A novel glycoprotein expressed on sheep T and B lymphocytes is involved in a T cell activation pathway

We have produced a new mouse mAb that identifies a sheep T cell activation Ag. The mAb B5-5 is specific for low m.w. components on nearly all sheep thymocytes and peripheral T and B lymphocytes but does not label immature B cells in Peyer's patches or germinal centers. After cross-linking of target structures either directly by plastic-bound mAb or indirectly using anti-Ig reagents, peripheral T cells, but not thymocytes or peripheral B cells, were activated. IL-2 was secreted by T cells after cross-linking and activation was strongly augmented in the presence of PMA. The addition of soluble B5-5 mAb to mitogen-stimulated cultures of sheep lymphocytes resulted in a suppression of PHA responses and augmentation of PWM responses and had a variable effect on Con A responses but had no effect on LPS- or protein A-induced proliferation. When added to alloantigen-stimulated cultures, B5-5 augmented the proliferative response. The B5-5 membrane component consists of 14- to 19-kDa glycoproteins but the banding patterns obtained during SDS-PAGE analysis of 125I-labeled Ag differed between thymocytes, peripheral T cells, and peripheral B cells. On the basis of its range of expression on lymphoid cells and known biochemical and functional properties, we conclude that the B5-5 component on sheep lymphocytes is different from T cell activation Ag in other species.     

Staphylococcus aureus at a maternity ward. II. Characterization of isolates by enterotoxigenicity and toxic shock syndrome toxin (TSST-1) production

Tests for enterotoxins A, B, C, D, E and TSST-1 production were carried out on 775 S. aureus strains isolated from various sources (50 mothers and neonates studied periodically, mothers and infants treated for various acute inflammatory conditions, members of hospital staff, environmental swabs) during the period 1981-1983 at a maternity ward chosen for a 3-year systematic study and on additional 97 isolates obtained in 1985 from another maternity ward. This had contributed to a better classification of strains within certain phage type groups. It was found that the distribution of S. aureus types in the particular sub-sets varied, depending on the source of isolates. At the maternity ward followed for 3 years there was a clear-cut trend towards the spread of phage-untypable isolates producing enterotoxin C whereas at ward examined for comparative purposes B enterotoxin producers of phage type 95 were predominant. The tests for enterotoxigenicity has also proved to be useful as the epidemiological marker characterizing the predominantly circulating S. aureus strain. It has been confirmed that the majority role in the spread of maternity-ward-staphylococci is played by the neonates and the factors of hospital environment.     

Immunological profiles in workers of a power plant burning coal rich in arsenic content

A group of 47 male adults working in a thermal power plant burning coal containing 900 to 1,500 g of arsenic per ton dry weight was examined on the blood serum immunoglobulins IgG, IgA and IgM content and levels of acute reactants alpha-1-antitrypsin (A1AT), alpha-2-macroglobulin (A2M), transferrin (TRF), orosomucoid (ORO) ceruloplasmin (CPL), and lysozyme (LYS). Investigations in the control group comprising 27 workers from another power plant in the same district where the coal content of arsenic was more than 10 times lower were analogous. The inter-group differences in means were evaluated by t-test, differences in the association of values by F-test, and the correlations with age and the length of exposure were assessed using the regression analysis method. The differences in mean IgG, IgA, IgM, LYS and A2M levels between the exposed and control groups of workers were insignificant or of borderline significance only. In contrast, differences in TRF, ORO and particularly CPL levels were statistically highly significant, in all instances P less than 0.001. In the control group, persons with abnormal values in at least two immunobiochemical tests used accounted for 3.7%, in the group of the exposed for 51% (P less than 0.002). All these findings, especially the rise in CPL concentration levels in the exposed group are discussed on the background of the rise in cancer mortality rates found previously in this group of power plant workers.     

The first clinical trial for determination of alpha 1 fetoprotein by means of Sevatest-ELISA AFP Kit (micro I)

At the Institute of Sera and Vaccines, Praha, was invented and tested on clinical samples a kit for detection and quantification of alpha 1 fetoprotein in human serum. It is a heterogeneous EIA on the "sandwich" principle. Rabbit antibody to alpha 1 fetoprotein (further AFP) was used for coating the solid surface and goat horse-radish peroxidase labelled antibody to AFP was used as the tracer. Microtitration plate of Czechoslovak manufacture (KOH-I-NOOR, Dalecín) type P with 96 wells was used as the solid phase. The range of an approximately linear part of the calibration curve was intentionally chosen between 10 and 400 ng/ml, since in this way it fills the detection gap in AFP determination between 10 and 200 ng/ml, which is, on the one hand, a physiological value of AFP in human serum and, on the other hand, the bottom limit of sensitivity of counter immunoelectrophoresis (CIEP). Attention was devoted both to reproducibility of the method, i.e. results of intra- and interassays, and comparability with other foreign ELISA Kits. According to the correlation analysis, the kit was ascertained to be very well comparable with kits of foreign provenance. The coefficient of variation (CV) for the interassays varied between 11 and 16% and for intraassays it equalled 15%.     

Distribution and excretion of 74As and 75Se in rats after their simultaneous administration. The effect of arsenic, selenium and combined pretreatment

The exposure of man to isolated toxic agent in the environment is rather a rare phenomenon. Therefore the study of a combined action of toxic substances is of increasing importance. The excretion and distribution of 74As (500 micrograms As.kg-1 b.wt.; Na74AsO2) and 75Se (525 micrograms Se.kg-1 b.wt.; Na275SeO3) was studied in rats after their separate and simultaneous i.v. injections. After simultaneous administration urinary as well as biliary excretion of 75Se and urinary excretion of 74As was increased in comparison with that in animals injected the radionuclides separately. Simultaneous administration of 74As and 75Se decreased concentration of 75Se in liver and increased concentration of 74As in kidney. In rats drinking water containing As (III) (0.66 mmol.l-1), Se(IV) (0.13 mmol.l-1) or combination As(III) + Se(IV) (at the same concentrations) for 7 or 28 days was studied the excretion and distribution of 74As and 75Se after their simultaneous i.v. injection (at the same concentrations and labelled compounds as mentioned above). The pretreatment with one element or with the combination of both elements significantly modified the distribution and excretion of subsequently administered 74As and 75Se.     

Characterization of envelope antigens of influenza A (H3N2) virus isolated during 1983-1985 epidemics and from sporadic cases of infection

Ten strains of influenza A (H3N2) virus isolated from an outbreak in 1983, and ten strains isolated in 1985 from sporadic cases of infection were included in the study. For characterization of envelope antigens were used the polyclonal and monoclonal antibodies tested in the reaction of haemagglutinin inhibition, neuraminidase inhibition, and by lectin test. The strains but slightly different in the tests with polyclonal antibodies could clearly be classified to 3-4 groups using 5 monoclonal antibodies to H antigen of A/Bangkok 1/79 and A/Philippines 2/82 strains. Strains from the 1983 epidemics represent a more homogeneous group of which only one of ten strains failed to react with monoclonals of the strains A/Bangkok and A/Philippines. Strains from sporadic cases of infection in 1985, except for two strains, did not react at all with the monoclonal discriminating A/Bangkok and A/Philippines. The other strains could be classified to three groups, i.e. whether they agreed with 4, 2 or none of the A/Philippines H antigen epitopes. Alterations of neuraminidase are less apparent, and cannot be defined by means of normal immune sera. With the use of monoclonal antibodies the strains under study do not react any more with the strains of 1968-1973 influenza virus; yet the monoclonals to A/Texas/77 strain still do recognize one or two epitopes of the 1983-1985 strains.     

Glucose-stimulated phosphorylation of yeast isocitrate lyase in vivo

Incorporation of 32P into Saccharomyces cerevisiae isocitrate lyase was observed after addition of glucose to a culture incubated with [32P]orthophosphoric acid. A band of 32P-labelled protein was coincident with the enzyme band when immunoprecipitates were subjected to SDS-PAGE and autoradiography. No label was found in the band corresponding to the isocitrate lyase when immunoprecipitation was done with a control pre-immune serum or in the presence of excess pure unlabelled enzyme. The incorporation of phosphate was associated with a decrease in enzyme activity. Phosphorylated isocitrate lyase was not proteolytically degraded when cells were cultured in mineral medium. The loss of protein antigenicity only took place when the yeast was grown in a complex medium containing glucose.     

Idiotype stimulation of T lymphocytes from Trypanosoma cruzi-infected patients

Anti-Trypanosoma cruzi epimastigote antibodies (anti-epi) from pooled and individual sera from patients with chronic Chagas' disease were purified on immunoaffinity columns of epimastigotes antigens (epi) coupled to activated Sepharose 4B. SDS-PAGE analysis of purified anti-epi preparations showed only the presence of human IgG H and L chains. These antibodies preparations showed similar Western blotting profiles as the sera pools from which they originated. The main polypeptides recognized by anti-epi had apparent molecular masses 31, 46, 51, 75 and 85 kDa. No difference in these patterns were detected between anti-epi from pooled sera of cardiac (anti-epiC) and indeterminate (anti-epiI) clinical forms. Anti-epi preparations (20 to 60 micrograms/ml) of pooled and individual sera stimulated proliferation of homologous and autologous PBMN or T-lymphocyte-enriched population. The stimulatory ability was dependent upon the PBMN-anti-epi combinations. There is no direct correlation between the level of PBMN response to epi and anti-epi stimuli. Comparison of the stimulatory activities of anti-epiC vs anti-epiI on PBMN of either cardiac or indeterminate group of patients indicate that anti-epiC is significantly more active than anti-epiI (p less than 0.025). These data demonstrate the presence of auto-anti-idiotypic-T cells in chagasic patients and lead to the possibility that idiotype/anti-idiotype interactions may play a role in determining the pathogenesis of chagasic cardiopathy.     

Calmodulin Acts as an intermediary for the effects of calcium on gap junctions from crayfish lateral axons

Summary Lateral axons from the abdominal nerve cord of cray-fish were internally perfused with the calcium receptor calmodulin (CaM) in solutions with low (pCa>7.0) or high (pCa 5.5) calcium concentrations and studied electrophysiologically and morphologically. Results from these experiments show that when the internal solution contains calcium-activated calmodulin (Ca²⁺-CaM) the junctional resistance between the axons increases from control values of about 60 to 500–600 k in 60 min. In contrast, axons perfused with calmodulin in low calcium solutions maintain their junctional resistance at control levels during the 60-min perfusion. Similar results are obtained when only one or both coupled axons are perfused.The morphological study shows that in the perfused axons the axoplasmic organelles are replaced or grossly perturbed by the perfusion solution up to the region of the synapses. Additionally, in axons perfused with Ca²⁺-CaM there are regions where the synaptic gap between the membranes decreases from a control 4–6 to 2–3 nm. Both electrophysiological and morphological results can be interpreted as indicating that calcium-activated calmodulin acts directly on the junctional channels to induce their closure.