Zeitschrift für Immunit?tsforschung: Immunobiology最新文献

Homozygeous nu/nu mice do not develop experimental autoimmune thyroiditis and circulating thyroglobulin autoantibodies after two immunizations with murine thyroid extract and fortified complete Freund's adjuvant. However, heterozygeous nu/+ mice are perfectly apt for the induction of both thyroiditis and thyroglobulin autoantibodies. These results provide further evidence for the assumption that the development of experimentally induced autoimmune thyroiditis depends on the presence of T-cells as opposed to the spontaneously occurring autoimmune thyroiditis in Obese strain (OS) chickens which is mediated by B-effector cells. The present data further show that thyroglobulin is a T-dependent antigen in the mouse.

Plasma membranes isolated from peripheral blood lymphocytes of normal donors, lymphocytes from patients with chronic lymphatic leukaemia (CLL), a T cell and B cell line (MOLT-3 and RPMI-1788) were analysed and compared for total carbohydrate contents. T cells and peripheral blood lymphocytes contained the highest relative amounts of sialic acid and fucose, whereas chronic lymphatic leukaemic cells possessed the highest amounts of N-acetylgalactosamine and also more total cell surface carbohydrate.

The Thomsen-Friedenreieh antigen (T_F) was detected serologically on membrane fractions by the use of anti-T_F containing sera and specific lectins from Arachis hypogaea, Agaricus bisporus and Vicia graminea. The disaccharide ß-D-galactosyl(1-3)-N-acetyl-D-galactosamine is the immunodominant carbohydrate group of the T_F antigen and was detected as its reduced form, by gas chromatography, in all cells, thus correlating serological and analytical evidence. The haemagglutinating activity of the lectins and sera used was only inhibited by plasma membranes after the removal of sialic acid showing that the native form of this antigen is normally masked by sialic acid in CLL cells as well as normal lymphocytes.

The effects of concanavalin A (Con A) and leucoagglutinin (LA) on the locomotor response of phagocytes have been studied in vitro. At concentrations of 1 to 4 μg/ml, Con A and LA induced maximal chemokinesis and chemotaxis of monocytes, macrophages and, to a lesser degree, also of neutrophils. The lectin-induced locomotion was accompanied by membrane alterations and metabolic changes, as shown by an increase of the ³H-uridine uptake and a rise of the hexose monophosphate shunt activity. The chemotactic activity of Con A was inhibited by α-methyl mannoside (50 mM) or by pretreatment of the cells with trypsin. These data indicate that lectins such as Con A induce chemotaxis by a specific binding to receptors of the cell membrane. It is suggested that bivalent ligand binding is required as a signal to elicit chemotactic locomotion.

DBA/2 mice were found to be quite susceptible to infection with herpes simplex virus (HSV) while C57BL/6 mice and F1 hybrids between the 2 strains were relatively resistant. This difference was most marked after ip infection, but could also be demonstrated after intracerebral, intravenous or subcutaneous infection. In both strains the LD₅₀ was considerably higher after ip infection than after iv infection, and a dose of X-irradiation was required to kill the mice by sc infection. A/J and BALB/c mice were equally susceptible after ip infection but differed significantly after iv infection. C57BL/6 were made susceptible to ip infection by immunosuppression with antilymphocyte serum or cyclophosphamide. LPS, when given simultaneously with HSV also markedly increased the susceptibility of C57BL/6 mice. Susceptible DBA/2 mice which survived a low dose of HSV ip were not immune but C57BL/6 mice surviving a high dose were immune against rechallenge. Both strains of mice could be protected by an apathogenic, tissue-culture-attenuated strain of HSV against infection with the virulent strain. They could also be protected by iv injection of a sublethal dose against a lethal ip infection.

Serum amyloid protein SAA and its low molecular weight derivative SAAL have been compared in immunodiffusion with an antiserum to amyloid A at different temperatures. At room temperature or at 37°C SAAL and SAA did precipitate with anti-AA forming a line of identity. At 4°C, however, only SAAL did react with anti AA. Experiments are described which show that the SAA-derivative SAAL has AA-related antigenic determinants exposed whereas these determinants are hidden in the parent SAA and are only exhibited as result of an unknown temperature-dependent process. Therefore, SAAL can also be distinguished from SAA by the availability of AA -related antigenic determinants for anti-AA antibodies at 4°C.

In studies concerning the natural cytotoxic activity of human blood lymphocytes we have found that: 1. T cells, which rosette with sheep erythrocytes can be separated by centrifuging on Ficoll the lymphocyte and erythrocyte mixture without previously pelleting and incubating in the cold. 2. Lysis of marker erythrocytes with ammonium chloride impairs the cytotoxic activity of lymphocytes. Incubation at 37 °C for 12 hr prior to the test restores the activity to some extent. 3. A high proportion of the so called «null» fraction i.e. cells remaining in the interface after removal of B cells (passage on nylon column) and sedimentation of E rosettes, sediments as rosettes with sheep EAC'indicating that these cells carry low density E and C₃ receptors. Rosetting with SRBC or ox EAC' gave significantly lower values.

On a per cell basis the «null» fraction was the most efficient one in natural cytotoxicity. Depletion of cells with low affinity E or E and C₃ receptors left highly active subfractions.

Female gonads of the perch (Perca fluviatilis) in various stages of development are tested for hemagglutinin activity against human erythrocytes. Based on the different agglutination patterns obtained, and on inhibition tests with L-fucose and a mature gonad of a male perch, the appearance of two different agglutinins in the course of the development of the female gonad is assumed.