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K S Landreth

Publications and source records attributed to K S Landreth.

At least 37 records · Page 2Linked to original sources
PubMed1989

Bone marrow stromal cell regulation of B-lymphopoiesis. II. Mechanisms of hydroquinone inhibition of pre-B cell maturation.

Previous investigations from our laboratory have shown that the benzene metabolite, hydroquinone (HQ), inhibits B cell production by preventing the maturation of pre-B cells. Data presented in this paper demonstrate that HQ interrupts B-lymphopoiesis indirectly by inhibiting the production of interleukin-4 (IL-4) by fibroblastic stromal cells. HQ exposure of fibroblastic stromal cells (SCL-173 and SCL-160) did not affect IL-4 production by these cell lines at any dose tested. Addition of untreated bone marrow-derived macrophages to HQ-treated bone marrow stromal cells (heterogeneous population of fibroblastic cells and macrophages) reversed inhibition of IL-4 production. However, addition of HQ-treated macrophages was without effect. Our studies suggest that HQ inhibits macrophage production of IL-1, a potent inducer of IL-4 production by bone marrow fibroblastic stromal cells. Interruption of IL-1 release from macrophages mediates the observed inhibition of B lineage cell maturation.

Animals↗
PubMed1988

Bone marrow stromal cell regulation of B-lymphopoiesis. I. The role of macrophages, IL-1, and IL-4 in pre-B cell maturation.

Our experiments have addressed regulation of B lymphocyte formation by bone marrow stromal cells. Stromal cells appear to produce a regulatory factor that acts at the pre-B cell stage to induce the expression of Ig L chains and surface Ig. Bone marrow stromal cell conditioned medium was found to contain this factor and the active component was partially purified by HPLC. This stromal cell-derived factor had a m.w. between 16,000 and 20,000, was specifically neutralized by anti-IL-4 mAb, 11B11, and enhanced the proliferation of anti-mu-stimulated B cells. We also found that rIL-4 induced B cell formation in culture. In our studies, IL-1 had no direct effect on pre-B cell maturation, however, IL-1 was found to stimulate the production of IL-4 by both heterogeneous bone marrow stromal cells and a cloned stromal cell line, SCL-160. These effects of IL-1 on factor production by stromal cells were duplicated by the addition of bone marrow-derived macrophages to SCL-160 cells. We conclude that stromal cell-derived IL-4 is a physiologic stimulator for B cell generation. In addition, macrophages appear to play a role in B cell formation by regulating the production of IL-4 by stromal cells via the secretion of IL-1.

Animals↗
PubMed1988

Pre-B cell generation potentiated by soluble factors from a bone marrow stromal cell line.

Two bone marrow stromal cell lines isolated from the adherent layer of a Dexter-type long term bone marrow culture differ markedly in their hemopoietic support capacity. S17 supports myelopoiesis and the differentiation of early B cell precursors into B lymphocytes while S10 supports myeloid cell differentiation and not B lymphopoiesis. The identification of a stromal cell line with B cell support capacity prompted an investigation of whether the effects of S17 were mediated via soluble factors. Results presented herein indicate that medium conditioned by S17 but not S10 contains an activity that can induce the expression of the 220,000 m.w. 14.8 antigen and cytoplasmic mu H chain of Ig in B lymphocyte progenitors that have not yet expressed these markers. Bone marrow cells were depleted of 14.8+, cytoplasmic mu+ pre-B cells on antibody-coated petri dishes. After 24-h liquid culture newly generated pre-B cells were enumerated as cells that expressed cytoplasmic mu H chain of Ig but not Ig L chains by immunofluorescence. Expression of Ly5(220) was monitored by 14.8 antibody binding. This pre-B cell differentiation activity was abrogated by digestion with pronase, aminopeptidase, or carboxypeptidase. Isoelectric focusing data revealed the activity to have isoelectric point of 5.9 to 6.2. S17-conditioned medium was fractionated using HPLC and each fraction tested for pre-B cell-generating activity. Fractions collected from a Superose 12 gel filtration column were found to have two peaks of activity associated with molecules of apparent m.w. of approximately 60,000 and 10,000. Virtually identical peaks of activity were observed when medium conditioned by heterogeneous stromal cell cultures was fractionated. Separation of S10-conditioned medium revealed no cryptic activity. S17-conditioned medium was further characterized by anion exchange chromatography and the majority of the pre-B cell generating activity shown to be associated with the void volume that eluted from a MonoQ column. These fractions were rechromatographed on Superose and the activity again found to be associated with two fractions corresponding to apparent m.w. of 60,000 and 10,000. The S17 pre-B cell differentiation activity appears to result from the presence of a novel molecule because other well characterized mediators had no activity in this short-term liquid culture system. No pre-B cell-generating activity was observed when IL-1 or conditioned medium containing IL-2, IL-3, or IL-4 (B cell stimulatory factor 1) were added to cultures.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1988

Effect of growth and differentiation stimuli on the development of antigen-responsive B cells in fetal liver.

The development of the B cell immune repertoire was studied using an in vitro fetal organ culture system. In order to analyze the mechanism by which B cell precursors clonally expand and diversify, fetal lymphoid tissues were incubated in the presence of several factors known to influence B cell differentiation: IL-1, IL-2, WEHI-3 culture supernatant containing IL-3, and a factor from a cyclic neutropenia patient (CNF). By analyzing the effect of exogenous factors on the frequency of antigen-responsive B cells, the ability of the factor to either inhibit or enhance clonal expansion was determined. It was found that the addition of IL-1, WEHI-3 supernatant, or CNF increased the frequency of DNP-responsive B cells suggesting an enhancement of clonal expansion. IL-2, on the other hand, did not alter the frequency of antigen-responsive B cells. The effect of added factors on the kinetics of appearance of phosphorylcholine (PC)-responsive B cells, which are known to be acquired in ontogeny about 2 weeks later than DNP-responsive B cells, was also analyzed. The data indicate that CNF, unlike IL-1, IL-2, and WEHI-3 culture supernatant, results in an earlier appearance of PC-responsive B cells. These results suggest that soluble factors may play a role in the generation of the B cell repertoire.

Animals↗
PubMed1987

Hydroquinone inhibits bone marrow pre-B cell maturation in vitro.

Environmental exposure to benzene results in both myelotoxicity and immunotoxicity. Although benzene-induced immunotoxicity has been well documented, no studies to date have addressed the possibility that benzene toxicity is due in part to altered differentiation of marrow lymphoid cells. We investigated the effect of acute exposure to the benzene metabolite, hydroquinone, on murine bone marrow B-lymphopoiesis. Bone marrow cell suspensions from B6C3F1 (C57BL/6J x C3H/HeJ) mice were depleted of mature surface IgM+ (sIgM+) B cells and cultured for 0, 24, 48, or 72 hr and production of newly formed B cells was assayed both by sIgM expression and colony formation in soft agar cultures. One hr exposure of bone marrow cells to hydroquinone before culture reduced the number of sIgM+ cells generated in liquid cultures. Small pre-B cells (cytoplasmic mu heavy chain+, sIgM-) were numerically elevated as compared with control cultures. Hydroquinone exposure also decreased the number of adherent cells found in cultures of bone marrow cells. These results suggest that short-term exposure to hydroquinone, an oxidative metabolite of benzene, may in some way block the final maturation stages of B cell differentiation. This apparent differentiation block resulted in reduced numbers of B cells generated in culture and a corresponding accumulation of pre-B cells. Reduction of adherent cells in treated cultures may also suggest that toxicity to regulatory cells for the B lineage may be in part responsible for this aspect of hydroquinone myelotoxicity.

Animals↗
PubMed1985

Pre-B cells in agammaglobulinemia: evidence for disease heterogeneity among affected boys.

Six immunodeficient boys were found to have agammaglobulinemia and lack circulating B cells. These patients could be divided into two groups based on bone marrow findings and clinical course. In one group, pre-B cells and lymphocytes were present at normal frequencies and in normal absolute numbers. Recurrent serious infections were documented in the first few months of life in these patients, and this consequently led to early diagnosis. In the second group, pre-B cells were virtually undetectable. Patients in this group did not present with recurrent infections until the second year and were thus diagnosed later than were those in the first group. Childhood agammaglobulinemia with deficiency of both pre-B and B lymphocytes appears to be a different disease from X-linked infantile agammaglobulinemia. This disease may involve an arrest of B-lineage cell development at an earlier stage than that responsible for X-linked agammaglobulinemia.

Adolescent↗
PubMed1985

Regulation of human B lymphopoiesis: effect of a urinary activity associated with cyclic neutropenia.

Urine from a patient with cyclic neutropenia was found to contain a lymphopoietic activity that acts as a growth factor for human pre-B cells. This biologic activity was detectable during the week preceding, but not during, the period of neutropenia. This corresponded with a periodic excessive accumulation of pre-B cells in the marrow of this patient. Urine preparations were added to cultures of normal human bone marrow that had been depleted of B cells. Pre-B cells were generated in these cultures but not in cultures containing urine preparations from normal donors. Pre-B cells were also generated from bone marrow that had been depleted of 177.17+ cells and the majority of pre-B cells. This is the first report of a hemopoietic activity which affects human pre-B cells. This activity may represent a normal regulatory molecule that is periodically produced in excess in this patient.

Adult↗
PubMed1984

Putative B lymphocyte lineage precursor cells in early murine embryos.

The emergence of putative B lymphocyte lineage cells in embryonic and neonatal tissues of mice was studied using monoclonal antibodies which recognize virtually all B cells, pre-B cells and an additional population of lymphoid cells. An extensive survey of extraembryonic and intraembryonic hemopoietic tissues indicated that cells displaying this marker first appear within liver of 45-50 somite stage embryos. Prior to this developmental stage, none were found in yolk sac or peripheral blood. Although some 14.8 antigen bearing cells were found in suspensions of ectoplacenta, these were small surface IgM+ lymphocytes which were presumably of maternal origin. Culture of embryonic liver fragments which initially contained small numbers of antigen positive cells resulted in their expansion. However, this did not occur when very early liver rudiments containing virtually no lymphoid cells were cultured. These findings document the earliest appearance of cells during ontogeny which may be committed to differentiate into functional B lymphocytes.

Animals↗
PubMed1984

B lymphocyte precursors in embryonic and adult W anemic mice.

Mice homozygous for mutations at the dominant spotting or W locus on chromosome 5 have been extensively used as models of severe macrocytic anemia caused by defective hemopoietic stem cells. We examined cells of the developing B lineage in adult and embryonic W anemic mice both by phenotypic analyses and by three distinctly different functional assays for B lymphocyte precursors. Adult W/Wv mice had normal numbers of B cells in the spleen and bone marrow, and normal numbers of pre-B cells and cells identified by a monoclonal antibody directed to a B lineage cell surface antigen (14.8) in the bone marrow. Embryonic W/Wv and Wx/Wx mice had hypoplastic liver development at 16 days gestation with a corresponding reduction in absolute numbers of pre-B cells, 14.8+ cells, and clonable granulocyte-macrophage progenitor cells, although their frequencies were normal. As expected, spleen colony-forming units were greatly reduced both in absolute number and frequency. Adult bone marrow cells and fetal liver cells from W anemic mutants generated B cells in vitro as well as did cells from normal littermates, but W anemic cells failed to generate B lymphocytes as well in vivo. These observations likely reflect differences in precursor cells that contribute to B cell formation in these assays, and suggest that early B lineage precursors are reduced or defective in W anemic mice.

Aging↗
PubMed1983

Cycling of peripheral blood and marrow lymphocytes in cyclic neutropenia.

A 16-month-old male patient with cyclic neutropenia was found to have cyclic fluctuations of monocytes, lymphocytes, platelets, and eosinophils in the peripheral blood. Changes in lymphocyte counts were not obviously related to B, T, or natural killer cells. All classes of immunoglobulins were elevated throughout the cycle. Studies of the marrow morphology revealed remarkable cyclic oscillations of lymphoid as well as myeloid lineage cells. Granulocyte-macrophage progenitors (CFU-c) cycled and were virtually absent 1 wk prior to the neutropenic nadir. The cyclic changes in marrow lymphoid cell numbers were primarily due to changes in numbers of surface immunoglobulin negative (sIg-), cytoplasmic Ig+ (cIg+) pre-B cells. Pre-B cell numbers cycled from normal to extraordinarily elevated values with the same periodicity but reciprocal to the neutrophil cycle. We propose that the primary defect in cyclic neutropenia may either be a periodic failure of an early myeloid differentiation factor or a blunted response of early myeloid precursors to a common hemopoietic growth factor. This may lead to periodic fluctuations in the production or delivery of growth factors (or factor) that influence early stages of differentiation of other hemopoietic cells, including pre-B cells. The essential periodic deficiency is consequently reflected in deficient production of CFU-c accompanied by excessive production or accumulation of pre-B cells (and probably other hemopoietic precursors) in the marrow.

Adult↗
PubMed1983

Phenotypic and functional characterization of murine B lymphocyte precursors isolated from fetal and adult tissues.

Murine fetal liver and adult bone marrow cells identified by monoclonal 14.8 antibody were enriched on antibody-coated polystyrene petri dishes. Cell surface immunoglobulin (sig)-bearing cells were depleted before this enrichment procedure, and the resulting preparations of 14.8+, slg- cells were characterized as to morphology, immunoglobulin gene expression, and functional potential in vivo and in vitro. All cells with detectable mu chains of IgM in the cytoplasm (cmu) were found to be included in the 14.8+ population. The enriched cells did not contain significant numbers of committed granulocyte-macrophage progenitor cells or putative hemopoietic stem cells. Selected cells from 16-day fetal liver were large, a majority of the cells had a lobulated rather than a spherical nuclear outline, and less than 1% had detectable cmu. Enriched cells from 19-day fetal liver were on the average smaller than those from 16-day-gestation liver and had a more typical lymphoid morphology; 30% were cmu+. Adult bone marrow 14.8+, slg- cells were similar to 19-day fetal liver cells in morphology, and approximately half were cmu+. These selected precursor cells retained the capacity to mature in vivo and in vitro. Fetal and adult 14.8+, slg- cells were efficient in generating newly formed B cells in vivo, and this maturation step appeared to be dependent on the presence of microenvironmental accessory cells. However, the ability of positively selected cells to mature in vitro was markedly decreased, and this potential was not rescued by providing known sources of accessory cells. Possible reasons for this difference are considered. This technique for positively selecting cells has allowed us to directly compare for the first time B cell precursors from fetal and adult tissues and will be invaluable for resolution of the cell compartments in the differentiation of B lymphocyte precursors, in the study of accessory cells known to facilitate this process, in the definition of humoral factors which may act on pre-B cells, in the study of immunoglobulin gene rearrangements which take place during normal differentiation, and for further comparative studies of fetal and adult lymphopoiesis.

Animals↗
PubMed1982

Age-dependent deficiency of B lymphocyte lineage precursors in NZB mice.

Adult NZB mice (greater than 15 wk old) have very few bone marrow cells that can give rise to sIg+ clonable B cells during liquid culture. This deficiency corresponds to extremely low numbers of cells with cytoplasmic but not surface mu chains of IgM and reduced numbers of cells bearing a high molecular weight B-lineage antigen. Depletion of Thy-1-bearing cells and appropriate mixing experiments did not provide evidence either that suppressor cells are responsible for this phenomenon or that accessory cells are defective in NZB mice. Nor did it seem that B cells were being produced in extramedullary sites. B cell precursors were detectable in very young NZB mice, exceeded control values at 4-5 wk of age, and then declined rapidly. In contrast, these persisted for greater than 1 yr in normal BALB/c, DBA/2, and CBA/H mice. It appears possible that intermediate stages in B-lineage differentiation become prematurely exhausted through an accelerated aging process in NZB mice. These chronological changes have implications for understanding the sequence of events that lead to B lymphocyte formation and the processes that normally regulate it.

Aging↗
PubMed1982

Enrichment of human marrow lymphocytes with monoclonal antibodies to murine antigens.

Two monoclonal antibodies, prepared against a murine B lymphoma and characterized as binding to a cell surface antigen represented primarily on cells of the B lineage, were found to bind to human hemopoietic cells. These antibodies recognize similar populations of cells in mice and humans. Antibodies from clones 177.17 and 83.4 bound to 6% of human bone marrow nucleated cells. This included all cells with detectable cell surface Ig (sIg+) and those that lack sIg but have detectable cytoplasmic mu (sIg-, c mu+), considered to be the immediate precursors of B lymphocytes (pre-B cells). In addition, these antibodies bound to a subpopulation of T cells and a proportion of null lymphocytes in marrow, spleen, and peripheral blood. An unexpected finding was that established pre-B cell lines were not recognized by these antibodies and possible reasons for this are considered. By using antibody-coated polystyrene plates for cell depletion and recovery, highly enriched preparations of c mu+, sIg- cells have been obtained. These antibodies and enrichment procedures should prove valuable in establishing the minimal requirements for maturation of these putative precursors in vitro, for comparative studies of immunodeficiency/autoimmune diseases in man and experimental animal models, and for monitoring the outcome of therapeutic marrow transplantation.

Animals↗