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Biomedical subjects

D M Knowles

Publications and source records attributed to D M Knowles.

At least 199 records · Page 11Linked to original sources
PubMed1984

A membrane antigen (HC1) selectively present on hairy cell leukemia cells, endothelial cells, and epidermal basal cells.

A monoclonal antibody (alpha HC1) raised against HCL cells reacted specifically with HCL cells and not with other normal or leukemic B cell types. It also reacted with BC and with vascular EC. One case of Kaposi's sarcoma, a tumor thought to derive from EC, was also stained by this antibody. Sinusoidal cells of liver and spleen and EC in the brain did not stain with alpha HC1, but EC from all other tissues and EC in culture were positive. Because the exact normal cell equivalent of the leukemic hairy cell is unknown, similarities in phenotype and function between EC and hairy cells are of particular interest.

Antibodies, Monoclonal↗
PubMed1983

Reactivity of monoclonal antibodies Leu 1 and OKT1 with malignant human lymphoid cells. Correlation with conventional cell markers.

This study delineated the distribution of reactivity of malignant human lymphoid cells with monoclonal antibodies Leu 1 and OKT1, and correlated this expression with that of conventional lymphoid cell markers. The presence of Leu 1 on benign lymph nodal T-cells and its absence from benign lymph nodal B-cells was confirmed. Twenty-two T-cell neoplasms, expressing a variety of intrathymic and mature peripheral phenotypes, expressed Leu 1, but this expression was heterogeneous with respect to percent-positive cells and antigenic density, and appeared to correlate with stages of T-cell differentiation. This study demonstrated the expression of Leu 1 by 33 of 36 cases of B-CLL, by 10 of 15 cases of the closely allied small lymphocytic cell lymphoma, and by 9 of 29 follicular center-cell lymphomas. This included B-cell malignancies of each surface immunoglobulin isotype, and some cases associated with a monoclonal protein spike. Leu 1 was not expressed by myeloma plasma cells, and was absent from non-B, non-T acute lymphoblastic leukemia cells in each of 15 cases studied. Finally, Leu 1 and OKT1 were expressed in parallel, with respect to percent-positive cells and staining intensity, on benign and malignant T-cells, and on malignant B-cells, wherever studied. Possible explanations for this shared antigen are the existence of a minor Leu 1+ B-cell subset, a transformation-associated event, or glycosylation.

Antibodies, Monoclonal↗
PubMed1983

Identification of T lymphocytes in ocular adnexal neoplasms by hybridoma monoclonal antibodies.

We performed indirect immunofluorescence with the OKT series of hybridoma monoclonal antibodies in order to determine the total number of T cells and their subset distribution, that is, the percentages of helper (OKT3+T4+T8-) and suppressor/cytotoxic (OKT3+T4-T8+) T cells, in 28 ocular adnexal lymphoid neoplasms. OKT3+T4+ (helper) T cells vastly predominated in each of ten benign, polyclonal ocular lymphoid proliferations. The helper-suppressor T-cell ratio (T4-8) ranged from 2.5 to 8.2 (mean, 5.4) in these ten cases. In comparison, the mean T4-T8 ratio in 24 benign reactive lymph nodes was 3.4. These findings strongly suggested that the polyclonal ocular lymphoid proliferations represent a T-cell antigen-dependent response characterized by a proliferation of helper T cells, which in turn drive B cells to proliferate and to differentiate, eventually resulting in the formation of a clinically detectable tumor. The mean T4-T8 ratio was 2.3 in 18 ocular and in 16 nodal monoclonal B-cell proliferations, suggesting that the benign T cells in these proliferations represent a residual cell population rather than a distinctive subset originating in response to the B-cell neoplasm.

Antibodies, Monoclonal↗
PubMed1983

The immunologic and ultrastructural characterization of the cellular infiltrate in acute cardiac allograft rejection: prevalence of cells with the natural killer (NK) phenotype.

The inflammatory cell infiltrates in 15 endomyocardial biopsies serially obtained from a human cardiac allograft during a 1 1/2-year period were characterized. An indirect immunofluorescent technique with hybridoma-derived monoclonal antibodies which preferentially react with B lymphocytes (anti-Ia), mature T cells (OKT3, Leu 1), and helper (OKT4b,d) and supressor/cytotoxic (OKT8) T-cell subsets and with natural killer cells, macrophages, and granulocytes (OKM1) was used. During each of seven rejection episodes the overwhelming majority of infiltrating cells in the endomyocardial biopsy were OKM1+Ia. These cells displayed short microvilli, a moderate amount of cytoplasm, numerous mitochondria, a large amount of rough endoplasmic reticulum, Golgi, and an indented nucleus, that is, the ultrastructural features of large, granular lymphocytes. Thus, they morphologically and phenotypically resemble those lymphoid cells which have been shown to possess natural killer (NK) functions in man. Occasional Leu 1+OKT3+ cells, some of which were OKT8+, were also seen during acute rejection. In each instance following therapy and resolution of the rejection episode only rare OKM1+Ia- cells were present. At this time the majority of the cells were Leu 1+OKT3+OKT8+. Routine biopsies, performed at times without evidence of rejection, showed only reactivity for Ia antigens by the capillary endothelium. These studies demonstrate the prevalence of cells with the natural killer phenotype in this human cardiac allograft during episodes of acute graft rejection.

Acute Disease↗
PubMed1983

Human sympathetic ophthalmia. An analysis of the inflammatory infiltrate by hybridoma-monoclonal antibodies, immunochemistry, and correlative electron microscopy.

A case of human sympathetic ophthalmia, enucleated after surgical trauma, was studied by means of hybridoma-derived monoclonal antibodies, histochemistry, and transmission electron microscopy. The choroidal infiltrate was composed predominantly of T-lymphocytes of the suppressor/cytotoxic subset (OKT8+); only 5% of the cells were immunoglobulin-producing B-lymphocytes (kappa or lambda light chain positive), thereby explaining the well-known paucity of plasma cells in the infiltrate. The epithelioid cells and phagocytic histiocytes in the choroid were la+ and OKM1+, antigenic determinants specific for bone marrow-derived monocytes, and their cytoplasms exhibited histochemical reactivity for alpha-1-antichymotrypsin and lysozyme. Ultrastructurally, the choroidal epithelioid cells contained single melanin granules in the cytoplasm, but these were membrane-bound and frequently associated with lysosomal material, features militating against these cells being transformed choroidal melanocytes. By means of immunologic and ultrastructural analysis, the Dalen-Fuchs nodules were found to be composed of a mixture of histiocytes (la+ and OKM1+) and depigmented retinal pigment epithelial cells (la- and OKM1-); the latter cells focally formed desmosomes and displayed inclusions of lipofuscin. Scattered within the Dalen-Fuchs nodules were small numbers of T-lymphocytes of the suppressor/cytotoxic subset. We have concluded that the uveitis and retinal pigment epithelial changes are mediated by a T-cell, delayed hypersensitivity pathogenetic mechanism (cell-mediated immunity), possibly directed at surface membrane antigens that may be shared by photoreceptors, retinal pigment epithelial cells, and choroidal melanocytes.

Animals↗
PubMed1983

A new human B-lymphocyte surface antigen (BL 2) detectable by a hybridoma monoclonal antibody: distribution on benign and malignant lymphoid cells.

A hybridoma-derived monoclonal antibody, produced by immunization with the Burkitt's tumor-derived B-lymphoblastoid cell line, B35M, was previously shown to detect a 68,000 dalton surface membrane protein, BL2, on the surface of peripheral blood B cells, which is absent from thymocytes, T cells, and granulocytes. In this study, we investigated the expression and distribution of BL2 on benign and malignant human lymphoid cells. Indirect immunofluorescent assay with this monoclonal antibody demonstrated that BL2 is expressed by cells within the fetal liver and by a variable proportion of lymph node, tonsil, and spleen B cells, but not by T cells. The neoplastic cells isolated from 18 T-cell malignancies were BL2- . BL2 was was heterogeneously expressed by a variable proportion of the malignant cells in 29/32 cases of B-chronic lymphocytic leukemia and 33/38 cases of B-cell lymphomas, but appeared to be lost in the terminal stages of B-cell differentiation, as myeloma plasma cells were BL2- . BL2 expression was not limited to B cells of a particular surface immunoglobulin isotype. Immunofluorescent staining for BL2 in cryostat tissue sections demonstrated that the majority, but not all, germinal center and interfollicular Ia+ (non-T) cells are BL2+. These findings suggest that BL2 is a B-cell lineage-specific differentiation marker that may be useful in the study of B-cell ontogeny and in defining subgroups of the B-cell malignancies.

Antibodies, Monoclonal↗
PubMed1983

The application of monoclonal antibodies to the characterization and diagnosis of lymphoid neoplasms: a review of recent studies.

Twenty-three T-cell neoplasms were divided, according to their reactivity with the OKT monoclonal antibodies as follows: Fourteen neoplasms of diverse histopathology expressed the OKT3+ OKT4+ phenotype, commonly associated with the helper T-cell subset; seven histologically similar lymphoblastic neoplasms expressed diverse phenotypes consistent with various stages of intrathymic differentiation and two neoplasms expressed the uncommon OKT3+ OKT10+ phenotype. Thus, T-cell neoplasms are divisible into phenotypes that correspond to normal stages of T-cell differentiation and functionally distinct T-cell subsets. Benign and malignant lymphoid cells were investigated in cell suspension and in cryostat tissue sections for their reactivity with OKB1, OKB2, OKB4, and OKB7, monoclonal antibodies known to detect distinctive B lymphocyte antigens. Fetal liver pre-B cells, cases of pre-B acute lymphoblastic leukemia, and common-type acute lymphoblastic leukemia were OKB2+ but unreactive with the other OKB antibodies. All mature lymphoid tissue B cells and 47/47 surface immunoglobulin (SIg)-positive B-cell neoplasms were OKB2+. Interfollicular, follicular center, and many, but not all, mantle zone B cells were OKB1+ OKB7+. Follicular center B cells were OKB4+ but mantle zone and interfollicular B cells were OKB4-. 45/47 SIg+ B-cell neoplasms were OKB1+ OKB4+. 45/46 SIg+ B-cell neoplasms were OKB7+. Benign and myeloma plasma cells were OKB-. T-cell neoplasms were OKB2- OKB4- but were occassionally OKB1+ and OKB7+. The OKB antibodies appear to detect distinctive antigens that may be expressed at different stages of B-cell differentiation.

Animals↗
PubMed1982

The immunologic characterization of 40 extranodal lymphoid infiltrates: usefulness in distinguishing between benign pseudolymphoma and malignant lymphoma.

In the studies described here, 40 extranodal lymphoid tumors obtained from 38 patients were evaluated by cell-marker analysis and the results correlated with the light microscopic features. These infiltrates were investigated for the present composition of cells expressing Ia antigens, surface immunoglobulin (SIg), including kappa and lambda light chains, sheep erythrocyte (E) rosette formation, and acid a-naphthyl acetate esterase (ANAE) activity. Fifteen biopsy specimens consisted of variable proportions of benign T and polyclonal B cells; these 15 lesions had the histopathologic features of benign pseudolymphomas. The remaining biopsy specimens consisted almost entirely of B cells bearing monoclonal SIg (18 cases) or a great preponderance of T cells (five cases) or non-B, non-T (null) cells (two cases); these 25 lesions were classified histopathologically as malignant lymphomas. Thus, the extranodal lymphoid infiltrates were divisible, according to their cell-marker characteristics, into two categories: lesions that are immunologically polyclonal and lesions that are immunologically monoclonal B-cell proliferations or consist of a great preponderance of T or null cells. In each case, polyclonality correlated with benign cytomorphologic features and monoclonality correlated with malignant histopathology. Cell-marker analysis appears to represent an important adjunct to light microscopy in distinguishing histologically problematic benign pseudolymphomas from malignant lymphomas that arise in the extranodal tissues. Cell marker analysis will undoubtedly provide insights into the histogenesis, natural history, and biologic behavior of the extranodal lymphoid neoplasms not attainable using light microscopy alone.

Adult↗
PubMed1982

Ocular adnexal lymphoid tumors. Correlative ultrastructural and immunologic marker studies.

Twenty-two ocular adnexal lymphoid infiltrates were analyzed by electron microscopy as well as immunologically and cytochemically. Five reactive polyclonal lesions were found to be preponderantly composed of small mature lymphocytes (presumably T cells) with clumped nuclear chromatin, sparse cytoplasmic organelles, and numerous monoribosomes. In 11 monoclonal B-cell lesions, both the 1-micrometer plastic sections examined by light microscopy and the electron micrographs disclosed immature cells, with more dispersed nuclear chromatin, prominent nucleoli, abundant cytoplasmic polyribosomes, and increased numbers of mitochondria and strands of endoplasmic reticulum particularly in plasmacytoid lesions). The remaining six monoclonal B-cell lesions were composed of comparatively well-differentiated cells requiring electron microscopy to show somewhat more prominent nucleoli, slightly less dense clumping of the nuclear chromatin, increased numbers of mitochondria and short segments of rough-surfaced endoplasmic reticulum, and monoribosomes rather than polyribosomes. The importance of distinguishing this group of well-differentiated monoclonal lesions from the less well-differentiated ones was underscored by the results of the follow-up examinations, in that no evidence of extraorbital disease has been discovered in the former group, while a 50% incidence occurred in the latter.

Adolescent↗
PubMed1982

Phenotypic heterogeneity of human T-cell malignancies: demonstration by monoclonal antibodies and cytochemical markers.

The present study sought to delineate the phenotypic heterogeneity of the human T-cell malignancies. Twenty T-cell neoplasms were investigated for reactivity with the OKT hybridoma monoclonal antibodies and expression of acid alpha-naphthyl acetate esterase (ANAE), beta-glucuronidase (BG), and acid phosphatase (AP) activity. Twelve cases (Mycosis fungoides, Sezary syndrome, cutaneous T-cell lymphoma, chronic lymphocytic leukemia) were OKT3'T4', ie, expressed the phenotype commonly associated with mature T-helper cells. These cases were further divisible into ANAE+BG+ (6 cases), ANAE-BG+ (5 cases), and ANAE-BG- (1 case) phenotypes. In contrast to the 12 OKT3+T4+ cases, the remaining 8 cases showed considerable inter- and intratumor heterogeneity with respect to reactivity with the OKT antibodies. Six of these cases (acute lymphoblastic leukemia, lymphoblastic lymphoma) expressed phenotypes consistent with various intrathymic stages of T-cell differentiation. Five of the latter 6 cases were AP+BG+ANAE-, analogous to the majority of normal cortical thymocytes; an OKT3+T4-T8+T10+ neoplasm was ANAE+, analogous to normal medullary thymocytes. Two cases expressed the previously undescribed OKT3+T4-T8-T10+ phenotype. These studies demonstrate that the T-cell malignancies are divisible into phenotypes which correspond to normal maturational stages of T-cell differentiation and functionally distinct T-cell subsets. Phenotypic analysis of the human T-cell malignancies may provide a basis for understanding their biological heterogeneity and may aid in the identification of transitional stages of T-cell differentiation and minor T-cell subsets.

Adolescent↗
PubMed1982

The expression of surface antigen Leu 1 by ocular adnexal lymphoid neoplasms.

Leu 1 is a surface membrane antigen expressed by benign systemic T cells, most cases of B-cell-derived chronic lymphocytic leukemia, and approximately one half of the systemic B-cell lymphomas. Benign systemic B cells are Leu 1-. Our studies showed that the percentage of Leu 1+ cells was essentially the same as the percentage of OKT3+E+ (T) cells in six ocular adnexal pseudolymphomas, strongly suggesting that the benign B cells in these lesions were similarly Leu 1-. These studies also showed that malignant B cells in six of 15 (40%) ocular B-cell lymphomas were Leu 1+. Thus, the expression of Leu 1 by some malignant ocular adnexal B cells but not by benign ocular adnexal B cells appears to be analogous to the situation for lymph nodal and other systemic B cells. Although the explanation for the existence of this shared determinant is unknown, Leu 1 expression may possess clinical and diagnostic significance as a marker of neoplastic B cells.

Antigens, Neoplasm↗
PubMed1982

Ocular adnexal lymphoid neoplasms: clinical, histopathologic, electron microscopic, and immunologic characteristics.

Clinicopathologic analysis of 400 ocular adnexal lymphoid neoplasms has demonstrated that the orbital lymphoid neoplasms occur primarily in the sixth and seventh decades of life; that their benignancy or malignancy is generally indistinguishable clinically; that the orbital malignant lymphomas are most commonly small cell lymphomas; that the orbital "histiocytic" lymphomas almost always represent an anomalous deposit of disseminated lymphoma; and that the percentage of patients with orbital lymphoma who develop systemic disease varies with the histopathology: two thirds of cases of poorly differentiated lymphocytic lymphomas, as defined cytomorphologically, have associated systemic disease. Prospective correlative clinicopathologic and immunologic analysis of 25 cases has shown that cell marker analysis divides the ocular adnexal lymphoid infiltrates into immunologically polyclonal proliferations, which show diverse but benign histopathologic features, and immunologically monoclonal B cell proliferations, which have the histologic features of malignant lymphomas. The benign, polyclonal ocular pseudolymphomas recapitulate the cell marker profile of a benign reactive lymph node with similar variations in the T cell:B cell ratio. The ocular adnexal and nodal B cell lymphomas are analogous in that they most commonly express surface IgM heavy chains and kappa light chains, express Ia antigens in parallel with SIg, and occasionally contain neoplastic B cells at various developmental stages--i.e., Ia+SIg+ and Ia+SIg-. Correlative immunologic and ultrastructural studies have demonstrated that electron microscopy is a reliable and reproducible technique for indirectly assessing the mono- or polyclonality of an ocular adnexal lymphoid neoplasm. This study is focused on the use of hybridoma-derived monoclonal antibodies, which are capable of detecting maturational stages of B and T cell differentiation and functionally distinct T cell subsets, in order to investigate the interactional and immunoregulatory defects that participate in the generation of the ocular adnexal lymphoid proliferations.

Alkaline Phosphatase↗
PubMed1982

OT-CLL: a human T cell chronic lymphocytic leukemia that produces IL 2 in high titer.

This report identifies and describes a human T cell chronic lymphocytic leukemia, OT-CLL, which can be triggered by selected mitogens (either PHA or Con A) to produce IL 2 in high titer. Optimal IL 2 production requires culturing OT-CLL cells at 2 to 5 X 10(6)/ml for 24 hr in the presence of 1 to 2% PHA-M. Under these conditions, the titer of IL 2 generated is greater than 20-fold that obtained from conventional sources, e.g., from mitogen-activated tonsillar lymphocytes. Two lines of experimental evidence suggest that the tumor cell product(s) is IL 2. First, in functional assays, suprenatants derived from cultures of PHA-activated OT-CLL cells trigger the proliferation and long-term growth of IL 2-dependent human TCL cells. Second, a partial biochemical purification of the active moiety(ies) derived from OT-CLL demonstrates marked similarity to conventional human IL 2. Thus, the biologically active material(s) precipitates in 50 to 70% saturated (NH4)2 SO4 solutions; elutes from DEAE-Sepharose in the presence of 0.04-0.08 M NaCl; and has an apparent m.w. of approximately 14,000, as determined by Sephadex G-100 gel filtration. In addition, analysis of OT-CLL cells by indirect immunofluorescence, utilizing a panel of monoclonal antibodies, confirms not only that these tumor cells are of T cell lineage but that they display surface antigens that define the normal human peripheral T cell subset subserving helper or inducer function: OKT3+, OKT4+ , OKT8-.

Cell Count↗
PubMed1982

Human T-cell malignancies: Correlative clinical, histopathologic, immunologic, and cytochemical analysis of 23 cases.

Twenty-three T-cell neoplasms were investigated for their reactivity with the OKT monoclonal antibodies and expression of certain cytochemical markers. Fourteen neoplasms with diverse histopathologic features, T-cell chronic lymphocytic leukemia, mycosis fungoides, the Sézary syndrome, T-immunoblastic sarcoma, and a pleomorphic large-cell lymphoma, expressed the T helper cell phenotype, OKT3+T4+. Nine other neoplasms displayed marked inter- and intra- tumor heterogeneity. Seven of these cases, lymphoblastic lymphoma, T-cell acute lymphoblastic leukemia, and tumors with feature of T-immunoblastic sarcoma or the multilobated lymphoma of Pinkus, expressed intrathymic phenotypes. The other 2 cases, a lymphoblastic lymphoma and a so-called Lennert's lymphoma, expressed the previously undescribed OKT3+T10+ phenotype. These studies demonstrate that the T-cell malignancies are divisible into phenotypes corresponding to normal maturational stages of T-cell differentiation and functionally distinct T-cell subsets. Such studies should provide a basis for understanding the biologic heterogeneity, clinical diversity, and significance of the variable cytomorphologic characteristics of T-cell malignant tumors and assist in the further delineation of normal human T-cell heterogeneity.

Aged↗
PubMed1981

Quantitative determination of T cells in ocular lymphoid infiltrates. An indirect method for distinguishing between pseudolymphomas and malignant lymphomas.

T lymphocytes may be identified by two comparatively simple techniques: sheep erythrocyte (E) rosette formation and cytochemically demonstrable acid alpha-naphthyl acetate esterase (ANAE) activity. We tested the quantitative determination of T cells in 17 ocular lymphoid tumors as an indirect method for characterizing their clonality. Six lesions containing greater than 40% T cells (47% to 73%; mean, 62%) were shown to be polyclonal proliferations and were classified as pseudolymphomas by histologic criteria. Seven lesions containing less than 30% T cells (3% to 20%; mean, 10%) were shown to be monoclonal B-cell proliferations and were classified as malignant lymphomas by histologic criteria. Only two lesions containing between 30% and 40% T cells could not be unequivocally assigned to the monoclonal or polyclonal category solely based on the percentage of T cells. In the final two lesions, the tissue specimen was too small to allow a full panel of immunologic studies; both tumors showed a predominance of T cells consistent with their benign histologic features.

B-Lymphocytes↗
PubMed1981

Induction of lymphocyte differentiation by epidermal cultures.

Human and murine lymphoid cell populations were induced to express terminal deoxynucleotidyl transferase, a marker of early lymphoid differentiation, by exposure to allogeneic or syngeneic epidermal cells. Control growth medium, fibroblasts, or a mammary epithelial cell line did not induce this marker. These findings suggest that epidermal cells can induce lymphoid cell differentiation in vitro.

Animals↗