Density gradient separation of marrow cells restricted for antibody class

Primitive cells of (C3H x C57BL/10)F(1) mouse bone marrow, participating with thymocytes in immune responses to sheep erythrocytes, are already committed to the immunoglobulin M or immunoglobulin G antibody class. By equilibrium centrifugation in discontinuous gradients of bovine serum albumin, cells responsible for production of IgM immunocytes migrate to the denser regions, whereas those responsible for IgG immunocytes remain in the lower density regions.     

Specific inhibition of plaque formation to phosphorylcholine by antibody against antibody

Spleen cells from BALB/c mice immunized with heat-killed rough pneumococci (strain R36A) or spleen cells from normal mice immunized in vitro with the same antigen produce direct hemolytic plaques against sheep erythrocytes coated with pneumococcal C polysaccharide or conjugated with phosphorylcholine. Formation of plaques is specifically inhibited by phosphorylcholine or by antiserum to mouse immunoglobulin A myeloma protein which binds phosphorylcholine. Thus, the myeloma proteins and normal BALB/c antibodies share similar idiotypic determinants. This experimental system is suitable for probing the role of the antigen receptor in the immune response.     

Restoration of antibody-forming capacity in cultures of nonadherent spleen cells by mercaptoethanol

Populations of mouse spleen cells, without those cells that adhere to glass or plastic, exhibit little or no capacity for formation of antibody to sheep erythrocytes in the Mishell-Dutton culture system. When 5 x 10(-5)M mercaptoethanol is added to the culture medium, the antibody-forming capacity of these nonadherent spleen cells is restored to that of unfractionated spleen cells.     

L-asparaginase induced immunosuppression: inhibition of bone marrow derived antibody precursor cells

The cooperation between bone marrow and thymus cells in restoring the hemolytic antibody response to sheep erythrocytes in immunosuppressed recipients was markedly inhibited when donor mice were treated with L-asparaginase, a known inhibitor of lymphocyte function. The marrow cell population was shown to be a major target for the immunosuppressive activity of asparaginase, since thymus cells from enzyme-treated animals interacted with marrow cells from normal animals to generate immunocompetent cells.     

Acute lymphoblastic leukemic cells with T (thymus-derived) lymphocyte markers

Five of nine children with acute lymphoblastic leukemia had lymphoblasts that bound sheep erythrocytes or reacted with antiserum to thymocytes, suggesting involvement of T (thymus-derived) cells. When lymphoblasts from all patients were examined by immunofluorescence they were found to lack a marker for B (bone marrow or bursa-equivalent) cells, that is, the presence of surface immunoglobulins.     

Antibody formation in nonimmune mouse peritoneal cells after incubation in gum containing antigen

Peritoneal cells from normal mice in a semisolid medium containing sheep erythrocytes were incubated at 37 degrees C for 2 or 3 days. During this period, hemolytic antibodies developed spontaneously. Arguments are presented that true de novo synthesis of antibody has taken place in previously uncommitted cells.     

Antigen competition: a paradox

Immunization of mice with pig erythrocytes caused impairment of the antibody response to subsequent immunization with sheep erythrocytes, a phenomenon called "antigen competition." Paradoxically, spleen cells from mice previously injected with pig erythrocytes produced an increased response when immunized in vitro with sheep erythrocytes. Augmentation of the in vitro response is due to an increase in one of the interacting cell types. "Antigen competition" is not due to competition for cells. Cell transfer experiments provided evidence that "antigen competition" observed in animals is the result of a humoral factor, presumably antibody, present in the animal but eliminated during preparation of cells for culture.     

Engraftment and development of human T and B cells in mice after bone marrow transplantation.

A model for human lymphocyte ontogeny has been developed in a normal mouse. Human bone marrow, depleted of mature T and B lymphocytes, and bone marrow from mice with severe combined immunodeficiency were transplanted into lethally irradiated BALB/c mice. Human B and T cells were first detected 2 to 4 months after transplantation and persisted for at least 6 months. Most human thymocytes (30 to 50 percent of total thymocytes) were CD3+CD4+CD8+. Human immunoglobulin was detected in some chimeras, and a human antibody response to dinitrophenol could be generated after primary and secondary immunization.     

松木刨花和枫木刨花水提取物对小鼠骨髓红细胞的影响

目的利用微核试验了解松木刨花和枫木刨花的遗传毒性。方法80只NIH种小白鼠随机分为8组,每组10只。其中3组分别以100、50、12.5g/kg剂量的松木刨花水提取物染毒,另3组分别以100、50、12.5g/kg剂量的枫木刨花水提取物染毒,1组(阳性对照组)以环磷酰胺50mg/kg染毒,1组((阴性对照组)以生理盐水染毒。染毒方法均是先经口染毒,24h后以同样剂量再次灌胃。6h后颈椎脱臼处死动物,制片,观察并计数嗜多染红细胞的微核率。结果以松木刨花及枫木刨花水提取物染毒的各组小白鼠的微核率与阳性对照组比较差异有统计学意义(P<0.01),与阴性对照组比较差异无统计学意义(P>0.05)。结论松木刨花和枫木刨花的水提取物对小鼠的骨髓细胞未见有何致突变性。     

Focal antibody production by transferred spleen cells in irradiated mice

Lethally irradiated mice were injected with small numbers of normal spleen cells and then immunized with sheep erythrocytes. Antibody activity was found in their spleens in localized areas whose number corresponded to the number of spleen cells injected. When sheep and pig erythrocytes were injected together, antibody against each was found in separate areas. Each area may consist of the progeny of a single precursor cell, restricted to forming a single antibody.     

Duplicate plating of immune cell products: analysis of globulin class secretion by single cells

Antibodies secreted by individual immune cells were collected focally in very thin "original" and "imprint" layers of agar containing the target antigen, sheep erythrocytes. Identical treatment of both layers led to mirror image patterns of hemolytic plaques. Development of one layer for immunoglobulin M hemolysins and the other for immunoglobulin G hemolysins produced unrelated plaque patterns indicating that few, if any, cells simultaneously release substantial amounts of both gammaM and gammaG antibodies.     

Murine lymphoma-induced immunosuppression: requirement for direct tumour cell contact

The FBL-3 lymphoma cell line caused impaired antibody formation in vivo when injected into mice intraperitoneally, and in vitro when added to normal syngeneic spleen cells immunized in vitro with sheep erythrocytes. Immunosuppression occurred only when intact viable tumor cells were cocultivated with the normal spleen cells. As few as 10(5) FBL-3 cells, when added to 5 X 10(6) normal cells, impaired antibody formation. However, cell-free extracts of filtrates from even much larger numbers of tumor cells did not affect antibody formation, either in vitro or in vivo. Heating the tumor cells at 56 degrees C or irradiation with as little as 1000 rads completely abolished immunosuppressive activity, both in vitro and in vivo. Separation of viable tumor cells from target antibody-forming cells by cell-impermeable membranes prevented immunosuppression, showing that direct cell-to-cell contact is required for immunosuppression.     

Depletion of conventional mature B cells and compromised specific antibody response in bovine immunoglobulin μ heavy-chain transgenic mice

In this study, we introduced the bovine immunoglobulin μ heavy-chain gene (the orphaned gene on BTA11) into mouse germline cells. Bovine IgM was highly expressed in selected transgenic lines, and it largely inhibited rearrangements of the endogenous immunoglobulin heavy chain (IgH) genes in these lines. The forced expression of bovine IgM resulted in reduced numbers of pro- and pre-B cells but increased the number of immature B cells in the transgenic mice. Bovine IgM-expressing B cells can migrate from the bone marrow to the spleen, but most of the cells are arrested at the T1 transitional B cell stage, leading to a significantly lower number of T2 transitional and mature B cells in the spleen. Although the serum concentrations of endogenous IgM and IgG in the transgenic mice were significantly decreased, the IgA levels were slightly increased compared to the WT mice. The bovine IgM level in the serum was only one-tenth to one-fifth of that of endogenous mouse IgM, suggesting that most of the serum immunoglobulin were contributed by endogenous IgH gene-expressing B cells. These transgenic mice also exhibited a lower frequency of unique complementarity determining region 3 (CDR3) sequences in their VH repertoire and Vκ repertoire but exhibited an increased frequency of unique CDR3 in their Vλ repertoire. Compared to the WT mice, the transgenic mice had a significantly higher percentage of mouse IgM-expressing B cells that expressed λ chains. Finally, we showed that the transgenic mice were deficient in a specific antibody response to antigen stimulation.     

Cell sorting: automated separation of mammalian cells as a function of intracellular fluorescence

A system for high-speed sorting of fluorescent cells was able to sort mouse spleen cells from Chinese hamster ovarian cells after development of fluorochromasia. Highly fluorescent fractions separated after similar treatment from mouse spleen cells immunized to sheep erythrocytes were enriched in antibody-producing cells by factors of 4 to 10.     

Immune response restoration with macrophage culture supernatants

Depression of the in vitro immune response of mouse spleen cell suspensions to sheep erythrocytes by removal of macrophages can be reversed by the addition of supernatants from peritoneal macrophage cultures. Supernatant activity can be absorbed by the red cell antigen, and supernatant-treated red cells are stimulatory in the absence of macrophages or supernatant.     

Immune response in vitro: independence of "activated" lymphoid cells

Antibody formation against sheep erythrocytes by mouse spleen cells in vitro requires interactions among antigen-treated macrophages and lymphoid cells in cell culsters for only a finite time. During this critical period of interaction, lymphoid cells become "activated" and thereafter can develop into antibody-producing cells independently of native antigen, macrophages, and cell clusters.     

Humoral immunosuppressive substance in mice bearing plasmacytomas

The mechanism by which plasmacytomas (PC) depress the primary immune response to sheep red cells was investigated by determining the ability of normal spleen cells to produce antibody when enclosed in Millipore chambers and implanted in PC-bearing mice. Chamber-enclosed normal spleen cells implanted in PC-bearing mice responded poorly to the sheep red cells when compared to similar cells enclosed in chambers and implanted in normal mice or in mice with other lymphoid and nonlymphoid tumors. The data suggest that PC-induced immune suppression is mediated by a humoral factor.     

Human monocytes: distinct receptor sites for the third component of complement and for immunoglobulin G

Human monocytes contain two distinct receptor sites, one specific for the third component of complement (C'3), the other for immunoglobulin G(gammaG). The two receptors may function either independently or cooperatively in the induction of phagocytosis. Ingestion of erythrocytes coated with immunoglobulin M antibody requires a relatively large number of bound C'3 molecules per cell. Ingestion of erythrocytes sensitized with gammaG antibody is independent of complement; however, the reaction is inhibited by concentrations of gammaG far below those in normal serum. Inhibition by gammaG-globulin is overcome by a relatively small number of bound C'3 molecules per cell. The two monocyte receptors exert a cooperative effect on ingestion by monocytes of erythrocytes coated with gammaG antibody in the presence of inhibitory amounts of free gammaG.     

Hypersensitivity: specific immunologic suppression of the delayed type

Delayed-type cutaneous hypersensitivity to sheep erythrocytes was induced in rats by intradermal injection of the antigen mixed with Freund's adjuvant; hypersensitivity was sustained by weekly injections. Either passive immunization with rat antiserum to sheep erythrocytes or intravenous injection of sheep erythrocytes partially suppressed induction of hypersensitivity; these procedures used together specifically and completely suppressed induction of hypersensitivity. Complete suppression was sustained by antigen given intravenously before each weekly injection of the mixture of antigen and adjuvant. These findings provide the rational basis of a simple method for prolonging survival of allografts with only the biological agents, antigen and antibody, of the immunological response.     

Immunosuppressant from group A streptococci

A cytoplasmic component of group A streptococci suppresses both 19S and 7S antibody responses of mice to sheep erythrocytes. Partial purification is achieved by differential centrifugation and gel filtration. When the direct and indirect hemolytic plaque techniques are used, a single injection of this group A material given before injection of erythrocytes produces more than 90-percent suppression of either primary or secondary immune response.