Ultrastructural localization of antibody by antigen label with peroxidase

Antibody-mediated activation of a defective beta-D-galactosidase. II. Immunological relationship between the normal and the defective enzyme

Two closely related protein antigens were used to study immunogenic competition. Namely, normal β-D-galactosidase of Escherichia coli (Z) and a genetically defective β-D-galactosidase (AMEF) which seems to differ from the normal in one amino acid substitution. A unique characteristic of this pair of antigens is that, although they are indistinguishable in precipitation and absorption tests with antibodies, the enzymatic activity of AMEF is specifically increased several-hundredfold in the presence of antibodies directed against Z. The following results show that Z and AMEF also differ in their immunogenic ability: (a) antibodies directed against Z activated AMEF; antibodies directed against AMEF did not activate, but competed specifically with activating antibodies. (b) Animals immunized with AMEF failed to produce activating antibodies when they were subsequently challenged with Z, although the presence of some cells primed to produce activating antibodies could be demonstrated by adoptive transfer. (c) Animals preimmunized with Z were stimulated in their production of activating antibodies by AMEF challenge, although not as efficiently as with Z. A model explaining these observations by competition for the immunogenic site among antigen-sensitive cells carrying cross-reacting receptors is presented.

The annulate lamellae--from obscurity to spotlight

This review aims to provide a comprehensive and in-depth survey of a cell organelle, the annulate lamellae, that is widely distributed and especially prevalent in both female and male sex cells as well as tumor and cancer cells. The organelle is also present in many somatic cells and plant cells. Emphasis is placed on the contributions that electron microscopy and associated experimental approaches have made in providing information about the distribution, ultrastructure, morphogenesis and relationships of annulate lamellae to other cellular organelles, especially the nuclear envelope and endoplasmic reticulum, as well as cell product. An increasing number of experimental manipulations have recently been shown to alter, either increase or decrease, the amount of annulate lamellae and these studies are explored in depth. Information about the origin and morphogenesis of annulate lamellae in different cells is summarized and extensive coverage is given to several hypotheses about possible annulate lamellae function. A detailed bibliography provides a thorough compilation of research dealing with annulate lamellae. A major goal of this extensive review is to generate increased awareness of, and interest in, this cell organelle for students and investigators of the cell who, by bringing current techniques in cell and molecular biology to bear, might focus and intensify studies on the function of an organelle whose precise role in the cell is presently enigmatic.

Immunoelectron microscopic localization of immunoglobulin in B-cell lymphomas

Subcellular localization of immunoglobulin (Ig) by immunoelectron microscopy was performed on 20 B-cell lymphomas of low- and high-grade malignancy. The efficiency in demonstrating Ig by pre-embedding technique depends on the antibodies used. F(ab')2 fragments of antibodies were more sensitive than both intact polyclonal and monoclonal antibodies in detecting cytoplasmic Ig. With immunoelectron microscopy Ig could be demonstrated in all cell types of B-CLL and LP-immunocytoma, even in some of the small lymphocytes in B-CLL. Thus, the presence of intracytoplasmic Ig has no diagnostic relevance in differentiating B-CLL from LP-immunocytoma. However, the amount of Ig in the tumor cells of LP-immunocytoma seemed to be greater than in B-CLL. Centrocytic lymphoma and centroblastic/centrocytic lymphoma could be differentiated by their different localization of Ig. In centrocytic lymphoma Ig was localized mainly on the surface membrane, whereas in centroblastic/centrocytic lymphoma moderate amounts of Ig could be detected in the rough endoplasmic reticulum and perinuclear space of the centroblasts and in roughly one third of the centrocytes. In malignant lymphomas of high-grade malignancy (ML centroblastic, ML immunoblastic, and ML lymphoblastic) Ig was localized mainly in the rough endoplasmic reticulum and sometimes in the perinuclear space.

Antral gastrin cell hyperplasia in patients with peptic ulcer

The total number of gastrin (G) cells in the stomach was determined by using a histologic counting method and planimetry in ulcerous and nonulcerous patients. The preoperative basal and postprandial serum gastrin values and the gastrin cell mass in the gastrectomy specimen could be compared in 16 surgical patients. There was a significant correlation between the integrated gastrin response to feeding and the total gastrin cell number in the stomach. No correlation was found between the basal serum gastrin level and the total gastrin cell count. A total gastrin cell number higher than 50 million was found in the stomach of three duodenal ulcer patients with preoperative postprandial hypergastrinemia as well as in one patient with normal serum gastrin values. Gastrin cell counts between 6 and 42 million were found in control stomachs and in patients with gastric ulcer. Preoperative feeding tests could be useful to select patients with an elevated antral G cell number.

Hodgkin's disease: ultrastructural localization of intra-cytoplasmic immunoglobulins within malignant cells

An immunoperoxidase technique has been applied to the detection of intracellular immunoglobulins at the light and ultrastructural levels in three untreated cases of Hodgkin's disease. The results are compared with those obtained in three treated cases. In both groups, 20-90% of malignant cells had intra-cytoplasmic immunoglobulins. There was no correlation between the percentage of immunoglobulin-containing cells and the histological type or the stage of the disease. At the ultrastructural level, immunoglobulins were constantly localized on cytoplasmic ribosomes, the later being either free in the cytoplasm or bound to the endoplasmic reticulum and to the external envelope of the perinuclear space. In addition, a very few malignant cells exhibited immunoglobulins within their perinuclear space and their endoplasmic reticulum. These results demonstrate that immunoglobulins in Hodgkin's malignant cells are present on the cellular sites of protein synthesis. They appear to be retained in their cytoplasm, and to be secreted only very occasionally. The significance of these findings as to the cellular origin of malignant cells in Hodgkin's disease is briefly discussed.

Electron microscopic immunohistochemical identification of endothelial cells in the rabbit

Antibody to tissue factor apoprotein was adsorbed against gamma-globulin and coupled to horseradish peroxidase; this complex was applied to various rabbit tissues. The distribution of the peroxidase marker then was observed by electron microscopy. We examined fixed or frozen sections, as well as breis of aorta, vena cava, brain, heart, lung, liver, spleen, kidney, bone marrow, mesothelial gut lining, erythrocytes, and platelets. All endothelial cells that had been exposed to the antibody complex were positive and in all cases only the endothelial cells showed localization of the electron-dense reaction product. Tissues that had been incubated with complexes prepared with gamma-globulin from animals not immunized with tissue factor apoprotein showed no staining. Prior treatment of the tissue with uncoupled anti-tissue factor gamma-globulin blocked binding by the coupled antibody. In blood vessel preparations that had been specifically designed to expose the media to the anti-tissue factor complex, medial smooth muscle cells and connective tissue showed no reaction product. Parenchymal cells of the other other organs mentioned likewise were devoid of reaction product. Similarly, the leukocytes and platelets occasionally observed in vessel lumens showed no evidence of binding. Platelets adhering to arterial subendothelial structure after injury also were unreactive. These findings suggest that in normal rabbits anti-tissue factor-horseradish peroxidase complex combines selectively with endothelial cells.

"A" protein of amyloidosis. Isolation of a cross-reacting component from serum by affinity chromatography

A nonimmunoglobulin protein (A protein) has been isolated from amyloidotic tissue of secondary type. Antisera prepared to this protein identified a cross-reacting substance in the sera of patients with secondary amyloidosis. Sera from 70 persons with amyloidosis, 120 normal adults, 20 aged persons, and 97 patients with chronic diseases were tested for this substance. One hundred percent of secondary amyloid sera had amounts of amyloid serum component detectable by double diffusion in agar, whereas only 19 percent of primary amyloid sera were positive. Approximately 60 percent of rheumatoid sera as well as 60 per cent of sera from aged individuals were positive. Only 3 percent or normal blood donors had detectable amounts of this circulating substance. Isolation of the serum component by affinity chromatography and partial characterization have shown that it is an alpha-globulins with a molecular weight of 100,000-120,000, that it is not related antigenically to immunoglobulin or amyloid P-compoment, and that it has an amino acid analysis that is markedly different from tissue A protein. The possible participation of this substance in the genesis of amyloid is discussed.

Nuclear envelopes. Structure and biochemistry of the nuclear envelope

The ultrastructure of the nuclear evelope is described in various cell types with special emphasis on its pore complexes (p.c.). The architecture of the p.c. is defined against the properties of other membranous pore formations. Evidence is presented that the non-membranous p.c. components contain ribonucleoproteins but do not represent the attachment sites of nuclear chromatin. The possible dynamic nature of the p.c. material is discussed in relation to nucleocytoplasmic translocation processes. DNA of the nuclear genome is firmly attached to interporous sections of the inner nuclear membrane. The stability of this attachment is demonstrated, and chemical and conformational characteristics as well as periods and kinetics of replication are given for both isolated membrane DNA and the corresponding chromatin in situ . The membrane-associated chromatin is dominated by a heterochromatinous character; it does not represent a transitory membrane interaction of replicating DNA. It is hypothesized that membraneattachment of specific regions of the chromosomes are a means to their ordered arrangement during interphase and prophase. Structure, lipid, protein and enzyme pattern of the nuclear membranes, as well as the incorporation kinetics, underline the relationship to the endoplasmic reticulum.

Envelope of mouse mammary tumor virus studied by freeze-etching and freeze-fracture techniques

As part of a study of the cell surface changes associated with the production of murine mammary tumor virus, the structure of the envelope of this virus has been examined by using freeze-fracture techniques. Both fracture and deep-etch surfaces were examined. The fracture faces contain 10-nm spheres comparable to those observed on fractured plasma membranes, although fewer in number. Surfaces exposed by etching possess a highly regular hexagonal array of pits 25 nm apart. By examining freeze-fracture and freeze-etch preparations of virus with ferritin covalently bound to its surface, it has been determined that the surface exposed by etching is the outer surface of the virus. The pitted exterior surface of the mammary tumor virus appears to be a unique surface structure.

Mouse thymus-independent and thymus-derived lymphoid cells. II. Ultrastructural studies

The ultrastructural features of B-, T-, and surface Ig(sIg)-bearing cells have been studied on cell suspensions from lymphoid organs of mice at different stages of immunization. The cells were identified by exposure to rabbit antibodies against mouse-specific lymphocyte antigens (MSLA) or brain-associated theta antigen (BAtheta) for T cells, mouse-specific bone marrow-derived lymphocyte antigens (MBLA) for B cells, and mouse Ig for sIg-bearing cells. The rabbit antibodies fixed on the cell surfaces were detected by peroxidase-labeled sheep anti-rabbit Ig antibodies or by a "bridge" technique using southern bean mosaic virus or bacteriophage T4 as the final markers. In some experiments, short-lived lymphoid cells were labeled in vivo with repeated tritiated thymidine and the ultrastructural detection of their surface antigens was combined with radioautography. MBLA+ lymphoid cells showed a whole range of ultrastructural patterns. Most were small and medium-sized lymphocytes with a clear cytoplasm containing mono- and polyribosomes, but they comprised also blasts and large cells with various amounts of endoplasmic reticulum, as well as plasma cells at different stages of maturation. sIg-bearing cells appeared to be identical with MBLA+ cells, except that sIg was less easily detectable on large blasts, and only very rarely observed on plasma cells. MSLA+ and BAtheta+ cells fell into three categories. One of them (T(1) cells) consisted of small to medium-sized lymphocytes with a clear cytoplasm and few organelles, mostly monoribosomes. A second consisted of large cells (T(2) cells) characterized by numerous polyribosomes often in a "rosette"-like pattern, occasional dark, membrane-bound granules, and a developing "filamentous network." The third, very characteristic type, (T(3) cells) was represented by dark small to medium-sized lymphocytes, usually containing large amounts of closely packed ribosomes and showing a striking accumulation of filamentous network, often condensed in large areas devoid of cell organelles. This filamentous network appeared to correspond to the cytochalasin B-sensitive system of microfilaments found in other cells and considered to be one of the contractile elements of the cell. The T(3) lymphocytes showed frequently vesicles suggestive of a strong pinocytic activity, and assumed a variety of shapes, including uropods. Evidence is presented that T(1) lymphocytes represent "virgin" T cells, T(2) "activated," and T(3) "differentiated" lymphocytes.

The localization of endogenous peroxidase in the lacrimal gland of the rat during postnatal development. Electron microscope cytochemical and biochemical studies

The distribution of endogenous peroxidase activity in the lacrimal gland of the rat during postnatal development was investigated by electron microscope cytochemistry Peroxidase activity is first found 6 hr after birth in only a few acinar cells At this stage, reaction product fills only localized segments of the scant rough endoplasmic reticulum and of the perinuclear cisternae. Peroxidase activity thus develops asynchronously in a given cell as well as in the secretory cell population as a whole 2 days after birth, all cisternae of the rough endoplasmic reticulum of a peroxidase-positive cell contain reaction product, but the majority of the acinar cells is still negative During the next days, the number of peroxidase-positive cells and the amount of the rough endoplasmic reticulum increase rapidly. By 15 days postparturition, all secretory cells are peroxidase-positive. Reaction product is then found in all cisternae of the rough endoplasmic reticulum including the perinuclear cisternae, in smooth surface vesicles located mainly between the rough endoplasmic reticulum and the Golgi stacks, in condensing vacuoles, and in all secretory granules The Golgi cisternae rarely contain reaction product In total homogenates and in fractions of glandular tissue of adult rats, peroxidatic and catalatic activities are demonstrable. The microsomal fractions and the postmicrosomal supernatants were used to separate peroxidase from catalase by precipitation with ammonium sulfate, and the following parameters were determined: substrate (H(2)O(2-)) optimum ( approximately 2.0 x 10(-4)M), pH-optimum (pH 6 5), temperature-optimum (42 degrees C), and the absorption maximum (415 nm before and 425 nm after addition of H(2)O(2)) The same parameters were obtained from lacrimal fluid peroxidase. Both peroxidase from lacrimal gland and that from lacrimal fluid are almost completely inhibited by 10(-3)M aminotriazole and are possibly identical enzymes. Peroxidase is secreted into lacrimal fluid, which does not contain catalase.

Tissue factor (thromboplastin): localization to plasma membranes by peroxidase-conjugated antibodies

Peroxidase-conjugated antibodies were used to determine the histologic and cytologic localization of bovine and human tissue factor (thromboplastin). Tissue factor antigen was found in highest concentration in the intima of blood vessels, particularly in the plasma membranes of endothelial cells and in human atheromatous plaques. Tissue factor was also found limited to the plasma membranes of many cell types. The presence of tissue factor in the plasma membranes of endothelial cells and atheromata suggests that it may play a significant role in hemostasis and thrombosis.

Detection of simultaneous antibody synthesis in plasma cells and specialized lymphocytes in rabbit lymph nodes

Antibody to horseradish peroxidase was localized by electron microscopic immunocytochemistry in cells of the popliteal lymph nodes of the rabbit after a single injection of antigen with complete Freund's adjuvant and after a second antigen administration. Synthesis of antibody, chiefly of 7S type, occurred simultaneously in two types of cells: large, clear, fixed, typical plasma cells, and small, dense, circulating cells which exhibit morphological characteristics of both small lymphocytes and plasma cells. We call the latter "lymphoplasmacytes" and propose that they arise from small lymphocytes. They secrete antibody by clasmatosis and continue to develop an elaborate endoplasmic reticulum after specific antibody synthesis ceases. In the presence of an additional antigenic stimulation, a second cycle of antibody synthesis may begin around the nucleus in the same cell, with antibody accumulating in the perinuclear space sometimes even before the previously synthesized antibody has been entirely secreted at the cell periphery. On this basis, we propose that the lymphoplasmacyte is a memory cell and that memory and antibody synthesis are two different activities of the same cell. The appearance of a small amount of 19S antibody may be correlated with the presence of a small number of antibody-containing, large lymphocytes.