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Biomedical subjects

M A Bean

Publications and source records attributed to M A Bean.

At least 19 recordsLinked to original sources
PubMed1995

Detection of maternal cells in human umbilical cord blood using fluorescence in situ hybridization.

Cord blood is a potential source of hematopoietic stem cells for transplantation and is being used on a growing number of patients. However, there are concerns that cord blood might be contaminated with maternal cells that could lead to graft-versus-host disease. To ascertain the extent to which maternal cell contamination of cord blood occurs, we examined 49 cord blood samples from male babies for maternal cells by fluorescence in situ hybridization using probes to the X and Y chromosomes. A minimum of 1,000 nuclei were scored from each sample, and maternal cells were found in 7 of the 49 cord bloods, at levels ranging from 0.04% to 1.0%. In addition, in 39 and 27 of the cord blood samples, respectively, we examined the CD8+ and CD34+ cell populations for maternal cells. Maternal cells were found in 5 of the 39 CD8 fractions and in 1 of the 27 CD34 fractions, at levels similar to that found in the unfractionated cord blood. In sum, maternal cells were found in either the unseparated mononuclear fraction or the CD8 or CD34 fractions in 10 of the 49 cord blood samples (20%). These results show that maternal cells are present in a substantial number of cord bloods, and that some of these maternal cells are T cells.

Antigens, CD↗
PubMed1991

Prevention of transfusion-induced sensitization to minor histocompatibility antigens on DLA-identical canine marrow grafts by gamma irradiation of marrow donor blood.

Dogs given total-body irradiation and marrow transplants from DLA-identical littermates exhibit prompt and sustained hematopoietic engraftment. However, animals given three preceding blood transfusions from the marrow donor before transplant become sensitized and reject the marrow graft. Rejection is due to exposure to polymorphic minor non-DLA histocompatibility antigens expressed on blood mononuclear cells. We sought to determine whether heat treatment would prevent blood from sensitizing recipients in this model since heating blood to 45 degrees C for 45 min abrogates the ability of blood mononuclear cells to stimulate in mixed lymphocyte culture. Three of 4 evaluable dogs given heat-treated blood before transplant rejected their marrow grafts. To prevent possible reexpression/reacquisition of mononuclear cell functional activity in vivo after transfusion, subsequent dogs were given heated blood that was additionally exposed to 2000 cGy gamma irradiation. Eight of 10 evaluable dogs given blood treated in this fashion engrafted. Unexpectedly, 9 out of 10 evaluable dogs transfused with blood treated only with gamma irradiation also engrafted. These results demonstrate that treatment of blood with gamma irradiation alone or in combination with heat prevents transfusion-induced sensitization to minor histocompatibility antigens. Results from this canine model suggest that blood products be gamma irradiated before transfusion in patients who are transplant candidates in order to prevent sensitization to minor histocompatibility antigens and reduce the risk of marrow graft rejection.

Animals↗
PubMed1990

Suppressed antidonor MLC responses in renal transplant candidates conditioned with donor-specific transfusions that carry the recipient's noninherited maternal HLA haplotype.

Forty-seven patients with end-stage renal disease were entered into a donor-specific transfusion protocol consisting of three infusions of whole blood every two weeks prior to transplantation. Fourteen of the patients became sensitized following transfusion and were not transplanted. Thirty-one patients received a transplant from the DST donor and have an estimated two-year graft survival of 97%, three-year survival of 88%, and four-year survival of 69%. Cells of eleven of the 36 recipients tested in one-way MLC before and two weeks after completion of DST exhibited a significantly decreased antidonor MLC response. Deletion of CD8+ positive lymphocytes from suppressed MLCs resulted in restoration of antidonor MLC reactivity in four of six patients. An analysis of the family HLA profile in patients exhibiting a decreased donor-directed MLC response revealed a significant (P less than 0.02) association between decreased MLC reactivity following DST and the expression of noninherited maternal HLA antigens by cells of the transfusion donor. These alterations in cellular immune responses noted in some patients following DST are consistent with the appearance of specific antidonor T suppressor cells as a result of donor-specific transfusion.

Blood Transfusion↗
PubMed1989

Detection of somatic mutations at the glycophorin A locus in erythrocytes of atomic bomb survivors using a single beam flow sorter.

A modified method was developed for measuring the frequency of variant erythrocytes at the glycophorin A locus using a single beam cell sorter (SBS). Fluorescein- or phycoerythrin-labeled monoclonal antibodies specific for the M or N glycophorin A alleles were used for the SBS assay. To prevent contamination of nucleated cells in the sorting windows, the nucleated cells in the fixed erythrocyte sample were stained with propidium iodide before flow sorting. Blood samples were obtained from atomic bomb survivors who were heterozygous for the MN blood type, and the frequencies of the hemizygous and homozygous variant of the M or N glycophorin A allele were measured by the SBS. For the three types of variants, hemizygotes for M and N allele (Nø and Mø) and homozygotes for M allele (MM), the variant frequency measured by the SBS correlated well with that previously determined by a dual beam cell sorter. Variant frequencies of the Nø, Mø, and MM cell types in atomic bomb survivors determined by SBS measurements were found to increase with radiation dose (DS86, kerma) as well as with the frequency of chromosome aberrations in lymphocytes.

Alleles↗
PubMed1989

Tubuloreticular structures and cylindrical confronting cisternae: a review.

Tubuloreticular structures (TRS) and cylindrical confronting cisternae (CCC) are unique subcellular structures that arise from the membranes of the rough endoplasmic reticulum of a variety of cell types. In vivo, they occur most frequently in endothelial cells and lymphocytes from patients with autoimmune diseases and viral infections; they are seen in these cells in almost all acquired immunodeficiency syndrome (AIDS) patients. The inducer(s) of TRS and CCC in vivo is (are) not firmly established. However, clinical and experimental studies indicate that the occurrence of these structures in these diseases is directly related to the endogenous elevation of alpha- and beta-interferon but not to gamma-interferon. Although CCC have been seen and reported to occur in human and primate cells since the late 1970s, their presence did not arouse much clinical and scientific interest until 1983 when they were observed in lymph node tissues of AIDS patients. The nature and pathogenesis of TRS and CCC are obscure. Through the years, many hypotheses have been proposed. They range from suggestions of these structures being incomplete viral particles to being nothing more than accumulated proteins; and from reference to these structures as specific markers for diseases to a generalized cell reaction to certain biological stimuli. In vitro investigations with lymphoblastoid cell lines have contributed a great deal in illuminating the potential clinical significance and the in vivo inducer(s) of TRS and CCC. Both the TRS and CCC are now known to be induced in vitro by alpha- and beta-interferon in some lymphoblastoid cell lines. However, only TRS and not CCC are induced in healthy donor lymphocytes and endothelial cells. Isolation of TRS and CCC using the lymphoblastoid cell system will help clarify the nature, the pathogenesis, and the importance of TRS and CCC in human diseases.

Acquired Immunodeficiency Syndrome↗
PubMed1988

Propagation and characterization of human blood basophils.

Basophils were isolated and propagated in large numbers from the blood of patients with chronic myelogenous leukemia. Propagation over 4-6 weeks of culture was dependent upon a growth factor(s) other than interleukin-2 obtained from a lectin-stimulated clone of the Jurkat cell line. Evidence that these basophils were dividing during culture included an increase in both the number of basophils and the histamine content of the cultures over time, as well as ultrastructural studies that demonstrated basophil cell division. The cells also had the capacity to be stimulated in an IgE-dependent manner characteristic of basophils. Cultured basophils passively sensitized with IgE underwent noncytotoxic degranulation after stimulation with specific antigen. Antigen-stimulated basophils released histamine, leukotrienes B4 and C4 and other 5-lipoxygenase products of arachidonic acid metabolism. Culture models such as this may permit the propagation and purification of sufficient numbers of basophils to allow biochemical and immunological analyses of basophil physiology.

Arachidonic Acid↗
PubMed1987

Perioperative blood transfusion does not increase the risk of colorectal cancer recurrence.

An adverse relationship between perioperative blood transfusions and the risk of subsequent recurrence of cancer was reported recently. We reviewed retrospectively the records of 171 patients who received initial therapy for colorectal adenocarcinoma from 1977 to 1979 at the Virginia Mason Medical Center. One hundred three patients (60%) received transfusions within 1 month of surgery and 37 patients (22%) developed recurrent cancer. No overall relationship between transfusion status (yes or no) and tumor recurrence or patient survival was found, although among subsets of patients (those with colon cancer or Dukes' Stage C2 disease), patients who had received transfusions were less likely to develop recurrent cancer than patients who had not (P = 0.01). No effect of transfusion on patient survival was found, even after consideration of potential confounding variables. The conflicting data regarding blood transfusion and cancer recurrence are reviewed, but it would appear to be premature to alter radically current blood transfusion practices based on the possibility that transfusion may adversely influence the risk of cancer recurrence.

Actuarial Analysis↗
PubMed1987

Evidence for increased somatic cell mutations at the glycophorin A locus in atomic bomb survivors.

A recently developed assay for somatic cell mutations was used to study survivors of the atomic bomb at Hiroshima. This assay measures the frequency of variant erythrocytes produced by erythroid precursor cells with mutations that result in a loss of gene expression at the polymorphic glycophorin A (GPA) locus. Significant linear relations between variant frequency (VF) and radiation exposure were observed for three different variant cell phenotypes. The spontaneous and induced VFs agree with previous measurements of radiation-induced mutagenesis in other systems; this evidence supports a mutational origin for variant cells characterized by a loss of GPA expression and suggests that the GPA assay system may provide a cumulative dosimeter of past radiation exposures. VFs for some survivors differ dramatically from the calculated dose response, and these deviations appear to result primarily from statistical fluctuations in the number of mutations in the stem-cell pool. These fluctuations allow one to estimate the number of long-lived hemopoietic stem cells in humans.

Antibodies, Monoclonal↗
PubMed1986

Antigen-specific functions of a CD4+ subset of human T lymphocytes with granular morphology.

We previously showed that a small proportion of the CD4+ human lymphocytes express the C3bi receptor (CD11). In the present investigation these cells were found to have the homogeneous morphology of granular lymphocytes. Between 70 and 80% of the cells reacted with antibody Leu-7, but they did not express Fc receptors and had no spontaneous cytotoxic activity against the NK-sensitive cell line K562. The CD11+/CD4+ cells uniformly expressed CD3 and could be induced to express IL 2 receptors by activation with PHA or anti-CD3 antibody. Compared with unfractionated T cells, however, CD11+/CD4+ granular lymphocytes had a reduced ability to produce IL 2 after stimulation with PHA or anti-CD3 antibody. Nevertheless, the CD11+/CD4+ subset generated specific allocytotoxicity after stimulation with allogeneic cells and culture in IL 2. Furthermore, the CD11+/CD4+ cells also proliferated after stimulation with tetanus toxoid and PPD. Thus some cells of the CD11+/CD4+ subset are capable of antigen-specific responses. These results indicate that certain CD11+ cells with granular morphology are mature T lymphocytes.

Antigens↗
PubMed1986

Helper (OKT4) T cells from human T cell colonies produce potent colony-stimulating activity.

Confluent T cell colonies were grown by culturing blood mononuclear cells in double agar layers containing autologous plasma and phytohemagglutinin (PHA) for one week (37 degrees C, 5% CO2). The plates were then overlaid with serum-free alpha medium which was harvested after 24 h. This medium was demonstrated to have colony-stimulating activity (CSA) of greater potency than conventionally prepared PHA-leukocyte conditioned medium, which was prepared by incubating cells from the same donors. Removal of OKT4-positive cells using a monoclonal antibody and complement abolished CSA production by cells from T cell colonies while the removal of OKT8-positive cells had no effect.

Antibodies, Monoclonal↗
PubMed1985

Monoclonal antibody 9.3 and anti-CD11 antibodies define reciprocal subsets of lymphocytes.

We have previously described antibody 9.3 which recognizes a 44-kDa polypeptide designated Tp44 expressed on 70-80% of peripheral blood T cells, including nearly all CD4+ cells and some CD8+ cells. Whereas the 9.3+ population contains helper cells, cytotoxic T cell precursors and cytotoxic T cell effectors, the 9.3- population has been reported in several models to contain precursors for suppressor cells. In this report, we demonstrate that 9.3- lymphocytes express CD11, an antigen which is also present on monocytes and granulocytes. Among lymphoid cells, Tp44 and CD11 represent markers that identify reciprocal, nonoverlapping subsets, each of which contains both CD8+ cells and CD4+ cells. With Tp44 and CD11, and CD4 and CD8, the development and function of T cells can thus be examined within the framework of two distinct systems of reciprocally expressed antigens.

Antibodies, Monoclonal↗
PubMed1983

The cell surface phenotype of a naturally occurring human suppressor T-cell of restricted specificity: definition by monoclonal antibodies.

A series of murine monoclonal antibodies was used to characterize the surface phenotype of a naturally occurring E+ B14-specific suppressor cell present in the blood of a patient with recurrent superficial bladder carcinomas. This suppressor T cell is different from the few naturally occurring suppressors of MLC reported by others in that its function does not require HLA-D compatibility with the cells being suppressed. This patient's T cells had decreased proportions of T3+, 10.2+, 9.3+, and T4+ cells, a normal proportion of T8+ cells, and a markedly increased proportion of Ia-positive cells. The MLC-suppressor assay was used to test the functional activity of cell populations selectively depleted by treatment with monoclonal antibodies and C or enriched by panning. The B14-specific suppressor T cells in this patient expressed T cell markers recognized by monoclonal antibodies 9.6, T3, and the T cell subset marker identified by OKT8 (T8+) but not the subset marker identified by OKT4 (T4-). Ia antigens were present on a substantial portion of these suppressor T cells. Thus, this unique, naturally occurring suppressor T cell has a phenotype similar to that of other T suppressor cells in humans, adding validity to the concept of functionally distinct T cell compartments in human blood.

Antibodies, Monoclonal↗
PubMed1983

Suppression of the responsiveness of lymphocytes from cancer patients triggered by co-culture with autologous tumor-derived cells.

The question as to whether or not cancer patients have "tumor antigen"-induced suppressor T cells is of considerable interest and importance. As an approach to that question, the effect of addition of autologous irradiated tumor-derived cells (TDC) on the mixed lymphocyte response (MLR) of patients' lymphocytes (Ly) and of healthy donor Ly was tested. The rationale for these experiments was based on the fact that circulating antigen-responsive blood lymphocytes can be reactivated in vitro by exposure to the appropriate antigen. Thus, if there are circulating tumor "antigen"-reactive suppressor Ly, exposure to TDC as a source of the antigen should reactivate those cells. Reactivation of suppressor cells might result in diminished responsiveness to other stimuli such as alloantigens in the mixed leukocyte culture. We found that the addition of TDC to Ly cultures produced four distinct patterns of reaction. In 26 of the 74 different patient-tumor assays, the addition of autologous TDC to the patient cultures inhibited MLR, but the addition of the same TDC to cultures of Ly from healthy donors had no effect or increased their responsiveness (Specific Suppression). In 21 cases, the addition of autologous TDC to the patient cultures suppressed the MLR and the addition of the same TDC to control cultures suppressed the response of some but not all the healthy donors (Selective Suppression). In four cases, the addition of TDC to the cultures suppressed the MLR of the patients and all of the control donors (Nonspecific Suppression). In 23 cases, the addition of autologous TDC resulted in no suppression of the patient MLR or of any of the simultaneously tested normal donors (No Suppression). When TDC of patients with noninvasive bladder cancer were added to their own Ly cultures, only four of 11 produced specific or selective suppression compared to 11 of 12 when TDC came from patients with superficially invasive cancer. These data provide indirect evidence to support the hypothesis that human tumors induce circulating suppressor cells that may be reactivated in vitro by co-culture with TDC.

Cell Transformation, Neoplastic↗