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Biomedical subjects

M Jondal

Publications and source records attributed to M Jondal.

At least 181 records · Page 10Linked to original sources
PubMed1976

In vivo and in vitro selection of mitogen responsive lymphocytes in patients with chronic lymphocytic leukemia.

The in vitro mitogen response of blood lymphoid cells from patients with chronic lymphocytic leukemia was observed to be low compared to lymphocytes from healthy subjects. However, highly responsive cells could be separated from the blood of such patients by a buoyant density centrifugation technique and such reactive cells were found to be enriched by treating the patients with chemotherapy or splenic irradiation.

Adult↗
PubMed1976

Antibody-dependent cellular cytotoxicity (ADCC) against Epstein-Barr virus-determined membrane antigens. I. Reactivity in sera from normal persons and from patients with acute infectious mononucleosis.

The capacity of antibodies, directed against EBV-determined membrane antigens (MA), to induce antibody-dependent cellular cytotoxicity (ADCC) against EBV superinfected lymphoid cell lines was investigated. Such reactive antibodies were found, at high dilutions, in sera from normal EBV-positive persons but not in sera from EBV-negative persons. Sera from patients with acute infectious mononucleosis (IM), which develop EBV-specific killer T cells, did not induce ADCC. The difference in specificity between ADCC and EBV-specific killer T cells is briefly discussed.

Antibodies, Viral↗
PubMed1975

Antibody-dependent cell-mediated cytotoxic activity in syngeneic moouse ascites tumors.

Eight different syngeneic murine ascites tumor preparations were tested for their ability to lyse antibody-coated chicken erythrocytes in an assay for antibody-dependent cell-mediated cytotoxicity (ADCC). All of the tumor preparations demonstrated significant ADCC effector activity, even at effector-cell:target-cell ratios of less than 1:1. In contrast, none of eight in vitro murine tumor-cell lines showed any consistent ability to function as ADCC effector cells. Several cell fractionation experiments were performed to ascertain the nature of the effector cells in the ascites tumors. Adherent cells were removed from tumor preparations by passage of cells over columns of Degalan plastic beads and 19S Fc-receptor-bearing cells were removed by sedimentation of EA rosette-forming cells. Although each of these procedures depleted only a minority of the total cells, all the ADCC activity was simultaneously removed in each case. Depletion of phagocytic cells by treatment of tumor preparations with carbonyl iron and magnetism only slightly diminished the ADCC activity. These results indicate that the ADCC activity associated with ascites tumors is due to effector cells most probably of host origin, but possibly representing an atypical sub-population of tumor cells. The characteristics of the effector cell closely parallel those defined for the major non-phagocytic ADCC effector cell in normal mouse spleen and peritoneal exudate.

Animals↗
PubMed1975

Classification of lymphocytes in nasopharyngeal carcinoma (NPC) biopsies.

Seven biopsies taken from nasopharyngeal carcinoma tissues were analyzed with regard to infiltrating B or T lymphocytes. The vast majority of these cells had the capacity to form SRBC rosettes (mean 87%) and were thus classified as T cells. Varying proportions of these were blast-transformed suggesting that they represented a host response against the tumor.

B-Lymphocytes↗
PubMed1975

Surface markers on human b and t lymphocytes. VI. Cytotoxicity against cell lines as a functional marker for lymphocyte subpopulations.

The spontaneous lymphocyte mediated cytotoxicity (SLMC) of cells from normal donors against 19 different established cell lines was analysed. All normal lymphocytes were cytotoxic in all combinations tested in a17h 51-Cr release assay. ALMC was found to be mediated by a minor subpopulation of lymphocytes with Fc/C3 receptors. Non-cytotoxic SRBC binding T-lymphocytes could be induced to become cytotoxic by the addition of Con A to the incubation medium. SLMC and lectin-induced cytotoxicity were briefly characterized. It is argued that SLMC is a non-specific non-immunological reaction which must be taken into consideration when lymphocytes from cancer patients are tested against tumour-cell lines in vitro. Futhermore, SLMC and letin-induced cytotoxicity are proposed as functional markers for Fc/C3-binding lymphocytes and SRBC binding lymphocytes respectively.

Azides↗
PubMed1975

Cytotoxic effector cells specific for B Cell lines transformed by Epstein-Barr virus are present in patients with infectious mononucleosis.

Peripheral lymphoid cells, from 12 cases of acute infectious mononucleosis (IM), were tested in a micro chromium-51 release assay for cytotoxic activity against a variety of cell lines that did or did not carry the Epstein-Barr virus (EBV) genome. Unfractionated lymphocytes from these patients were cytotoxic to both types of cell lines, as were lymphocytes from healthy individuals. If, however, lymphocytes bearing complement receptors were removed, the residual IM lymphocyte fraction was specifically cytotoxic for EBV-genome-carrying cell lines. The residual lymphocyte fraction in normal donors had no such effect. Heterophile-positive IM is caused by EBV, and these results indicate that, during the acute phase of this disease, patients harbor killer cells, probably T cells, which specifically kill EBV-genome-carrying B cells in vitro. No such specificity for EBV-genome-psitive target cells was found in normal lymphocytes stimulated in vitro with autologous EBV-genome-positive lymphoblastoid cells. Such stimulated cells were highly cytotoxic to both genome-positive and negative lines after removal of complement receptor-positive lymphocytes.

Cell Line↗
PubMed1975

Surface markers on human B and T lymphocytes. VII. Rosette formation between peripheral T lymphocytes and lymphoblastoid B-cell lines.

Almost 100% of peripheral T lymphocytes are shown to have the capacity to form rosettes with human lymphoblastoid B-cell lines, predominantly at 4 degrees C and with lines having surface-bound IgG. Blast-transformed T cells retained this capacity and formed rosettes even at 37 degrees C. Unstimulated T cells bound less readily to B-cell blasts, stimulated by pokeweed mitogen for 72 hr. Even though rosettes, formed at 4 degrees C, were stable for several hours at 37 degrees C, no T-cell-mediated cytotoxicity could be detected during overnight incubation. Extreme pH values and trypsinization decreased rosette formation, whereas neuraminidase treatment enhanced the reaction. Rosette formation was independent of bivalent cations and unimpaired in the presence of inhibitors (NaF, NaN3), undiluted human or fetal calf sera, protein A, sonicated sheep erythrocyte membranes, and normal or heat-aggregated human IgG. Anti-Ig, anti-beta2-microglobulin, or anti-T cell sera did not influence rosette formation.

Animals↗
PubMed1975

Stimulation of normal lymphocytes with autologous lymphoid cell lines: properties of derived killer cells.

Lymphocytes from normal adults, with or without serological signs of previous Epstein-Barr virus (EBV) infection, could be stimulated to proliferate and produce killer cells by incubation with autologous EBV-genome-positive lymphoid cell lines (LCLs). The stimulated cells were most probably of T-cell origin, although at the peak of stimulation many of them lacked the sheep erythrocyte marker. Direct effector-target cell contact was necessary for lysis to occur. The cytotoxicity of autologously stimulated (AS) lymphocytes was not restricted to EBV-genome-positive LCLs, nor to cell lines of hematopoietic origin. It was equally broad if cells carrying complement receptor had been removed before stimulation. Fresh lymphocytes, blasts induced by phytohemagglutinin or concanavalin A, and Burkitt's lymphoma biopsy cells were resistant or considerably less sensitive. Mouse cells--even cell lines--were resistant. The sensitivity of target cells to lysis correlated positively with their capacity to block AS lymphocyte lysis of autologous LCLs in competition experiments. The cytotoxicity of AS lymphocytes was blocked by EBV-genome-positive and -negative cell lines, whereas the EBV-related cytotoxicity of T cells from acute cases of infectious mononucleosis was blocked by EBV-genome-positive LCL only.

Animals↗
PubMed1975

Cytotoxic lymphocytes from normal donors. A functional marker of human non-T lymphocytes.

A phenomenon we have termed spontaneous lymphocyte-mediated cytotoxicity (SLMC) by non-thymus-derived lymphocytes from normal donors has been described. The phenomenon can be demonstrated using human and xenogeneic (mouse) cell lines as the target cell in a microplate 51Cr release assay which is simple and reproducible. In this paper, SLMC against xenogeneic targets has been evaluated as a potential marker of lumphocytotoxic function with respect to: (a) the nature of the target cell; (b) the variability of the cytotoxic function of lymphocytes from different donors, and from the same donor tested on different days; (c) the nature of the effector cell. Using buoyant density centrifugation of iron plus magnetpurified lymphocytes forming rosettes with sheep red blood cells (SRBC) (T-cells) or SRBC-rabbit 19S anti-SRBC-mouse complement (complement receptor lymphocyte), it has been demonstrated that the cytotoxic activity lies in the non-T-lymphocyte fraction, and is probably caused by the complement receptor-bearing lymphocyte. The potential usefulness of this phenomenon as a functional marker of non-T-LYMPHOCYTE CYTOTOXIC Ability, and for the assessment of serological factors ehich may affect this cytotoxicity, has been discussed.

Animals↗
PubMed1974

Continuous lymphoid cell lines with characteristics of B cells (bone-marrow-derived), lacking the Epstein-Barr virus genome and derived from three human lymphomas.

Three exceptional cell lines have been tested for the presence of the Epstein-Barr virus genome by nucleic acid hybridization (complementary RNA.DNA) and Epstein-Barr virus-determined nuclear antigen tests. Two lines were derived from Swedish lymphoma cases and one from an African Burkitt-like lymphoma biopsy that was negative for Epstein-Barr virus DNA and the virus-determined nuclear antigen. All three lines apparently lacked the viral genome. Two of the three lines clearly had characteristics of B-cells (bone-marrow-derived).

Antigens, Viral↗
PubMed1973

Surface markers on human B and T lymphocytes. II. Presence of Epstein-Barr virus receptors on B lymphocytes.

Human peripheral lymphocytes were investigated for receptors binding Epstein-Barr virus (EBV) because of the regular association of this virus with infectious mononucleosis and Burkitt's lymphoma. This was done by a cytoadherence technique where virus-producing cells, displaying fresh viral determinants in their cytoplasmatic membrane, were mixed with lymphocytes. Unfractionated lymphocytes were found to adhere to these cells in contrast to column-purified T lymphocytes. The specificity of the binding was confirmed by blocking experiments that showed that sera containing high titers of antibodies directed against the virus could partially inhibit the adherence in contrast to low-titer sera. It is concluded that B lymphocytes, in contrast to T lymphocytes, have receptors for EBV. In a second line of experiments it was found that established human lymphoblastoid lines that carry the EBV genome had receptors characteristic for B lymphocytes and did not form T-lymphocyte rosettes. In contrast, a line of known T-lymphocyte origin that did not carry the EBV genome had receptors characteristic for T lymphocytes. EBV-transformed simian lymphoblastoid lines had surface markers indicating a B-lymphocyte origin in contrast to HVS-transformed simian lines that lacked surface immunoglobulin but carried receptors for sheep red blood cells.

Animals↗