits display respectively cyclic-AMP binding and phosphorylating properties. Divalent cations such as Ca++, Mg++ or Mn++ are required for enzymatic activity. ATP which is an obligatory cosubstrate acts as an inhibitor when its concentration is higher than 10(-6)M.