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J Clagett

Publications and source records attributed to J Clagett.

At least 19 recordsLinked to original sources
PubMed1985

Detection of a surface antigen on NIH3T3 cells transfected with a human leukemia oncogene.

This study was conducted to examine the cell surface changes associated with oncogene induced transformation. Using the transfection technique the DNA of a human acute lymphocytic leukemia (ALL) was used to transform murine NIH3T3 cells. Balb/c mice were immunized with these transfectants and their immune splenocytes were used to produce a monoclonal antibody (17-9H3). Antibody 17-9H3 was demonstrated to bind to the cell membranes of transfectants and leukemia cells but not normal 3T3 cells in an enzyme linked immunosorbent assay. Fresh human leukemias, cultured leukemia lines and normal hemopoietic cells were examined with immunoperoxidase staining techniques to determine the specificity of 17-9H3. Our data suggest that the antigen associated with a human acute lymphocytic leukemia oncogene is ubiquitous, distributed among both neoplastic and normal hemopoietic cells. Among fresh human leukemias the antigen appears to be present primarily on fresh null ALLs and chronic myelogenous leukemia (CML) in blast crisis. This antigen was also found to be expressed by the majority of cultured T-cell lines tested.

Animals↗
PubMed1985

Immunoregulation in severe generalized periodontitis.

Severe generalized periodontitis (SGP) is an inflammatory disease which leads to extensive alveolar bone loss in young adults. Peripheral blood lymphocytes from SGP patients have been previously reported to exhibit an in vitro hyperproliferative response when exposed to B cell mitogens derived from Staphylococcus aureus and Actinomyces viscosus. Therefore hyperresponsiveness to B-cell mitogens could be an important pathogenic factor in the susceptibility to and progression of SGP. We have tested whether the hyperproliferative response of lymphocytes from SGP patients was due to (i) a functional deficiency of suppressor T cells, or (ii) to numerical alterations of lymphocytes. Supernatant fluids from concanavalin A-stimulated T cells from 14 SGP patients and 14 normal subjects were compared for their ability to suppress the IgM synthesis of B-cell mitogen-stimulated mouse splenocytes. No significant differences were noted in suppressor T-cell function between control subjects and SGP patients. However, SGP patients had significantly higher lymphocyte counts than control subjects, and there was a positive correlation between high lymphocyte counts and high mitogen-stimulated proliferation. SGP patients also had higher lymphocyte:monocyte ratios than control subjects, suggesting that a defect in macrophage-mediated suppression might be involved in the hyperproliferation phenomenon. Our data do not support the hypothesis that a suppressor T-cell defect is the cause of mitogen-induced hyperproliferative responsiveness of peripheral blood lymphocytes from SGP patients. Rather, hyperproliferation may be due to an expansion of the lymphocyte pool which responds to mitogens, or/and a regulatory disturbance which arises because of altered lymphocyte:macrophage ratios.

Actinomyces↗
PubMed1985

Cytokine production and utilization by the motheaten mouse.

Splenocytes from the motheaten mouse, after stimulation with alloantigen, lack the ability to utilize exogenous interleukin 1 (IL 1) or interleukin 2 (IL 2), express receptors for IL 2, or produce (IL 2). However, in contrast to other models of autoimmunity and immunodeficiency, after mitogen stimulation, motheaten splenocytes produced as much IL 1 or IL 2 as their normal littermates. In addition, these splenocytes expressed functional IL 2 receptors in the same quantity as normal littermate or wild-type splenocytes. Furthermore, motheaten thymocytes and splenocytes, like their normal littermates, respond synergistically to IL 1 on co-stimulation with mitogen, suggesting expression of an IL 1 receptor. Thus, motheaten mouse splenocytes are unable to utilize an antigen-delivered signal and convert it into cytokine production or IL 2 receptor expression. If the antigen signal is bypassed with mitogen, cytokine production and receptor expression appear normal.

Animals↗
PubMed1985

Effects of the motheaten gene on murine B-cell production.

The rapidly fatal autoimmune disease in the mutant mouse known as motheaten is caused by an autosomal recessive gene and is characterized by hypergammaglobulinemia and autoantibody production, among other defects. The cellular kinetics of B-cell maturation were investigated in three-week-old motheaten mice and their normal littermates to determine whether any abnormality in cell production of the B lineage could be correlated with B-cell hyperactivity. The production rates and renewal times of newly produced bone marrow, splenic small B-lymphocytes, and splenic plasma cells were examined by in vivo tritiated-thymidine administration using a pulse-chase protocol and radioautography of immunofluorescence-stained cells. Because small B-lymphocytes in both organs were produced at comparable rates in the mutant mice and in their normal littermates, primary B-cell production was unaffected in the mutant mice. In contrast, splenic plasma cells were produced 10-30 times faster in motheaten mice than in normal mice. The enhanced rate of plasma cell production in motheaten mice could be correlated with a concurrent increased loss of labeled large B-lymphocytes, presumably rapidly dividing activated B cells. Thus, the excessive antibody production in motheaten mice may be reflected by the increased plasma cell production.

Animals↗
PubMed1984

Mitogen-induced hyperproliferation response of peripheral blood mononuclear cells from patients with severe generalized periodontitis: lack of correlation with proportions of T cells and T-cell subsets.

Severe generalized periodontitis (SGP) is a localized inflammatory disease which differs clinically from common periodontitis in that it leads to remarkable extensive alveolar bone loss in relatively young adults. There is evidence that B-cell responses to bacterial substances may play a major role in the pathogenesis of this disease. In the present report, we show that a B-cell mitogen from Actinomyces viscosus (AVIS) bacteria provokes a hyperproliferation response of peripheral blood mononuclear cells (PBMNC) from these patients. In addition, AVIS-stimulated PBMNC from SGP patients proliferate for longer periods in culture than do PBMNC from control subjects. There were, however, no differences between patients and controls in the numbers of immunoglobulin-secreting cells in these cultures as determined by an indirect plaque-forming cell assay. The possibility that differences in numerical proportions of regulatory T-cell subsets may play a role in the mitogen-induced hyperproliferation phenomenon is examined. PBMNC were stained with fluorescein isothiocyanate-conjugated monoclonal antibodies OKT3, OKT4, and OKT8 in order to identify, respectively, total T cells, helper/inducer, and suppressor/cytotoxic subsets. Flow cytometric analysis of such specifically stained cell preparations from 14 control subjects and 14 SGP patients did not reveal any significant differences between the proportions of total T cells or T-cell subsets of the two groups. Furthermore, there were no statistically significant correlations between the magnitude of proliferation responses and the proportions of total T cells or either of the T-cell subsets.

Adult↗
PubMed1984

Spontaneous production of colony-stimulating activity by splenic Mac-1 antigen-positive cells from autoimmune motheaten mice.

Cultured splenocytes from 3-wk-old autoimmune motheaten mice (me/me) spontaneously produced colony-stimulating activity (CSA), which stimulated the formation of bone marrow myeloid colonies. The production of CSA was not dependent on the presence of serum; this activity was not produced by spleen cells from their phenotypically normal littermates (+/-) or from other normal mouse strains. The peak level of CSA occurred early during the culture period, and within 48 hr the activity was markedly diminished. Cell fractionation studies demonstrated that cells expressing Mac-1 antigen produce CSA and are most likely to be mononuclear phagocytes. The unusual proliferative capacity in vitro of splenic mononuclear phagocytes from motheaten mice probably results from the spontaneous production of CSA by Mac-1 antigen-positive cells. Defective regulation of the production of monokines may contribute to the severity of the immunologic disease of these mutant mice.

Animals↗
PubMed1983

Accelerated rate of mononuclear phagocyte production in vitro by splenocytes from autoimmune motheaten mice.

The rapidly fatal autoimmune disease accompanied by pneumonitis in the mutant mouse known as motheaten is caused by an autosomal recessive gene. The proliferative capacity and production rate of splenic mononuclear phagocytes at different maturational stages, defined by morphologic criteria, were examined by two in vitro tritiated thymidine administration protocols and radioautography. The replicative rate of splenic promonocytes from 3-week-old normal mice was found to approximate that of adult bone marrow cells. Monocytes, macrophages, and previously described macrophagelike cells from motheaten mice had an accelerated rate of maturation in vitro, compared with similar cells from normal mice. These differences in the production rates could be attributed to the shorter period of time that promonocytes from the mutant mice are in the S phase of the cell cycle. Evidence, also, verified that the macrophagelike cells were derived from promonocytes via the monocyte-macrophage compartment. The unusual in vitro growth characteristics of the splenic mononuclear phagocytes from motheaten mice could be a manifestation of an in vivo abnormality of this lineage that could contribute to the development of pulmonary disease in these animals.

Animals↗
PubMed1982

Abnormal in vitro proliferation of splenic mononuclear phagocytes from autoimmune motheaten mice.

Motheaten mice develop combined immunodeficiency and fatal autoimmune disease that follow autosomal recessive inheritance. In splenocyte cultures of motheaten mice, supplemented with 5% normal serum proliferating cells (MP) were present exhibiting morphologic characteristics of mononuclear phagocytes at light and electron microscopic levels. The macrophage nature of these cells was confirmed by the lack of Thy-1 antigen and immunoglobulins; the expression of Mac-1 antigen, FcR for IgG, and Ia antigens on their cell surfaces; their ability to phagocytize EA and adhere to plastic; the presence of nonspecific esterase and lysomal enzymes in their cytoplasm; and the pattern of peroxidase localization similar to monocyte-derived macrophages. MP from motheaten mice exponentially grew in culture in the absence of exogenous growth factors with a doubling time of approximately 76 hr. Although these cells were present in splenocyte cultures of normal controls, their number did not increase during the culture period under the same conditions. The addition of dextran sulfate further enhanced the proliferation of MP from motheaten mice, and induced exponential growth of these cells from normal controls, reaching only the level of unstimulated cells from motheaten mice. Radioautographic analysis demonstrated that MP substantially contributed to the elevated spontaneous and dextran sulfate-induced DNA synthesis in splenocyte cultures. Therefore, the in vitro abnormality of MP may be indicative of in vivo aberrancies of macrophages from motheaten mice and lends credence for investigating the role of macrophages in immunodeficiency and autoimmunity that develop very early in motheaten mice.

Animals↗
PubMed1981

Immune responsiveness of SM/J mice. Cellular characteristics and genetic analysis of hyperresponsiveness to B cell mitogens.

We tested the proliferative responses of splenocytes from a panel of inbred mouse strains to AVIS, a B cell mitogen from Actinomyces viscosus bacteria. The SM/J strain was found to exhibit severalfold higher responsiveness than any of the other strains. SM/J splenocytes were also hyperresponsive to the B cell mitogens lipopolysaccharide, dextran sulfate, and purified protein derivative of tuberculin, but responsiveness to the T cell mitogen phytohemagglutinin was normal. (B6 X SM)F1 and F1 x B6 backcross mice were tested for AVIS and lipopolysaccharide responsiveness, and it was determined that hyperresponsiveness was under polygenic, autosomal, non-H-2-linked gene control. Genetic control of response to B mitogens in SM/J mice appears to be expressed solely through the B lymphocyte because removal of T lymphocytes or macrophages did not reduce the magnitude of responsiveness in vitro. SM/J mice may provide a useful model for testing questions regarding B cell triggering, differentiation, and function, and to examine the genes involved with B cell proliferation.

Animals↗
PubMed1981

Deficiency in cells expressing terminal transferase in autoimmune (motheaten) mice.

The extensive breakdown of immune homeostasis in the motheaten mouse (me/me) has been ascribed to a single gene defect on chromosome 6 (ref. 1). These mice develop skin lesions within the first week of life, do not thrive, and die within the first 3--8 weeks. There is severe hypergammaglobulinaemia with multiple species of circulating autoantibody and deposition of immune complexes in the thymus, skin, lungs and kidneys. A single gene defect producing such catastrophic results may provide an important model for understanding autoimmune phenomena. We report here a virtual absence of terminal deoxynucleotidyl transferase-positive (TdT+) cells in the bone marrow, thymus and spleen of motheaten mice. TdT is a DNA polymerase which has the unique capacity to polymerize nucleotides in the absence of template direction. Although no in vivo biological function of this enzyme has been established, its unique appearance in the bone marrow and thymus of adult mammals and its in vitro biochemical activity have led to a proposed role for TdT in the somatic diversification of lymphocytes. Bone marrow TdT+ cells have been shown to belong to both T and B cell populations and may also include precursor cells common to these lineages. Although the role of TdT in the acquisition of appropriate T- and B-cell specificities is not known, our results are the first to correlate the virtual absence of TdT+ cells with a severe autoimmune syndrome. We investigated the level of TdT+ cells in neonatal me/me mice and their normal littermates and the susceptibility of TdT+ cells to circulating autoantibody in motheaten mouse serum.

Animals↗
PubMed1981

Myelogenous production and maturation of B lymphocytes in the mouse.

Cells of the B lymphocyte lineage in young adult murine bone marrow were identified and resolved into compartments based on cell size and the expression of the mu heavy chain of IgM in the cytoplasm (cmu) or on the cell surface (smu). The proliferative status, renewal rate, and intercompartmental transit of cells through the defined compartments were determined using established protocols of in vivo tritiated thymidine (3H-TdR) administration, followed by radioautography of bone marrow smears. In addition, we specifically tested whether any of the defined cell compartments were derived from long-lived lymphocytes that are known to enter the marrow. Only large cells immediately incorporated the DNA precursor and both small cmu+ smu- and cmu+ smu+ cells were postmitotic lymphocytes. Large cmu+ smu- cells were found to be a rapid transit compartment in which the last mitosis of B lymphocyte differentiation takes place. All large cmu+ smu- cells divided only once, and both daughter cells entered the postmitotic small cmu+ smu- population. Large cmu+ smu- cells relied for their maintenance entirely on cell input from an Ig- progenitor compartment. Progenitors of cmu+ smu- large cells were not small lymphocytes, proliferated less rapidly than their descendants, and maintained the input of large cmu+ smu- cells for up to 40 hr. Approximately 70% of small cmu+ smu- cells were the immediate division products of large cmu+ smu- cells, whereas the remainder were derived from a precursor with no detectable mu synthesis. Small cmu+ smu+ cells were the maturation products of small cmu+ smu- cells. This conversion appeared to take place at random rather than as a function of postmitotic age. Renewal times for small cmu+ cells without or with detectable smu were calculated to be 48 and 96 hr, respectively. Only the cmu- smu+ compartment included long-lived cells. All other mu+ populations either proliferated or were replaced by newly produced cells. A conspicuous minor population of large smu+ B cells were detected, and the data relating to these were subjected to several interpretations. These observations provide insight into the origin and fate of B lineage precursors in the marrow and suggest a scheme for the terminal stages of B lymphocytes formation that is similar to the myelogenous production of other hemopoietic cells.

Animals↗
PubMed1980

In vitro expression of immunoglobulin M and G subclasses by murine B lymphocytes in response to a polyclonal activator from Actinomyces.

A cell wall extract from the gram-positive bacterium Actinomyces viscosus contains the mitogen AVIS, a potent polyclonal B-cell activator for murine B lymphocytes. Cultures of splenocytes from heterozygous nude mice in the presence of an optimal concentration of AVIS responded by a deoxyribonucleic acid synthesis response, and proliferaction reached maximal levels after 3 to 4 days. There was no requirement for T cells in the deoxyribonucleic acid synthesis, proliferactive, immunoglobulin M (IgM), or IgG responses. Significant numbers of IgM-producing cells were present as early as day 2 of culture, whereas later in the culture periods (days 3 to 6) IgG-producing plasmablasts and plasma cell were observed. In cultures of splenocytes from nude mice stimulated with AVIS for 4 to 5 days, 20 to 25% of the recoverable cells synthesized IgM, and 10% contained only IgG2 or IgG3; 5 to 8% of the cells stained for both IgM and IgG2 or both IgM and IgG3. Fine-structure analysis of AVIS-stimulated splenocytes from heterozygous nude mice after 3 days of culture demonstrated that 20 to 25% of the cells were activated to various degrees. Of most importance, all of the activated cells had the characteristic of B lymphoblasts, plasmablasts, or plasma cells. This is the first demonstration of a polyclonal B-cell activator other than lipopolysaccharide which induces IgG3 synthesis. We suggest that AVIS may be a useful probe for the exploration of the functional activities of subpopulations of B cells.

Actinomyces↗
PubMed1979

A cat model for the evaluation of mechanisms of bone resorption: induction of bone loss by simulated immune complexes and inhibition by indomethacin.

When simulated immune complexes (SIC) (heat-aggregated IgG) possessing many of the properties of true antigen-antibody complexes were injected via the root canal into the periapical tissues of cat maxillary cuspids, radiographically and histologically evident bone resorption occurred at these sites within 7 days. Bone loss was accompanied in all cases by inflammation of the surrounding collagenous connective tissues and was characterized by the presence of osteoclasts. Bone resorption, but not the accumulation of inflammatory cells, was blocked by the systemic administration of indomethacin, an inhibitor of prostaglandin synthetase. The most likely explanation is that SIC-activated mechanisms such as the complement cascade, prostaglandin synthesis, and neutrophil degranulation were responsible for the bone loss. The minor inflammation and bone loss that followed the repeated injections of BSA and of monomeric IgG can best be explained as a response to trauma. The data presented establish that the cat maxillary cuspid is a useful model in which to explore the mechanism underlying pathological bone resorption.

Animals↗