The ABCs of ABGs or how to interpret a blood gas value.
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The influence of HLA matching was studied in 319 informative cases of primary cadaveric kidney transplantations performed in Gothenburg 1969--1976. Foreign HLA-B antigens seemed to be of more importance for graft survival than foreign HLA-A or -C antigens. The prognosis for graft survival was significantly improved for match-grades with one foreign HLA-B antigen from the period 1973--1976 compared to those from the period 1969--1972. Match-grades with two foreign HLA-B antigens had significantly reduced graft survival during the period 1973--1976.
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A long-used inventory technique can help lower laboratory supply costs by pinpointing items which justify creative administrative attention.
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Shared idiotypy between B- and T-cell receptors specific for the antigen L-tyrosine-p-azophenyltrimethylammonium [tyr(TMA)] was studied in an antigen-binding assay using idiotypic antisera. These idiotypic reagents were prepared by inoculation of rabbits with purified anti-tyr(TMA) antibody raised in strain 13 guinea pigs. The antisera blocked 78-83% of the antigen-binding T cells (T-ABC) and 50-55% of the antigen-binding B cells (B-ABC) from tyr(TMA)-immune strain 13 and outbred lymph node cells (LNC). An excess of normal guinea pig Ig in the ABC assay did not affect the ability of the idiotypic antisera to block T- and B-ABC. Nylon wool-passed tyr(TMA)-immune LNC were trypsin treated resulting in a 75% loss of T-ABC. The trypsin-treated population was then cultured for 16 h which resulted in a return of T-ABC to 92% of pretrypsin values. 77% of these regenerated T-ABC could be blocked with idiotypic antisera. Specificity of the idiotypic antisera was tested in L-tyrosine-p-azobenzenearsonate-immune guinea pig LNC. Neither T- nor B-ABC were blocked in this heterologous system. Further blocking experiments were performed to characterize the nature of the T-ABC receptor. A variety of anti-Ig reagents, some of which block B-ABC, do not inhibit T-ABC suggesting that variable regions on T cells are not linked to Ig Constant regions.
BACKGROUND: Anaplastic lymphoma kinase (ALK) tyrosine kinase inhibitors (TKIs) are highly effective in treating ALK-rearranged non-small-cell lung cancer (NSCLC). However, at least 40% of patients develop acquired resistance during treatment. Adaptive or acquired resistance to ALK TKIs could be mediated through epidermal growth factor receptor (EGFR) and mesenchymal-epithelial transition factor (MET) signaling. Sixteen percent of acquired resistance cases are linked to bypass signaling. METHODS: In this study, we evaluated the effects of amivantamab, a bi-specific antibody targeting both EGFR and MET, on ALK-rearranged NSCLC cells. We investigated the effect of amivantamab on the ALK-rearranged NSCLC cell lines H3122, ABC-19, and ABC-11. RESULTS: Combining alectinib with amivantamab resulted in greater inhibition of cell growth inhibition in H3122 and ABC-19 cells compared to alectinib alone, but not in ABC-11 cells. EGFR TKI erlotinib showed similar efficacy in H3122 and ABC-19 cells, whereas MET TKI tepotinib was ineffective in both, suggesting that the efficacy of amivantamab is through EGFR inhibition. Unlike H3122 and ABC-19 cells, ABC-11 cells were resistant to EGFR/MET signaling inhibition. Interestingly, amivantamab enhanced alectinib efficacy against ABC-11 cells in the presence of peripheral blood mononuclear cells (PBMCs), despite showing no effect alone without PBMCs, suggesting action through non-signal inhibitory mechanisms. Finally, we treated alectinib-resistant cellswith alectinib, with or without amivantamab, and found that amivantamab restored the sensitivity of these cells to alectinib. CONCLUSION: The bi-specific antibody amivantamab, which targets EGFR and MET, enhanced the efficacy of alectinib through both signal and non-signal inhibitory mechanisms in ALK-rearranged NSCLC cells.
A biochemical parameter of lymphocyte activation, lipid synthesis, has been measured in a purified specific antigen-binding cell population (ABC). ABC isolated form immune and nonimmune animals by sequential centrifugation on buoyant density and sedimentation velocity gradients have a 2- to 7-fold higher rate of 14-C choline incorporation into phospholipid than either unfractionated spleen cells or cells depleted of ABC. Aslo ABC from immune animals were shown to have a 4- to 7-fold higher rate of 14C-acetate incorporation into their neutral lipids than nonbinding controls. The elevated lipid synthesis seen in both nonimmune SRBC-ABC and TNP-SRBC ABC indicates that antigenic contact via the B cell immunoglobulin receptor results in signal transduction and activation of the specific receptor-bearing lymphocyte population. Binding of the same particle (SRBC) to B cells via their Fc receptors did not regularly result in activation of lipid synthesis. The magnitude of the increased lipid synthesis in ABC populations approached that seen in LPS-stimulated spleen cells. We propose that the measurement of early activation events in purified ABC may be a more appropriate criterion for antigen-induced signals that later events such as thymidine incorporation or antibody secretion.
Artificial body cavities (ABC) were created by the insertion of hollow polyethylene balls in the subcutaneous tissue of rabbits. After two months no inflammatory reaction could be detected, the ABC was enveloped by a membranous structure, and the cavity contained about 20 ml of fluid. The protein concentration was about 3 times, and the IgG about 8 times, lower in the ABC fluids than in the corresponding serum. At the same time the antibody titers against sheep red blood cells (SRBC), human IgG and herpes simplex virus type 1 (HSV) were about 20 200 times lower than in the corresponding serum samples. The IgG molecules appeared to be undamaged as shown by the presence of various allotypes and by the elution pattern from G-200 column. Testing the protective activity of ABC fluids and of serum against HSV infection showed that ABC fluids had no protective activity. The experiments suggest that the membranous structure selected among classes of Ig and probably among other serum proteins. In addition, the IgG molecules with antibody activity against various inoculated antigens were selectively excluded to penetrate in the ABC. The ABC might be considered analogous to virtual cavities of the body surrounded by membranes and possibly to the extravascular compartment.
A two-step centrifugation procedure has been developed to isolate greater quantities of highly purified sheep erythrocyte antigen-binding cells (ABC) than previously possible. The first step involves partially separating sheep erythrocyte rosettes from unrosetted lymphocytes by their difference in buoyant density on Ficoll-Hypaque. Subsequent passage through a linear 5 to 10% Ficoll gradient produces further purification of rosettes by sedimentation velocity. Approximately 4.5 X 10(6) ABC can be obtained at 50 to 100% purity from 10(9) immune spleen cells (5 days post-immunization) and 1 X 10(5) ABC at 20 to 40% purity from 10(9) nonimmune spleen cells. The purified ABC from 5-day immune animals are 80 to 90% B cells and 10 to 20% T cells, and represent between 30 and 40% of the original ABC in the spleen cell population. Less than 0.2% of the purified ABC are plaque-forming cells (PFC) and less than 2% have intracellular immunoglobulin (Ig) or J chain. The quantities of ABC obtained are sufficient for investigating biochemical parameters of antigen-induced lymphocyte activation and for direct analysis of the surface isotypes found on antigen-binding cells after immunization.
The 52 alveolar brush cells (ABC) were revealed in the semi-thin sections of the rat lung tissue, metachromatically stained with toluidine blue. Characteristic features of the ABC on the light microscope level were the following: pyramidal body shape, basal position of the nucleus, darker stain tinge of the cytoplasm than that of other alveolar cells, the presence of microvilli on the small free cell surface. There is one ABC per 21 alveocytes, type 2, and 15 alveocytes, type 1. 41.1% of the ABC are localized in places of adjacent alveolus walls junction, 32.7%--on the alveolus wall facing the alveolus cavity, 16.8%--near the alveolus entrance; 9.4% of the cells are directed into the cavities of two neughbo ring alveoli or settle down near the pores of Kohn. In parallel electron microscopy there was revealed in ABC a form of granular cytoplasmic reticulum (unusual for other alveolocytes) in the form of blocks made up of 5-8 cysternae as if adherent one to another, bundles of filaments and microtubules, vacuoles in the apical cytoplasm. The ultrastructure of ABC, their topography, and incidence in the alveoli of rats evidenced their chemoreceptor nature.
The bone marrow and spleen of normal unimmunized chicks contain lymphoid cells which form rosettes with quail red blood cells (QRBC), but not with sheep red blood cells. The number of these antigen binding cells (QRBC-ABC) were restored to their original level 2-3 weeks after whole body X-irradiation following a temporary but drastic decrease in the number of QRBC-ABC. This recovery is not observed in chicks which have been thymectomized or thymectomized and bursectomized. However, QRBC-ABC numbers were restored in bursectomized chicks comparable with those levels in control chicks. Anti-thymic serum effectively blocked rosette formation and it seems that QRBC-ABC are a thymus-dependent population. Possibly, the thymus exerts an influence on the genesis of QRBC-ABC through a humoral mechanism.
The numbers and fate of antigen-binding cells (ABC) in neonatal and adult mice rendered tolerant to fluorescein (FL)-labeled heterologous gamma-globulins were studied. Similar numbers of FL-ABC were observed 1 day after tolerogen in both adult and neonatal mouse spleens: by 7 days after tolerization, no FL-ABC were observed in either case. Reinjection with FL-tolerogen at 7 days led to the detection of normal numbers of ABC in adult mice but significantly reduced numbers in neonates. This suggests that neonatal ABC either have been deleted or have failed to resynthesize surface receptors. Two weeks after tolerance induction, spleen cells from these tolerant mice were cultured with Escherichia coli lipopolysaccharide (LPS), a polyclonal B cell mitogen, or with specific antigen. Tolerant adult spleen cells made an equivalent anti-FL response to that of the uninjected controls when stimulated with LPS, but were unresponsive to specific antigenic triggering. In contrast, spleen cells from neonatally tolerized mice were unresponsive to either specific or nonspecific (LPS) stimulation. Thus, these neonatally tolerized spleen cells lose sensitivity to polyclonal-stimulating agents (along with their receptors), or more simply, are deleted.
Bursal and splenic lymphocytes in developing chick embryos were examined for the number of antigen binding cells (ABC) which could form rosettes with red blood cells from sheep, guinea-pig, rabbit or dinitrophenylated sheep red blood cells (DNP-SRBC). The kinetics of the development of bursal ABC to rabbit red blood cells (RRBC) did not vary significantly with age of embryo examined, and its frequency was constantly high. The number of cells which bind to SRBC, guinea-pig red blood cells (GPRBC) or DNP-SRBC was low in the bursa and increased in an approximately linear fashion with the age of embryo. With the exception of RRBC-ABC, similar results were obtained with splenic ABC. Furthermore, the frequencies of ABC were higher in the spleen than in the bursa. These events suggest the antigen-independent generation of clonal diversity during the developmental stage of chick embryos.
Antigen-binding cells (ABC) from spleens of HGG-immunized, bursectomized agammaglobulinemic (Bx) chickens were detected by direct autoradiography with 125I-HGG and by sandwich autoradiography with HGG plus 125I-goat-anti-HGG. The specificity of antigen binding was demonstrated by 1) inhibition of binding of 125I-HGG by preincubation with unlabeled HGG and 2) a specific increase in ABC after immunization. The ABC from Bx chickens were not B cells, as shown by the virtual absence of immunoglobulin-bearing cells in this population and by the lack of inhibition of antigen binding by anti-immunoglobulin sera. The ABC were not macrophages and did not bind HGG via Fc receptors because their frequency was unchanged after passage over nylon wool or incubation with antigen-antibody complexes. The temperature dependence and azide stabilization of the ABC were characteristic of antigen-binding T cells. Therefore, T cells capable of binding soluble antigen were demonstrated in Bx chicken spleen, which is free of contamination by B cells and passively adsorbed antibody.
Data are presented comparing different methods for the fractionation and enrichment, respectively, of specific antigen binding lymphoid cells from immunized chickens. The bovine serum albumin (BSA) anti-BSA system was chosen as a model. To enrich avian antigen binding cells (ABC) from a mixture of chicken peripheral blood and spleen lymphocytes 3 different methods were used: (1) separation of cells forming rosettes with antigen-coated sheep red blood cells (SRBC) from non-rosetting cells by density centrifugation; (2) isolation of ABC by their specific adherence to antigen bound to immunoadsorptive surfaces (gelatin, plastics); (3) column affinity chromatography with antigen-coated agarose, cross-linked dextran for plastic beads. The most efficient method was column affinity chromatography with antigen-coated polyacrylamide beads which affords up to 12-fold enrichment of ABC. Both the other methods are also suitable for separation and enrichment of specific ABC but can only with difficulty be adapted for processing the large numbers of cells which would be necessary, e.g., for in vivo transfer studies.
Antigen-binding cells (ABC) could be detected regularly by autoradiography among haemic cells in the liver of human fetuses ranging in age from 8 to 24 weeks. For radioiodine-labeled thyroglobulin, the antigen mainly used in these studies, counts of ABC ranged from 5.0 to 24.3 per 1,000 cells scanned. There was a trend for counts of ABC in liver to be highest at 10-12 weeks of fetal life. Binding of labeled thyroglobulin was inhibited by excess unlabeled thyroglobulin, but not by other protein antigens. Artifacts due to binding of antigen to normoblasts, which comprised 90% of the haemic cells in fetal lines, and to cells with 'sticky' surfaces were excluded as far as possible. There was no response by fetal liver cells to phytohaemagglutinin. Although there was only minimal inhibition of binding by anti-immunoglobulin sera of known potency, the ABC in human fetal liver were assumed to correspond to immunoglobulin-bearing precursors of B cells described by others in the liver of the fetal mouse.