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Biomedical subjects

H D Flad

Publications and source records attributed to H D Flad.

At least 235 records · Page 13Linked to original sources
PubMed1978

[The cellular immune status in normal subjects, patients with and without neoplasms].

The distribution of lymphatic subpopulations in the peripheral blood of patients with malignant solid tumors has been studied in two steps. Firstly, it was investigated whether there are changes in the distribution of blood lymphoid cell populations in tumor patients (n = 101) compared to normal individuals (n = 39) and whether there is a correlation between the distribution pattern and the clinical stage of the disease. There was found a significant reduction of T-lymphocytes in patients with cancer, which was marked in the advanced tumor disease (n = 34). In a further step the influence of curative tumor-resection on the lymphatic subpopulations was studied, when 26 operated tumor patients were compared with 23 operated patients without neoplasia. In the group with non-malignant diseases there could not be found a significant pre- and postoperative difference concerning the T- and B-lymphocyte counts. Tumor patients showed after resection of the tumor a significant increase of the absolute and relative number of preoperatively reduced T-lymphocytes. The pathophysiological possibilities for the phenomena of a reversible reduction of T-lymphocytes by the curative resection of the tumor are discussed.

Cell Count↗
PubMed1978

[Quantitative and functional response of a lymphatic subpopulation during adjuvant intermittent chemo-immunotherapy in breast cancer].

In this study, an attempt was made to describe and evaluate in vitro immune parameters in patients with breast cancer undergoing modified radical mastectomy and adjuvant chemoimmunotherapy. T and B lymphocytes and their in vitro functions were markedly reduced by intermittent combination chemotherapy with adriamycin and cyclophosphamide. Laevamisole was not found to influence immune parameters, neither when given between chemotherapy treatments nor when given after chemotherapy. Lymphocytes expressing Fc receptors and mediating antibody-dependent cell-mediated cytotoxicity were less affected and were even found to be elevated in some patients prior to initiation of therapy. Whether or not antibody-dependent cell-mediated cytotoxicity plays a role in patient defense against tumors remains to be investigated.

Antibody-Dependent Cell Cytotoxicity↗
PubMed1978

Expression and specificity of FcIgG receptor sites on neoplastic lymphocytes.

We investigated the ability of an FcIgG receptor marker to discriminate between subtypes of malignant lymphoproliferative diseases that differed in their clinical presentations. A quantitative radioimmuno assay was established that enabled us to evaluate average receptor densities on a population basis. Surface receptors were first saturated with IgG complexes. The number of membrane associated IgG molecules was subsequently determined with 125I-staphylococcal protein A. Results obtained with this assay on a battery of malignant lymphocytes suggested that the range of receptor densities of malignant B and T cells might overlap each other but would correlate with the degree of tumor cell differentiation and the clinical stage of the underlying disease. This behavior limits the use of this marker in the characterization of the derivation of malignant lymphocytes; these findings, however, may be useful in the prognostic classification of lymphomas of known origin.

Binding Sites, Antibody↗
PubMed1978

Promotion of L1210 tumour growth by macrophages.

Low numbers (10(4)) of peritoneal exudate L1210 mouse lymphoma cells were injected into DBA/2 mice subcutaneously and the development of tumours was followed. Tumour takes occurred in 100% of the animals within 9 days after tumour transplantation. The latent period of tumour development was prolonged by 6-10 days when tumour cells of the peritoneal exudate, depleted of adherent/phagocytic cells, were used in the inoculum or when tumour cells derived from continuous cell cultures were used. Addition of adherent cells in high numbers to in-vitro-derived L1210 cells accelerated tumour growth. This effect was found to be not specific for adherent/phagocytic cells, as liver cells had the same influence on tumour growth. It is concluded that, under certain experimental conditions, a cell population with the functional properties of macrophages is able to promote tumour development, most likely due to their non-specific effect on the micro-environment of the growing tumour.

Animals↗
PubMed1977

The role of fetal calf serum in the primary immune response in vitro.

The mode of action of 2-mercaptoethanol (2-ME) on the primary immune response in vitro was investigated. Fetal calf serum (FCS) was preincubated with 2-ME and lyophilized to remove free 2-ME. This 2-ME-treated FCS was able to substitute the function of adherent cells in the primary immune response against sheep red blood cells (SRBC) in vitro; Fractionation of 2-tme-treated FCS on a Sephadex G-100 column showed that 2-ME acted on a high molecular serum component which after activation, could substitute for macrophages. In order to obtain a humoral immune response against SRBC in vitro, spleen cells require selected FCS. These "good" sera could be distinguished from "deficient" sera by their higher content of this 2-ME-activated factor. The height of the in vitro immune response to SRBC was dependent on the amount of activated factor added to the culture medium. FCS normally required in the culture medium could be completely replaced by the factor-containing fraction without deleterious effect on the culture medium. The factor should be added to the spleen cells during the first 24 h of culture and remain there for 72 h in order to obtain an optimal immune response. The factor could be partially absorbed by spleen cells but not by SRBC. The relationship between macrophage, 2-ME, and FCS in eliciting an in vitro primary immune response is discussed.

Antibody Formation↗
PubMed1977

K cell activity of normal and chronic lymphocytic leukaemia lymphocytes: association with lymphocytes bearing receptors for human C3b.

Blood lymphocytes of patients with chronic lymphocytic leukaemia (CLL) and of normal individuals were depleted of EAC3b- or EAC3d-rosette-forming cells (RFC), respectively and assayed for K-cell activity in a system measuring antibody-dependent-cell-mediated cytotoxicity (ADCC). K-cell activity was found to be associated with a cell population bearing receptors for C3b.

Antibody-Dependent Cell Cytotoxicity↗
PubMed1977

Humoral primary immune response in vitro in a homologous mouse system: replacement of fetal calf serum by a 2-mercaptoethanol or macrophage-activated fraction of mouse serum.

The primary immune response in mouse spleen cell cultures against heterologous red cell antigens is dependent on the medium being supplemented with selected batches of fetal calf serum. Mouse serum itself is not able to support this response. The active immune response-supporting component in fetal calf serum seems to be a distinct factor (s), which has been partially purified by Sephadex G-100 filtration and termed MaSF-2-mercaptoethanol-activated serum factor. In this report it is demonstrated that MaSF is also present in mouse serum. For functional detection, mouse MaSF has to be separated from higher m.w. inhibitors, and has to be activated by 2-ME. After separation and activation mouse MaSF can support the primary immune response in a completely homologous in vitro culture system. Evidence is presented that MaSF can also be activated by macrophages. It is concluded that macrophages and 2-ME have the same mode of action in the primary immune response in vitro, i.e., induction of lymphocyte competence by activation of a serum factor.

Animals↗
PubMed1976

Polyclonal stimulation of lymphocytes by macrophages.

To analyze the interaction between macrophages and splenic lymphocytes with reference to time and concentration, the Mishell-Dutton system was divided into two experimental steps. Step 1 consisted of the cocultivation of spleen cells with various doses of macrophages for different periods of time, while in step 2 macrophages were removed, spleen cells transferred to fresh petri dishes and cultivated until plaque assay. Cocultivation of spleen cells with high doses of macrophages for 4--8 h markedly enhanced the DNA synthesis and plaque-forming cell (PFC) response of sheep red blood cell-stimulated and unstimulated cultures. A cocultivation longer than 24 h resulted in an inhibition of both DNA synthesis and PFC response of spleen cells. These studies suggest a nonspecific function of macrophages on proliferation and differentiation processes in antibody formation.

Animals↗
PubMed1976

A case of impaired chemotaxis and lymphocyte transformation.

The report describes the clinical syndroms of a 14-year-old boy which suffered from recurrent infections since early infancy. The clinical and general laboratory findings were similar to "the granulomatous disease of childhood" as described by Bridges et al. (8). The following serum factors were determined: Immunoglobulins, complement factors, isoagglutinins. The following assays with normal or patient's granulocytes were done: Chemotactic activity, nitroblue-tetrazolium test, bactericidal assay, fungicidal assay, myeloperoxidase, monocytes fungicidal assay. Immunological studies include kinetics of phytohaemagglutinin response, effect of serum of the patient on lymphocytic reactivity in vitro and skin tests. The following results were obtained: 1) Assays with normal or patient's granulocytes showed an impaired chemotatic activity, when serum of the patient was added. There was strong indication by treatment of the patient with plasma infusions, that the chemotactic defect is a serum dependent factor. 2) It could be demonstrated that the patient's serum also inhibited the response of lymphocytes to tuberculin and phytohaemagglutinin. Therefore the patient report focuses attention upon the possibility of serum related abnormalities that may influence granulocytic as well as lymphocytic functions leading to recurrent bacterial, fungal and viral infections.

Adolescent↗
PubMed1976

Adjuvant and suppressor activity of the polycation protamine hydrochloride in the primary immune response of mice.

The effect of protamine hydrochloride (PH), a polycation, on the primary immune response of mice to sheep red blood cells (SRBC) was studied. Like other adjuvants, PH enhances or depresses the immune response depending on the time of injection of PH in relation to the antigenic challenge. The suppressive effect of PH correlated with the appearance of "activated" macrophages in the peritoneal cavity. A second injection of PH together with antigen abolished this suppressive effect. Transfer of "activated" macrophages resulted in an enhanced immune response when antigen was administered at the time of transfer, and in a depressed response when the antigen was given 1 or 2 days after transfer. It is concluded that the duration of the influence of "activated" macrophages on T or B cells determines the subsequent immune reactivity. It is discussed that the basic mechanism of action of PH is its ability to release lysosomal enzymes from macrophages. The mechanism by which these enzymes amplify the immune response remains to be clarified.

Adjuvants, Immunologic↗