Concanavalin A receptors on the surface membrane of lymphocytes from patient's with Hodgkin's disease and other malignant lymphomas

Molecular Engineering of Near-Infrared Fluorescent Probes for Cell Membrane Imaging

Cell membrane (CM) is a phospholipid bilayer that maintains integrity of a whole cell and relates to many physiological and pathological processes. Developing CM imaging tools is a feasible method for visualizing membrane-related events. In recent decades, small-molecular fluorescent probes in the near-infrared (NIR) region have been pursued extensively for CM staining to investigate its functions and related events. In this review, we summarize development of such probes from the aspect of design principles, CM-targeting mechanisms and biological applications. Moreover, at the end of this review, the challenges and future research directions in designing NIR CM-targeting probes are discussed. This review indicates that more efforts are required to design activatable NIR CM-targeting probes, easily prepared and biocompatible probes with long retention time regarding CM, super-resolution imaging probes for monitoring CM nanoscale organization and multifunctional probes with imaging and phototherapy effects.

Sensitive and Multiplexed SERS Nanotags for the Detection of Cytokines Secreted by Lymphoma

The sensitive and simultaneous detection of cytokines will provide new insights into the physiological process and disease pathways due to the complex nature of cytokine networks. However, the key challenge is the lack of probes that can simultaneously detect multiple cytokines in a single sample. In this contribution, we proposed an alternative approach for sensitive cytokine detection in a multiplex manner by the use of a new set of surface-enhanced Raman spectroscopy (SERS) nanotags. Typically, the newly designed SERS nanotags are composed of gold nanoparticles as the core, tuneable Raman molecules as the reporters, and a thin silver layer as the shell. As demonstrated through rigorous numerical simulations, enhanced Raman signal is achieved due to a strong localization of light in the 0.2 nm thin, optically deep-subwavelength region between the Au core and the Ag shell. Sensitive detection of cytokines is realized by forming a sandwich immunoassay. The detection limit is down to 4.5 pg mL^-1 (S/N = 3). The specificity of the assay is proved as negligible signals were detected for the false targets. Furthermore, multiple cytokines are simultaneously detected in a single assay from the secretion of B-lymphocyte cell line (Raji) after concanavalin A (Con A) stimulation. The results indicate that our method holds a significant potential for sensitive and multiplexed detection of cytokines and offers the opportunity for future applications in clinical settings.

Differences in the binding affinities of dimeric concanavalin A (including acetyl and succinyl derivatives) and tetrameric concanavalin A with large oligomannose-type glycopeptides

Dimeric derivatives of concanavalin A (Con A) such as acetyl- and succinyl-Con A have been used for years as probes of cellular membranes. The altered binding and biological activities of these derivatives relative to native tetrameric Con A have generally been attributed to their reduced valence. However, the present study shows that acetyl- and succinyl-Con A possess lower affinities than tetrameric Con A toward certain oligomannose-type glycopeptides which are found on the surface of cells. It has previously been shown that native tetrameric Con A possesses 5-30-fold enhanced affinities toward Man7-Man9 oligomannose-type glycopeptides, respectively, relative to Man5 and Man6 oligomannose-type glycopeptides [Bhattacharyya, L., & Brewer, C. F. (1989) Eur. J. Biochem. 178, 721-726]. Using titration microcalorimetry and hemagglutination inhibition measurements, methyl alpha-D-mannopyranoside, methyl 3,6-di-O-(alpha-D-mannopyranosyl)-alpha-D-mannopyranoside (which binds with about 60-fold higher affinity than methyl alpha-D-mannopyranoside and is the major Con A binding epitope on oligomannose-type carbohydrates), and a Man5 oligomannose-type oligosaccharide are shown to bind to underivatized dimeric Con A at pH 5.2 and acetyl- and succinyl-Con A at pH 7.2 with affinities equal to those of native tetrameric Con A. However, a mixture of Man7 and Man8 glycopeptides and a Man9 oligomannose-type glycopeptide were shown to bind to underivatized dimeric Con A and acetyl- and succinyl-Con A with affinities only about 2-fold higher than the Man5 oligosaccharide, in contrast to the higher affinities of native tetrameric Con A for these carbohydrates.(ABSTRACT TRUNCATED AT 250 WORDS)

Metal ion binding and conformational transitions in concanavalin A: a structure-function study

The affinity of the lectin Concanavalin A (Con A) for saccharides, and its requirement for metal ions such as Mn2+ and Ca2+, have been known for about 50 years. However the relationship between metal ion binding and the saccharide binding activity of Con A has only recently been examined in detail. Brown et al. (Biochemistry 16, 3883 (1977)) showed that Con A exists as a mixture of two conformational states: a "locked" form and an "unlocked" form. The unlocked form of the protein weakly binds metal ions and saccharide, and is the predominate conformation of demetallized Con A (apo-Con A) at equilibrium. The locked form binds two metal ions per monomer with the resulting complex(es) possessing full saccharide binding activity. Brown and coworkers measured the kinetics of the transition of the unlocked form to the fully metallized locked conformation containing Mn2+ and Ca2+. They also demonstrated that Mn2+ alone could form a locked ternary complex with Con A, and that rapid removal of the ions resulted in a metastable form of apo-Con A in the locked conformation which slowly (hours at 25 degrees C) reverted back to (predominantly) the unlocked conformation. The ability to form either conformation in the absence or presence of metal ions has thus allowed us to explore the relationship between metal ion binding and conformational transitions in Con A as determinants of the saccharide binding activity of the lectin. Based on the kinetics of the transition of unlocked apo-Con A to fully metallized locked Con A, and X-ray crystallographic data, it appears that the transition between the two conformations of Con A involves a cis-trans isomerization of an Ala-Asp peptide bond in the backbone of the protein, near one of the two metal ion binding sites. The relatively large activation energy for the transition (approximately 22 kcal M-1) results in relatively slow interconversions between the conformations (from minutes to days), whereas the equilibria with metal ions and saccharide are rapid. Thus, many metastable complexes can be formed and a variety of transition pathways between the two conformations studied. We have identified and characterized binary, ternary, and quaternary complexes of both conformations of Con A containing Mn2+ and saccharide, and have determined both metal ion and saccharide dissociation constants for all of them, as well as equilibrium and kinetic values for the conformational transitions between them.(ABSTRACT TRUNCATED AT 400 WORDS)

Diminished capping of lymphocytes from pregnant women

The capping of lymphocytes from normal pregnant women is diminished. Decreased capping is observed for both anti-Ig and for Con A receptors. The altered capping response appears between the tenth and the twelfth week of pregnancy. The diminution in capping persists until about 2 weeks after delivery. The possible association between the decreased capping response and the altered immune responses known to occur during pregnancy is discussed. The factors underlying the altered capping response in pregnancy may be related to the factors responsible for the parallel phenomenon in pathological conditions.

Hodgkin's disease: unfolding concepts concerning its nature, management and prognosis

The evolution of our concepts concerning the fundamental nature and natural history of Hodgkin's disease is reviewed. Recent evidence establishes that it is indeed a malignant neoplasm, albeit a curious one, the giant cells of which display aneuploid karyotypes, often with marker chromosomes indicating their clonal derivation, and the functional and surface marker properties of cells of the mononuclear phagocyte series. The disease tends initially to spread by contiguity from one lymph node chain to others with which direct lymphatic channel communications exist. Essentially all patients, even those with limited disease, have some degree of impairment of cell-mediated immunity, apparently due to inhibition of T-lymphocyte function. Lymphangiography, computed tomography, and laparotomy with splenectomy have greatly improved the accuracy of clinical staging. Total lymphoid megavoltage radiotherapy and/or multidrug combination chemotherapy now permit the eradiction of disease of all stages, resulting in a dramatic improvement in prognosis and an increasing frequency of permanent cure of this once inevitably fatal condition.

Cap formation on lymphocytes from patients with leukemic diseases induced by four different lectins

When ficoll purified peripheral blood lymphocytes were treated with fluorescein conjugated lectins from lentils (LCH), castor beans (RCA) and phaseolus coccineus beans (L-and E-PHA) for 15 min and the percentages of the cap forming cells were examined, the values of leukemic lymphocytes were reduced compared to the values obtained with normal lymphocytes. The reduction was more than half in patients with acute and chronic myelogenous leukemia and immunoblastoma, it was only one quarter in patients with chronic lymphocytic leukemia, Hodgkin's disease and lymphosarcoma. The lowest number of cap forming cells was found in lymphoblasts of established lymphoblastoid cell lines. The four different lectins showed nearly the same capacity in the induction of caps. After successive binding, the different lectins showed cocapping on the lymphocyte surface.

Establishment in continuous culture of a new type of lymphocyte from a "Burkitt like" malignant lymphoma (line D.G.-75)

The isolation and establishment in vitro of a hitherto undescribed type of lymphocyte designated D.G.-75 is reported. The original inoculum was derived from the pleural effusion of a child with a primary abdominal lymphoma, which clinically and histologically resembled Burkitt's lymphoma. In addition to the absence of the EBV genome and EBV receptors, this line possesses a number of other properties which distinguish it from previously described lymphoblastoid cell lines. It has different growth characteristics and morphology; does not form EAC or E rosettes (representative of B and T) cell surface markers, respectively); possesses IgM-kappa immunoglobulins on the cell surface (B lymphocyte), has an unusually high cap-forming ability and low agglutinability with fluorescent concanavalin A. One homologue of the No.14 chromosome pair possesses extra chromatin material as revealed on chromosome banding. This abnormal chromosome marker is similar to that described in biopsies and cultured tumor cells from patients with African Burkitt's lymphoma.

Properties of the K562 cell line, derived from a patient with chronic myeloid leukemia

The K562 cell line derived from a CML patient in blast crisis was examined for properties of B and T lymphocytes and cell lines. K562 lacks the B markers of immunoglobulins, Epstein-Barr virus (EBV) genome and associated nuclear antigen, and receptors for EBV. A low proportion of cells from rosettes with sheep erythrocytes, the frequency of which is considerably increased after neuraminidase treatment. Unlike B lines but like T lines, K562 cells are lysed rapidly by C'/Fc receptor-positive human blood leukocytes and do not stimulate MLC reactions. On the other hand, K562 lacks T antigen, high radiosensitivity and sensitivity to growth inhibition by thymidine. The cells do not contain N-APase, an enzyme found in all lines derived from lymphoid cells and in lymphoproliferative diseases. By scanning electron microscopy, K562 cells were seen to be rounded and relatively smooth, with small numbers of short microvilli resembling undifferentiated leukemic cells. A few cells had narrow ridge-like profiles and small ruffles similar to granulocytic leukemic cells. K562 is strongly positive for immunoglobuln Fc receptors and pinocytosis, but does not phagocytose or mediate antibody-dependent phagocytosis or cytolysis. Among histochemical stains, K562 is positive for esterase, lipid, and acid phosphatase. There seems to be no doubt that K562 is not a B cell line. While it has some T cell properties, these are not exclusive. Some of its characteristics indicate that it is probably not lymphoid. Due to its low level of differentiation, its nature cannot be stated with certainty. On the basis of the possible presence of the cellular marker of chronic myeloid leukemia, the Ph chromosome, it may be regarded as belonging to the granulocytic series of cells.

Concanavalin A receptors on the surface membrane of lymphocytes from patients with African Burkitt's lymphoma and lymphoma cell lines

Lymphocytes isolated from the peripheral blood and from tumor tissues of patients with African Burkitt's lymphoma have been studied for cap formation and agglutinability by Concanavalin A (Con A). Peripheral blood from healthy adult persons served as a normal control and blood from patients with carcinoma served as a non-lymphoma control. These studies included 29 patients with Burkitt's lymphoma, 93 with carcinoma, and 105 healthy adult persons, as well as tumor tissues from 13 patients with Burkitt's lymphoma. The great majority of the carcinomas were from the face and neck regions. Lymphocytes from the blood of the majority of patients with Burkitt's lymphoma, as well as those from tumor tissues, exhibited a reduced cap-forming ability (2-6%) and increased Con-A-induced agglutinability compared to lymphocytes from healthy normal donors and from patients with carcinoma, although some of the lymphocytes from patients with carcinoma had a somewhat lower range of cap formation than the lymphocytes from healthy donors. No difference was observed in the interaction with Con A of lymphocytes from the different types of carcinoma studied. Eight lymphoid cell lines were established in our laboratory from the tumor tissues of patients with Burkitt's lymphoma. The cap-forming ability and agglutinability by Con A of these lines was examined and compared to those of the "classical" lymphoma lines: Raji, Daudi and P3HR1. All cell lines exhibited an increased Con-A-induced agglutinability and a reduced cap-forming ability compared to normal lymphocytes, except for P3HR1 cells which exhibited a cap-forming ability of 15-20%. These findings are discussed in relation to the association of the lymphocytes with malignancy and as a possible aid in the differential diagnosis between malignant lymphomas and other diseases.