Noncytolytic inhibition of X4 virus by bulk CD8(+) cells from human immunodeficiency virus type 1 (HIV-1)-infected persons and HIV-1-specific cytotoxic T lymphocytes is not mediated by beta-chemokines.

Human immunodeficiency virus (HIV)-specific cytotoxic T lymphocytes (CTL) mediate immunologic selection pressure by both cytolytic and noncytolytic mechanisms. Non cytolytic mechanisms include the release of beta-chemokines blocking entry of R5 HIV-1 strains. In addition, CD8(+) cells inhibit X4 virus isolates via release of as yet poorly characterized soluble factors. To further characterize these factors, we performed detailed analysis of CTL as well as bulk CD8(+) T lymphocytes from six HIV-1-infected individuals and from six HIV-1-seronegative individuals. Kinetic studies revealed that secreted suppressive activities of HIV-1-specific CTL and bulk CD8(+) T lymphocytes from all HIV-1-infected persons are significantly higher than that of supernatants from seronegative controls. The suppressive activity could be blocked by monensin and brefeldin A, was heat labile, and appeared in a pattern different from that of secretion of chemokines (MDC, I-309, MIP-1alpha, MIP-1beta, and RANTES), cytokines (gamma interferon, tumor necrosis factor alpha, and granulocyte-macrophage colony-stimulating factor), and interleukins (interleukin-13 and interleukin-16). This suppression activity was characterized by molecular size exclusion centrifugation and involves a suppressive activity of >50 kDa which could be bound to heparin and a nonbinding inhibitory activity of <50 kDa. Our data provide a functional link between CD8(+) cells and CTL in the noncytolytic inhibition of HIV-1 and suggest that suppression of X4 virus is mediated through proteins. The sizes of the proteins, their affinity for heparin, and the pattern of release indicate that these molecules are not chemokines.

The alphaphone - - a method for measuring thin-film absorption at laser wavelengths.

A sensitive infrasonic method for measuring the absorption of thin films at laser wavelengths has been demonstrated. A fraction of the heat absorbed from the beam by the film passes through a thin layer of gas to the back wall of the Alphaphone, while the remaining absorbed energy heats the supporting window. The gas temperature and pressure rise is then measured with a capacitance microphone. Sensitivity as great as 1.5 x 10(-7) absorption per surface could be achieved with 10 W input by allowing irradiation to continue until the window is saturated with heat. However, the waiting time for saturation even with thin windows would be about 5 min, and with lock-on amplifier demodulation the total measurement time would be several hours. If the chopping speed is increased to 1.5 sec for irradiation and 1.5 sec for cooling, adequate sensitivity of 10(-4) absorption with a signal-to-noise ratio of 9 is achieved with a total measurement time of 1 min. The samples we tested were KRS-5 substrates coated with layers one quarter-wave thick at 10.6 microm. One sample was a single layer of calcium fluoride. Other samples had a layer of zinc sulfide over a binder layer of thorium fluoride. The instrument may be calibrated absolutely with a thin-film heater described large as several percent.

The laser illuminated absorptivity spectrophone: a method for measurement of weak absorptivity in gases at laser wavelengths.

A spectrophone measures absorptivity by sensing thermal expansion in a confined sample gas. Laser source excitation provides sufficient radiation to measure precisely very weak absorptivities at laser wavelengths. This paper describes the theoretical capability, design considerations, and experimental testing of a pulsed ruby laser absorptivity spectrophone and a cw CO(2) laser absorptivity spectrophone. A spectrum of the water vapor line at 6943.8 A was obtained. The peak absorptivity was 3 x 10(-6)cm(-1). In the vicinity of 9.6 micro, absorptivities of CO(2)-N(2) mixtures were measured down to 1.2 x 10(-7)cm(-1).