Paired Epstein-Barr virus (EBV)-negative and EBV-converted Burkitt lymphoma lines: stimulatory capacity in allogeneic mixed lymphocyte cultures

Epstein-Barr virus (EBV)-negative Burkitt lymphoma lines (BLE-) and their in vitro EBV-converted sublines (BLEc), obtained by infection with the P3HRI and B95-8 strains of EBV, were compared for their capacity to induce T-lymphocyte proliferation in allogeneic mixed lymphocyte cultures (MLC). Regardless of the virus strain used for conversion, the BLEc lines induced a considerably stronger primary MLC response than their EBV-negative parentals. Only the BLEc lines were able to maintain T-lymphocyte proliferation in repeated stimulations. The low proliferative response observed in cultures stimulated with BLE- cells was not due to the generation of suppressor cells or to the release of inhibitory factors. The increased stimulatory capacity of BLEc lines was unrelated to changes in expression of MHC class-I and class-II antigen, or of B-cell activation markers, and was not due to the reactivation of EBV-specific memory T cells, since lymphocytes from EBV-seropositive and seronegative donors responded similarly. The results indicate that the capacity of BL cells to elicit cellular immune responses may be influenced by their EBV-carrying status.     

Safer, more expensive iodinated contrast agents: how do we decide?

The advantages of the new, safer, but more expensive iodinated contrast agents are discussed, and opinions on which patient groups should receive the agents are presented.     

抗胆碱药3-(2-苯基-2-环戊基-2-羟基-乙氧基)奎宁环烷的立体化学和构效关系

研究了强效抗胆碱药dl-3-(2-苯基-2-环戊基-2-羟基-乙氧基)-奎宁环烷的四个光学异构体的两种不对称合成方法,用HPLC检测了异构体含量,讨论了构效关系。     

Pulmonary artery catheterization: a modified technique

A modified technique for catheterization of the pulmonary artery was developed. It involves the passage of a tapered, movable-core, J-tipped guide wire across the right ventricle into the pulmonary artery followed by the advancement of a straightened Grollman pigtail catheter. The technique was successful in 34 of 34 pulmonary artery catheterizations. The method avoids prolonged catheter manipulation within the right ventricle. In addition, since the catheter does not cross the tricuspid valve until the guide wire has been advanced, the occasional complication of the pigtail "hooking" on a tricuspid valve leaflet or chordae tendineae during catheter withdrawal and manipulation is prevented.     

Differential expression of hla antigen of HLA anigens on human B-cell lines of normal and malignant origin: A consequence of immune surveillance or a phenotypic vestige of the progenitor cells?

Pairs of BL-derived cell lines and in vitro EBV-transformed LCLs, derived from the same patient, were compared for the expression of MHC class-I antigenic determinants as shown both by monoclonal antibody (MAb) binding and by sensitivity to HLA-specific CTL clones. BL lines expressed all polymorphic determinants tested at a lower level than the corresponding LCLs, as indicated by the binding of the MAbs AUF 5.13 (anti-HLA A3,A11), GS 142.1 (anti-HLA A1), GS 114.1 (anti-HLA A24), GSP 35.1 (anti-HLA A2,A28), GSP 55.1 (anti-HLA A25,A32), TER MA32 (anti-HLA A32), GSP 145.2 (anti-HLA B27), B27 M.1 (anti-HLA B27,B7) and GSP 8.1 (anti-HLA B8). The difference was most pronounced for HLA A11 and least for B27,A1 and B8 with intermediate differences for the other specificities. The BL lines were also less sensitive to lysis by HLA-specific CTL clones directed to the same and to additional antigens. The polymorphic determinants detected by the AUF 5.13 and GSP 35.1. MAbs were expressed at a lower level in resting T and B cells compared to mitogen- and EBV-induced blasts. An analogous change in the expression of polymorphic determinants was observed in EBV-converted sublines of originally EBV-negative BLs that have become more "LCL-like" after conversion. The appearance of B-cell activation markers was paralleled by the up-regulation of both the serologically defined and the CTL-target epitopes. The findings suggest that the low expression of HLA determinants on the BL cells is a phenotypic vestige of the normal BL precursor.     

Specific and non-specific components in the triggering of proliferative and cytotoxic responses of T lymphocytes with different cell density

We hve analyzed the functional behavior of lymphocyte subsets separated on the basis of cell density. Low and high density subpopulations were cultured in FCS, alone or with allogeneic irradiated PBL, and then examined for proliferation and cytotoxic activity against autologous (responder) and allogeneic (stimulator) PHA-induced blasts, K562 and Daudi. In the high density subset proliferation and generation of anti-K562 and anti-Daudi effects were induced by FCS and to higher extent by allospecific stimulation. Exposure to alloantigens induced allospecific cytotoxicity. Autologous PHA blasts were not affected. The results with the low density subset differed. Independently of the type of stimulus imposed, the low density fraction showed little if any proliferation, but its cytotoxic activity was stronger against all targets tested. In some of the experiments, anti-alloblast cytotoxicity was generated in the control cultures. Thus, polyclonal activation induced by FCS triggered in this fraction allospecific cytotoxicity. In this subset, the effect against allogeneic PHA blasts comprised a specific and a non-specific component because autologous PHA blasts were also lysed. Limiting dilution analysis involving allostimulation showed higher frequency of cytotoxic precursors in the low density subset. Split minicultures were tested for lysis of auto- and allogeneic blasts. Alloreactive cultures that did not lyse the autologous target were more frequent in the cultures initiated with the high density cells. There was no conclusive evidence for the existence of autoreactive cultures that did not lyse the allogeneic blasts.