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Pulsed femtosecond lasers can generate acoustic pulses propagating in solids while displaying either diffraction, attenuation, nonlinearity and/or dispersion. When acoustic attenuation and diffraction are negligible, shock waves or solitons can form during propagation. Both wave types are phonon wavepackets with characteristic length scales as short as a few nanometer. Hence, they are well suited for acoustic characterization and manipulation of materials on both ultrafast and ultrashort scales. This work presents an overview of nonlinear ultrasonics since its first experimental demonstration at the beginning of this century to the more recent developments. We start by reviewing the main properties of nonlinear ultrafast acoustic propagation based on the underlying equations. Then we show various results obtained by different groups around the world with an emphasis on recent work. Current issues and directions of future research are discussed.

International audience; Pulsed femtosecond lasers can generate acoustic pulses propagating in solids while displaying either diffraction, attenuation, nonlinearity and/or dispersion. When acoustic attenuation and diffraction are negligible, shock waves or solitons can form during propagation. Both wave types are phonon wavepackets with characteristic length scales as short as a few nanometer. Hence, they are well suited for acoustic characterization and manipulation of materials on both ultrafast and ultrashort scales. This work presents an overview of nonlinear ultrasonics since its first experimental demonstration at the beginning of this century to the more recent developments. We start by reviewing the main properties of nonlinear ultrafast acoustic propagation based on the underlying equations. Then we show various results obtained by different groups around the world with an emphasis on recent work. Current issues and directions of future research are discussed.

Previously, we have demonstrated that phagocytosis of IgG1-coated particles by macrophages in vitro is impaired by deletion of Fc gamma RIII in mice, suggesting that IgG1 may interact preferentially with Fc gamma RIII. In the present study, the biologic relevance of this observation was addressed by triggering various effector functions of the immune system in Fc gamma RIII(-/-) mice, using panels of mAbs of different IgG subclasses. Both binding and phagocytosis of IgG1-coated sheep or human erythrocytes by Fc gamma RIII(-/-) macrophages in vitro were strongly impaired, indicating that the impaired ingestion of complexed IgG1 by Fc gamma RIII(-/-) macrophages is due to a defect in binding. An in vivo consequence of the defective phagocytosis was observed by resistance of Fc gamma RIII-deficient mice to experimental autoimmune hemolytic anemia, as shown by a lack of IgG1-mediated erythrophagocytosis in vivo by liver macrophages. Furthermore, trapping of soluble IgG1-containing immune complexes by follicular dendritic cells in mesenteric lymph nodes from Fc gamma RIII(-/-) mice was abolished. Whole blood from Fc gamma RIII(-/-) mice was unable to induce lysis of tumor cells in the presence of IgG1 antitumor Abs. Finally, IgG1 mAbs proved unable to mount a passive cutaneous anaphylaxis in Fc gamma RIII(-/-) mice. Together, these results demonstrate that IgG1 complexes, either in particulate or in soluble form, trigger in vitro and in vivo immune effector functions in mice predominantly via Fc gamma RIII.

We describe a monoclonal antibody, WT-31, that reacted with all human T lymphocytes. Electrophoretic analysis of the material reacting with WT-31 revealed that it precipitated predominantly an 80-kD disulfide-linked heterodimer from the cell surface-labeled T leukemic cell line HPB-ALL. This heterodimer was identical to the one precipitated with a recently described monoclonal reagent, T40/25, which recognizes a clonotypic structure on HPB-ALL. The target antigen of WT-31 comodulated with T3 after incubation of T cells with excess anti-T3 antibody, indicating that the WT-31 target antigen is associated with T3. We also found that anti-T3 reagents, but not the clonotypic reagent T40/25, blocked binding of FITC-labeled WT-31 to HPB-ALL cells. This indicates that the T cell receptor epitope recognized by WT-31 is located close to the epitopes recognized by the anti-T3 reagents anti-Leu-4 and SPV-T3b but distal from the clonotypic T40/25 epitope. Functional studies showed that WT-31 reacts similar to anti-T3 antibodies. It is mitogenic for resting T cells, blocks cytolysis mediated by alloantigen-specific CTL clones, and induces antigen-nonspecific cytolysis by CTL clones against Daudi target cells. WT-31 did not inhibit the formation of conjugates, but it blocked cytolysis just before or during the Ca2++-dependent programming for lysis. We conclude that WT-31 is an antibody that recognizes a common determinant on the T cell receptor for antigen. The present results support the notion that the two chains of the T cell receptor (alpha and beta) form a functional protein ensemble with the three invariable T3 polypeptide chains (T3-gamma-, delta-, epsilon).

When citrate plasma and serum of the same individual were tested simultaneously in the C1q-binding assay (C1qBA), binding levels in plasma were found to be 90-400% higher than in serum. The difference in 125I-Clq binding was due to the presence of fibrinogen in plasma. It was shown that complex formation between fibrinogen and 125I-Clq occurs and that this complex precipitates in the presence of polyethylene glycol, leading to the false positive results in the ClqBA. When heparin plasma was used to the assay, heparin itself also induced an increase in 125I-C1q binding that was not based on the presence of immune complexes. The effect of both fibrinogen and heparin could be inhibited by addition of protamine sulphate. Therefore, pretreatment of plasma with protamine sulphate makes it possible to use plasma samples for a reliable determination of C1q-binding levels. However, serum that is well clotted should be used preferentially.