Zeitschrift für Immunit?tsforschung: Immunobiology最新文献

A modified histochemical procedure for nonspecific acid α-naphthyl acetate esterase (ANAE) activity in human lymphocytes was used to identify a subpopulation of E-rosette forming cells. Performing a one hour reaction at pH 6.5 the distinct dot-like staining pattern was almost exclusively observed on high affinity E-rosettes which sedimented readily in a regular Ficoll-Metrizoate gradient. By combining latex phagocytosis with staining for ANAE activity, a clear-cut distinction between mononuclear phagocytes and lymphocytes could be made. An attempt was undertaken to relate the ANAE marker on human lymphocytes to their functional capacity in spontaneous cell-mediated cytotoxicity (SCMC) reactions. Using as targets two allogeneic (K562,IGR3) and a xenogeneic cell line (L1210) it could be clearly demonstrated that high SCMC activity is mediated by ANAE negative mononuclear cells, whereas enrichment for ANAE positive lymphocytes resulted in a loss of SCMC.

Erythrocytes of different species (chicken, sheep, man, mouse, rat, guinea pig) except rabbit erythrocytes strongly adhere to the marginal zone of mouse spleen follicles in frozen sections. This adherence reaction (AR) is not restricted to red blood cells but is also observed with human lymphocytes. Pretreatment of the tissue sections with trypsin, mercaptoethanol, periodate, chloroform/methanol, acetone, and heating the sections abolishes AR whereas neuraminidase (VCN) treatment of the sections has an amplifying effect. AR is inhibited by preincubation of the neuraminidase- or untreated sections with neuraminic acid (NA). Treatment of the erythrocytes with VCN completely abolishes AR whereas treatment with other enzymes (hyaluronidase, collagenase) is ineffective in this respect. Determination of NA in the erythrocyte membrane before and after VCN treatment reveals a positive correlation between the amount of NA and AR. Rabbit red blood cells have the lowest NA content in their membranes and, in addition, there is little effect of VCN treatment in further reducing it. It is possible that a lectin-like substance is responsible for AR. The biologic significance of AR is hypothetical, but since AR occurs in an area of the spleen playing a role in antigen trapping it is conceivable that this trapping may be mediated by an interaction of NA and NA receptor(s).

E and EAC rosette-forming cells in the peripheral blood and in the liver of subjects with acute and chronic hepatitis were studied. We found a highly significant reduction (P < 0.01) of E rosette percentage in the lymphocytes isolated from the liver of patients with chronic persistent, and chronic active, hepatitis. EAC rosette-forming cells were significantly increased in the liver of patients with chronic active hepatitis (P < 0.01). In this condition lymphocytes with Fc receptor were also found.

Gel filtration of the cytoplasmic fraction of homogenate from human peripheral lymphocytes incubated with <ce:inf>65</ce:inf>Zn gave five separate peaks with molecular weights of > 150,000, 90,000, 65,000, 20 000, and < 1000 daltons. Peaks I–IV consisted of proteins. The low molecular weight (peak V) may consist of nucleotides, polyamines and amino acids. After gel filtration 75–80% of the ₆₅Zn activity was found in peak V. Lectin-induced stimulation of normal lymphocytes revealed a distribution pattern of ₆₅Zn binding similar to that of unstimulated cells. There was only a slightly enhanced incorporation into the protein peaks I–IV. When peripheral lymphocytes of B lymphocyte origin from patients with chronic lymphocytic leukemia were incubated with ₆₅Zn the same peaks were seen as with supernatants obtained from normal lymphocytes. Lectin-induced stimulation of leukemic lymphocytes had no significant effect on the ₆₅Zn distribution pattern.

Peptidoglycan monomer (PGM), a water soluble and nontoxic disaccharide pentapeptide unit obtained from Brevibacterium divaricatum, was administered intravenously into mice, and the humoral immune response to sheep erythrocytes was assayed by means of Jerne's technique for plaque-forming cells (PFC) in the spleen. The PFC response was evidently stimulated. The counts were increased to practically the same extent over a great range of doses of PGM (from 25 to 1600 μg per animal), and the effect was present in the mice immunised with optimal, as well as in those immunised with suboptimal, doses of antigen. The magnitude of the immunostimulation depended only on the timing of PGM administration: it was maximal if PGM was injected 1 or 2 days after the antigen. In vitro, in a 4-day culture of spleen cells, PGM did not stimulate PFC formation. We conclude that stimulation of the humoral immune response to sheep red blood cell antigens by PGM probably occurs without cell multiplication and probably involves more than simply a contact of immunocompetent cells with PGM.

An adaptation of the nephelometric assay for serum immunoglobulins has been developed for detection and quantitation of extracellular immunoglobulins in cultures of lymphoblastoid cell lines. This assay employs the standard equipment for laser nephelometry and commercial reagents for immunoglobulin quantitation. By adjusting dilutions of controls and sample volumes of culture supernatants, amounts of IgG and IgM below 1 μg/ml can be detected in culture supernatants. At concentrations between 1 and 4 μg/ml, day-to-day and within-run variations for IgM assays were 16 and 11% respectively. The possibility of measuring immunoglobulins secreted by cell lines by conventional laser nephelometry opens several areas of application in the study of the functional activity of B cells and of cell-cell interactions.

The influence of opsonization on ingestion and digestion of C-resistant E. coli was tested in a phagocytic system consisting of a monolayer of human PMN to which was added E. coli opsonized in different ways. At the end of the phagocytosis, noningested bacteria were separated and the monolayer was removed. The cells were then fractionated. The number of bacteria at different time intervals and the amount and distribution of lysosomal enzymes in the cell fractions were determined. It became apparent that the ingestion of cell-attached bacteria was independent of opsonins. However, the intracellular destruction was enhanced following opsonization with C only, although this was not the result of a greater discharge of lysosomal enzymes into the phagosome. We postulate that sublethal damage of E. coli by C renders the bacteria more sensitive to the bactericidal activity of the phagocytes.

This paper describes a method for the simultaneous determination of human thymus-dependent lymphocyte (T cell) and thymus-independent lymphocyte (B cell) populations by mixing lymphocytes, sheep red blood cells, and immunobeads. This method also detects lymphocytes possessing both T and B cell markers.

T cells are detected by rosette formation with AET-treated sheep red blood cells and B cells are identified by rosette formation with polyacrylamide gel coated with antibody specific to immunoglobulin classes. The major advantages of this technique is that it is simple, convenient, and reproducible. Three different types of rosettes are distinguishable under light microscopic observation. The detection of double marker lymphocytes, using this combined technique, may have further application in clinical investigation.