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Biomedical subjects

T M Chused

Publications and source records attributed to T M Chused.

At least 37 records · Page 2Linked to original sources
PubMed1987

HLA-DR antigens in systemic lupus erythematosus: association with specificity of autoantibody responses to nuclear antigens.

HLA-DR antigens and autoantibodies to the nuclear or cytoplasmic antigens Ro/SSA, La/SSB, Sm, and RNP were determined in North American and Austrian patients with systemic lupus erythematosus (SLE). Analysis of the association of antibodies to these ribonucleic acid (RNA)-protein antigens with HLA-DR antigens showed that HLA-DR3 was related to the presence of anti-Ro/SSA or anti-La/SSB, or both. In contrast, anti-Sm or anti-RNP, or both were associated with HLA-DR4. HLA-DR5 was associated with absence of these autoantibodies. The data extend evidence for the complexity and heterogeneity of SLE. Moreover, they indicate that, in SLE, genes linked to those coding for HLA-DR antigens, are related to the specificity of autoantibody responses rather than to the primary immunological abnormalities of this disorder.

Adolescent↗
PubMed1986

A quantitative fluorescent method for measurement of bacterial adherence and phagocytosis.

We have developed a new two-color fluorescent method for the quantitative measurement of adherence and ingestion of Streptococcus pneumoniae by human monocytes. The method employs a fluorescent naphthalimide, Lucifer Yellow VS, that has been covalently linked to the bacterial cell wall. Bacteria were opsonized and allowed to adhere to monocytes. Lucifer Yellow did not alter the bacterial interaction with complement in serum or with the phagocytic cell. The ability of monocytes to ingest the adherent bacteria was tested under a variety of conditions. Rabbit antibody to Lucifer Yellow derivatized with Texas Red was used to detect monocyte-bound, but uningested bacteria. Dual laser flow cytometry simultaneously quantitated the total number of monocyte-associated S. pneumoniae and the number that remained surface adherent. This method allows separate analysis of the opsonins and receptors involved in bacterial adherence to phagocytes and in the ingestion process.

Adhesiveness↗
PubMed1986

Tolerance defects in New Zealand Black and New Zealand Black X New Zealand White F1 mice.

The susceptibility of autoimmune NZB and (NZB X NZW)F1 mice to the induction of tolerance by monomeric BSA was compared with several normal mouse strains. Unresponsiveness in T and B lymphocyte compartments was probed by challenging with DNP8BSA and measuring anti-DNP and anti-BSA antibodies separately. Tolerance induced by monomeric BSA was carrier specific, and there was no evidence of epitope-specific suppression. Normal NZW, NFS, and B10.D2 mice were easily rendered tolerant with monomeric BSA and did not produce anti-DNP or anti-BSA antibodies after challenge with DNP8BSA. By contrast, the lack of anti-DNP antibody response in similarly treated NZB mice was dependent on the dose of monomeric BSA, indicating that the helper T cells were partially resistant to tolerance induction. NZB mice treated with a high dose of monomeric BSA produced anti-BSA, but not anti-DNP, antibodies after immunization. Thus, the anti-carrier B cells in NZB mice may have been primed by monomeric BSA. The presence of the xid gene on the NZB background rendered the mice susceptible to induction of tolerance, suggesting that the tolerance defect in NZB mice involves the B cell compartment. This abnormal antibody response was a dominant trait: (NZB X NFS)F1 and (NZB X B10.D2)F1 mice had the same characteristics as NZB mice. These F1 hybrids do not develop autoimmune disease, indicating that resistance to experimental tolerance induction expressed at a B cell level may not be sufficient for disease development. In contrast to NZB and other NZB F1 hybrids, (NZB X NZW)F1 hybrids treated with monomeric BSA and challenged with DNP8BSA responded to both DNP and BSA. The contribution of a B cell defect to the tolerance abnormality of (NZB X NZW)F1 mice was examined by analyzing the effect of the xid gene on the progeny of (NZB.xid X NZW)F1 mice. Unlike the effect of the xid gene on NZB mice, both phenotypically normal heterozygous female and phenotypically xid hemizygous male mice produced anti-DNP and anti-BSA antibodies after tolerance induction and immunization, demonstrating that a major helper T cell abnormality was present in (NZB X NZW)F1 mice. The (NZW X B10.D2)F1 hybrid was rendered tolerant by this procedure, indicating that the helper T cell defect (NZB X NZW)F1 mice may have resulted from gene complementation with the NZB mice contributing partial resistance of T helper cells to tolerance induction.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1986

Increased number of Leu-2-bearing non-T cells with natural killer activity in chimpanzees.

Peripheral blood lymphocytes from adult and adolescent chimpanzees, as well as adult humans, were studied for phenotypic surface markers by flow cytometry. Lymphocytes from chimpanzees were found to have increased numbers of Leu-1-, Leu-2+ cells as compared to humans. These cells, following preparative electronic cell sorting, were shown to possess natural killer function. Further analysis of this subpopulation indicated that they lacked responsiveness to a number of T-cell mitogens. The differences in lymphocyte subpopulations between chimpanzees and humans can almost be totally accounted for by the Leu-1-, Leu-2+ cells. Phylogenetic disparity between these two species may also be found within this population.

Animals↗
PubMed1986

Immunoregulatory disorders associated with hereditary angioedema. II. Serologic and cellular abnormalities.

Hereditary angioedema is defined biochemically by a deficiency in the functional activity of the inhibitor of Cl, Cl esterase inhibitor (Cl INH). Deficiency of this regulator of the early classic pathway of complement results in chronic activation of this cascade with a resultant deficiency of C4 and C2. Ninety-seven patients with either complicated (associated with autoimmune disorders) or uncomplicated hereditary angioedema were evaluated for laboratory evidence of immunoregulatory defects. Specific cellular and humoral abnormalities were found and included increased mean total lymphocyte counts, increased mean Leu 4+ (total) and Leu 3+ (helper) T cells, an increased mean Leu 3/Leu 2 (helper/suppressor T cell) ratio, polyclonal B cell activation, and evidence of circulating immune complexes. C4 functional titers were negatively correlated with percent Leu 3+ cells and absolute Leu 3+ cell numbers. We failed to detect any evidence of immune deficiency in this population, and yet a statistically significant number of patients demonstrated elevated levels of antibodies to Epstein-Barr virus antigens when patients were compared to a control group. Thus, early classic complement pathway activation and/or partial complement component deficiency may effect T cell subpopulations and B cell activation. However, additional predisposing factors (e.g., genetic or viral) appear necessary for the development of a particular autoimmune disease in hypocomplementemic patients.

Adolescent↗
PubMed1986

Increased amplifier T cell activity in autoimmune NZB mice and its possible significance in the expression of autoimmune disease.

The expression of amplifier- and helper-T cell activity was examined in NZB/N mice of different ages. Amplifier T cell activity develops in a cyclic manner; it decreases between 16 and 35 wk of age and then increases to maximal levels in mice older than 50 wk of age. The loss of suppressor T cell activity and increased amplifier T cell activity coincide with the development of autoimmune diseases in aging NZB/N mice. Although helper T cell activity is evident in young NZB/N mice, it is absent in old NZB/N mice expressing maximal amplifier T cell activity. This provides additional support for the fact that amplifier and helper functions are mediated by different subpopulations of T cells.

Age Factors↗
PubMed1986

Differentiation antigen on murine B lymphocytes defined by monoclonal antibodies.

Spleen cells from an AKR/J X DBA/2J F1 mouse immunized with NZB/BIN spleen cells were fused with SP2/0-Ag14. Two hybrid cell lines, B220-1 and B220-2, were established that secreted antibody to the B-lineage specific B220 antigen. B220-1 and B220-2 are present on 45-55% of splenic and bone marrow lymphocytes and absent from thymus. By flow cytometry, all immunoglobulin-bearing cells were stained by these monoclonal antibodies. Although these monoclonals do not stain thymocytes, they do react weakly with Lyt-2+ peripheral T cells. Dual parameter analysis of B lymphocytes using RA3-3A1 or 14.8 show that these monoclonals recognized the same population. Prior incubation with RA3-3A1 or 14.8 was unable to completely block the binding of B220-1 or B220-2, implying that the epitopes recognized are different from the previously described monoclonal antibodies. Immunoprecipitation of the splenic lymphocyte reveals a molecule which migrates on SDS-PAGE as a single band with MW of 220,000 daltons. Expression of the distinct antigens recognized by B220-1 and B220-2 varied among mouse strains, indicating previously unappreciated polymorphism of the B220 molecule. These monoclonals are useful for cytotoxic elimination of B cells and for three-color flow cytometry.

Animals↗
PubMed1985

Early T lymphocytes. Differentiation in vivo of adult intrathymic precursor cells.

A minor subpopulation of adult murine thymocytes (less than 5%) that is Lyt-2-, L3T4-, and expresses low levels of Ly-1 (designated dLy-1 [dull] thymocytes) has been identified, isolated, and characterized. This study assesses the differentiation potential of dLy-1 thymocytes in the thymus in vivo. Using multiparameter flow cytometry, radiation chimeras of C57BL/6 mice congenic at the Ly-1 or Ly-5 locus, and allelic markers to discriminate host and donor, we showed that transferred dLy-1 cells were able to generate thymocytes expressing both cortical and medullary phenotypes in a sequential manner. The proportion of donor-derived thymocytes obtained was directly related to the number of dLy-1 thymocytes transferred. Transfer of purified Lyt-2+ or Lyt-2+ + L3T4+ thymocytes, which constitute greater than 94% of total thymocytes, failed to generate any donor-derived thymocytes in irradiated recipients. Transfer of bone marrow (BM) cells produced the same sequential pattern of differentiation as that produced by dLy-1 cells, but was delayed by 4-5 d. Transferred dLy-1 thymocytes exhibited a limited capacity for self-renewal, and resulted in a single wave of differentiation in irradiated hosts. Thus, thymic repopulation by donor-derived cells after transfer of dLy-1 thymocytes was transient, while repopulation by BM was permanent. These findings suggest that the isolated dLy-1 thymocytes described herein are precursor thymocytes that represent a very early stage in intrathymic development.

Animals↗
PubMed1985

Selective elimination of lymphocyte subpopulations by monoclonal antibody-enzyme conjugates.

A novel method for the selective depletion of lymphocyte subpopulations has been developed. Conjugates of glucose oxidase (GOx) and phospholipase-C (PL-C) coupled to a monoclonal mouse anti-rat IgG (MAR) were shown to be selectively cytotoxic for targeted lymphocyte subsets in the presence of various rat monoclonal antibodies directed toward murine cell surface antigens. The ability of both conjugates to bind specifically to rat monoclonal antibodies was demonstrated by flow cytometry. The PL-C-MAR conjugate was more stable than the GOx-MAR conjugate. The PL-C conjugate, in conjunction with primary rat anti-mouse monoclonal antibodies, produced selective killing of T or B cells as detected by a loss of proliferative capacity in response to mitogens and by specific cell depletion demonstrated by flow cytometry. Normal mouse serum protected against the cytotoxicity of free enzymes but had no protective effect on enzyme conjugates. Because the substrates of these enzymes are abundant in vivo and serum did not interfere with their cytotoxicity, these enzyme-antibody conjugates may be valuable for selective lymphocyte depletion in vivo.

Animals↗
PubMed1985

Analysis of B-cell subpopulations. I. Relationships among splenic xid, Ly 1+, and Lyb 5+ B cells.

The phenotypic and functional relationships among the various B-cell subsets is of importance for better understanding studies of the immune system. In this report, the realm of B cells encompassed by Lyb 5, Ly 1, and xid has been examined through the use of the alloantiserum anti-Lyb 5, the unique functional properties of Ly 1+ B cells, and the spontaneous autoantibody producing congenic xid mice, NZB.xid. By functional and phenotypic analysis, we have shown that (i) Lyb 5- B cells and B cells of xid mice are largely, but not completely, overlapping; (ii) xid spleen cells contain a population which is Lyb 5+; (iii) Ly 1+ B cells fall largely in the Lyb 5+ compartment; and (iv) the autoantibody-producing Ly 1+ B cells are predominantly Lyb 5+.

Animals↗
PubMed1985

Voltage-sensitive cyanine dye fluorescence signals in lymphocytes: plasma membrane and mitochondrial components.

The origin of the cyanine dye fluorescence signal in murine and human peripheral blood leukocytes was investigated using the oxa- and indo-carbocyanines di-O-C5(3) and di-I-C5(3). Fluorescence signals from individual cells suspended with nanomolar concentrations of the dyes were measured in a flow cytometer modified to permit simultaneous four-parameter analysis (including two-color fluorescence or fluorescence polarization measurements). The contributions of mitochondrial membrane potential (psi m) and plasma membrane potential (psi pm) to the total voltage-sensitive fluorescence signal were found to depend on the equilibrium extracellular dye concentration, manipulated in these experiments by varying the ratio of dye to cell density. Hence, conditions could be chosen that amplified either the psi m or the psi pm component. Selective depolarization of lymphocytes or polymorphonuclear leukocytes (PMN) in mixed cell suspensions demonstrated that defining the partition of dye between cells and medium is requisite to assessing the heterogeneity of cell responses by cyanine dye fluorescence. At extracellular dye concentrations exceeding 5 nM in equilibrated cell suspensions, both mitochondrial and plasma membrane dye toxicity were observed. In murine splenic lymphocytes, plasma membrane toxicity (dye-induced depolarization) was selective for the B lymphocytes. Certain problems in calibration of psi pm with valinomycin at low dye concentrations and perturbations of psi pm by mitochondrial inhibitors are presented. These findings address the current controversy concerning psi m and psi pm measurement in intact cells by cyanine dye fluorescence. The finding of selective toxicity at low cyanine dye concentrations suggest that purported differences in resting psi m among cells or changes in psi pm with cell activation may reflect variable susceptibility to dye toxicity rather than intrinsic cell properties.

B-Lymphocytes↗
PubMed1985

Lymphocyte membrane potential and Ca2+-sensitive potassium channels described by oxonol dye fluorescence measurements.

A method is described for quantitative measurement of lymphocyte transmembrane electrical potential difference (psi) by flow cytometric recording of the oxonol dye fluorescence of single cells. Both the simultaneous collection and analysis of multiple optical parameters and the use of a negatively charged oxonol probe allowed more accurate measurement of psi than may be obtained by bulk cell suspension techniques employing cationic voltage indicators. Mouse spleen and human blood lymphocyte psi was calculated to be -70 mV. T and B lymphocytes maintain a constant psi as extracellular K+ is varied from 2 to 10 mM and the deviation from K+ equilibrium potentials (EK) is shown to result from Na+ permeability. At [K+]o values greater than 10 mM, lymphocytes behave as K+ electrodes. Examination of lymphocyte subsets showed that hyperpolarization induced by the Ca2+ ionophore A23187 occurs only in T cells. This response was identified as activation of a Ca2+-sensitive K+ channel by pharmacologic manipulations. Hence, T cells depolarized by 4-aminopyridine (4-AP, 10 mM) were observed to return to resting psi by A23187-induced elevation of [Ca2+]i. Cells depolarized by quinine (100 microM) were unaffected by A23187. The Ca2+-activated channel does not contribute to resting psi in T cells since it may be selectively blocked by quinine (20 microM) or modulated by calmodulin antagonists (5 microM trifluperazine) without affecting resting psi.

4-Aminopyridine↗
PubMed1985

Cellular distribution of a human I-A-like (DS/DC) antigen on normal and neoplastic lymphoid cells.

Previous biochemical studies have shown that B cell specific, monoclonal antibody, McAb 33.1, reacts with a class II antigen that represents a human analogue of murine I-A (DS/DC) antigens (J. Exp. Med. 158:1924, 1983). McAb 33.1 recognizes a polymorphic human B lymphocyte specific antigen present on mu+, B1+ peripheral B cells, B lymphoid cell lines, activated B cells, and neoplastic B lymphoid cells. Of 100 HLA-D/DR typed EBV-transformed lymphoblastoid cell lines tested, only those from DR3,3 and DR7,7 individuals failed to react with McAb 33.1. The 33.1 antigen is present at lower concentrations on B cells from blood, tonsil, spleen, and lymph node when compared to B cell lines. By contrast, the antigen is not detectable on blood T lymphocytes, T cell lines, or mitogen activated T cells and it is absent on monocytes of some individuals or is present only on a minor subpopulation (approximately 20%). McAb 33.1 should facilitate the functional, structure, and molecular dissection of the human Ia system.

Animals↗
PubMed1985

Systemic lupus erythematosus: delineation of subpopulations by clinical, serologic, and T cell subset analysis.

Patients with systemic lupus erythematosus (SLE) (n = 194) were analyzed for correlation of clinical features. In addition, the proportions of the two major T cell subsets were determined in 87 subjects. Two patient subgroups were discerned: one in which severe renal disease, leukopenia, and thrombocytopenia predominated, and a second in which sicca syndrome and involvement of the central nervous system, lungs and muscle occurred. The ratio of T helper/inducer to T suppressor/cytotoxic cells was reduced in the first group and increased in the second. We conclude that SLE does not comprise a single disease entity, but rather represents a number of syndromes with overlapping clinical features. The correlation of clinical symptoms with the proportions of circulating T cell subsets suggests that several immunologic mechanisms may underlie the various types of SLE.

Adult↗
PubMed1985

Proliferation of infected lymphoid precursors before Moloney murine leukemia virus-induced T-cell lymphoma.

NFS/N mice inoculated with Moloney murine leukemia virus (M-MuLV) developed T-cell lymphoma after a 10-week latent period. Expression of lymphoid differentiation antigens, appearance of M-MuLV-encoded cell surface antigens, and rates of cellular proliferation were measured in splenic and bone marrow subpopulations during this latent period. At 2 weeks of age, Thy-1-and surface immunoglobulin-negative null cells of spleen and bone marrow expressed M-MuLV antigens whereas T- and B-lymphocytes did not. During the 3d and 4th weeks, the number of splenic null cells increased to six times the number found in uninfected controls. These null cells included the precursors of lymphocytes and hematopoietic cells. For the remainder of the latent period, the percentage of null cells undergoing proliferation was three times greater in the infected mice, while the total number of null cells remained constant. This proliferation was not accompanied by terminal differentiation or emigration of mature cell types from the spleen. Proliferation was substantially delayed in CBA mice, which are resistant to lymphoma induction.

Animals↗
PubMed1985

Two defects in old New Zealand Black mice are involved in the loss of low-dose paralysis to type III pneumococcal polysaccharide.

Treatment of normal mice with a subimmunogenic dose of type III pneumococcal polysaccharide (SSS-III) results in the development of an antigen-specific state of unresponsiveness termed low-dose paralysis. This unresponsiveness is mediated by T suppressor cells and can be transferred by Lyt-2+ T cells, but not by L3T4+ T cells, obtained 18 hr after priming. As autoimmune New Zealand Black (NZB) mice age, there is a progressive decrease in low-dose paralysis to SSS-III. The defect in older NZB mice resulting in decreased suppressive activity was investigated by transferring primed Lyt-2+ T cells from young into old mice, and vice versa. Enlarged Lyt-2+ T cells from old NZB mice could not suppress the SSS-III response of young recipients. However, Lyt-2+ T cells of normal cell size were efficient in inhibiting the antibody response upon transfer. Primed Lyt-2+ T cells from young NZB mice did not affect the response of old recipients, but effectively suppressed the response of young mice. These results suggest that there are two defects involved in the decline of low-dose paralysis to SSS-III in aging NZB mice: Enlarged Lyt-2+ T cells may lose their ability to function as mediators of suppression; and B cells may become resistant to T cell-mediated suppression.

Aging↗
PubMed1985

Comparison of response to stem cell differentiation signals between normal and autoimmune mouse strains.

Normal DBA/2 and autoimmune NZB mice were studied with regard to signals eliciting differentiation and division of bone marrow stem cells. Irradiated (NZB X DBA/2)F1 mice were repopulated with various combinations of T-depleted bone marrow from NZB and DBA/2 mice. In response to the repopulation signal of irradiation, recipients of autoimmune NZB marrow initially demonstrated expansion of LY-5+ lymphoid and hemopoietic cells, particularly of the B cell lineage. The greater the proportion of NZB marrow, the higher the percentage of lymphoid cells observed 2 wk post-repopulation. B cells (ThB-positive cells) were increased in disproportionate numbers in recipients of NZB marrow, even those that had received as little as 20% NZB bone marrow cells. However, by 2 mo, the initially observed increase in lymphoid cells in recipients of NZB marrow was no longer observed. Up to 6 mo post-repopulation, cytogenetic analysis revealed that irradiated recipients were repopulated in the same proportion of DBA/2: NZB as was in the injected marrow. Endogenous colony formation assays indicated that recipients of 100% NZB, 80% NZB, and 20% NZB marrow all had greater numbers of splenic endogenous colonies than did recipients of DBA/2 marrow alone. These studies indicated that autoimmune NZB marrow repopulated irradiated mice in the proportion in which it was injected, but there was a disproportionate early increase in cells of the B lineage as well as a disproportionate increase in splenic colony formation.

Animals↗