Immunologic effects of interleukin 2 in primary immunodeficiency diseases

Five children with primary deficiencies of T cell function were studied to assess the effects of highly purified exogenous Interleukin 2 (IL 2) on their in vitro T cell responses. The lymphocytes from one child with Nezelof's T cell deficiency demonstrated absence of endogenous IL 2 production and improved proliferative responses to mitogen or alloantigen in the presence of exogenous IL 2. Moreover, during in vitro mixed lymphocyte culture in the presence of exogenous IL 2, his lymphocytes were able to develop into cytotoxic effector cells. A second child with Nezelof's syndrome demonstrated a different type of defect. The lymphocytes from this child had less impairment of endogenous IL 2 production. Although IL 2 increased the proliferation of his cells in response to PHA, similar augmentation was not seen after stimulation with OKT3 or alloantigen. In cell-mediated cytotoxicity assays, after mixed lymphocyte culture, natural killer-like activity was strongly boosted in the cultures that contained IL 2, but T cell-mediated cytotoxicity was not. The lymphocytes from three patients with severe combined immunodeficiency did not show improved proliferative responses in the presence of IL 2. Thus, only one of the five patients demonstrated the combination of defective endogenous IL 2 production, but preservation of the ability to respond appropriately to exogenous IL 2. This child may therefore have suffered from a T cell defect pathophysiologically similar to that seen in nude or aged mice.     

The lymphocyte restimulation system: Evaluation by intra-HLA-D group priming

Homozygous typing cells (HTC) were primed, using responding and stimulating lymphocytes of the same HLA-D groups. These intra-HLA-D group primings showed strong specific responses. Restimulation by HLA-D heterozygous and homozygous cell panels showed no correlation between the restimulating determinant and HLA-D. On the other hand, an unrelated individual, not carrying Dw4 and primed to Dw4 HTC, is restimulated by three of four Dw4-HTC. Thus, one non-HLA-D-associated restimulating determinant and another HLA-D-associated determinant could be identified. The differences among the four Dw4 HTC recognized in secondary MLC could reflect either recognition of separate gene products or recognition of separate determinants on the same gene product.     

Climate‐driven rampant speciation of the Cape flora

Aim To test whether the radiation of the extremely rich Cape flora is correlated with marine‐driven climate change. Location Middle to Late Miocene in the south‐east Atlantic and the Benguela Upwelling System (BUS) off the west coast of South Africa. Methods We studied the palynology of the thoroughly dated Middle to Late Miocene sediments of Ocean Drilling Program (ODP) Site 1085 retrieved from the Atlantic off the mouth of the Orange River. Both marine upwelling and terrestrial input are recorded at this site, which allows a direct correlation between changes in the terrestrial flora and the marine BUS in the south‐east Atlantic. Results Pollen types from plants of tropical affinity disappeared, and those from the Cape flora gradually increased, between 10 and 6 Ma. Our data corroborate the inferred dating of the diversification in Aizoaceae c. 8 Ma. Main conclusions Inferred vegetation changes for the Late Miocene south‐western African coast are the disappearance of Podocarpus‐dominated Afromontane forests, and a change in the vegetation of the coastal plain from tropical grassland and thicket to semi‐arid succulent vegetation. These changes are indicative of an increased summer drought, and are in step with the development of the southern BUS. They pre‐date the Pliocene uplift of the East African escarpment, suggesting that this did not play a role in stimulating vegetation change. Some Fynbos elements were present throughout the recorded period (from 11 Ma), suggesting that at least some elements of this vegetation were already in place during the onset of the BUS. This is consistent with a marine‐driven climate change in south‐western Africa triggering substantial radiation in the terrestrial flora, especially in the Aizoaceae.     

M241 (CD1) expression on B lymphocytes

The human thymus leukemia-like antigens (CD1a-c) consist of three similar glycoproteins found on subpopulations of normal thymocytes, T cell acute leukemias, and cutaneous dendritic cells. The CD1c antigen recognized by the M241 monoclonal antibody was detected on the circulating mononuclear cells of three children with severe combined immunodeficiency disease (SCID). Two-color immunofluorescence analysis demonstrated that M241 expression (43 to 95%) was limited to cells expressing the B cell-restricted antigens B4 (CD19), B1 (CD20), and surface immunoglobulin. To confirm M241 expression on normal cells of the B lineage rather than aberrant expression limited to SCID B cells, its expression was demonstrated serologically and biochemically on purified B cells from spleen, tonsil, and peripheral blood. Parallel analyses with monoclonal antibodies NA1/34 and 4A76 demonstrated that the CD1a and CD1b molecules were negative on all B cells that were studied. It has been hypothesized that the CD1 molecules represent the human counterpart of the murine thymus leukemia antigens due to their similar size, limited tissue distribution, and association with beta 2-microglobulin. This study suggests that a subset of CD1 antigens detected by M241 (CD1c) may represent a human analog of a murine Qa antigen due to its extended distribution on normal peripheral B cells.     

Farnesylacetone, a sesquiterpenic hormone of Crustacea, inhibits electron transport in isolated rat liver mitochondria

Farnesylacetone (C18 H30 0) is a male hormone extracted from the androgenic gland of crab, Carcinus maenas. Appropriate enzymatic assays, as well as spectrophotometric studies, indicate that micromolar concentrations of farnesylacetone interact with the electron transport pathway of rat liver mitochondria. By the use of artificial electron donors and electron acceptors, it is shown that farnesylacetone immediately inhibits the electron transfer within complex I (NADH ubiquinone reductase activity) and complex II (succinate ubiquinone reductase activity). It is proposed that farneylacetone could interact with these two complexes of the respiratory chain at the level of the iron-sulfur centers implicated in the dehydrogenase activities. These observations are compared with the results obtained with terpenic molecules which interact with mitochondrial respiration.     

The utilization ofL-amino acids as carbon source by yeasts of the generaHansenula andTrichosporon

The assimilation of singleL-amino acids as carbon source in the absence of added nitrogen has been studied for all the described species in the generaHansenula andTrichosporon. The range in the number of amino acids used by individual species varied in the two genera, inHansenula from 0 to 6, inTrichosporon from 0 to 16. These characters were considered in relation to the phylogenetic scheme and ecological origin ofHansenula.     

Heterostyly in the Canarian endemic Jasminum odoratissimum (Oleaceae)

Jasminum odoratissimum is a Madeira and Canary Islands endemic showing classic heterostyly, i.e. with long-styled flowers with anthers at a low level in the corolla tube and short-styled flowers with anthers at a high level in the corolla tube. Short-styled flowers have large pollen, whereas long-styled flowers have small pollen. The two types are present in equal frequencies in the population.     

Localization of a proton-translocating ATPase on sucrose gradients

Ionophore-stimulated ATPase activity and ATP-dependent quinacrine quench were enriched in parallel when microsomal vesicles were prepared from corn (Crow Single Cross Hybrid WF9-Mo17) roots and collected on a cushion of 10% dextran. Activities were highest in the apical 1.5 centimeters of the roots. Vesicles collected on the dextran cushion also contained NADH cytochrome c reductase (enriched in the apical 0.5 cm of the root) and nucleoside diphosphatase (distributed throughout the first four cm). On continuous sucrose gradients, ATP-dependent proton transport and ionophore-stimulated ATPase activity coincided in a broad band extending from 1.08 to 1.15 grams per cubic centimeter with maximum activity at 1.10 to 1.12 grams per cubic centimeter. Large portions of the proton-translocating ATPase activity and ionophore-stimulated ATPase activity were clearly separable from mitochondrial membranes containing cytochrome c oxidase activity and azide-sensitive, pH 8.5 ATPase activity and from membranes bearing β-glucan synthetase I and II. The vesicles coincided with a minor portion of the NADH-cytochrome c reductase and nucleoside diphosphatase activities. It is suggested that the vesicles are of tonoplast origin.     

Differential behavior of cytotoxic effector cells against HLA antigens in strong genetic linkage disequilibrium

Five sets of cytotoxic effector cells were generated, using haploidentical, first degree relatives in five different families, against the HLA-A3; B7 serological determinants combined with different DR antigens. When tested against a panel of cells bearing combinations of the HLA-A, -B and -DR antigens it was shown that the HLA-B7 antigen was as strong a CML target determinant alone as it was in the presence of HLA-A3. The strength of the HLA-A3 antigen as target determinant varied. With effector cells primed to the HLA-A3; B7; DR2 haplotype, the A3 antigen alone behaved as a weak target determinant. When the same target cells were tested with the effector cells generated against HLA-A3; B7 without DR2, the A3 antigen behaved as a strong target determinant. A number of target cells lacking the serologically detectable HLA determinants present on the sensitizing HLA haplotype were identified as being killed by specific effector cells. These data suggest either a number of new CML target determinants controlled by different loci or the presence of a single, new locus with multiple alleles controlling CML targets.     

The effect of anesthetics on cardiovascular reactivity to isoprenaline in rats]

Compared study was performed in rats under chloral or urethanne anaesthesia after venous infusion of isoproterenol. Cardiovascular haemodynamics and capillary regional blood flows of digestive tract showed changes; cardiac output was increased only under chloral anaesthesia; nutritional flows were different according to anaesthesia.