Zeitschrift für Immunit?tsforschung: Immunobiology最新文献

The influence of the Lewis blood group system on transplant survival was studied retrospectively in 161 kidney transplantations. Le (a- b+) recipients had significantly higher graft survival rates than Le (a+ b-) or Le (a- b-) recipients. From the known distribution of the Lewis blood groups among the European population, a high percentage of Lewis-compatible transplants would be expected among Le (a- b +) recipients in contrast to the Le (a+ b -) and Le (a- b -) recipients. Other factors which are known to influence transplant prognosis such as HLA-match between donor and recipient, ischemic time of the transplants and pretransplant blood transfusions did not differ significantly in any of the three groups studied. Our data again suggest the relevance of the Lewis blood group system for clinical kidney transplantation. The findings should be confirmed by prospective typing of donor and recipient for Lewis antigens.

Groups of rabbits were subjected to one, two and three intratracheal exposures to a crude culture of Micropolyspora faeni (Mf). Another group was immunized by a single subcutaneous injection of Mf in complete Freund's adjuvant. The immune response was evaluated by in vitro lymphocyte stimulation tests, agar gel precipitation tests and Prausnitz-Küstner reactions, using as antigens a whole soluble Mf extract (glycine extract) and different protein fractions obtained by Chromatographic fractionation on Sephadex G 150.

Our results suggest the development of an active cell-mediated response soon after the first intratracheal exposure, the humoral response becoming stronger only after 2 or 3 exposures. Skin sensitizing antibodies were found only in one intratracheally exposed rabbit after 3 exposures.

Although great individual variations in the immune response were observed after intratracheal exposure, our results suggest that the high molecular weight protein fractions of the M. faeni extract are the most immunogenic. Following subcutaneous immunization, on the other hand, the immune response is more homogeneous and is directed against a larger variety of Mf-antigens.

Rosette formation of human lymphoid cells with mouse erythrocytes has recently been proposed as a marker for a subpopulation of B lymphocytes. In this work we studied the percentage of mouse rosette forming cells (MRFC) in normal and pathological conditions and compared them to the percentage of sheep rosette forming cells (SRFC) a marker for T lymphocytes.

Peripheral blood lymphocytes (PBL) from normal donors contained 6.2 ± 1.1% (mean ±1 S.D.) MRFC. High percentages of MRFC were found in CLL patients, and a slight increase was observed in patients with systemic lupus erythematosus.

MRFC were absent in Bruton's type agammaglobulinaemia, but were normally present in patients with T cell defects.

Cryopreservation of lymphocytes in 10% DMSO did not significantly affect the mean percentages of SRFC and MRFC, though a slight increase of the former and a small reduction of the latter was observed.

Double binding experiments on peripheral blood lymphocytes showed a predominant association of MRFC with cells staining for surface IgM and/or IgD. In all samples tested, we also observed a small population of MRFC negative for sIgM or sIgD and a few sIgM or sIgD positive cells that did not rosette with mouse erythrocytes.

The γ-emitting aminoacid ⁷⁵Se-selenomethionine (⁷⁵SeM) was examined as a target cell label in cytotoxic assays. It was efficiently taken up by activated, intensely metabolizing cells of various types but hardly at all by resting or low-metabolizing cells. Culturing activated cells in methionine-deficient medium with 3–5 μCi ⁷⁵SeM/ml for 18–22 h usually resulted in an uptake of 3–20 cpm/cell which was 3–200 times that of ⁵¹Cr marked cells. ⁷⁵SeM-labelled cells kept in medium at ambient temperature or at 37°C, maintained a high radioactivity per cell and a viability above 85% for at least 72 h without significant increase in spontaneous isotope release or loss in sensitivity in subsequent cytotoxic tests. ⁷⁵Se-labelled material released from target cells was not reutilized by unlabelled lymphoid cells. Provided the cells were carefully washed after labelling and kept in optimal culture conditions, the reasonably low baseline release (usually 0.6–1.8% of input/h) in the medium control allowed performance of long-term assays of up to 54 h. However, strong cytotoxic reactions (e.g. ADCC) could cause over 50% specific ⁷⁵Se-release within 5 h. With constant amounts of effector cells (3.6 × 10³ up to 3 × 10⁵/well) identical or even higher, specific releases were obtained on 6 × 10² targets as compared to 1 × 10⁴ targets/well. Thus, the ⁷⁵Se-release assay offers a single monitoring system suitable for short (3–6 h) and long term (usually up to 44 h) cytotoxic reactions on a microscale, using 1 × 10³ or less targets/well. Its sensitivity permits evaluation of strong and weak reactions as well as early and delayed onset cytotoxicity. In addition, with a γ-spectrometer the radioactivity of ⁷⁵Se can easily be distinguished from that of ⁵¹Cr. Due to this, and an improved method for ⁵¹Cr labelling of cells (10 μCi ⁵¹Cr/ml medium for 18–22 h), a double γ-labelling of cellular proteins is available which provides new possibilities for monitoring cellular interactions in short and long term tests.

The effects of Isoptin® i) on isolated microtubules, ii) on the anti-immunoglobulin and the Concanavalin A induced changes in the plasma membrane topography of murine lymphocytes and iii) on murine lymphocyte activation by lipopolysaccharide and by Concanavalin A was investigated.

Isoptin® and lidocaine (a local anaestetic) inhibited repolymerisation of tubulin into microtubules and induced depolymerisation of microtubules. Isoptin® and lidocaine inhibited competitively binding of colchicine (a classical microtubules disrupting agent) to tubulin. Isoptin® induced changes in the plasma membrane topography resembling effects caused by local anaesthetics or by a combination of colchicine and cytochalasin B (an agent affecting microfilament function).

Isoptin®, lidocaine, colchicine and hydroxyurea when present in the culture medium during the whole incubation period inhibited DNA synthesis induced by lipopolysaccharide or Concanavalin A. RNA synthesis was completely inhibited by lidocaine but not by Isoptin® or by colchicine. If Isoptin®, colchicine or hydroxyurea were removed from the culture medium at 20 h of culture period, the cells immediately started to incorporate ³H-Thymidine. The inhibitory action of lidocaine was irreversible.

These results show that Isoptin®, a drug which depolymerizes microtubules in vitro and disturbs the mitogen induced changes in plasma membrane topography of lymphocytes (believed to be controlled by microtubules and microfilaments), does not abolish commitment of the cells for DNA synthesis.