Effect of Storage on Insulin Receptor Binding in Human Erythrocytes

The authors established the specificity, reliability, and precision of human erythrocyte insulin radioreceptor assay. On the basis of insulin binding, cell viability, and degree of hemolysis, heparin sodium was found to be a more suitable anticoagulant than sodium fluoride, ethylenediaminetetraacetic acid, sodium oxalate, or sodium citrate. In two sets of experiments carried out at 4°C and 23°C, human erythrocytes were stored as whole blood or isolated erythrocytes suspended in Tris-{4-(2-hydroxyethyl)-1-piperazine-ethanesulfonic acid} buffer. The effect of storage under these conditions was evaluated by erythrocytespecific insulin binding. Human erythrocytes can be stored for 72 hours at 4°C without any change in insulin binding, insulin receptor sites per cell, or average affinity constant at the empty sites. Isolated erythrocytes can also be stored in plasma for 72 hours or in buffer G for 24 hours at 4°C without any change in insulin binding. It is not advisable to store human erythrocytes in plasma or as whole blood for more than 24 hours at 23°. These findings are useful in preserving insulin receptor activity when storage of erythrocytes is unavoidable.     

Human Agglutinins to Rabbit Erythrocytes

Crude preparations inhibiting the agglutination of rabbit erythrocytes by pooled human serum were obtained by extraction of erythrocyte stromata with various solvents (chloroform/methanol, trichloroacetic acid, and so forth). Highest inhibiting activity was found in a preparation containing sphingoglycolipid; 0.8 mug inhibited 2 agglutinating units of serum. The active preparations retained their activity after 5 min of incubation in a boiling water bath and after treatment with proteolytic enzymes or neuraminidase. Treatment with periodate abolished the activity. The antigenic site is therefore probably determined by the sugars of the sphingoglycolipid.     

Bartonella henselae Infects Human Erythrocytes

Bartonella henselae, a facultative intracellular bacterium, has been known as the agent of cat scratch disease, bacillary angiomatosis, peliosis hepatis, endocarditis, and bacteremic syndrome in humans. Bartonella species can cause intraerythrocytic infections and have been isolated from the bloodstream of patients by several methods. It was demonstrated that B. bacilliformis and B. quintana infect human endothelial cells and human erythrocytes and B. henselae infects erythrocytes of cats. The aim of this study was to investigate through transmission electron microscopy whether B. henselae infects mature human erythrocytes. One red blood cell (RBC) unit received an experimentally standard strain of B. henselae. Blood aliquots were collected from the infected unit immediately after inoculation, at 30 min and 1, 5, 10, and 72 h for ultrastructural evaluation. B. henselae was seen adhering to human erythrocytes 10 h after inoculation and inside the erythrocyte after 72 h. This study demonstrates that B. henselae adheres to and invades mature human erythrocytes. The results favor the possibility that erythrocytes can serve as a primary target in Bartonella spp. infections. From this observation, further studies are warranted to prevent Bartonella spp. transfusional transmission.     

The Immunology of the Insulin Receptor

We have detected and characterized anti-insulin-receptor autoantibodies which circulate in several patients with insulin resistant diabetes. These antibodies are predominantly IgG and are polyclonal. They inhibit insulin binding to its receptor on a variety of tissues from widely separated species. Antibodies obtained from different patients appear to bind to different determinants on the receptor and alter receptor function in several ways. Some anti-receptor antibodies are capable of stimulating insulin-like effects on target tissues, while others block insulin-stimulated effects. Direct labeling of anti-receptor antibody with I permits use of these antibodies as an assay and probe of insulin receptors.     

The Immunology of the Insulin Receptor

We have detected and characterized anti-insulin-receptor autoantibodies which circulate in several patients with insulin resistant diabetes. These antibodies are predominantly IgG and are polyclonal. They inhibit insulin binding to its receptor on a variety of tissues from widely separated species. Antibodies obtained from different patients appear to bind to different determinants on the receptor and alter receptor function in several ways. Some anti-receptor antibodies are capable of stimulating insulin-like effects on target tissues, while others block insulin-stimulated effects. Direct labeling of anti-receptor antibody with I permits use of these antibodies as an assay and probe of insulin receptors.     

Human Fecal Agglutinins to Rabbit Erythrocytes

Antibody activity in feces was investigated by testing for agglutinins to rabbit erythrocytes Extracts of freeze-dried feces from 13 of 14 infants and children agglutinated the rabbit erythrocytes, as did the sera from ill all these individuals. Feces from I-month-old infants gave relatively high titres, whereas sera gave loss titres compared with what was found in older children. Thus, the intestinal agglutinins seemed to be produced independently of those in serum. The fecal agglutinins correlated well with the concentration of IgA in feces and were inhibited with antiseri In IgA. indicating that IgA in feces was mainly responsible for the agglutination Results of preparative ultracentrifugation and gel filtration as well as immunization studies were in line with this There is thus evidence that only IgA retains its, activity in the gut. even when IgG and IgM are present in feces. Since agglutinins to rabbit erythrocytes in serum are mainly confined to IgG and IgM, this activity in feces seems to be a useful market for locally produced intestinal IgA.     

Adherence of Mycoplasma gallisepticum to Human Erythrocytes

Pathogenic mycoplasmas adhere to and colonize the epithelial lining of the respiratory and genital tracts of infected animals. An experimental system suitable for the quantitative study of mycoplasma adherence has been developed by us. The system consists of human erythrocytes (RBC) and the avian pathogen Mycoplasma gallisepticum, in which membrane lipids were labeled. The amount of mycoplasma cells attached to the RBC, which was determined according to radioactivity measurements, decreased on increasing the pH or ionic strength of the attachment mixture. Attachment followed first-order kinetics and depended on temperature. The mycoplasma cell population remaining in the supernatant fluid after exposure to RBC showed a much poorer ability to attach to RBC during a second attachment test, indicating an unequal distribution of binding sites among cells within a given population. The gradual removal of sialic acid residues from the RBC by neuraminidase was accompanied by a decrease in mycoplasma attachment. Isolated glycophorin, the RBC membrane glycoprotein carrying almost all the sialic acid moieties of the RBC, inhibited M. gallisepticum attachment, whereas asialoglycophorin and sialic acid itself were very poor inhibitors of attachment. Only part of the (125)I-labeled glycophorin bound to mycoplasmas could be removed by neuraminidase or by exchange with unlabeled glycophorin. It is suggested that glycophorin, representing the isolated major RBC receptor for M. gallisepticum, binds to the mycoplasmas both specifically, through its sialic acid moieties, and nonspecifically, through its exposed hydrophobic polypeptide moiety.     

Binding of Sheep Erythrocytes to Human Lymphocytes

The study concerned the binding of sheep red blood cells by human peripheral blood lymphocytes. The results indicate that the phenomenon (rosette formation) is probably dependent on thymus-derived lymphocytes (T lymphocytes) and not due to bone marrow lymphocytes (B lymphocytes). These data were obtained by a gradient centrifugation technique separating B lymphocytes from rosette-forming cells, by direct study of B lymphocytes and rosette-forming cells in the same preparations, and from the study of patients with selective immunodeficiency diseases and chronic lymphocytic leukaemia. Furthermore, inhibition of rosette formation was absent or very weak after incubation of lymphocytes with anti-immunoglobulin antisera, but considerable following their incubation with unspecific mitogens (phytohaemagglutinin, pokeweed mitogen, concanavalin A, anti-lymphocyte antiserum) and also after trypsin treatment. Incubation temperature was important for the frequency of rosettes, and experiments with metabolic inhibitors showed that to form rosettes the lymphocytes required an intact energy production.     

Mechanisms of Penicillin Antibiotic Interactions with Human Erythrocytes

Significant effects of penicillin antibiotics, used in pediatrics, on the erythrocyte structural characteristics were detected by recording kinetic curves of osmotic and acid hemolysis. Possible relationships between erythrocyte properties and concentrations, duration of exposure to, and structure of antibiotics were revealed. Recommendations for dose correction for effective use of antibiotics in medicine with consideration for individual features of the patient are proposed. Translated from Byulleten’ Eksperimental’noi Biologii i Meditsiny, Vol. 146, No. 10, pp. 419-423, October, 2008     

Human Rotavirus Detection by Agglutination of Antibody-Coated Erythrocytes

We sensitized sheep erythrocytes (SRBC) with antibodies against human rotavirus strain Wa (SRBC-antiWa) and antibodies against calf rotavirus strain NCDV (SRBC-antiNCDV). These were readily agglutinated in the presence of homologous antigens, i.e., human rotavirus and calf rotavirus. By the hemagglutination of SRBC-antiWa and SRBC-antiNCDV (reverse passive hemagglutination [RPHA]), titration of rotavirus in extracts from feces of children suffering from diarrhea (61 specimens) was carried out. We found that the ratio of titers determined with SRBC-antiWa and SRBC-antiNCDV varied remarkably from specimen to specimen. This indicated that the antigenic determinants on human rotavirus in patients feces cross-react with antibodies against NCDV to varying extents. To express the cross-reactivity of human rotavirus with antibodies to NCDV, we propose a Wa/NCDV rotavirus index which can be calculated from the RPHA titer with SRBC-antiWa and SRBC-antiNCDV as follows: Wa/NCDV rotavirus index = (antiWa-RPHA titer of specimen/antiWa-RPHA titer of NCDV)/(antiNCDV-RPHA titer of specimen/antiNCDV-RPHA titer of NCDV).     

Recombinant Human Insulin Analogues

The recent introduction of recombinant DNA technology has made possible the manufacture of insulin analogues with altered pharmacokinetic properties. Such analogues include insulins with single or multiple amino acid substitution(s) in the A or B chains of human insulin. The modification of the amino acid sequence results in a lower tendency towards aggregation of the insulin analogues when compared with human insulin. In particular, the subcutaneous injection of rapid-acting insulin analogues generates a peak that is superimposable on the peripheral plasma insulin profile of healthy individuals after a meal, without the need for a time interval between the injection and the meal. However, long term multicentre trials with rapid-acting insulin analogues have not shown an improvement in glycated haemoglobin (HbA(1c)) values despite an improvement in post-meal (2 hour) glycaemic control. This result is probably due to the shorter action of insulin analogues compared with human regular insulin, causing higher glycaemic values at 4 hours after insulin administration despite lower values at 2 hours. Thus, the simple substitution of rapid-acting analogues for regular insulin can lead to a potential deterioration of metabolic control, causing hyperketonaemia in patients without residual C-peptide secretion. Such patients should receive supplemental intermediate insulin at bedtime and also, at low dosages and on the basis of glucose values, at any time the interval between meals is longer than 4 hours.     

Reactions of Infectious Mononucleosis Sera with Glutaraldehyde-Treated Human Erythrocytes

Infectious mononucleosis sera gave positive results in enzymoimmunoassay with glutaraldehyde-treated human erythrocytes. This unexpected reaction appeared to be caused by the interaction of Paul-Bunnell (P-B) antibodies with a partial P-B antigen that apparently appears on human red blood cells in a hidden form and becomes exposed by the treatment with glutaraldehyde.     

Release of the Soluble Interleukin-6 Receptor from Human T-Cells

The soluble Interleukin-6 receptor (sIL-6R) is capable of confering the Interleukin-6 (IL-6) signal onto cells lacking the gp80 ligand binding protein. Here we investigate the release of sIL-6R from T-cells. After 2 h stimulation with PMA, a release of sIL-6R from peripheral human T-cells was observed which was insensitive to the protein synthesis inhibitor cycloheximide. This release was accompanied by a decrease of membrane-bound (mb) IL-6R. After 24 h, however, the observed sIL6-R release did prove to be sensitive to cycloheximide. These results suggest that both shedding and de-novo-synthesis may be responsible for the PMA-induced sIL-6R release. In contrast to PMA, neither anti-CD3, a positive, nor IL-10, a negative regulator of IL-6 release from T-cells affected the production of the sIL-6R. The differential regulation of sIL-6R and IL-6 production by T-cells might be relevant for the immunomodulatory potential of the sIL-6R with respect to the interaction of T- and non-T-cells.     

Release of the Soluble Interleukin-6 Receptor from Human T-Cells

The soluble Interleukin-6 receptor (sIL-6R) is capable of confering the Interleukin-6 (IL-6) signal onto cells lacking the gp80 ligand binding protein. Here we investigate the release of sIL-6R from T-cells. After 2 h stimulation with PMA, a release of sIL-6R from peripheral human T-cells was observed which was insensitive to the protein synthesis inhibitor cycloheximide. This release was accompanied by a decrease of membrane-bound (mb) IL-6R. After 24 h, however, the observed sIL6-R release did prove to be sensitive to cycloheximide. These results suggest that both shedding and de-novo-synthesis may be responsible for the PMA-induced sIL-6R release. In contrast to PMA, neither anti-CD3, a positive, nor IL-10, a negative regulator of IL-6 release from T-cells affected the production of the sIL-6R. The differential regulation of sIL-6R and IL-6 production by T-cells might be relevant for the immunomodulatory potential of the sIL-6R with respect to the interaction of T- and non-T-cells.     

Similarity of Bovine Rotavirus Receptor and Human Rotavirus Receptor

Rotavirusesaretheleadingcauseofviralgastroenteritis worldwide.Theseviruses,includinghumanrotavirus (HRV)andbovinerotavirus(BRV),whichprimarilyin fectchildrenandyounganimals,cancauseseveredehy dratingdiarrhearesultinginsignificantmorbidity,mortali tyand…     

当归对人红细胞变形性和聚集性的影响

目的 :研究当归对红细胞变形性和聚集性影响。方法 :健康献血者红细胞 ,自身血浆稀释至红细胞压积为 40 %。用红细胞聚集仪和激光衍射光学旋转细胞分析仪分别测定红细胞聚集性和变形性。结果 :当归组加入当归注射液 2 0mg/ml孵育后与正常对照组比较 ,可显著降低红细胞聚集速度 (Ta :2 .5 9± 0 .35 ,Tf:33.5 4± 2 .6 3vsTa :1.80±0 .16 ,Tf:2 7.11± 1.78,P <0 .0 5 ) ,但不影响红细胞解聚能力。加入Ca2 + 螯合剂可使红细胞变形性降低。当归可以显著逆转A2 3187导致的红细胞变形性降低 (EI:0 .2 9±0 .0 47vs 0 .17± 0 .0 2 4,P <0 .0 1)。结论 :当归可以降低正常红细胞聚集速度 ,减轻Ca2 + 螯合剂导致的红细胞变形性降低。     

Mouse/Human T-Cell Hybrids Rosetting with Sheep Erythrocytes

Hybrid cells have been recovered from selective culture medium after fusion of concanavalin-A-activated human lymphocytes with an AKR mouse thymoma (BW 5147). After 6 months of culture twenty-seven out of forty-nine clones still contained human chromosomes. Human chromosome 6 was present in 89% of these clones, and human X in 70%. Clones from one hybrid line contained several human chromosomes. In twelve of the clones carrying human chromosomes, the rosetting with sheep Erythrocytes (SRBC) was 3 times as high as In the BW 5147 cell line. All these clones Carried the human chromosome 6, and eight clones contained the human X chromosome as well. In some of these clones (25%) chromosome 6 was the only human one present. In the two clones In which human chromosome 6 was completely missing, the resetting with SRBC was at the level of the BW line. We therefore suggest that genes on human chromosome 6 are responsible for rosetting with SRBC.     

Cytotoxic Effects of Activated Human Monocytes and Lymphocytes to Anti-D-treated Human Erythrocytes in Vitro

Incubation of human monocytes, derived from peripheral blood, with cell-free supernatants from mixed lymphocyte cultures resulted in morphological and functional changes in the mature macrophages. Activation of monocyte-derived macrophages by these factors resulted in a significant increase in their capacity to lyse anti-D-treated human erythrocytes. The lytic activity of both normal and activated macrophages appeared to be independent of erythrophagocytosis. T lymphocytes activated by either allogeneic cells or the mitogen phytohaemagglutinin were not cytolytic to treated erythrocytes even at high effector to target cell ratios.