Native Red Blood Cells Research Articles

Immunität der Haut — Infektion und perkutane Immunisierung von Kaninchen mit E. coli ATCC 13676

After intracutaneous infection of rabbits with a suspension of E. coli which was followed by a transient local inflammation, the local and systemic immune responses were determined using the lymphocyte stimulation test (LTT) and the hemolysis plaque assay (HPA). Lymphocytes of the lymphatic system draining the infected skin area and blood lymphocytes were used. With lymphocytes derived from the local lymph nodes, a substantial increase of specific stimulation in the LTT was detected beginning at day 3 after infection and lasting up to the termination of the experiment (3 weeks). Blood lymphocytes were stimulated at a lower level: The activity showed a peak at day 4 and an elevated level only during a 10-day period. After the intracutaneous infection with E. coli, increasing numbers of antibody-releasing lymph node cells were detected in the HPA. The antibody-secreting cells of the IgM and IgG classes clearly showed an increasing specificity for E. coli lipopolysaccharide coupled to sheep red blood cells. As with the LTT, the highest activities (values of specificity and number of plaque-forming lymphocytes) were observed at the end of the experimental period. An emulsified preparation of a heat-inactivated E. coli culture ( E. coli-BKS) which had been applied locally onto the artificially altered skin evoked a similar immunological response after a 2 or 3-weeks treatment. In such animals an increased activity of lymph node cells could be registered by LTT and HPA as compared to reactions from placebo-treated control animals. However, the topical immunization with nonviable E. coli stimulated not only lymphocytes which produced antibodies directed specifically against E. coli lipopolysaccharide as demonstrated by the HPA. An increased number of lymphocytes reacted even with native sheep red blood cells. This observations is discussed in respect of a polyclonal B-cell activation by lipopolysaccharide of the E. coli-BKS.

Intravenously Administered Lecithin Liposomes: A Synthetic Antiatherogenic Lipid Particle

INTRAVENOUSLY ADMINISTERED LECITHIN UPOSOMES: A SYNTHETIC ANTIATHEROGENIC UPID PARTICLE KEVINJON WILUAMS* VICTORIA P. WERTHJ andJON A. WOLFFt 1. Introduction Almost 3 decades ago, intravenous administration of lecithin was shown to induce regression of experimental atherosclerosis in rabbits [1—6]. This was confirmed by several groups using different animal models [7-9]. No satisfactory explanation for this phenomenon has been offered [4, 5, 8, 10-12]. We propose that lecithin induces regression of experimental atherosclerosis by forming a synthetic antiadierogenic lipid particle, the lecithin liposome. We are proposing the following. Intravenously injected lecithin forms circulating liposomes, which take up cholesterol from many sources, including the arterial wall. In this way, lecithin liposomes become carriers ofendogenous cholesterol. These liposomes are gradually removed from the circulation by the liver, which catabolizes liposomes and excretes their cholesterol. Mobilization and excretion of endogenous cholesterol are further enhanced by the interactions of circulating liposomes with native lipoproteins and red blood cells. For example, circulating liposomes pick up apoproteins from native lipoproteins. Apoproteins directly augment the ability of liposomes to extract tissue cholesterol and may facilitate their catabolism by the liver. In addition, liposomes remove cholesterol from, and donate phospholipid to, native lipoproteins. These modifications The authors thank Simeon Margolis and Henry Seidel of The Johns Hopkins University , Ferd E. Williams of the University of Delaware, and Anne L. Williams for their generous guidance and support. ?Department of Internal Medicine, Division of Endocrinology, Yale University, 333 Cedar Street, New Haven, Connecticut 06510. (Work done while at the University of Chicago.) tDepartment of Medicine, Northwestern University, Chicago, Illinois 60611.¿Department of Pediatrics, University of California, San Diego, California 92103.©1984 by The University of Chicago. AU rights reserved. 0031-5982/84/2703-0396$01.00 Perspectives in Biology and Medicine, 27, 3 ¦ Spring 1984 \ 417 may enhance the ability of native lipoproteins to extract cellular cholesterol and may reduce any further lipoprotein-mediated transport of cholesterol into the arterial wall. Finally, liposomes remove cholesterol from the membranes of red blood cells. Cholesterol-depleted red blood cells may act as additional intermediaries in the extraction of arterial cholesterol deposits. In die following sections, we first review die studies demonstrating regression of experimental atherosclerosis with intravenous administration of lecithin. We then examine the evidence diat lecidiin mobilizes tissue cholesterol by the formation of liposomes composed of lecithin and cholesterol, that these liposomes are disposed of by die liver, and Uiat interactions of liposomes with lipoproteins and red cells enhance these processes. Finally, we review literature from which we infer that die cholesterol of human atheromata may be susceptible to mobilization and excretion by intravenously administered liposomes. 2. Regression ofExpérimental Atherosclerosis with I.V. Lecithin The cholesterol-fed rabbit is widely used as an experimental model of atfierosclerosis. In diis model, rabbits fed on a diet containing 1-5 percent added cholesterol develop witfiin 4—12 weeks deposits of cholesterol in many tissues, including die intima of large arteries. These intimai deposits remain die same size or even progress when the rabbits are returned to their usual cholesterol-free diet [13]. In contrast, intravenous administration of lecidiin preparations of varying purity (0.53 .5 g two to three times a week) resulted in rapid, substantial regression of the intimai lesions, with resolution in 1-4 weeks or after a total phospholipid dose of about 2-12 g [1-4, 6]. Lecithin-induced regression occurred even while the rabbits were maintained on die cholesterol-rich, adierogenic diet [6]. Similar results were observed in other models. Experimental atherosclerosis produced in rabbits by a semisyndietic cholesterol-free diet rich in saturated fat regressed with infusions of lecithin [5]. In baboons, the incidence and severity of experimental atherosclerosis, induced over 6 months by combining cholesterol feeding widi injections of bovine serum albumin (to produce vasculitis and intimai injury), were significandy reduced by concurrent thrice-weekly infusions of polyunsaturated lecidiin [7]. Quail fed on a high-cholesterol diet for 3 mondis developed intimai deposits diat resolved during 3 subsequent months of intravenous lecidiin administration, despite continuation of the adierogenic diet [8]. Extravascular cholesterol deposits in the subcutaneous tissues of rats regressed witfi topical lecidiin [9]. In several of diese experimental models, polyunsaturated lecidiin from soybeans...

A spectrin-like protein from mouse brain membranes: immunological and structural correlations with erythrocyte spectrin.

Membrane-associated mouse brain spectrin is a 972,000 Mr, 10.5S, (alpha beta)2 tetramer containing two approximately 240,000 Mr subunits and two approximately 235,000 Mr subunits. Two-dimensional [125I]tryptic peptide mapping indicates that these subunits share only limited and equivalent overlap with the alpha- and beta-subunits of red blood cell (RBC) spectrin. Both the 220,000 Mr beta-subunit of RBC spectrin and the 235,000 Mr beta-subunit of brain spectrin are phosphorylated in the intact mouse. In vitro analysis suggests that both are phosphorylated by a cAMP-independent protein kinase. Antibodies against pure native mouse red blood cell spectrin cross-react with brain spectrin, and antibodies against pure brain spectrin cross-react with both the alpha- and beta-subunits of mouse RBC spectrin. Both antibodies have been utilized to localize brain spectrin within distinct cellular entities of the mouse cerebellum. Granule cell neurons of the internal granule layer and Purkinje cell neurons demonstrated intense fluorescence of the cortical cytoplasm immediately adjacent to the plasma membrane and unstained nuclei, when either RBC or brain spectrin antibodies were utilized for staining. The molecular layer of the cerebellum stained only lightly, and oligodendrocytes and astrocytes appeared to have little fluorescence. Therefore, while brain is a tissue rich in nonerythroid spectrin, the concentration of these immunoreactive analogues is quite variable within distinct cellular entities of the cerebellum.

EFFECT OF RED CELL RIGIDITY ON GAS TRANSPORT BY SHEARED FLOWING BLOOD†

By means of a blood flowing model the dependence of oxygen uptake by red blood cells (RBC) on the deformation of the RBC was investigated. The model allows measurements of oxygen transfer in flowing sheared blood. Simultaneously secondary flows can be produced, which enhances oxygen transfer rate of whole blood considerably. The model is applied to analyse the effect of an artificial rigidification of RBC on oxygen uptake by the cells. A diminution of RBC deformations, obtained by an oxidation of membrane SH-groups, is shown to result in a decrease of O2-uptake by RBC. This decrease is assumed to be due to a reduction of intracellular convection, which diminishes intracellular mixing of haemoglobin. Glutardialdehyde treatment results in an even higher decrease of oxygen uptake. In this case the complete lack of deformations of the RBC and of orientation in shear flow, which is typical for native RBC and is maintained in diamide RBC, is proposed to be responsible for this greater loss of O2-uptake. A shift...

Antibody-dependent, cell-mediated cytotoxicity against human red blood cells: correlation of effector cell type with enzymatic alteration of the target cell surface.

Target cell factors, which contribute to the determination of the effector cell type in an antibody-dependent, cell-mediated cytotoxicity system were studied. Human red blood cells (RBC) were treated with papain and investigated by transmission and scanning electron microscopy (TEM and SEM). Both untreated (native) and treated 0 Rh+ RBC were labeled with 51Cr, sensitized with anti-D immunoglobulin and incubated with unfractionated autologous peripheral blood mononuclear cells. With native RBC, immune lysis was proportional to the number of phagocytes: enrichment of effectors in phagocytes increased lysis, while depletion of phagocytes from effectors decreased lysis. Following papain treatment of target RBC, lysis by unfractionated mononuclear effectors was markedly augmented; since this effect was not diminished by decrease of phagocytes to less than 2%, the augmented lysis was not due to the number of phagocytic effectors. TEM and SEM of enzyme-treated RBC showed spherocytosis with varying degrees of crenation and blurring and irregularities of the cellular membranes. The results suggest that papain-induced alterations in the target RBC rendered them susceptible to lysis by interaction between anti-D antibody and peripheral blood lymphocytes.

The biological recognition of foreign from native particles as a problem in surface chemistry

There is a large area of cellular interactions in biological systems which has not been thoroughly explored from a physical chemiCal point of view. One reason for this is the inherent difficulty of the systems (from both a biological and physical chemical point of view), but another reason is without question that in several vital areas of biological interest the colloid and surface chemist is not aware of the problems which in the author's opinion would be well served by a closer inspection by the colloid scientist (1). I t is the intention in this paper to point out both the biological and surface chemical problems involved in the by the body of non-native particles, such as bacteria, which somehow enter the blood stream. Foreign particles entering the mammalian blood stream are usually removed in a matter of minutes. They are removed from the blood stream by cells located largely in the liver and spleen which are capable of recognizing these foreign particles and cause them to enter the cell by the process of phagocytosis. It is important to recognize that these are in fact two distinct processes (2): firstly, recognition, which in the present context may be regarded as a sticky collision, and secondly, the actual process of engulfment. The subsequent fate depends upon the balance of the powers of the enzyme system of the cell to destroy the particles and ultimately to initiate antibody formation, and the power of the bacteri~ to resist the enzymes, multiply, and attack the host. The powers of the in the mammalian system are extremely acute; for example, native red blood cells have a lifetime in man of the order of 100 days. At the end of this time they are recognized as different and removed. Only recently (3) has this been attributed to a measurable change in the chemical composition of the red cell. It should further be remembered that any foreign particles will normally be diluted by other particles, i.e., red cells and white cells, by several orders of magnitude. This paper will consider only the first or recognition part of the problem, but since it is of considerable interest to surface chemists the second process will be here mentioned briefly. Tait (4), Ferm (5), and Ponder (6) discussed at length the process of engulfment in terms of interfacial tensions. Unfortunately their hypotheses were difficult to test and have largely been ignored, although it has been pointed out by Pethica (7) that it is questionable whether surface tension can be interpreted in the manner proposed by these workers. Some work on the effect of detergents on the process of phagocytosis has been reported (8, 9), but in view of the interactions of detergents with proteins and their lyric action, it is difficult to interpret. Further, it treats the process of phagocytosis as a whole and does not allow us to consider recognition and engulfment separately. This of course raises the point, which must always be kept in mind, that the processes are separated only for convenience and that we are deMing with a living system. The metabolic processes involved in phagocytosis have been studied by Karnovsky (10) and others and well illustrate the preceding point. The problem of can be and