Showing papers in "European Journal of Immunology in 1977"

Evidence for a similar or common mechanism for natural killer cell activity and resistance to hemopoietic grafts

Abstract: Two types of host reactivities not requiring immunization in the mouse and not mediated by T lymphocytes were compared: resistance of irradiated and nonirradiated F1 hybrids to accept parental grafts of normal or malignant hemopoietic cells (Hh system), and the natural killer cell activity against mouse lymphomas (NK system). The effects of six independent variables known to influence resistance to marrow grafts were investigated in the NK system using YAC-1 lymphoma cells as targets. The following properties were shared: (a) maturation during the fourth week of life; (b) low sensitivity to acute total body irradiation; (c) dependence on the integrity of bone marrow as demonstrated by reduced reactivity in 89Sr-treated mice; (d) suppression by a single injection of rabbit anti-mouse bone marrow serum; (e) suppression by a single injection of the anti-macrophage agents silica and i-carrageenan; and (f) suppression by multiple injections of parental spleen cells into F1 mice. These positive correlations are particularly significant because most of the variables have either opposing or no effect on conventional immunity. F1 mice rendered specifically unresponsive to parental marrow grafts, could retain NK cell activity, and genetically susceptible mice could be rendered hyporeactive in terms of NK cells, indicating that the specificities of YAC-1 and Hh-1 incompatible targets were different. It is extremely unlikely that this remarkable parallelism is fortuitous. These results indicate that either a very similar, or more likely a common mechanism is operative in the two cell-mediated natural reactivities: effector cells in the NK and Hh systems do not bear B or T lymphocyte markers but are nevertheless endowed with “specificity”. They are dependent for generation in vivo (presumably by maturation or by recruitment) on the interaction with nonlymphoid accessory cells not endowed with specificity, capable of also interacting in vitro with Thy-1-positive F1 hybrid prekiller cells specific for parental targets. Because of thymus independence in vivo and apparent restriction to target cells of the hemopoietic system, these reactivities should be effective in the regulation of hemopoiesis and surveillance over leukemogenesis.

Immunofluorescent studies of the development of pre-B cells, B lymphocytes and immunoglobulin isotype diversity in humans

Abstract: Immunofluorescent techniques were used to examine several aspects of B cell ontogeny in humans. Large lymphoid cells containing intracytoplasmic IgM (pre-B cells) were present in fetal liver as early as 7 weeks of gestation, approximately 2 weeks prior to the appearance of surface IgM positive (sIgM+) B lymphocytes. Pre-B cells outnumbered sIgM+ B lymphocytes in fetal liver up until the 13th week of gestation. In fetuses older than 13 weeks, pre-B cells and sIgM+ B lymphocytes were present in approximately equal proportions in liver and bone marrow. Pre-B cells in fetal liver, and fetal and adult marrow, were large and small (indicating a heterogeneous population of cytoplasmic IgM+. SIg- cells in these sites), while only the small pre-B cells were present in fetal spleen, blood and lymph node. Lymphocytes bearing sIgG were detected earlier than those bearing sIgD or sIgA, which were present by the 12th gestational week. Using double-staining techniques, we determined that during fetal life, (a) the proportion of B lymphocytes bearing only sIgM, as opposed to those bearing both sIgM and sIgD, was much higher in liver and bone marrow than in spleen, blood and lymph node, and (b) sIgG, sIgA and sIgD appear independently on lymphocytes bearing sIgM. Studies of the frequency of double-stained cells for each combination of the four sIg isotypes indicated that B lymphocytes from neonatal humans may simultaneously bear three or more sIg isotypes, whereas sIgG+ and sIgA+ B lymphocytes in adult blood usually express only the single isotype. Lower concentrations of anti-y antibodies were required for modulation of sIgM from B lymphocytes of fetal liver and adult bone marrow than for equivalent removal of sIgM from circulating B cells of mature individuals. In conjunction with data obtained in mice, our observations indicate that (a) the presence of large and small pre-B cells, (b) a high ratio of sIgM single to sIgM.sIgD double B lymphocytes, and (c) increased sensitivity to modulation of B cell sIgM by divalent anti-μ antibodies define the fetal liver and adult bone marrow as bursa-equivalent sites in humans. Our results are consistent with a model of isotype diversification in which immature sIgM+ cells give rise to B cell sublines devoted to synthesis of each of the Ig classes, and sIgD is secondarily expressed on unstimulated B cells of all of these sublines.

Hypothalamic changes during the immune response.

Abstract: The immune system is subject to an array of identified autoregulatory processes, but immunoregulation may also have a further basis in a network of immune-neuroendocrine interactions. Two antigens each produced an increase of more than 100% in electrical activity of individual neurones in the ventromedial but not in the anterior nucleus of the rat hypothalamus. Animals that failed to respond to antigen manifested no increase in the firing rate. These findings constitute the first evidence for a flow of information from the activated immune system to the hypothalamus, suggesting that the brain is involved in the immune response.

Accessory cell dependence of lectin-induced proliferation of mouse T lymphocytes.

Abstract: Mouse lymph node cells were exposed to carbonyl iron and a magnet to remove phagocytic cells, and passed over Sephadex G-10 and nylon wool and incubated for 12 h on plastic to remove adherent cells and their precursors. More than 99 % of the cells in this macrophage-depleted population (which constituted 3-5 % of the starting population) were Thy-1+ and Ly-1+, while less than 2 % were Ly-2+. These cells usually did not synthesize detectable amounts of DNA when cultured with concanavalin A and responded poorly to phytohemagglutinin. These proliferative responses were completely reconstituted by small numbers of syngeneic or allogeneic peritoneal cells, purified peritoneal macrophages or cells from tertiary cultures of mouse embryo ‘fibroblasts’, but not by 3T3 cells, P815 mastocytoma cells or Nulli SCC-1 embryonal carcinoma cells, or by 2-mercaptoethanol. The reconstituting peritoneal cells were Thy-1−, Ia+ and present in nu/nu mice; although they had to be alive to reconstitute, they did not have to divide. These results are consistent with the hypothesis that T cell proliferation induced by lectins, like that induced by antigens, may involve the dual recognition of stimulating ligand in association with major histocompatibility complex (la) determinants.

Genetic defect in responsiveness to the B cell mitogen lipopolysaccharide.

Abstract: Splenic B cells from C57BL/10ScCr mice fail to respond to the mitogenic principle of lipopolysaccharide (LPS), and do not express a serologically defined “LPS receptor”. In contrast, polyclonal B cell responses to both purified protein derivative of tuberculin and lipoprotein are conserved.

Molecular structure of human histocompatibility antigens: the HLA‐C series

Abstract: The HLA-CW2 antigen of the B lymphoblastoid cell line BRI 8 is structurally homologous to the HLA-A and B antigens as judged by various criteria. Each antigen comprised a glycosylated polypeptide of 43 000 molecular weight that is noncovalently associated with beta2-microglobulin (beta2m). Some small differences in molecular parameters were, however, revealed. Thus, the deoxycholate-solubilized HLA-CW2 antigen sedimented at the same rate as the HLA-A antigens but at a slightly faster rate than the HLA-B antigens. This variation is apparently is apparently due to different amounts of bound deoxycholate. Also, whereas essentially all of the HLA-A and B antigens and about half of the HLA-CW2 antigen were adsorbed strongly by Lens culinaris lectin-Sepharose, the remaining HLA-CW2 antigen was bound much more weakly and did not require sugar for elution. This difference reflects some structural heterogeneity in the carbohydrate moiety of the HLA-CW2 antigen. The results of various studies suggest that the HLA-CW2 antigen is expressed to a lower extent than the HLA-A or B antigens and that essentially all of the beta2m of the BRI 8 plasma membrane is associated with the HLA-A, B and C alloantigenic polypeptides.

Characterization of a carcinogen‐induced murine B lymphocyte cell line of C3H/eB origin

Abstract: A carcinogen-induced lymphoid tumor, denoted 38C-13, obtained in a T cell-depleted mouse of C3H/eB strain, was adapted to continuous culture in vitro and characterized with respect to its cell surface components. The cells possess IgM class immunoglobulins on their surface but do not secrete it. This membrane IgM is composed of mu and L-chains that are similar in apparent molecular weight to those of an IgM myeloma protein. It is also homogeneous as revealed by isoelectric focusing. The cells possess Fc receptors but lack complement receptors as well as Thy-1 and Ia alloantigens. These characteristics indicate that 38C-13 cells are transformed counterparts of small B lymphocytes at an early stage of differentiation.

Idiotypic analysis of the response of C57BL/6 mice to the (4-hydroxy-3-nitrophenyl)acetyl group.

Abstract: Strain C57BL/6 mice produce a highly restricted primary response to the (4-hydroxy-3-nitrophenyl)acetyl (NP) group. This response is composed of molecules having mu or gamma1 heavy chains and light chains of the lambda type. A guinea pig anti-idiotype was raised to the purified C57BL/6 primary anti-NP immunoglobulin. After suitable absorption, this anti-idiotype was shown to detect markers present on the primary anti-NP immunoglobulin only of those strains which express the Ig-1b allotype. Breeding experiments demonstrated that the marker segregated with the heavy chain linkage group.

Rat bile as a convenient source of secretory IgA and free secretory component

Abstract: Rat hepatic bile contains three proteins as major constituents: secretory IgA (SIgA), free secretory component (FSC) and albumin. Traces of alpha-macroglobulin, transferrin, IgG and IgM are also detectable. The bile duct daily pours between 5-12 mg each of SIgA and FSC into the rat duodenum. The origin and function of these proteins in bile may represent important clues in the understanding of the SIgA system.

Cytotoxic T cells to type A influenza virus; viral hemagglutinin induces A-strain specificity while infected cells confer cross-reactive cytotoxicity.

Abstract: This paper deals with the generation and specificity of cytotoxic T cells directed to cells infected with type A influenza viruses. Mice were primed in vivo and their spleen cells restimulated in vitro. Four type A viruses with serologically distinct surface proteins are equally effective in secondary stimulation of cytotoxicity regardless of the viral strain used for priming. The resulting cytotoxic cells will lyse cells infected with any of the 4 type A viruses. Cross-reactivity between type A and B influenza viruses does not occur. Competition experiments show that the cross-reactive cytotoxic T cells contain a minor population of cells with increased affinity for the type A virus strain used for priming, but the majority of the cells do not distinguish between the type A virus strains. Virus replication is not required for the secondary generation of cytotoxic T cells; inactivated virus and viral hemagglutinin can serve as stimulators. Hemagglutinin derived from type A/Jap/Bel selects cytotoxic cells with specificity restricted to A/Jap/Bel originally used for priming and A/Jap which shares the hemagglutinin. This secondary stimulation can be achieved only when either of those two type A viruses are used for priming. The results indicate that hemagglutinin is one of the viral proteins recognized by cytotoxic T cells; however, it is not clear which viral protein(s) are responsible for cross-reactivity.

Studies on the lymphocytes of sheep. III. Destination of lymph-borne immunoblasts in relation to their tissue of origin.

Abstract: Lymph-borne immunoblasts were labeled in vitro with 125I[]iodo-deoxy-uridine, washed and returned by intravenous injection to the sheep from which they had been collected. Twenty h later the sheep were killed and the distribution of the immunoblasts was determined by assaying the radioactivity in various organs. Immunoblasts from the efferent lymph of peripheral somatic lymph nodes (PSLN) went mainly to the spleen, lungs and other PSLN, while immunoblasts from intestinal lymph went mainly to the small gut. This ability of intestinal immunoblasts to home to the gut was demonstrated also in the sterile environment of fetuses in utero; apparently the migratory behavior of immunoblasts, like that of small lymphocytes, is not primarily "antigen-driven". A technique was devised for the collection of peripheral (i.e. afferent to the mesenteric node) intestinal lymph which was found to contain 10-20 times the numbers of small lymphocytes that occur in the peripheral lymph from other tissues. Immunoblasts from peripheral intestinal lymph also homed to the gut. The immunoglobulin content of immunoblasts was studied by making detergent extracts of lymph cells, by applying immuno-peroxidase techniques to cell films and by investigating the incorporation of 14C-labeled amino acids into immunoglobulins by immunoblasts in vitro. Immunoblasts from both somatic and intestinal lymph contained and made IgG and IgM, but many intestinal immunoblasts contained and made IgA. It is not known whether this immunoglobulin mediates the extravasation of immunoblasts into the gut. Nonetheless, there is compelling evidence that there are two major migratory pathways for lymphoid cells; one through the gut-associated lymphoid tissue and the other through the somatic-splenic lymphoid tissues.

Interaction between IgE complexes and macrophages in the rat: a new mechanism of macrophage activation.

Abstract: In earlier studies we found that normal rat macrophages, preincubated at 37°C with the serum of syngeneic rats immune to Schistosoma mansoni, strongly adhered to S. mansoni schistosomules whereas no significant adherence was induced with serum from normal rat. Using51 chromium release assay, it now proved that immune serum-incubated macrophages lysed the schistosomules in 18 h. Absorption experiments and ultracentrifugation of the immune serum showed that immune complexes containing specific IgE antibody against S. mansoni and soluble parasite antigens induced macrophage adherence and cytotoxicity. Using various labeling techniques, the binding of aggregated rat IgE to the macrophage surface at 37°C is evident in conditions where endocytosis is negligible. The binding of immune complexes containing IgE antibody to S. mansoni elicits dramatic ultra structural changes in the macrophage and an increase of its lysosomal enzymes together with specific lytic activity for the schistosomules. The parallel development of immune serum-induced macrophage adherence or cytotoxicity with the level of circulating IgE antibody to the parasite in correlation with the development of immunity in the rat, suggests that this new mechanism of macrophage activation could play a role in immune effector mechanisms against S. mansoni. Therefore, IgE acts as a humoral mediator of cellular immunity.

Mercuric chloride-induced anti-glomerular basement membrane antibodies in the rat: genetic control.

Abstract: Mercuric chloride induces anti-glomerular basement membrane antibodies in the Brown-Norway rat. Various other inbred rat strains (Lewis, Wistar AG, August, PVG/c) were not found t o be able to produce such antibodies under the same experimental conditions. Hybrids (F1, F2 and F1 × LEW) were bred from Brown-Noway and Lewis rats and injected with mercuric chloride. It has been demonstrated that the induction of anti-glomerular basement membrane antibodies by mercuric chloride in these crosses is under genetic control. The response was found t o depend on two or three genes one of which was H-1-linked. The negative results obtained with L.BN congenic rats were in complete agreement with this conclusion.

Natural cytotoxicity in man: activity of lymph node and tumor-infiltrating lymphocytes.

Abstract: Lymphocytes from blood, lymph node and tumor have been tested for cytotoxicity against the K562 cell line which is known to be highly sensitive to lysis by spontaneously reactive cells. Cytotoxicity was found in all 13 samples from healthy donors and in 17/32 cancer patients. By contrast, activity was determined in only 1/18 lymph node and 1/14 preparations of tumor-infiltrating lymphocytes. Lymph node cells were similarly nonreactive against 3 other cell lines known to be sensitive to natural cytotoxicity. Studies of the composition of the effector populations revealed no absolute deficit of a particular cell type although there were differences between them resulting from the different isolation procedures used. Enrichment of the lymph node population for non-T, non-B lymphocytes was ineffective in inducing cytotoxicity in previously non-reactive samples although this procedure uniformly increased the cytotoxic potential of blood lymphocytes. Tests with blood taken during operation showed that the lack of reactivity in these preparations was unlikely to be a result of the effects of anesthesia or surgery. The reason for the low cytotoxicity in the lymph node and tumor-infiltrating lymphocytes is as yet undefined.

The immune response to allogeneic rat platelets; Ag-B antigens in matrix form lacking Ia.

Abstract: Allogeneic rat platelets fail to induce either primary antibody or cell-mediated immune responses despite repeated injections. Platelets bear Ag-B epitopes which are capable of being recognized by antigen-reactive T and B cells since primed rats develop secondary responses after challenge with allogeneic platelets. The secondary responses induced decrease rather than increase on repeated injection of platelets. Repeated injection of allogeneic platelets into nonprimed rats leads to a state of specific, partial non-reactivity; recipients given such treatment show marked depression of cytotoxic antibody responses, but normal cellular immunity after challenge with viable lymphoid cells taken from the platelet-donor strain. Injection of normal rats with allogeneic platelets mixed with 3rd party, viable lymphoid cells, does not provoke an anti-platelet Ag-B antibody response.

The induction of hapten-specific T cell tolerance using hapten-modified lymphoid membranes. II. Relative roles of suppressor T cells and clone inhibition in the tolerant state.

Abstract: The cellular nature and specificity of suppressor cells and the mechanisms of tolerance to 2,4-dinitrophenyl-l-fluorobenzene (DNFB) in mice was investigated. Mice tolerized with hapten-modified self membrane, i.e. dinitrophenylated spleen cells (DNP-SC), generated suppressor cells as shown by their ability to transfer unresponsiveness to normal animals. Such suppressor cells were specific for DNFB as they did not interfere with sensitization of normal animals with 2,4,6-trinitro-1-chlorobenzene (picryl chloride). These suppressor cells were of the thymus-derived lymphocyte (T cell) lineage as (a) their activity was abolished by treatment with anti-Θ serum plus complement, and (b) these cells could not be raised in T cell-deprived mice. Kinetic studies of the development of tolerance showed discrepancies between the rate of induction of unresponsiveness in the donor (“phenotypic” tolerance) and the ability to transfer tolerance. One day after receiving 5 × 10 DNP-SC mice were phenotypically tolerant but could not serve as the donors of suppressor cells. 7 days after tolerization with DNP-SC mice were still fully tolerant and also contained suppressor cells, which were no longer demonstrable 14 days after tolerization when mice were still phenotypically tolerant. The ability to transfer tolerance was eliminated by pretreatment with cyclophosphamide (Cy). We postulate that two independent mechanisms of tolerance occur after tolerization with DNP-SC - the rapid induction of clone inhibition and the slower, transient induction of suppressor T cells. Cy had no effect on clone inhibition but eliminated the precursors of suppressor T cells.

Separation and properties of EA‐rosette‐forming lymphocytes in humans

Abstract: Human peripheral blood lymphocytes were separated into subpopulations enriched or depleted with respect to B lymphocytes (Ig-bearing cells), T lymphocytes, (cells forming rosettes with sheep erythrocytes: E-RFC) and Fc receptor-bearing lymphocytes (EA-RFC). From the distributions and recoveries of the various cell types it could be concluded that there was very little overlap between Ig-bearing lymphocytes and EA-RFC. The latter cells partly belonged to “null” (non-T, non-B) cells; it was however demonstrated that 30 % of the EA-RFC were T cells (E-RFC). The lytic capacity in antibody-dependent lymphocytotoxicity (ADL) was shown to correspond with the proportions of EA-RFC in the various fractions. Non-T cells showed enhanced ADL activity when compared to the unseparated cells. Purified T cell populations also displayed ADL activity. Since the latter could not be due to contaminating non-T cells, this activity was ascribed to Fc receptor-bearing T lymphocytes.

Imbalances in T cell subpopulations associated with immunodeficiency and autoimmune syndromes

Abstract: Abnormal proportions of the distinct T cell subpopulations binding the Fc portion of IgM (T·M) cells and those bearing receptors for the Fc portion of IgG (T·M) cells, were observed in blood samples from patients who had congenital or acquired abnormalities of the thymus, severe combined immunodeficiency, or an unexplained primary deficiency in cell-mediated immunity; most had too few circulating T·M cells and often an overabundance of T·G cells. In an in vitro evaluation of lymphocytes from one of three thymoma patients with an elevated T·G subpopulation, removal of T·G cells abrogated the suppression of T·M cell help of B cell differentiation induced by pokeweed mitogen. A spectrum of patients with sex-linked infantile agammaglobulinemia, variable hypogammaglobulinemia, and selective IgA deficiency, and a few patients with autoimmune syndromes infrequently had distorted representation of these T cell subpopulations in the circulation. This suggests that B cell dysfunction in many of these patients is not merely due t o numerical excesses or insufficiencies of helper or suppressor T cells.

Immune interferon I. Production by lymphokine‐activated murine macrophages

Abstract: Unfractionated murine spleen cells produce immune interferon (type II) upon stimulation with antigen or mitogen. When spleen cells were passed over glass bead columns, interferon production decreased whereas the mitotic response to the stimulants drastically increased. When these cells were further purified over nylon wool columns, interferon production was totally abolished whereas thymidine incorporation in stimulated cultures was invariably high. Interferon production by nylon wool column-purified lymphocytes could be restored with macrophages grown from bone marrow cultures or spleen cells but not with macrophages from proteose peptone-induced peritoneal exudate cells. It was also found that pure macrophage cultures from spleens of BCG-immunized mice consistently produced interferon activity without any further stimulation. When culture supernatants of activated T lymphocytes, which did not contain any interferon activity, were transferred to macrophage cultures from different sources and incubated for 45 h, interferon activity could be detected in supernatants of macrophage cultures from bone marrow and spleen but not in those from proteose-induced peritoneal exudate cells. It is concluded that certain macrophage populations can be induced to produce interferon activity whereas others are refractory to this induction which appears to be linked to their differentiation state.

T lymphocyte tissue culture lines produced by cell hybridization.

Abstract: This study describes the generation of permanent T cell tissue culture lines by cell fusion techniques. The AKR strain-derived T cell tumor BW 5147 was hybridized in the presence of polyethylene glycol with various T cell populations isolated from antigen-sensitized mice. Surface analysis of resulting hybrid cell lines showed expression of both Thy-1.2 and H-2 antigens which are characteristic for the lymphocyte used for fusion. In contrast, in hybrids derived from spleen cells neither expression of Ig nor of B cell-typicyl Ia determinants was found suggesting either preferential hybridization of BW 5147 cells with T lymphocytes or extinction of B cell markers in hybrid cells. These hybrid lines which may display the immunological properties of the T cell population chosen are presently investigated for their antigen reactivity.

Isolated hapten-binding receptors of sensitized lymphocytes. I. Receptors from nylon wool-enriched mouse t lymphocytes lack serological markers of immunoglobulin constant domains but express heavy chain variable portions.

Abstract: Hapten-binding receptor material was isolated from hapten-sensitized mouse lymphocytes, as described previously (Eur. J. Immunol 1976.6: 529; Cold Spring Harbor Symp. Quant. Biol.1977. 41: 285). The material was separated into a fraction expressing immunoglobulin determinants (anti-Ig+ fraction) and a fraction lacking determinants of the known Ig constant domains (anti-Ig−fraction). We present further evidence in support of the notion that the anti-Ig+ fraction is B cell-derived, whereas the anti-Ig− fraction originates from T lymphocytes. Receptors derived from C57BL/6 mice of the anti-Ig_ phenotype with specificity for the hapten (4-hydroxy-3-nitrophenyl)acetyl (NP) are found to express markers which are characteristic for the variable portion of primary anti-NP antibodies. One of these markers relates to the fine specificity of hapten binding [6, 24], the other is defined by anti-idiotypic antibodies. Genetic studies show that the expression of these markers both in antibodies and the anti-Ig− receptor fraction is controlled by genes in the heavy chain linkage group. The results demonstrate that in this system, humoral antibodies and receptor molecules of both the anti-Ig+ and anti-Ig− phenotype bind the hapten with strikingly similar affinity and fine specificity. More specifically, they suggest that the molecules in the anti-Ig− receptor fraction carry the variable region (and in fact the en tire variable region) of the Ig heavy chain.

Idiotype-bearing and antigen-binding receptors produced by blood T lymphocytes in a case of human myeloma.

Abstract: Twenty-five to 30 % of blood lymphocytes from a myeloma patient with an IgGl(k) protein with antibody activity to horse α2-macroglobulin (α2M) reacted with purified IgG from a rabbit antiserum to the idiotypic determinants of this protein. A small proportion of these idiotype-bearing lymphocytes were IgG-bearing B cells, but most of them were T cells. Several experiments demonstrated the actual synthesis of the idiotypic structures carried by the T lymphocytes. All idiotype-bearing lymphocytes bound horse α2M, and the structures that bore the idiotype and bound the antigen were shown to completely cocap. After biosynthetic labeling with 14C-labeled amino acids, immunoprecipitation and sodium dodecyl sulfate gel electrophoresis, the anti-idiotypic serum and the α2M antigen were found to react with the same molecules. Preliminary data on the size of these antigen-binding T lymphocyte-derived molecules are in accord with those of Binz and Wigzell (Scand. J. Immunol. 1976. 5: 559) in the rat. The finding in this patient with multiple myeloma of a homogeneous and possibly malignant population of T lymphocytes, synthesizing identical antigen receptors which share idiotypic (but not isotypic) determinants of the immunoglobulin molecule produced by the malignant B cell clone, therefore confirms in man the results of several recent studies in other mammalian species.

Regulation of delayed-type hypersensitivity. I. T suppressor cells for delayed-type hypersensitivity to sheep erythrocytes in mice

Abstract: Mice injected with 1 X 10(8) sheep red blood cells (SRBC) into the footpad showed high levels of delayed-type hypersensitivity (DTH) to SRBC 4-8 days after the injection. In contrast, mice injected intravenously with 1 X 10(9) SRBC were unresponsive to DTH induction through 1 X 10(8) SRBC injected into the footpad. This suppression of DTH was maintained for at least 6 weeks and was transferable spleen, lymph node and thymus cells to normal syngeneic recipients. Bone marrow cells, on the other hand, did not contain the suppressor cells. The suppression of DTH was antigen-specific in that DTH to chicken red blood cells and contact sensitivity to 2,4-dinitrofluorobenzene was not affected. The suppressor cells were theta-positive and Ig-negative. They appeared in the spleen in optimum number 3-4 days after induction. The suppressor cells affected both the induction and manifestation of DTH. The presence of suppressor and effector cells for DTH inducible by different routes of antigenic presentation reflects the dynamic balance in the regulation of DTH.

A Myeloma Hybrid Producing Antibody Specific for an Allotypic Determinant on "IgD-like" Molecules of the Mouse

Abstract: A hybrid cell line was produced by fusing a mouse myeloma line with spleen cells from BALB/c mice immunized with B10 cells. The hybrid line grew in tissue culture and in syngeneic mice and produced IgM antibody specific for "IgD-like" molecules of mice with the Igb haplotype. The concentration of monoclonal antibody in the serum of tumor-bearing animals reached about 2 mg/ml and gave cytotoxic titers of up to 1:800 000. The derivation of the line, some properties of the antibody secreted and the nature of its antigenic target are described.

Surface immunoglobulins of lipopolysaccharide-stimulated spleen cells. The behavior of IgM, IgD and IgG.

Abstract: The nature of Ig receptors carried by lipopolysaccharide (LPS)-stimulated mouse spleen B cells was analyzed by surface iodination, direct antiserum precipitation and polyacrylamide gel electrophoresis. LPS activation led to a rapid decrease of surface IgD to 20 % and 80 % of the original level on days three and five of culture, respectively. Efficiency of iodination of cells doubled after culture but the proportional radioactivity in IgM reace of cells, but only in small amounts (1 % of total surface Ig) and this expression of IgG remained constant during 5 days of culture. We could definitively identify gamma-chains on the surface of cells, but only in small amounts (1% of total surface Ig) and this expression of IgG remained constant during 5 days of culture.

Evidence for suppressor cells in Lewis rats' experimental allergic encephalomyelitis

Abstract: In this work we demonstrate a suppressive activity on the induction of experimental allergic encephalomyelitis (EAE) in Lewis rats, transferable to syngeneic animals, challenged with encephalitogenic mixture (myelin basic protein, complete Freund's adjuvant plus Bordetella pertussis organisms) 24 h later. This activity is probably effected by T cells and not by (an) inhibitory serum factor(s). The induction of this specific protection could be due to the penetration of the myelin basic protein antigen into the thymus where we first found suppressive cells. From the thymus, suppressor cells could then emigrate to spleen (on day 15) and to nondraining lymph nodes (on day 17). In the course of normal EAE in Lewis rats and especially at the time of self cure, this suppression is not demonstrated, but possible.

B lymphocyte development in fetal liver. I. Development of reactivities to B cell mitogens "in vivo" and "in vitro"

Abstract: Single cell suspensions of fetal liver cells, prepared from embryos at day 13 of gestation until birth, develop mitogen bacterial lipopolysaccharide (LPS)-reactive B cells “in vitro” within the same time as they do “in vivo”. The development of these mitogen LPS-reactive B cells in vitro is dependent on unknown components of fetal calf serum, found in some but not all batches. It does not require the presence of the corresponding B cell mitogens, i.e. LPS, in culture. Fetal liver cells, put in culture at different times of gestation, all acquire LPS reactivity at the equivalent of birth in vitro. When the cells have become LPS-reactive, they are then stimulated by LPS to growth and maturation into clones of IgM-secreting, IgA-secreting and IgG-secreting plaque-forming cells (PFC). The development of these PFC responses is mitogen-dependent: in the absence of LPS only 2-5 % of the LPS-stimulated PFC responses develop. Only the magnitude, but not the development in time, of LPS reactivity of fetal liver cells is different in vivo and in vitro. This may indicate either that an early precursor cell to LPS-reactive B cells can only divide in vivo but not in vitro, or that early precursors continue to migrate with time of gestation into fetal liver. After birth B cells in liver are immediately reactive to LPS; however, they rapidly leave the liver. Few, if any, dextrans sulfate or lipoprotein-reactive B cells, yielding a PFC response, develop in fetal liver cells either in vivo or in vitro. Neonatal spleen contains immediately mitogen-reactive B cells. Comparable numbers of LPS, dextran sulfate and lipoprotein-reactive cells are found. Development of fetal liver cells to Ig-secreting PFC, occurs, therefore, in two stages. The first (pre-B B) is independent of externally added mitogen (such as LPS), the second (B PFC) requires the addition of mitogen. The majority of spleen cells have already passed this first stage of development.

Regulation of the immune response. II. Repressor t cells in cyclophosphamide-induced tolerant mice.

Abstract: Specific antibody unresponsiveness was induced in adult CBA/H mice by the injection of cyclophosphamide 24 h after immunization with a large dose of horse red blood cells (HRBC). Four lines of experimental evidence indicated that this unresponsive state was maintained by active T cell repression. First, the cellular basis of the unresponsive state was in the T cell rather than the B cell population. Second, when normal spleen cells were transferred into the unresponsive animals, they were unable to break the unresponsive state. Third, the induction of unresponsiveness was antagonized by anti-lymphocyte serum. Finally, T cells from unresponsive mice specifically repressed the anti-HRBC antibody response of normal spleen cells when these were mixed together and injected into irradiated recipients. However, although the mice were unresponsive to HRBC at the humoral level, via active T cell repression, they simultaneously expressed high levels of delayed-type hypersensitivity (DTH) to HRBC. In contrast, we have reported recently (Eur. J. Immunol. 1976. 6: 674) that T cells from mice expressing humoral immunity to HRBC can specifically suppress the development of DTH to HRBC. On the basis of these two sets of observations, it is suggested that the frequently observed inverse relationship between humoral and cell-mediated immunity is mediated by different types of inhibitory T cells. The role of T cell help in the induction of these different types of immunity is also discussed.

Lymphokine‐induced secretion of plasminogen activator by murine macrophages

Abstract: Thioglycollate-stimulated macrophages are known to release a plasminogen activator (PA) into the medium. In this study it was investigated whether macrophages could be activated to release PA after exposure to lymphokines. Macrophage monolayers obtained by 24 h culture of proteose peptone-elicited murine exudate cells were incubated with lymphocyte culture supernatants. After 48 h the supernatants were replaced by serum-free medium and the macrophages were incubated for another 24-48 h. These supernatants were assayed for PA as measured by the lysis of 125I-labeled fibrin. The following results were obtained: (a) Supernatants of antigen or mitogen-stimulated spleen cells induced PA secretion by macrophages whereas control supernatants were ineffective. The same was found with supernatants of mitogen-stimulated lymph node cells. (b) PA secretion by macrophages seems to be induced by a rather narrow concentration range of lymphokines. (c) Lymphokine-induced PA secretion by macrophages is enhanced after phagocytosis of latex beads. The results show that PA secretion by activated macrophages can be considered as a parameter of immunoactivation.

Inhibition of lymphocyte proliferation by factor(s) produced by Schistosoma mansoni

Abstract: Normal spleen cells of CBA mice or Fischer rats were cultured with mitogens or allogeneic cells, together with various substances of Schistosoma mansoni origin, and thymidine uptake was measured. The proliferation (DNA synthesis) of normal lymphocytes was inhibited by the incubation product of the parasite as well as by cell-free supernatant of schistosome culture. Inhibition was obtained only when active materials were added at the beginning of the culture. Both T and B cell proliferation were inhibited. The inhibitory activity found in cell-free supernatant suggested the release by the parasite of some factor(s) interfering with lymphocyte proliferation. Moreover, serum from rats infected by S. mansoni inhibited lymphocyte proliferation also. The inhibitor(s) appeared heat resistant, dialyzable and of low molecular weight (500-1000). Incubation of normal spleen cells with S. mansoni inhibitor(s) did not enhance the release of nonspecific suppressor cell factor. The inhibition of product(s) released by the parasite could explain part of the immunosuppression status found in schistosomiasis.