Time-resolved X-ray diffraction diagnostic development for the National Ignition Facility

We present the development of an experimental platform that can collect four frames of x-ray diffraction data along a single line of sight during laser-driven, dynamic-compression experiments at the National Ignition Facility. The platform is comprised of a diagnostic imager built around ultrafast sensors with a 2-ns integration time, a custom target assembly that serves also to shield the imager, and a 10-ns duration, quasi-monochromatic x-ray source produced by laser-generated plasma. We demonstrate the performance with diffraction data for Pb ramp compressed to 150 GPa and illuminated by a Ge x-ray source that produces ∼7 × 1011, 10.25-keV photons/ns at the 400 μm diameter sample.

Extended X-ray absorption fine structure of dynamically-compressed copper up to 1 terapascal

Large laser facilities have recently enabled material characterization at the pressures of Earth and Super-Earth cores. However, the temperature of the compressed materials has been largely unknown, or solely relied on models and simulations, due to lack of diagnostics under these challenging conditions. Here, we report on temperature, density, pressure, and local structure of copper determined from extended x-ray absorption fine structure and velocimetry up to 1 Terapascal. These results nearly double the highest pressure at which extended x-ray absorption fine structure has been reported in any material. In this work, the copper temperature is unexpectedly found to be much higher than predicted when adjacent to diamond layer(s), demonstrating the important influence of the sample environment on the thermal state of materials; this effect may introduce additional temperature uncertainties in some previous experiments using diamond and provides new guidance for future experimental design.

X-ray diffraction at the National Ignition Facility

We report details of an experimental platform implemented at the National Ignition Facility to obtain in situ powder diffraction data from solids dynamically compressed to extreme pressures. Thin samples are sandwiched between tamper layers and ramp compressed using a gradual increase in the drive-laser irradiance. Pressure history in the sample is determined using high-precision velocimetry measurements. Up to two independently timed pulses of x rays are produced at or near the time of peak pressure by laser illumination of thin metal foils. The quasi-monochromatic x-ray pulses have a mean wavelength selectable between 0.6 Å and 1.9 Å depending on the foil material. The diffracted signal is recorded on image plates with a typical 2θ x-ray scattering angle uncertainty of about 0.2° and resolution of about 1°. Analytic expressions are reported for systematic corrections to 2θ due to finite pinhole size and sample offset. A new variant of a nonlinear background subtraction algorithm is described, which has been used to observe diffraction lines at signal-to-background ratios as low as a few percent. Variations in system response over the detector area are compensated in order to obtain accurate line intensities; this system response calculation includes a new analytic approximation for image-plate sensitivity as a function of photon energy and incident angle. This experimental platform has been used up to 2 TPa (20 Mbar) to determine the crystal structure, measure the density, and evaluate the strain-induced texturing of a variety of compressed samples spanning periods 2-7 on the periodic table.

Probing the Solid Phase of Noble Metal Copper at Terapascal Conditions

Ramp compression along a low-temperature adiabat offers a unique avenue to explore the physical properties of materials at the highest densities of their solid form, a region inaccessible by single shock compression. Using the National Ignition Facility and OMEGA laser facilities, copper samples were ramp compressed to peak pressures of 2.30 TPa and densities of nearly 30  g/cc, providing fundamental information regarding the compressibility and phase of copper at pressures more than 5 times greater than previously explored. Through x-ray diffraction measurements, we find that the ambient face-centered-cubic structure is preserved up to 1.15 TPa. The ramp compression equation-of-state measurements shows that there are no discontinuities in sound velocities up to 2.30 TPa, suggesting this phase is likely stable up to the peak pressures measured, as predicted by first-principal calculations. The high precision of these quasiabsolute measurements enables us to provide essential benchmarks for advanced computational studies on the behavior of dense monoatomic materials under extreme conditions that constitute a stringent test for solid-state quantum theory. We find that both density-functional theory and the stabilized jellium model, which assumes that the ionic structure can be replaced by an ionic charge distribution by constant positive-charge background, reproduces our data well. Further, our data could serve to establish new international secondary scales of pressure in the terapascal range that is becoming experimentally accessible with advanced static and dynamic compression techniques.

X-Ray Diffraction of Solid Tin to 1.2 TPa

We report direct in situ measurements of the crystal structure of tin between 0.12 and 1.2 TPa, the highest stress at which a crystal structure has ever been observed. Using angle-dispersive powder x-ray diffraction, we find that dynamically compressed Sn transforms to the body-centered-cubic (bcc) structure previously identified by ambient-temperature quasistatic-compression studies and by zero-kelvin density-functional theory predictions between 0.06 and 0.16 TPa. However, we observe no evidence for the hexagonal close-packed (hcp) phase found by those studies to be stable above 0.16 TPa. Instead, our results are consistent with bcc up to 1.2 TPa. We conjecture that at high temperature bcc is stabilized relative to hcp due to differences in vibrational free energy.

Planetary science. Shock compression of stishovite and melting of silica at planetary interior conditions

Deep inside planets, extreme density, pressure, and temperature strongly modify the properties of the constituent materials. In particular, how much heat solids can sustain before melting under pressure is key to determining a planet's internal structure and evolution. We report laser-driven shock experiments on fused silica, α-quartz, and stishovite yielding equation-of-state and electronic conductivity data at unprecedented conditions and showing that the melting temperature of SiO2 rises to 8300 K at a pressure of 500 gigapascals, comparable to the core-mantle boundary conditions for a 5-Earth mass super-Earth. We show that mantle silicates and core metal have comparable melting temperatures above 500 to 700 gigapascals, which could favor long-lived magma oceans for large terrestrial planets with implications for planetary magnetic-field generation in silicate magma layers deep inside such planets.

Ramp compression of diamond to five terapascals

The recent discovery of more than a thousand planets outside our Solar System, together with the significant push to achieve inertially confined fusion in the laboratory, has prompted a renewed interest in how dense matter behaves at millions to billions of atmospheres of pressure. The theoretical description of such electron-degenerate matter has matured since the early quantum statistical model of Thomas and Fermi, and now suggests that new complexities can emerge at pressures where core electrons (not only valence electrons) influence the structure and bonding of matter. Recent developments in shock-free dynamic (ramp) compression now allow laboratory access to this dense matter regime. Here we describe ramp-compression measurements for diamond, achieving 3.7-fold compression at a peak pressure of 5 terapascals (equivalent to 50 million atmospheres). These equation-of-state data can now be compared to first-principles density functional calculations and theories long used to describe matter present in the interiors of giant planets, in stars, and in inertial-confinement fusion experiments. Our data also provide new constraints on mass-radius relationships for carbon-rich planets.

Solid iron compressed up to 560 GPa

Dynamic compression by multiple shocks is used to compress iron up to 560 GPa (5.6 Mbar), the highest solid-state pressure yet attained for iron in the laboratory. Extended x-ray absorption fine structure (EXAFS) spectroscopy offers simultaneous density, temperature, and local-structure measurements for the compressed iron. The data show that the close-packed structure of iron is stable up to 560 GPa, the temperature at peak compression is significantly higher than expected from pure compressive work, and the dynamic strength of iron is many times greater than the static strength based on lower pressure data. The results provide the first constraint on the melting line of iron above 400 GPa.

Plasma-accelerated flyer-plates for equation of state studies

We report on a new technique to accelerate flyer-plates to high velocities (∼5 km/s). In this work, a strong shock is created through direct laser ablation of a thin polyimide foil. Subsequent shock breakout of that foil results in the generation of a plasma characterized by a smoothly increasing density gradient and a strong forward momentum. Stagnation of this plasma onto an aluminum foil and the resultant momentum transfer accelerates a thin aluminum flyer-plate. The aluminum flyer-plate is then accelerated to a peak velocity of ∼5 km/s before impact with a transparent lithium fluoride (LiF) window. Simulations of the stagnating plasma ramp compression and wave reverberations within the flyer-plate suggest that the temperature at the flyer-plate impact surface is elevated by less than 50 °C. Optical velocimetry is used to measure the flyer-plate velocity and impact conditions enabling the shocked refractive index of LiF to be determined. The results presented here are in agreement with conventional flyer-plate measurements validating the use of plasma-accelerated flyer-plates for equation of state and impact studies.

Streaked radiography measurements of convergent ablator performance (invited)

The velocity and remaining ablator mass of an imploding capsule are critical metrics for assessing the progress toward ignition of an inertially confined fusion experiment. These and other ablator rocket parameters have been measured using a single streaked x-ray radiograph. A regularization technique has been used to determine the ablator density profile ρ(r) at each time step; moments of ρ(r) then provide the areal density, average radius, and mass of the unablated, or remaining, ablator material, with the velocity determined from the time derivative of the average radius. The technique has been implemented on experiments at the OMEGA laser facility.

A high-resolution two-dimensional imaging velocimeter

Velocity interferometers are typically used to measure velocities of surfaces at a single point or along an imaged line as a function of time. We describe an optical arrangement that enables high-resolution measurements of the two-dimensional velocity field across a shock front or shocked interface. The technique is employed to measure microscopic fluctuations in shock fronts that have passed through materials being considered as ablators for indirect-drive inertial confinement fusion. With picosecond time resolution the instrument captures velocity modes with wavelengths as short as 2.5 microm at a resolution of approximately 10 m/s rms on velocity fields averaging many km/s over an 800 microm field of view.

Diamond at 800 GPa

A new compression technique, which enables the study of solids into the TPa regime, is described and used to ramp (or quasi-isentropically) compress diamond to a peak pressure of 1400 GPa. Diamond stress versus density data are reported to 800 GPa and suggest that the diamond phase is stable and has significant material strength up to at least this stress level. Data presented here are the highest ramp compression pressures by more than a factor of 5 and the highest-pressure solid equation-of-state data ever reported.

Epitope mapping of human recombinant interferon alpha molecules by monoclonal antibodies

The epitopes of six recombinant human interferon alpha (IFN alpha) subtypes have been analysed using 22 monoclonal antibodies (MAbs) obtained from different sources. The IFN alpha subtype specificity of each MAb was determined by a combined immunoprecipitation-bioassay. Eight different epitopes were identified; the number of epitopes on a given IFN alpha subtype varied between four and eight. Each subtype possessed a unique combination of epitopes. Using the best pair of monoclonal antibodies, predicted from epitope mapping studies, subtype-specific two-site (tandem) assays were developed. It was observed that some non-cross-reactive MAbs influenced each other's binding, indicating the flexible nature of IFN molecules. Competitive radioimmunoassay and the combined immunoprecipitation-bioassay were used to identify a common epitope, present on IFN alpha-A, B, C, F and J but not on IFN alpha-D. In neutralization studies, all MAbs that identified this common epitope inhibited the antiviral activity of all IFN alpha molecules tested. It was concluded that the epitope is located within the receptor-binding region of IFN molecules and is important for biological activity. A tentative localization of the common epitope and the other identified epitopes is proposed.

Protection of mice against SV40 tumours by Pam3Cys, MTP-PE and Pam3Cys conjugated with the SV40 T antigen-derived peptide, K(698)-T(708)

The intraperitoneal injection of Balb/c mice with synthetic analogues of adjuvants S-[2,3-bis(palmitoyloxy)-(2-RS)-propyl]-N-palmitoyl-R-cysteine (Pam3Cys) or muramyltripeptide phosphatidylethanolamine (MTP-PE) inhibited the tumourigenic growth of subcutaneously injected VLM cells, a syngeneic simian virus 40 (SV40)-transformed cell line. Furthermore, the Pam3Cys conjugate of K698-T708 (KT), which represents the C-terminal undecapeptide of the SV40 large tumour (T) antigen, was tumour-protective. Also syngeneic spleen cells, preincubated in vitro with this Pam3Cys-KT derivative, which anchores spontaneously at the cell membrane, were, through SV40 tumour mimicry, tumour-protective. The protection was impaired by treatment of the mice with either anti-CD4, anti-CD8 IgG, anti asialo GM1 antiserum or dextrane sulfate, which deplete the CD4+, CD8+ and NK cells or the macrophages, respectively. In summary, SV40 tumour transplantation resistance can be experimentally elicited by a tumour-epitope-specific vaccine. In the absence of an immunogenic epitope protection was obtained by administration of biological response modifiers. Protection is effected by SV40-T-antigen-specific cytotoxic lymphocytes in cooperation with NK cells and macrophages.

Human immunoglobulin preparations suppress the occurrence of Epstein-Barr virus-associated lymphoproliferation

Suppression of Epstein-Barr virus (EBV) lymphoproliferation by three commercial human immunoglobulin (hu-Ig) preparations, one enriched with immunoglobulin A (hu-IgA-IgG) and the other two containing more than 97% immunoglobulin G (hu-IgG) with anti-EBV antibodies was studied. All three human preparations suppress EBV-induced lymphoproliferation in vitro and reduce release of interleukin (IL)-6 and IL-10 dose-dependently, irrespective, however, of the titer of EBV-specific antibodies present. This result was unexpected. Human Ig also reduces human recombinant IL-6-induced lymphoproliferation in EBV-free cultures and augments low-dose human recombinant IL-10-provoked suppression. In vivo studies used mice with severe combined immunodeficiency (SCID), reconstituted with human tonsillar mononuclear cells, and then infected with EBV from B95-8-derived supernatants. Immediate injection of hu-Ig after EBV infection, if given only once, delayed, and if given every two or four weeks, abolished the induction of EBV-associated lymphomas. Delay of hu-Ig injection by 48 hours after infection was less effective. Hu-IgG was consistently more efficacious than hu-IgA-IgG. Under these conditions the best survival rates were obtained with sustained hu-IgG administrations every two weeks. Serum hu-IL-6 and hu-IL-10 were detectable only in lymphoma-bearing SCID mice. Hu-Ig treatment reduced the detectability of both cytokines. These results suggest that hu-Ig-with antibodies to EBV-may exert a beneficial treatment potential for EBV-induced lymphoproliferation in immunocompromised patients. The dependence of this suppressive effect of hu-Ig on specific anti-EBV antibodies in vivo remains to be resolved.

Quantitative cytofluorimetric determination of cell membrane-associated large tumor antigen on SV40-transformed cells

The aim of this study was to quantitate the number of cell membrane-located SV40 large tumor antigen (large T) molecules of SV40-transformed cell lines by cytofluorimetric analysis. Five different SV40-transformed cell lines were labelled by either a biotin- or a fluorescein-conjugated monoclonal antibody, PAb1605, which is specific for the large T carboxyterminus. The conjugated-antibody fluorescence signals of the stained large T molecules of transformed cells were measured via cytofluorimetry. Comparison of the fluorescence signals of calibrated beads bearing a known number of fluorescein molecules to the signals of conjugated PAb1605 antibodies bound on microbeads to a defined number of IgG binding sites made it possible to determine the number of antibody-accessible large T molecules per SV40-transformed cell. The numbers (x10(-4)) found per cell were 1.0 (ELONA, hamster), 3.0 (VLM, mouse), 3.5 (mKSA, mouse), 11 (C57SV, mouse), and 5.5 (SV80, human), respectively. Thus, the technique described allows a precise quantitation of surface-exposed, antibody-accessible viral antigen expression.

Monospecific polyclonal anti-anti-idiotypic antibodies to the carboxyterminal undecapeptide of the SV40 large tumour antigen

The murine monoclonal antibody PAb1605 defines an epitope, peptide Lys(698)-Thr(708) (KT), on the carboxyterminus of the tumour(T)antigen of SV40-transformed cells. In vivo and in vitro experiments had shown that this sequence represents an epitope for both humoral and cellular immune responses. When injected into rabbits PAb1605 induces anti-idiotypic antibodies (Ab-2). Ab-2 beta (internal image type) was purified by adsorption chromatography and characterized by the ability of KT to compete with the binding of ab-2 with ab-1. Murine anti-anti-idiotypic antibodies (ab-3) were obtained by immunization of mice with ab-2 beta. Both ab-1 and ab-3 JgG showed affinities to immunoprecipitated SV40 T antigen by immunoblot analysis and to nuclear SV40 T antigen by the immunofluorescence assay. The binding of ab-3 to SV40 T antigen was completely inhibited by competition with KT. We conclude that the polyclonal ab-3 is of the ab-3 subtype and specific for only one epitope which is represented by KT and defined by ab-1. The results demonstrate that the specificity for a defined peptide epitope of an antibody was conserved even after two consecutive steps of anti-idiotypic-antibody formation in two host species. Since this postulate of network theory could be verified for a sequence of a tumour-associated antigen which represents a B- and T cell epitope, this model is of great interest for further tumour immunological studies.

A phase I/IIA clinical study with a chimeric mouse-human monoclonal antibody to the V3 loop of human immunodeficiency virus type 1 gp120

A phase I/IIA clinical trial with the chimeric mouse-human monoclonal antibody CGP 47,439 to the principal neutralization determinant in the V3 region of human immunodeficiency virus type 1 (HIV-1) strain IIIB envelope protein gp120 is reported. The trial was an uncontrolled single-center, open-label, multidose tolerability, immunogenicity, and pharmacokinetic study in homosexual men with advanced HIV disease. Patient groups were formed on the basis of the reactivity of the antibody with the gp120 of their HIV-1 isolates. Intravenous infusions of 1, 10, and 25 mg of antibody were followed by seven escalated doses of 50, 100, and 200 mg, every 3 weeks. The antibody was well tolerated; no toxicity was observed. Some patients showed a transient but insignificant antibody response to the antibody with no apparent adverse reactions or accelerated elimination of it. Substantial serum levels of the antibody were maintained with a mean t1/2 beta of 8-16 days. A virus burden reduction was observed in some patients.

The cell-binding carboxyterminal undecapeptide of SV40 tumour antigen provides protective cell-dependent immunity

This paper describes the use of the synthetic carboxyterminal undecapeptide of large SV40 tumour antigen, lys698-thr708 (KT) to protect Balb/c mice against growth of subcutaneously transplanted tumorigenic SV40-transformed cells (VLM). The vaccine was prepared by conjugation of KT with 3-(2-pyridyldithio)propionic acid N-hydroxysuccinimide (SPDP). Addition of the SPDP-derivative of KT to syngeneic spleen cells rendered KT covalently linked to free thiol-groups of the cell membranes by the formation of -S-S-CH2-CH2-CO-epsilon-NH-lys698 bonds. Vaccination with KT-conjugated cells was intraperitoneal. Alternatively, KT-conjugated cells were generated in the peritoneum by injection of PDP-KT ((2-pyridyldithio)propionic acid-KT). As a control 60Co-irradiated VLM cells were used. In five experiments all VLM-vaccinated and the majority of the PDP-KT-(or KT-spleen cell)-vaccinated mice were protected against tumour growth. However, mice pretreated with saline, unconjugated spleen cells, free KT, KT conjugated to bovine serum albumin, or KT with incomplete Freund's adjuvant developed tumours. Treatment of PDP-KT-vaccinated mice with anti-CD4 or anti-CD8 immunoglobulin abolished tumour immunity completely. Thus, covalent binding of the carboxyterminal undecapeptide of SV40 tumour antigen to viable, untransformed cells yielded a vaccine which protects Balb/c mice against SV40 tumours.

Covalent immunochemical membrane labeling of viable cells with K698-T708, a simian virus 40 tumor antigen-derived peptide

The process of covalent immunochemical linking of viable cell membranes with a Simian Virus 40 (SV40) tumor antigen-derived undecapeptide, K(698)PPTPPPEPET(708) (KT), is described. The principle applied was the reaction of the lysine residue, K 698, of the undecapeptide with the succinimidyl moiety of a heterobifunctional linker molecule, N-succinimidyl-3-(2-pyridyldithio)propionate (SPDP) or sulfosuccinimidyl(4-iodo-acetyl)aminobenzoate (sulfo-SIAB). Thereby, upon release of N-hydroxy-succinimide, the rest of the linker molecule reacts covalently with the epsilon-NH2 group of lysine. Upon release of pyridyl-2-thion or hydrogen iodide, respectively, the second reactive moiety of the linker is then ready to form a covalent bond with SH-groups of cell membrane compounds. As a result, KT is covalently linked onto the cell membrane by an -SS- or an -S-bond, respectively. Binding is prevented by treatment of the candidate cells with iodoacetamide, an SH-reactive compound. This artificial cell membrane epitope can be demonstrated by surface immunofluorescence and by binding to immunomagnetic beads loaded with PAb1605, a KT-specific monoclonal antibody. Quantitation by cytofluorimetry shows some 10(4) KT molecules bound per cell, a number that is in the range of the number of SV40 tumor antigen molecules of genuine SV40-transformed mammalian cells.

PAb1614, a monoclonal antibody reactive with the tumor antigens of SV40, JC, BK, and polyoma virus, and other JC virus tumor antigen cross-reactive antibodies of the PAb1601-1636 panel

PAb1614, an SV40-specific monoclonal antibody of the panel PAb1601-1636 reacts with large and small tumor antigens of SV40, BK and JC virus, and with polyoma virus large and middle tumor antigens, but not with the large tumor antigen of the lymphotropic papova virus. Using immunofluorescence and immunoblot competition assays and ELISA with synthetic peptides, it is shown that the epitope is represented by the SV40 tumor antigen undecapeptide, K39-E49. This peptide comprises the tumor antigen consensus sequence, H42-G47, of the polyoma viruses. However, the epitope of PAb1614 probably does not exactly coincide with this hexapeptide. This explains why some cross-reactions are less strong, or absent, as in the case of the lymphotropic papova virus. Further antibodies of the PAb1601-1636 panel that cross-react with the JC virus large tumor antigen are PAb1602, 1604, 1606, 1618, 1621, 1622, 1623, 1624, 1626, 1629, and 1633.

hu-PBL-SCID mice can be protected from HIV-1 infection by passive transfer of monoclonal antibody to the principal neutralizing determinant of envelope gp120

OBJECTIVE

To determine whether passive transfer of a monoclonal antibody specific for the principal neutralizing determinant in the V3 region of HIV-1IIIB gp120 can protect mice with severe combined immunodeficiency (SCID) transplanted with normal human peripheral blood leukocytes (hu-PBL), designated hu-PBL-SCID mice, from subsequent challenge with the homologous viral strain.

DESIGN AND METHODS

hu-PBL-SCID mice were given intraperitoneal injections of an anti-HIV-1 neutralizing murine monoclonal antibody (BAT123), its mouse-human chimeric form (CGP 47 439), or a control murine antibody (PNTU), at a dose of 40 mg/kg. The mice were then challenged intraperitoneally with 10 mouse infectious doses of HIV-1IIIB. Three weeks later the mice were killed, and spleen cells and peritoneal lavage collected for determination of infection by coculture for viral isolation and by detection of HIV-1 DNA using polymerase chain reaction (PCR).

RESULTS

All three antibodies had similar serum half-lives of 9-12 days. No toxicity was observed in the animals. HIV-1 was recovered by coculture from five out of the six mice given PNTU, and by PCR from two out of the six mice given PNTU, but was not recovered by either technique from any of the 12 mice given BAT123 or CGP 47 439.

CONCLUSION

BAT123 and CGP 47 439, which are specific for the principal neutralizing determinant of HIV-1IIIB, protect hu-PBL-SCID mice from infection by this viral strain. Our findings support the use of the hu-PBL-SCID mouse as an in vivo model for studying protection against HIV-1 infection by passive immunization with anti-HIV-1 neutralizing antibodies.

Structure of cis-1-([4-(1-imidazolylmethyl)cyclohexyl]methyl)imidazole- succinic acid complex

CGS 14796C, C14H20N4.C4H6O4, Mr = 362.43, monoclinic, C2/c, a = 28.148 (4), b = 9.722 (1), c = 19.200 (2) A, beta = 133.06 (1) degree, V = 3838.88 A3, Z = 8, Dx = 1.26 Mg m-3, lambda (Cu K alpha) = 1.5418 A, mu 0.702 mm-1, F(000) = 1552, T = 294 K, R = 0.075 for all 3285 reflections. The structure is composed of linear chains of alternating CGS 14796C and succinic acid molecules. The CGS 14796C molecule is in an extended conformation.

Structure of (+/-)-aminoglutethimide

(+/-)-3-(4-Aminophenyl)-3-ethyl-2,6-piperidinedione, C13H16N2O2, Mr = 232.3, monoclinic, P2(1)/n, a = 16.895 (2), b = 8.519 (1), c = 8.762 (1) A, beta = 95.71 (1) degree, V = 1254.9 (2) A3, Z = 4, Dx = 1.23 g cm-3, lambda(Mo K alpha) = 0.71069 A, mu = 0.785 cm-1, F(000) = 496, T = 294 K, R = 0.064 for all 3676 reflections. The molecule is L shaped with the p-aminophenyl and the piperidinedione groups forming the vertical arm and the base, respectively. The polar imide half of the piperidinedione group is in front of the L for the active + enantiomer and at the back for the less-active - enantiomer. The structure is very similar to that of phenobarbital. Intermolecular interactions include one strong and one weak hydrogen bond and an apparent interaction between one of the amino H atoms with the pi cloud of the phenyl ring.

Safety and immunogenicity of a genetically engineered human immunodeficiency virus vaccine

A phase 1 trial of a candidate human immunodeficiency virus type 1 (HIV-1) vaccine was done in 25 healthy seronegative subjects. The antigen, env2-3 (SF2), was a nonglycosylated polypeptide representing the gp120 region of the env gene of the HIV-1(SF2) isolate. It was produced in genetically engineered yeast as a denatured molecule incapable of binding CD4. A synthetic lipophilic muramyl tripeptide (MTP-PE) was used as an adjuvant. Ten subjects received adjuvant alone and 15 received 50- or 250-micrograms doses of env2-3 (SF2) administered intramuscularly in two immunization regimens. In general, adjuvant and vaccine were well tolerated. Antibody responses to both the homologous antigen, env2-3 (SF2), and antigens from other highly divergent HIV isolates were elicited in the majority of vaccine recipients. However, antibody titers were low, without neutralizing activity. In 9 of 11 subjects who received the complete vaccine immunization series, a significant specific T lymphocyte response was observed.

Structure-activity studies of non-steroidal aromatase inhibitors: the crystal and molecular structures of CGS 16949A and CGS 18320B

The crystal and molecular structures of 4-(5,6,7,8-tetrahydroimidazo[1,5-a]pyridin-5-yl)benzonitrile hydrochloride (CGS 16949A) and bis(p-cyanophenyl)imidazo-1-yl methane hemisuccinate (CGS 18320B) have been determined as part of structure-activity relationship studies of non-steroidal aromatase inhibitors. CGS 18320B crystallizes with two inhibitor molecules in the asymmetric unit that are similar in conformation. The cyanophenyl groups and the imidazole moieties in the CGS 18320B molecules display a propellor-like arrangement. The orientation of the imidazole ring in CGS 16949A, which is constrained by the piperidine ring, differs by about 80 degrees from the orientations in both CGS 18320B molecules. The conformations of both compounds are consistent with the proposed model (Banting et al. (1988) J. Enz. Inhibit., 2, 216) for inhibitor binding by positioning of the cyanophenyl group in the steroid A-ring binding site and interaction of the imidazole nitrogen with the iron of the haem.

Immunolabeling of JC virus large T antigen in neonatal hamster brain before tumor formation

Using immunolabeling methods, the JC virus (JCV) early or regulatory protein, large T antigen, was demonstrated in frozen sections of neonatal hamster brains before tumor formation. Three days after intracerebral inoculation of 2500 hemagglutinating units of JCV, T antigen was expressed predominantly in nuclei of cells in the external granular layer and newly forming internal granular layer of the cerebellum and also in cell nuclei located in the hippocampus, periventricular areas, and the olfactory bulb. At 7 days postinoculation (p.i.), most cerebellar T antigen-containing cells had migrated to the internal granular layer, but by 15 days p.i., cells that expressed T antigen was greatly reduced in number or absent. However, by 30 days p.i., the internal granular layer of the cerebellum again contained T antigen-positive cells. In contrast to the scattered cells seen at 3 or 7 days p.i., these cells appeared in dense clusters thought to represent pretumor foci. Since JCV capsid proteins were not detected at any time, JCV may establish a latent or abortive infection in cells during their mitotic phase and these cells initially express T-antigen during migration or become immunoreactive later before tumor formation.

Reversible inhibition of human placental microsomal aromatase by CGS 18320B and other non-steroidal compounds

The effect of bis-(p-cyanophenyl)imidazo-1-yl-methane hemisuccinate (CGS 18320B) and other non-steroidal compounds on the aromatization of androstenedione by human placental microsomal aromatase was studied. CGS 18320B exhibited competitive inhibition with an apparent Ki of 0.16 nM, a 90 and 3800-fold increase in affinity compared to 4-hydroxyandrostenedione and amino-glutethimide, respectively. The inhibition is not time-dependent, indicating that the active site interaction is reversible. CGS 18230B showed a two-fold increased affinity as compared to 4-(5,6,7,8-tetrahydroimidazo[1,5a]pyridin-5-yl)benzonitrile (CGS 16949A) and cis-1-[(4-[(1-imidazoyl)methyl]cyclohexyl)methyl]-imidazole succinate (CGS 14796C) which showed Ki values of 0.35 and 0.39 4M, respectively. 1-[2-[1-(4-carboxyphenyl)-3-ureido]ethyl]-2-(4-pyridyl)-2-imidazoline monohydrochloride (CGP 15720A) showed negligible inhibition.

Synthetic oligopeptides define epitopes at the amino- and carboxy-terminus of simian virus 40 large tumor antigen which are recognized by monoclonal antibodies

Synthetic oligopeptides were used to define the epitopes recognized by monoclonal antibodies directed against the SV40 large tumor (T) antigen. The two monoclonal antibodies PAb 1622 and PAb 1626 reacted with the N-terminal undecapeptide Met(1)-Leu(11) as detected by inhibition of nuclear SV40 T antigen immunofluorescence. Antibody PAb 1605 recognized the hexapeptide Thr(701)-Pro(706) at the carboxy-terminus of the SV40 T antigen as detected by inhibition of an enzyme-linked immunosorbent assay. The specificities of these monoclonal antibodies differ from those of antibodies previously raised against the respective synthetic oligopeptides.

Chromogenic labeling of milk oligosaccharides: purification by affinity chromatography and structure determination

Oligosaccharides from human milk were derivatized with 4'-N,N-dimethylamino-4-amino-azobenzene (DAAB) by reductive amination and purified by affinity chromatography on immobilized antibodies followed by resolution of the retained antigenic molecules by adsorption chromatography on HPLC. The visibility to the naked eye and the favorable handling properties of the DAAB-oligosaccharides (desalting, quantification) offered distinctive advantages over underivatized oligosaccharides. Analysis by MS and NMR identified the two major antigens as the Lewis a active pentasaccharide and the Lewis b active hexasaccharide, respectively. Further derivation of DAAB-oligosaccharides by palmitoylamidoacetaldehyde generated glycolipid-like compounds suitable for immunological detection by in situ overlay techniques after separation by thin-layer chromatography.

Characterization of a monoclonal antibody against infective larvae of Brugia malayi

Monoclonal antibodies were produced following immunization of mice with live infective larvae of Brugia malayi. One of these, 46.08.76, is an antibody that promotes adherence of mouse peritoneal macrophages and human peripheral blood leucocytes to the infective larvae of B. malayi and Wuchereria bancrofti, respectively, and kills them. Fresh normal serum, as a source of complement, augments this effect. The same monoclonal antibody conferred 89% protection to jirds (Meriones unguiculatus) against challenge infection of B. malayi stage-three larvae. This monoclonal antibody recognizes antigens of 80,000, 67,000, 52,000 and 36,000 MW proteins present among the antigens of larvae, as detected by an immunoblotting technique. The antibody also reacts with antigens of infective larvae of Litomosoides carinii, Dipetalonema viteae and B. pahangi, but to a smaller extent.

The proliferative response of human peripheral blood lymphocytes to group A streptococcal vaccine

The proliferative response of human peripheral blood mononuclear cells to group A streptococcal vaccine (strain J17A4) was assessed by measurement of [3H]thymidine incorporation. This was maximal after 7 days in cultures containing 1 X 10(5) lymphocytes. Cells from 33 out of 38 adult donors (87%) yielded stimulation indices between 2.0 and 81. Responding cells were predominantly of the OKT4+, Ia+, Tac+ phenotype expressed by activated helper T lymphocytes. In contrast, no response was observed in 10 out of 12 samples of cord blood lymphocytes. Addition of conventional rabbit or monoclonal murine anti-Ia (HLA-DR) antibodies to the culture medium abrogated the vaccine-induced proliferative response. Frequencies of responding cells estimated by limiting dilution analysis were between 1 in 2370 and 1 in 4580 lymphocytes. The results suggest that lymphocyte stimulations induced with streptococcal group A vaccine represented an in vitro anamnestic cellular immune response.

Monoclonal antibodies to the multienzyme enniatin synthetase. Production and use in structural studies

Monoclonal antibodies have been prepared against the multifunctional enzyme enniatin synthetase, which catalyses the biosynthesis of the cyclodepsipeptide antibiotic enniatin. Five different antibodies (designated 1.56, 21.1, 25.91, 28.7 and 28.34) were characterized. 1.56, 21.1 and 25.91 were of IgG1 and 28.7 and 28.34 of IgM subclass. Binding studies showed that 21.1 and 25.91 are obviously directed against determinants based on the primary structure of the enzyme, whereas 28.7, 28.34 and 1.56 bind to the native enzyme. All antibodies inhibited enniatin formation. Based on their ability to inhibit different partial reactions of the multienzyme the antibodies could be divided into three groups: 21.1 and 25.91 inhibit valyl thioester formation, 1.56 additionally inhibits D-2-hydroxyisovaleric acid thioesterification, and 28.7 and 28.34 block both thioester sites as well as the N-methylation step. None of the antibodies affected the formation of L-valyl or D-hydroxyisovaleryl adenylate by the enzyme. The results indicate that there must be distinct thioester activation sites for valine and D-hydroxyisovalerate close to each other and in the neighbourhood of the methyltransferase site. The adenylation sites for D-hydroxy-isovalerate and L-valine are obviously located at some distance.

Serotyping and electron microscopy studies of Staphylococcus aureus clinical isolates with monoclonal antibodies to capsular polysaccharide types 5 and 8

Monoclonal antibodies to Staphylococcus aureus capsular polysaccharide types 5 and 8 were prepared and used to serotype 821 clinical isolates of S. aureus from four countries. The capsular polysaccharide-binding sites on the bacterial membrane were examined by transmission and scanning electron microscopy.

Characterization of monoclonal antibodies to a crystal protein of Bacillus thuringiensis subsp. kurstaki

Ten monoclonal antibodies were produced against a k-1-type crystal protein of Bacillus thuringiensis subsp. kurstaki. Eight of the antibodies belong to the immunoglobulin G1 (IgG1) subclass, with pI values ranging from 5.5 to 8.6, one could be assigned to the IgG2b subclass, and one could be assigned to the IgM class. Competitive antibody-binding assays and analysis of antibody specificity indicated that the 10 antibodies recognized at least nine distinct antigenic determinants. Eight antibodies bound to both protoxin and toxin, whereas the other two interacted with protoxin only. One antibody completely inhibited the biological activity of the delta-endotoxin, five antibodies reduced it by 15 to 82%, and four antibodies did not affect it at all. Based on cross-reaction studies, homologies and differences in the crystal protein structures of different B. thuringiensis subspecies were revealed. All of the monoclonal antibodies strongly cross-reacted with crystal proteins from strains of B. thuringiensis subsp. tolworthi, B. thuringiensis subsp. galleriae, B. thuringiensis subsp. dendrolimus, B. thuringiensis subsp. sotto, and B. thuringiensis subsp. subtoxicus. Some antibodies interacted only weakly with crystal proteins from strains of B. thuringiensis subsp. morrisoni and B. thuringiensis subsp. entomocidus, and some of these did not interact with B. thuringiensis subsp. kenyae and B. thuringiensis subsp. darmstadiensis. No cross-reaction was found with the parasporal inclusion protein of B. thuringiensis subsp. israelensis. Studies with the monoclonal antibodies also disclosed that crystal proteins from strains of the same subspecies can exhibit substantial differences in antigenic structure. In particular, striking strain-specific differences in the protoxins of B. thuringiensis subsp. kurstaki and B. thuringiensis subsp. thuringiensis were observed.

Combinatorial diversity in the generation of antibody molecules. The complete amino-acid sequence of the variable domain of a monoclonal anti-streptococcal group A polysaccharide antibody

The first complete amino-acid sequence of the variable region of the gamma 3 heavy chain from a murine anti-streptococcal group A polysaccharide (A-CHO) immunoglobulin (monoclonal antibody 2S1.3) is described. Therefore, in conjunction with the previously published 2S1.3 light chain sequence, a V kappa 25 structure, the entire variable domain of this antibody has been determined. In addition, four partial amino-terminal heavy chain sequences of other antibodies with the same specificity are reported. These heavy chains share a high degree of homology with heavy chains from fructosan-binding murine myeloma proteins with the exception of those positions known to be encoded by the D (diversity) segment in germ line DNA. The light chains associated with the heavy chains reported here are products of the V kappa 25, V kappa 27, and J kappa 5 genes. Up to date three VH and four V kappa subgroups have been shown to contribute genetic material to the assembly of antibodies specific for the A-CHO. Unlike other experimental systems employing structurally completely resolved full antigens the antistreptococcal immune response uses V genes previously shown to be involved in the formation of antibodies with different specificities. This provides further experimental evidence for the physiological relevance of heavy/light chain association as a posttranscriptional diversification mechanism in the generation of the antibody repertoire in addition to those somatic diversifiers acting directly upon the genes encoding the variable regions of individual chains.

Transformation-related cellular protein p53: increased level in untransformed rat cells following treatment with the tumorpromoter, tetradecanoylphorbol-acetate

12-O-Tetradecanoylphorbol-13-acetate (TPA, 100 ng ml-1), a tumor promoting phorbol ester, is able to induce enhanced levels of the transformation-associated cellular antigen p53 in normal rat 2 cells which had not been previously initiated by a carcinogen. p53 was estimated in ethanol-fixed treated cells on microtiter plates with ELISA using the monoclonal antibody Pab 1620 [EMBO J. 7, 1485, (1984)]. Induction of p53 was confirmed by immunoblotting. This effect of TPA is an additional phenotypic characteristic of tumor cells which can be induced by TPA in untransformed rodent cells.

Thrombin specificity. Selective cleavage of antibody light chains at the joints of variable with joining regions and joining with constant regions

Selective cleavage of polypeptides by alpha-thrombin can be reasonably predicted [Chang, J.Y. (1985) Eur. J. Biochem. 151,217-224]. This knowledge was applied to the selective cleavage of antibody light chains with the aim of producing intact fragments of both variable region and constant region. (a) Mouse kappa light chains 10K26 and 10K44 from anti-(azobenzene arsonate) antibodies contain 20 Arg/Lys-Xaa bonds. Only two of them, one ProArg-Thr bond located at the joint of the variable region with the joining peptide and one ValLys-Ser bond located near the carboxyl-terminal end of the constant region, were selectively cleaved by alpha-thrombin. The ProArg-Thr bond has a 50% cleavage time of about 10 min under the designated conditions, whereas the ValLys-Ser has a 50% cleavage time approx. 9-10 h. A single selective cleavage at the joining position of the variable region and joining peptide can be achieved by short-time thrombin digestion. Fragments containing intact variable region (1-96) and intact joining peptide-constant region (97-214) obtained from both denatured and native light chains of 10K26 can be separated by gel filtration. (b) lambda light chains from both human and mouse all begin with the GlnProLys-(Ala/Ser) structure (positions 108-111) at their constant regions. This ProLys-Ala/Ser bond is also susceptible to specific thrombin cleavage. Four human lambda chain (KERN, NEI, NEW, VOR) and one mouse lambda chain (RPC20) were shown to be selectively cleaved by thrombin at these ProLys-Ala/Ser bonds. For human lambda chains, the 50% cleavage time at this ProLys-Ala bond was approx. 3-4 h under the designated conditions. Six additional thrombin specific cleavages were also detected within the variable regions of NEI, VOR and RPC-20. (c) Heparin inhibits thrombin cleavage of Arg/Lys-Xaa bonds located near the center of the antibody light chain, but slightly activates thrombin cleavage of those located near the amino or carboxyl-terminal ends of the protein. The significance of these findings is threefold. (a) It demonstrates that selective cleavage of large polypeptides by alpha-thrombin can also be reasonably predicted. (b) It provides a useful method for light chain fragmentation which can greatly facilitate amino acid sequencing of antibodies. (c) It serves to generate fragments containing intact variable regions and constant regions from antibody light chains of human and mouse. Such fragments may be useful for chemical semisynthesis of a human-mouse light chain chimeras.

Rheumatic fever-associated B cell alloantigens as identified by monoclonal antibodies

Mice immunized with B lymphocytes obtained from patients who had had well-documented rheumatic fever in the past yielded 2 monoclonal antibodies, termed 83S19.23 and 256S10, which identified certain alloantigens present on the B cells of these patients. The frequency of the B cell marker detected by clone 83S19.23 in rheumatic fever patients was found to be 59%, 77%, and 74% in India, New Mexico, and New York, respectively. Monoclonal antibody 256S10 identified 75% of those rheumatic fever patients who were nonreactive to clone 83S19.23. Thus, the 2 antibodies identify approximately 92% of all rheumatic fever patients and suggest the presence of a diallelic genetic marker for susceptibility to rheumatic fever.

Chromogenic labeling of monosaccharides using 4'-N,N-dimethylamino-4-aminoazobenzene

Twenty-three monosaccharides, e.g., D- or L-pentoses, D- or L-hexoses, heptose, 2- or 6-deoxyhexoses, 2-deoxy-2-aminohexoses, hexuronic acids, and N-acetylmuramic acid, were coupled to the azo dye 4'-N,N-dimethylamino-4-aminoazobenzene by reductive amination using sodium cyanoborohydride as reducing agent and in the presence of pentaerythritol. The structure of the colored glycamines was established by mass spectrometry. The average yield of the reaction was more than 80%. The sugar derivatives were separated either by silica-gel thin-layer chromatography or by high-performance liquid chromatography. Spectrophotometric quantitation was performed in the visible range at the picomole level. The method was applied to the determination of the sugar composition of the glycosphingolipid globotetraosyl ceramide and the human milk oligosaccharide lacto-N-fucopentaose I.

Biological activities of human recombinant interferon alpha/beta targeted by anti-Epstein-Barr virus monoclonal antibodies

The requirement of high doses of interferon (IFN) during therapy severely restrict its application. Thus a model using an Epstein-Barr virus (EBV) membrane antigen (MA) specific monoclonal antibody (MAb) was developed to assess the feasibility of coupling minimal amounts of IFN to a MAb and specifically delivering the IFN to the target cells. Coupled IFN was first shown to retain fully both its anti-viral and anti-proliferative properties when tested on human tumor cell lines QIMR-WIL (EBV-MA+) and the U-266 (EBV-MA-). A series of in vitro pulsing experiments demonstrated the specific targeting of both the anti-viral and anti-proliferative properties of IFN to the EBV-MA+ QIMR-WIL cells and not EBV-MA- cell lines.

Induction of tumouricidal leucocytes by the intranasal application of MTP-PE, a lipophilic muramyl peptide

Single intranasal applications of MTP-PE, a lipophilic muramyl peptide, induce tumouricidal and tumouristatic leucocytes in the lungs of rats. In ex vivo assays the tumouristatic activity was detectable for 8 days after drug administration. By separation of the effector cells on Ficoll-Hypaque gradients, it was shown that both neutrophils and macrophages are responsible for this activity. Using the B16/BL6 melanoma system in mice, there was a high survival rate after repeated intranasal applications of MTP-PE.

Murine V kappa 25 and V kappa 27 amino-acid sequences of C57B1/6 origin: monoclonal antibodies 17S29.1 and 22S25.1 specific for the group A-streptococcal polysaccharide

Antibodies 17S29.1 and 22S25.1 are monoclonal, hybridoma-derived gamma 3 kappa murine immunoglobulins with specificity for N-acetyl-glucosamine beta 1----3-linked to the L-rhamnose backbone structure, the immunodeterminant of the streptococcal Group A polysaccharide. The VL 17S29.1 amino-acid sequence is the third complete one reported from an antibody with this specificity, the second fully determined V kappa 25 structure and the first complete V kappa sequence of C57B1/6 origin derived from a carbohydrate-specific antibody. VL22S25.1 is a member of the V kappa 27 isotype of murine immunoglobulin VL regions. V kappa 17S29.1 and the determined part of the V kappa 22S25.1 sequence are compared to the previously described V kappa regions of streptococcal Group A polysaccharide-specific antibodies and to 12 selected partial and complete V kappa regions of antibodies with other specificities, predominantly to carbohydrate antigens. Both V kappa 17S29.1 and V kappa 22S25.1 increase the variability of known murine V kappa regions. They are the most homologous to the other V kappa regions derived from antibodies with streptococcal Group A polysaccharide specificity and share with them the amino-acid residue Arg74, so far characteristic for V kappa regions from antibodies with this specificity. The analysis of groups of independently expressed, highly homologous V kappa regions, namely V kappa 17S29.1 and V kappa 2S1.3 as one and V kappa 7S34.1 and V kappa 22S25.1 as a second group, offers the possibility of estimating the minimal number of V kappa germline genes involved in the immune response to the structurally defined streptococcal Group A polysaccharide antigen.(ABSTRACT TRUNCATED AT 250 WORDS)

Murine V kappa 21A isotype sequence: monoclonal antibody 50S10.1 specific for the group A streptococcal polysaccharide

Antibody 50S10.1 is a hybridoma-derived gamma 3 kappa antibody of BAB-14 mouse strain origin, with specificity for N-acetylglucosamine beta 1----3 linked to L-rhamnose, the immunodeterminant of the streptococcal Group A polysaccharide. The VL50S10.1 amino acid sequence is the fourth complete one reported with this specificity and the first fully determined V kappa 21A structure. Furthermore it is the first V kappa 21A isotype sequence derived from an antibody with known antigen specificity. The V kappa region of this and the previously described monoclonal anti-streptococcal Group A polysaccharide antibodies 7S34.1, 2S1.3 and 17S29.1 are compared, showing that in monoclonal antibody 50S10.1 a V kappa germline gene is expressed which is unrelated to those previously shown to be expressed in antibodies of this specificity. V kappa 50S10.1 increases the variability of known murine V kappa regions and confirms stretches of V kappa 21A sequences previously established.

Glycosphingolipid-blotting: an immunological detection procedure after separation by thin layer chromatography

A method for detecting glycosphingolipids (GSL) in situ after thin layer chromatography is described. The separated GSL are transferred by diffusion to nitrocellulose. The replica is incubated with poly- or monoclonal antibodies and bound antibodies are detected with second antibodies coupled to peroxidase. Advantages of the procedure are its speed, the non-radioactive detection method, and its suitability for screening applications. In addition, small scale affinity purification of antibodies from the replicas is possible. The presence of Forssman antigen in mouse tissues and the reaction of monoclonal antibodies with human GSL is demonstrated.

Monoclonal antibodies against simian virus 40 nuclear large T tumour antigen: epitope mapping, papova virus cross-reaction and cell surface staining

Thirty six cloned hybridomas have been isolated which produce monoclonal antibodies directed against simian virus 40 (SV40) large T tumour antigen. They have been shown to recognize at least six different epitopes along the T antigen polypeptide according to their reaction with the various truncated forms of T antigen expressed by adenovirus-SV 40 hybrid viruses. Sixteen antibodies cross-react with cells infected by the closely related human BK virus. Only two antibodies, PAb1604 and PAb1614, directed against different epitopes of the SV40 T antigen, cross-react with polyoma large T tumour antigen which has a more limited amino acid sequence homology. This cross-reaction is rarely seen with polyclonal antibodies. Monoclonal antibody PAb1620 gave nuclear immunofluorescence only with murine cells transformed by SV40 and was found to react with a complex of T-antigen and 53 000-dalton host-coded protein. All the monoclonal antibodies react with nuclear T antigen and all but four antibodies stained the surface of SV40-transformed cells. These were four of the five antibodies directed against the central third of the T antigen. Thus the monoclonal antibodies show that cell surface T antigen differs from nuclear T antigen, either in accessibility or structure.

Microisolation of DABITC-derivatized protein by gel electrophoresis: application to the purification of antibody heavy and light chains

Proteins and polypeptides are derivatized with dimethylaminoazobenzene isothiocyanate (DABITC) before their separation on sodium dodecyl sulfate-polyacrylamide gels. DABITC-derivatized proteins are detected visually in the picomole range without further staining and destaining procedures. The recovered colored protein can also be used for direct sequence determinations. This method was applied to purify heavy and light chains of murine hybridoma-derived antibodies. Starting with ammonium sulfate-precipitated protein mixture, this method allows, in a one-step procedure, the isolation of pure light and heavy chains suitable for automatic sequencing.