摘要:

AbstractSpleen cells from normal unimmunized adult mice were subjected to a 2‐stage fractionation procedure designed to prepare a subpopulation highly enriched for the capacity to form antibody to the hapten fluorescein (FLU). First, the spleen cell suspension was rocked in a petri dish coated with a thin layer of FLU‐gelatin (15 min at 4 °C), the nonadherent cells washed away and the adherent cells recovered by melting the gelatin and treated with collagenase. The cells were relabeled with a fluorescent protein, usually FLU‐gelatin at 100 μg/ml, (25 °C, 15 min). After washing, the cells were sorted into cohorts of relatively homogeneous fluorescence intensity in the fluorescence‐activated cell sorter (FACS). Finally, the sorted cells were again collagenase‐treated and stimulated with FLU‐coupled polymerized flagellin in a limit dilution microculture system capable of generating single clones of anti‐hapten plaque‐forming cells (PFC).It was found that the cohort of cells representing the 10 % most intensely fluorescent cells, yielded PFC clones with a frequency of 1 in 8, about 5 times higher than the hapten‐gelatin‐enriched cells. Less fluorescent cohorts gave progressively lower frequencies of clonable PFC precursors. Some evidence was obtained, suggesting that the most highly fluorescent cells produced antibody of higher median avidity than the FLU‐gelatin‐fractionated cells, which in turn showed higher avidity than unfractionated spleen cells, findings consistent with the clonal selection hypothesis.Somewhat surprisingly, cells with high fluorescence intensity prepared by FACS sorting of FLU‐gelatin‐labeled unfractionated spleen cells, yielded much lower PFC precursor frequencies than cells of equivalent fluorescence intensity derived through the 2‐stage fractionation procedure.Spleen cells from newborn mice were subjected to 2‐stage fractionation. The method proved equally applicable to them, and preparations with a 1 in 11 PFC precursor frequency could be readily generated. However, the neonatal cells differed from the adult cells in responding significantly better to the polyclonal B cell activator, lipopolysaccharide, than to antigen.The theoretical implications of these findings and the potential uses of pure populations of hapten

ISSN:0014-2980    

DOI:10.1002/eji.1830080302

出版商:WILEY‐VCH Verlag GmbH    

年代:1978

数据来源: WILEY

摘要:

AbstractEstablished, H‐2 incompatible, mouse skin allografts are destroyed in 24–48 h by a single intravenous injection of specific alloantibody and heterologous complement (C) from rabbits (RC), guinea pigs (GpC) or humans (HC). Mouse complement (MC) itself is inefficient in this respect since grafts are not destroyed by the injection of antibody alone. This is in keeping with the low efficiency of MC inin vitrocytolysis.We have studied the role of different C factors in this model. Two patterns were observed. (a) Three C‐deficient sera (GpC‐R4, GpC‐R3, RC‐R6) showed neither activityin vitro(C‐mediated lymphocytotoxicity in a trypan blue assay) nor did they induce graft destruction. Activityin vitroandin vivocould be completely reconstituted with the appropriate C component. (b) Two C‐deficient sera (GpC‐R1 and HC‐R9) were inactive inin vitrocytotoxicity but, nevertheless, induced destruction of the skin grafts if injected with antibody. Thus,in vivo, the mouse seemed to provide the deficient factor, and this was confirmed by the observation thatin vitrocytotoxicity could be reconstituted not only with the appropriate C component, but also with normal mouse serum. The results show that the inefficiency of MCin vitroandin vivodoes not reside in the factors C1 or C9. Furthermore, in our model C is activated via the classical pathway, and at least exogenous C4, C3 and C6 are required to induce acute antibody‐mediated graft destruction.From the experiments with C6‐deficient serum which has normal chemotactic properties, it is concluded that activation of chemotactic factors with attraction of granulocytes is not sufficient to induce rejection, but that the activation of the membrane

ISSN:0014-2980    

DOI:10.1002/eji.1830080303

出版商:WILEY‐VCH Verlag GmbH    

年代:1978

数据来源: WILEY

摘要:

AbstractThe immunological role of a naturally proliferating subpopulation of splenic T cells was investigated using the graft‐vs.‐host (GvH) reaction in the mouse. Normal parental spleen cells, purified splenic T cells or lymph node cells were pulse‐treated for one hourin vitrowith tritiated thymidine of high specific activity ([3H]dThd, “thymidine suicide”). The treatment specifically and selectively kills proliferating cells which are actively synthesizing DNA,i.e.cells in S phase. Following treatment, the cells were transferred to F1recipients and the GvH reaction measured by the splenomegaly assay. The results showed that the GvH effector cells in the donor spleen and lymph node are nonproliferating T cells. Furthermore, donor spleen cells treated with [3H]‐dThd consistently had enhanced GvH reactivity when compared to the controls, while the phytohemagglutinin response of these same treated cell suspensions was significantly inhibited. When purified splenic T cells were used, treatment with [3H]dThd also caused an increase in the GvH reaction, showing that a T cell population was being affected by the cycleactive agent. These results indicated that some naturally proliferating T cells have suppressor functions, and their specific inactivation allows nonproliferating effector T cells to mount a more vigorous G

ISSN:0014-2980    

DOI:10.1002/eji.1830080304

出版商:WILEY‐VCH Verlag GmbH    

年代:1978

数据来源: WILEY

摘要:

AbstractAn antigen‐specific suppressor factor for delayed‐type hypersensitivity (DTH) to sheep red blood cells (SRBC) in mice is described. Lymph node cells and spleen cells from mice injected intravenously with 1 × 109SRBC 4 days previously were incubatedin vitrofor 48 h in culture medium. Supernatant obtained from the culture inhibited the induction of DTH to SRBC in normal mice. It also suppressed the expression of DTH in presensitized mice. The suppression is specific as the suppressor factor had no effect on the DTH to a noncross‐reacting antigen, chicken red blood cells. Treatment of the spleen cells with anti‐theta serum and complement prevented the production of the suppressor factor, whereas treatment with anti‐Ig serum and complement had no effect. Suppressor factor produced by H‐2kmice suppressed the DTH in H‐2bmice. The factor thus seems to act across the H‐2 barrier. The suppressor factor was not removed by adsorption with goat anti‐mouse immunoglobulin immunoadsorbent, but could be adsorbed by SRBC. It was stable at 56 °C for 1 h, but was partially inactivated by freezing and thawing. The factor has a molecular weight of less

ISSN:0014-2980    

DOI:10.1002/eji.1830080305

出版商:WILEY‐VCH Verlag GmbH    

年代:1978

数据来源: WILEY

摘要:

AbstractA previous study (Eur. J. Immunol.1977.7: 714) has shown that mice injected intravenously (i.v.) with 1 × 109sheep red blood cells (SRBC) produce cells which suppress delayed‐type hypersensitivity (DTH). These suppressor cells are Θ‐positive, antigen‐specific and act via a soluble factor which does not bear immunoglobulin determinants (Eur. J. Immunol.1978.8: 168). The present paper demonstrates that these suppressor cells are inhibitable by cyclophosphamide (CY). Mice injected with graded amounts of CY two days prior to SRBC injection, showed maximum augmentation of DTH at 200 mg/kg body weight, a dose which completely suppressed the appearance of splenic plaque‐forming cells (PFC) to SRBC. In contrast, lower doses of CY enhanced both DTH and PFC responses. Time course studies showed that CY inhibited the precursors of suppressor cells and had little or no effect on suppressor cells which have already encountered antigens. This was further confirmed by passive transfer studies which showed that suppressor cells were inhibited if CY was administered at the same time or 2 days before SRBC injection, but were not affected if CY was given after antigen stimulation. Direct evidence for the effect of CY on suppressor cells was obtained by cell fractionation with a Ficoll density gradient. The denser suppressor cell population was absent from the spleens of mice treated with 200 mg/kg of CY 2 days before i.v. injection with 1

ISSN:0014-2980    

DOI:10.1002/eji.1830080306

出版商:WILEY‐VCH Verlag GmbH    

年代:1978

数据来源: WILEY

摘要:

AbstractSpleen cells from pairs of inbred mice (age‐ and sex‐matched) were challengedin vitrowith a T‐independent antigen. The specific plaque‐forming cell(PFC) response in cultures containing cells from both donors was not intermediate to the responses of independently cultured donor spleen cells. Instead, a pattern of significant suppression (67 % of pairs tested) or enhancement (22 % of pairs tested) was observed. The suppression or enhancement was antigen‐specific and did not represent a general phenomenon within the mixed cultures. A suppressive outcome in mixed cell cultures seems to be associated with cells from the donor with the higher individual PFC response. The converse is true for enhancement.The nonadditive nature of the PFC response in mixed cultures and the frequency of suppression to enhancement (3:1) imply that (a) specific, ongoing immunoregulation occurs even in the naive individual, and (b) this regulation is characterized by regular cycles of specific suppression and en

ISSN:0014-2980    

DOI:10.1002/eji.1830080307

出版商:WILEY‐VCH Verlag GmbH    

年代:1978

数据来源: WILEY

摘要:

AbstractThe synthesis of cyclic AMP by mouse peritoneal macrophages in response to stimulation by isoproterenol was studied as a function of drug concentration, incubation time and cell density. Cyclic AMP levels of macrophages increased 3 to 3.5 times over the control level 20 sec after the addition of 10−3Misoproterenol. Under these conditions the dose response could be followed down to an isoproterenol concentration of 10−6to 10−7M. When cell suspensions were inactivated as early as 1 sec after the addition of the drug, the increase in cyclic AMP was much greater (153vs.25 pmol/107cells). Macrophage suspensions of high cell density were less responsive than those of low cell density. In the absence of any inhibitor of phosphodiesterase, the stimulatory effect of isoproterenol was always of short duration. The maximal effect of β‐adrenergic stimulation probably occurs in less than 1 sec at a cell density less than 2 × 106cells/ml. The β‐blocking drug Visken abolished the obse

ISSN:0014-2980    

DOI:10.1002/eji.1830080308

出版商:WILEY‐VCH Verlag GmbH    

年代:1978

数据来源: WILEY

摘要:

AbstractIncubation of lymphocytes with lecithin liposomes enriched with cholesterol, elevated the cholesterol level of the cells relative to phospholipids. Treatment of lymphocytes with pure lecithin liposomes resulted in the converse effect. Both these treatments resulted in suppression of the induction phase of the response to concanavalin A and were practically reversible. It is suggested that these changes induce modulations of the fluidity of the lymphocyte membrane which may also take placein vivoby serum lipoproteins. Based on this study, the possible effects of lipids on lymphocyte activation are discussed.

ISSN:0014-2980    

DOI:10.1002/eji.1830080309

出版商:WILEY‐VCH Verlag GmbH    

年代:1978

数据来源: WILEY

摘要:

AbstractIn vitroconverted, Epstein‐Barr virus (EBV) genome‐carrying cell lines showed a reduced ability to shed surface‐bound antibodies, compared to their EBV‐free parental B lymphoma lines. On the other hand, antibody degradation was higher with EBV‐positive cells. Analysis of antibody‐coated single cells revealed that cells which failed t o redistribute or cap their ligand‐bound surface components at 37 °C, were also capable of shedding bound antibody. This suggests that capping and shedding are essentially independent phenomena, although both may be influenced by the same virally induced change in the lateral mobility of membran

ISSN:0014-2980    

DOI:10.1002/eji.1830080310

出版商:WILEY‐VCH Verlag GmbH    

年代:1978

数据来源: WILEY

摘要:

AbstractUsing cultured mouse myeloma cells, it has been possible to derive cells which are now synthesizing products similar to human heavy chain disease proteins. An initial mutant was isolated which synthesized a heavy chain with an internal deletion and a normal light chain. In a subsequent step, a variant was identified in which the synthesis of the heavy chain with the deletion persisted in the absence of light chain synthesis. These experiments also demonstrate that in the MPC‐11‐derived cultured cell line, the continued synthesis of heavy chain does not require the synthesis of light ch

ISSN:0014-2980    

DOI:10.1002/eji.1830080311

出版商:WILEY‐VCH Verlag GmbH    

年代:1978

数据来源: WILEY