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Biomedical subjects

R Benner

Publications and source records attributed to R Benner.

At least 163 records · Page 9Linked to original sources
PubMed1982

Quantitative aspects of the nonspecific humoral immune response to sheep erythrocytes.

The kinetics and magnitude of the nonspecific humoral immune response was studied at the cellular level in mice immunized with sheep erythrocytes (SRBC). Intravenous injection of the antigen evoked, in addition to a specific anti-SRBC response, a nonspecific response of all immunoglobulin (Ig) classes and subclasses. This nonspecific response peaked on day 4 or 5 after immunization, irrespective of the Ig class. The absolute number of nonspecific Ig-secreting cells induced by immunization varied with the different Ig-classes, and it was not proportional to the background level of Ig-secreting cells of the various classes. The nonspecific IgM-IgG1- and IgG2-response was 3 to 4 times as large as the antigen-specific responses of these classes. The nonspecific IgA-response, however, was many times greater.

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PubMed1982

Low dose X-irradiation of thymus filler cells in limiting dilution cultures of LPS-reactive B cells reduces the background Ig-secreting cells without affecting growth-supporting capacity.

Frequencies of lipopolysaccharide (LPS)-reactive B cells in the mouse can be determined in the limiting dilution culture system developed by Andersson et al. (1976, 1977a) which is completely dependent upon the presence of thymus filler cells, usually of rat origin. The assessment of B cell clones of mouse origin, however, can be hampered by the occurrence of varying numbers of thymus-derived immunoglobulin (Ig)-secreting cells. The number of these background Ig-secreting cells can be significantly reduced by low dose (110 mgray = 11 rad) X-irradiation of the rat thymus filler cells, without affecting their growth-supporting capacity.

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PubMed1982

Antibody formation in mouse bone marrow during secondary type responses to various thymus-independent antigens.

The data presented in this paper show that different thymus-independent (TI) antigens have a differential capacity of inducing antibody formation in mouse bone marrow, both after primary and secondary intravenous immunization. Primary immunization with certain TI antigens (e.g., lipopolysaccharide [LPS], TNP-LPS, DNP-Ficoll) induces the appearance of antibody-forming cells not only in the spleen, but also in the bone marrow. A single injection of certain other TI antigens (e.g., pneumococci [Pn], TNP-conjugated detoxified LPS [TNP-dLPS], TNP-conjugated Brucella abortus bacteria [TNP-BA] ), on the other hand, induces antibody formation in the spleen only. After secondary immunization with these TI antigens only TNP-BA induces a PFC response in the bone marrow. Pn, TNP-dLPS and TNP-BA, but also DNP-Ficoll, are unable to induce bone marrow antibody formation after secondary injection of the antigen, in spite of the clear-cut secondary type character of the splenic response. Thus, the absence of a bone marrow PFC response after secondary immunization with these antigens is not due to a failure to induce memory B cells. This data implies that either two subpopulations of memory B cells exist, one giving rise to antibody formation in the spleen and the other accounting for the bone marrow response, or that antibody can selectively inhibit the secondary bone marrow antibody response to certain TI antigens.

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PubMed1982

The effect of x-rays on the precursors of antibody forming cells (B cells) as measured with the in vitro limiting dilution assay.

The effect of X-irradiation upon murine antibody-forming cell precursors (B cells) was established in cultures of spleen cells stimulated with the B cell mitogen lipopolysaccharide (LPS). At day 5 and 7 the numbers of IgM- and IgG2-secreting cells were determined in cultures of irradiated and nonirradiated spleen cells. From these numbers a Do of 0.6-1.2 Gy for the IgM, and of 0.9-2.1 Gy for the IgG2 response was calculated. Similar Do values were obtained under limiting dilution culture conditions. In the limiting dilution assay the effect of irradiation upon the size of the IgM-producing clones could also be determined. It was found that irradiation reduced the number of LPS-reactive B cells without affecting the size of the clones produced by the surviving cells.

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PubMed1982

Quantitation of antibody production in mouse bone marrow during the secondary response to sheep erythrocytes.

The antibody production per organ was quantitated during the secondary response to sheep erythrocytes (SRBC) by measuring the hemolysin production in short-term cultures of spleen and bone marrow cells. Using this assay it was shown that during the first 5 days of the response the spleen is the major site of antibody production, whereas thereafter the bone marrow is the major source. By comparing the hemolysin production per organ and the total number of hemolysin-producing plaque-forming cells (PFC) per organ it was shown that the mean antibody production per PFC varied both in spleen and bone marrow during the secondary response. The mean antibody production per PFC was minimal when the PFC response was maximal. In the bone marrow the mean production per PFC decreased from day 3 to day 5, probably due to immigration of low producing PFC from the spleen. Beyond day 6 the production per cell increased in both spleen and bone marrow, indicating a further maturation of the PFC.

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PubMed1982

The capacity and mechanism of bone marrow antibody formation by thymus-independent antigens.

Primary immunization of mice with certain thymus-independent (TI) antigens (i.e., TNP-LPS and DNP-Ficoll) leads to antibody formation in the bone marrow (BM). TNP-Brucella abortus, Pneumococcus pneumoniae organisms, and alpha-(1,6) dextran, on the other hand, do not induce a BM antibody-producing plaque-forming cell (PFC) response. This paper deals with the mechanism underlying antibody formation in the BM to TNP-LPS and DNP-Ficoll. The majority of the BM-localizing PFC induced by TNP-LPS are formed within the BM from the proliferating lymphocyte pool, because this response was found to be resistant to splenectomy and sensitive to treatment with hydroxyurea (HU) before immunization. This local activation of newly formed B cells requires in addition to the antigenic signal of TNP-LPS the mitogenic signal from the lipid A component of LPS. In contrast, the BM PFC response to DNP-ficoll was reduced in splenectomized mice and resistant to HU treatment before the primary immunization. Thus, antibody formation in the BM to DNP-Ficoll is mainly dependent on long-lived B cells that migrate from the peripheral lymphoid organs into the BM.

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PubMed1982

Differential requirement for B-memory and T-memory cells in adoptive antibody formation in mouse bone marrow.

During the secondary response of mice to T-dependent antigens, antibody-producing plaque-forming cells (PFC) appear not only in peripheral lymphoid organs, but also in the bone marrow. This bone marrow antibody formation is feeble after primary immunization. The capacity of bone marrow antibody formation is dependent on the presence of antigen-specific memory cells at the moment of secondary immunization. We investigated whether hapten-primed B memory, carrier-primed T memory or both B-memory and T-memory cells are required for the adoptive PFC response in the bone marrow to T-dependent hapten-carrier conjugates. Adoptive antibody formation in the bone marrow was found after transfer of hapten-primed spleen cells, but not after transfer of carrier-primed spleen cells or virgin spleen cells. Thus, B-memory cells are obligatory for adoptive antibody formation in the bone marrow, in contrast to T-memory cells. However, T-memory cells did facilitate the bone marrow PFC response mediated by the infused B-memory cells.

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PubMed1981

Clones of helper T cells mediate antigen-specific, H-2-restricted DTH.

It is now well established that in the mouse, helper T cells and killer T cells are two distinct thymus-derived lymphocyte subpopulations, differing from each other in Lyt phenotype and H-2 restriction, among other parameters. Helper T cells are Lyt-1+ and their action in immune responses involves restriction at the H-2I region of the major histocompatibility complex (MHC). Killer cells, on the other hand, are Lyt-23+ and their activity is restricted by H-2K/D (refs 1, 3). In most instances, T cells mediating delayed-type hypersensitivity (DTH) responses share the Lyt phenotype and H-2 restriction of the helper T cell. This raises the question of whether or not helper activity and DTH can be mediated by the same activated T cell. Arguments for both views have been reported. We analysed this question using clones of specific helper T cells, which were obtained by long-term culture in vitro of in vivo primed T cells, followed by single-cell cloning. Here we show that these clones of helper T cells mediate antigen-specific and fully H-2-restricted DTH. The restricting element lies to the left of the I-B region in genetic maps of the mouse MHC.

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PubMed1981

Immunoglobulin isotype expression. II. Frequency analysis in mitogen-reactive B cells.

The frequency of lipopolysaccharide (LPS)-reactive B cells developing into clones that secrete the various immunoglobulin (Ig) classes has been determined in vitro, in cells from BALB/c mice, under culture conditions which detect all growth-inducible cells. Secretion of the different Ig classes was assessed in the protein A plaque assay for Ig-secreting, plaque-forming cells by using developing antisera specific for either IgM, IgG1, IgG2a, IgG2b, IgG3 or IgA. In all lymphoid organs tested (spleen, bone marrow, mesenteric lymph nodes and thoracic duct), a considerable proportion of all B cells (5-20%) was induced by LPS to yield a clone of IgM-secreting cells. Frequency determinations of LPS-reactive cells giving rise to descendants secreting other Ig isotypes revealed that, on an average, and irrespective of the origin of the cells, 7% of all IgM-secreting clones switched to the synthesis of IgG1, 39% to IgG2, 41% to IgG3 and 1% to IgA. Roughly the same frequencies of B cells switching CH gene expression were found among spleen cells of athymic nude mice. No correlation was found between the clonal frequencies of CH gene expression in polyclonally activated B cells and the in vivo "background" Ig-secreting cells suggesting that the CH gene expression in B cells is influenced by the quality of stimulation and other regulating influences.

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PubMed1981

Improvement of the protein A plaque assay for immunoglobulin secreting cells by using immunoglobulin-depleted guinea pig serum as a source of complement.

This paper describes a modification of the protein A hemolytic plaque assay for the enumeration of immunoglobulin (Ig)-secreting cells independent of antibody specificity of the Ig. This assay was originally developed by Gronowicz et al. (1976), and is based upon binding of the Fc portion of IgG to protein A. Ig-secreting cells are mixed with protein A-coated sheep erythrocytes, developing rabbit anti-Ig antiserum and guinea pig serum as a source of complement. This mixture is either pipetted between two microscope slides, or added to agarose and plated on a petri dish or microscope slide. The hemolytic plaques are enumerated after incubation at 37 degrees C. Here we show that purification of the guinea pig complement over a Sepharose-protein A column in order to eliminate the IgG fraction facilitates plaque formation. This modification reduces the incubation period required for plaque formation, and yields a higher number of, and more discrete plaques, than the original method.

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PubMed1981

Suppression of antigraft immunity by preimmunization. I. Kinetic aspects and specificity.

Intravenous injection of 2,000 rad of irradiated allogeneic cells can suppress the development of antigraft delayed-type hypersensitivity (DTH) to major and minor histocompatibility (H) antigens which normally arises after s.c. immunization. Secondary type DTH responses to minor H antigens were also largely suppressed by an i.v. injection of irradiated allogeneic cells 1 week preceding the s.c. priming injection. The extent of suppression of primary DTH to allogeneic H-2-incompatible cells depended on the dose of i.v. injected irradiated cells. After a dose of 1 x 10(7) irradiated spleen cells i.v., the suppression persisted for at least 40 days. Intravenous injection of cells incompatible for minor H antigens could not suppress the DTH to H-2 alloantigens and vice versa. Suppression of DTH to H-2 alloantigens was haplotype specific. Proliferation studies indicated that the immunosuppressed mice do not respond upon s.c. immunization with an increased proliferative activity in the draining lymph nodes, in contrast to nonsuppressed mice. The data suggest that i.v. preimmunization with allogeneic cells induces specific suppression of antigraft immunity acting at the induction stage of the immune response.

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PubMed1981

Genetic control of lipopolysaccharide-induced mobilization of CFUs. Dissociation between early and delayed mobilization of CFUs in complement C5-deficient mice and LPS non-responder mice.

Lipopolysaccharide (LPS)-induced mobilization of CFUs from haemopoietic tissues into the circulation has a biphasic pattern. The first rise occurs within 30 min of LPS injection, the second 4-7 days later. This second rise coincides with an increase of the CFUs number in the spleen from about 3000 to about 50,000. We have investigated the relationship between the two peaks by making use of complement C5-deficient mouse strains and the LPS non-responder mouse strains C3H/HeJ and C57BL/10ScCr. These latter two strains lack a serologically identifiable structure ('LPS-receptor') which is present in all LPS-responder strains. After injection of eleven different mouse strains with LPS, the numbers of circulating CFUs increased rapidly in all strains, except in the C5-deficient A/J, AKR/J, DBA/2J and B10.D2/oSn mice. On the other hand, the delayed LPS-induced accumulation of CFUs in blood and spleen occurred in all mouse strains tested, including the C5-deficient strains, but not in the LPS non-responder strains C3H/HeJ and C57BL/10ScCr. These results show that (a) early LPS-induced mobilization of CFUs is dependent on the availability of C5, in contrast to the delayed CFUs accumulation in blood and spleen, (b) the presence of the LPS receptor is not required for early CFUs mobilization by LPS and (c) recognition of the mobilizing agent by a specific receptor is required for the delayed accumulation of CFUs in blood and spleen.

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PubMed1981

Leukocyte mobilization in mice by polyanions. Decline of leukocyte mobilizing capacity after transplantation of lymphoma.

The leukocyte mobilizing polyanions dextran sulphate (DS) and polymethacrylic acid (PMAA) were administered to AKR and (C57BL x CBA) F1 mice at various times after transplantation of syngeneic lymphoma cells. In nonleukaemic mice DS and PMAA increased the number of circulating leukocytes 3--4-fold. The extent of leukocyte mobilization in leukaemic mice depended on the interval between transplantation of the lymphoma cells and injection of the polyanion. During the development of leukaemia in AKR as well as in (C57BL x CBA) F1 mice the capacity to react upon injection of polyanions with leukocyte mobilization gradually decreased. For DS, this decrease started before the number of leukocytes increased in the peripheral blood. On the other hand, the capacity for PMAA-induced leukocyte mobilization was fully preserved for several more days. In heavily leukaemic mice neither DS nor PMAA could further increase the number of peripheral blood leukocytes. In such mice the distribution pattern of leukaemic blast cells, small lymphocytes, granulocytes and monocytes was also hardly or not affected by injection of the polyanion.

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