Immunoregulatory effects of fraction 5 thymus peptides. I. Thymosin alpha 1 enhances while thymosin beta 4 suppresses the human autologous and allogeneic mixed lymphocyte reaction

Thymosin alpha 1 and thymosin beta 4, two peptides isolated from preparations of calf thymus fraction 5, were tested in the human mixed lymphocyte reaction (MLR). Thymosin alpha 1 was found capable of enhancing both the allogeneic and autologous MLR. On the contrary, thymosin beta 4 suppressed MLR proliferative responses. Study of the responses of the T cell subpopulations revealed that T4+ (helper/inducer) cells but not T8+ (suppressor/cytotoxic) are responsible for the enhanced, proliferative response to allo- and autoantigens in the presence of thymosin alpha 1. Both the autologous and the allogeneic proliferative responses of either T4+ cells or T8+ cells were not influenced by the addition of thymosin beta 4 in the cultures. However, when T4+ and T8+ subsets were cocultured, thymosin beta 4 was capable of activating T8+ cells to suppress the allogeneic and the autologous proliferative response of T4+ cells. These studies show that thymosin fraction 5 peptides exert immunoregulatory effects on the human MLR proliferative responses in vitro.

Polyadenylic acid metabolizing enzyme levels during induction of differentiation in a human leukemia T-cell line with phorbol ester

Induction of differentiation of MOLT3 cells with 12-O-tetradecanoylphorbol-13-acetate (TPA) was found to affect the activity levels of the polyadenylic acid [poly(A)] metabolizing enzymes. TPA administration at a concentration of 16 nM resulted in an increase of poly(A) exonuclease and poly(A) polymerase activities after 2 and 2.5 hours, respectively, and in a decline to control levels thereafter. Cordycepin, an inhibitor of poly(A) polymerization, prevented the increasing binding of OKT11A monoclonal antibody induced by TPA treatment, whereas TPA-induced reduction in OKT6 monoclonal antibody binding persisted. The alterations in the poly(A) metabolizing enzyme activities following treatment of the cells with TPA, as well as the inhibitory effect of cordycepin, may suggest that these enzymes may be involved in the regulation of the differentiation process.

Effect of two thymosin fraction 5 polypeptides on human peripheral blood lymphocytes

Thymosin fraction 5 polypeptides beta 4 and alpha 1 were tested for their ability to affect certain immunological parameters of human peripheral blood lymphocytes (PBL). PBL were cultured with various concentrations of the peptides for 24 hours. Thymosin beta 4 was found to induce a significant decrease in the expression of the Fc alpha receptors of PBL, as well as in their ability to express antibody dependent cellular cytotoxic (ADCC) activity. In addition, this peptide had the ability to increase the percentage of T4 lymphocytes in normal and immunosuppressed donors and to decrease the percentage of T8 positive cells in normal donors. Finally, beta 4 peptide caused a small increase in the capacity of peripheral blood lymphocytes to form sheep red blood cell (SRBC) rosettes (ER). In parallel experiments thymosin alpha 1 was found inactive. The results presented here indicate that thymosin beta 4 may be used as an immunoregulatory molecule in patients with immunodeficiencies.

Dexamethasone caused alterations in poly(A) polymerase levels of a human leukemic cell line

The effect of glucocorticosteroids upon the poly(A) synthetic and degrading activity has been studied in steroid sensitive and resistant human leukemic cell lines. At least a two-fold increase in the levels of poly(A) polymerase activity was found in soluble, cytoplasmic extracts from the steroid sensitive human malignant T-cells of the MOLT3 line after 24-h treatment with dexamethasone. Longer exposure time of the cultured cells to the steroid resulted in a gradual decrease of the poly(A) polymerase activity level. Pretreatment of the cells with progesterone, a competitive inhibitor of dexamethasone, prevented the dexamethasone induced increase in the level of poly(A) polymerase activity, while progesterone alone had no effect on the enzyme level. In contrast, the levels of poly(A) nucleases activity remained constant following steroid treatment. In the steroid resistant human leukemic B-cell line Daudi no alterations in the poly(A) metabolizing enzymes could be measured in response to dexamethasone. Thus we suggest that poly(A) polymerase levels may be used to predict sensitivity of leukemic cells to glucocorticosteroid treatment.

Thymosin beta 4 induced phenotypic changes in Molt-4 leukemic cell line

Thymosin beta 4 was tested for its ability to induce phenotypic changes in the human T-cell line Molt-4. Cells were cultured with nanogram concentrations of thymosin beta 4 for up to 16 days and were analyzed with a panel of monoclonal antibodies, sheep erythrocyte rosetting, peanut agglutinin binding (PNA) and an antibody to the enzyme, terminal deoxynucleotidyl transferase (TdT). Thymosin beta 4 induced Molt-4 cells to reduce the expression of a T-cell lineage specific antigen, with preferential expression on T blast-cells, detected by WT 1 monoclonal antibody. Thymosin beta 4 also induced an increase in sheep erythrocyte rosettes and PNA binding as well as an increased expression of OKT 11 A and OKT 8 in Molt-4 cells. TdT was found to be unchanged, however. Analysis of thymosin beta 4-treated cells with other monoclonal antibodies (OKT 3, OKT 6, OKT 9) showed no change when compared to controls. These results showed that thymosin beta 4 is capable of inducing phenotypic changes in Molt-4 cells. Such changes may represent a differentiation process of these cells through the early stages of the maturation process of thymus-dependent lymphocytes, albeit not to the stage of mature T cells.

The biological effect of three thymosin fraction 5 polypeptides in the murine mixed lymphocyte reaction

The biological effects of three thymosin fraction 5 polypeptides, designated as beta 10, beta 4, and alpha 1 were tested in the MLR of mouse splenocytes, lymph node cells and thymocytes against syngeneic or allogeneic stimulators. It was found that all three polypeptides, after in vivo and in vitro treatment of the responder cell population, could enhance the allogeneic MLR. These polypeptides were also able to induce significant syngeneic MLR in systems where responder cells were used against irradiated syngeneic splenocytes. In addition, while beta 4 was shown to have a weak stimulatory effect on allogeneic MLR utilizing thymocytes as the responder cell type, alpha 1 could strongly induce such responses when syngeneic splenocytes were included into the culture system. Preincubation of purified mature T cells or thymocytes with alpha 1 has shown these cells to be the target of this polypeptide action. Thus, it appears that thymosin fraction 5 polypeptides not only initiate differentiation processes of immature T cells, but also exert their effects on mature T lymphocytes.

13C CP/MAS nuclear magnetic resonance of crystalline methylxylopyranosides

The 13C nmr spectra of solids, acquired using the Cross Polarization/Magic Angle Spinning (CP/MAS) technique, are very sensitive to the detailed nature of crystalline packing. These effects are illustrated in the CP/MAS spectra of the α and β anomers of methyl-D-xylopyranoside. In the spectrum of the α anomer, which crystallizes with two molecules per unit cell, individual spectra can be resolved for the two molecules in the asymmetric unit of this crystal.

Establishment and characterization of a B-cell line from a patient with acute lymphoblastic leukemia

A permanent lymphoblastoid cell line was established from the peripheral blood of a child with acute lymphoblastic leukemia. The cell line, designated SDK, grows in a stationary suspension culture, forming aggregates, in RPMI medium supplemented with 10% FCS, with a doubling time of 50-60 h. Immunologic markers and cytological features suggested that the SDK cells should be identified as being of B-cell origin. The cells failed to form rosettes with sheep erythrocytes, did not express T-cell antigens as defined by monoclonal antibodies, and exhibited surface and cytoplasmic immunoglobulin determinants. Chromosome analysis revealed the presence of three cell populations with (a) 46XY; (b) t(8q-; 14q+) or 2p-; 14q+) and (c) cells with unidentifiable markers. SDK demonstrated susceptibility to TPA-induced differentiation toward plasma cells.

Imide derivatives of 3-nitro-1.8-naphthalic acid: their inhibitory activity against DNA viruses

The antiviral action of a new drug, 5-amino-2-(dimethylaminoethyl)-benzo-[de]-isoquinolin-1.3-dione has been studied against herpes simplex type 2 (HSV-2) and adenovirus type 5 (Ad-5) grown in Vero cells. The concentration of the drug which gives a 5 log10 reduction in virus titer was 4 micrograms/ml (maximum tolerated concentration) for HSV-2. The anti-HSV-2 activity of this compound was one log. more powerful than that of iododeoxyuridine (IDU). At this concentration the drug shows virucidal activity against HSV-2. No inhibition was found when the drug was tested against Ad-5. The inhibition of virus production has been studied depending upon the amount of drug or virus, and drug addition-time after infection. Reversibility of inhibition after drug removal, and drug resistance in the presence of the drug have also been determined.

Rotamers arising from restricted motions and electromc interactions of acetoxymethyl groups in carbohydrates

The two dimensional conformational spaces available for acetoxymethyl groups in carbohydrates are reported. The studies were performed on two molecules differing in their C-4 configurations, i.e. gluco and galacto. The acetoxymethyl group was assigned a mean geometry derived from the computation of 19 equivalent groups as found in pertinent acetylated carbohydrates. The internal energy calculations were performed by including the partitioned contributions arising from the non-bonded energies, electrostatic interactions, and torsion energy. An instability rating of 3 kcal/mol was assigned to conformations involving peri interactions, i.e., trans–gauche and gauche–gauche forms in gluco and galacto carbohydrates, respectively. The results which are best described in term of topology show that several conformations corresponding to the trans and gauche states of the C—O single bond are preferred. However, significant shifts from perfect staggering are observed. The predicted regions of low energy are found to be in good agreement with experimental data from crystal structures of acetylated carbohydrates.

The inotropic memory of amphibian myocardium

(1) Experimentally observed changes of contractile force induced by changes in the pattern of stimulation of frog ventricular myocardium were compared with predictions computed on the basis of a model for the contractile conditioning, proposed in a previous paper. (2) For this purpose, two functions (Potentiation and Inhibition) which describe in the model the effect of previous contractions, were determined experimentally. (3) It is shown that the model adequately predicts : force-frequency curve Inotropic Effect Curves at different basal frequencies, effect of the suppression of a contraction in a sequence of definite frequency, frequency-staircases, and strength-interval curves. (4) The formal characteristics of the model are discussed, and it is suggested that the potentiation mechanism results from the recirculation of activator calcium in two types of compartments, from which calcium passes to the myofilaments during the contractions or is lost to the exterior with first order kinetics during the rest period. Possible locations for these compartments are proposed. Various hypothesis on the nature of the inhibitory mechanism are considered.

Crystal structure of β-D-acetyl cellobiose, C28H38O19

The crystal structure of β-D-acetyl cellobiose was studied by X-ray crystallography. The crystal data are a = 31.814(4), b = 19.414(5), c = 5.614(1) Å, space group P212121, Z = 4. The structure, solved by direct method, was refined by block-diagonal least-squares to a final R value of 0.075 for 2605 observed reflections. The molecular conformation involves 4C1 pyranose rings with glycosidic torsion angles corresponding to near maximum extension of the molecule. Substantial differences in conformational angles were observed between this molecule and the unacetylated counterpart. The molecules lie along the a-axis of the unit cell.