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Enhancement of chicken lymphocyte activation and lymphokine release by avian influenza virus.

We had previously found that inactivated avian influenza virus (AIV) could enhance the response of chicken lymphocytes to mitogen or antigen activation. An investigation into the possible mechanisms of this enhancement was undertaken. Peripheral blood lymphocytes (PBL) were incubated with AIV expressing different hemagglutinin (HA) types (H1-H13) along with doses of concanavalin A (Con A) which induce maximum (0.5 microgram) or submaximum (0.125 microgram) PBL activation. The lymphocyte activation was measured 72 h later. All of the HA types except H13 enhanced the Con A response. Diminished but significant enhancement could be observed when AIV administration was delayed by as much as 48 h of the 72-h incubation time. The AIV A/ck/Ala/75 (H4N8) was also examined for its effect on interleukin 2 (IL 2) synthesis by Con A-activated PBL and was found to modestly increase the synthesis of this lymphokine. All of the AIV hemagglutinin types agglutinated the PBL with titers slightly lower than that observed for the chicken erythrocyte agglutination. These results indicate that the AIV-induced enhancement of Con A responsiveness by chicken PBL is due, at least partly, to increased synthesis of IL 2 and that the effect may be due to some viral component other than the agglutinin.

Agglutination↗

AGGLUTINATION REACTIONS OF HUMAN LEUCOCYTES.

Agglutination tests with various sera and leucocytes from 58 leukaemic patients and 61 patients without leukaemia are reported. The agglutination of white blood cells by guinea-pig serum is of limited value in the diagnosis of leukaemia, though the test may be helpful in distinguishing leukaemia from other lymphomatous disorders.Leuco-autoagglutinins were demonstrated more frequently than expected. Eleven leukaemic and six non-leukaemic sera agglutinated autologous leucocytes. White blood cell agglutinins showed no apparent relationship to maturity or numbers of circulating leucocytes or to previous blood transfusions, x-irradiation, or therapy with antimetabolites.

Agglutination↗

[Significance and course of a cold agglutinin in Eperythrozoon suis infection of swine].

After infection with Eperythrozoon suis, pigs began to produce cold agglutinins of immunoglobulin type IgM, that because of the similarity between the pathogenic antigen and antigen on the erythrocyte membrane caused agglomeration. The progression of this cold agglutinin was measured with an enzyme immunoassay especially invented for this purpose, and compared with serum-IgM, agglutination strength, pathogenic effect as well as number of erythrocytes in the blood. The cold agglutinin extracted from the erythrocyte membrane at 40 degrees C showed, in comparison to the initial figures, a higher level (1259 micrograms/ml) at 6 days after the illness peak, reaching its maximum (2435 micrograms/ml) at 12 days. Similar results were achieved at lower extraction temperatures (22 degrees C, 0 degree C). A high correlation could be shown between the levels of IgM and of cold agglutinin, as well as the parallel increase in the agglutination strength of the blood. At the time of maximal pathogenic effect, no agglutination of blood was observed. The number of erythrocytes decreased in acute phases of an attack to a constant mean of 2.32 Mill./microliters of blood and then increased, at the same rate as the cold agglutinin level decreased, almost reaching normal values. These experiments confirm the fact that an organism following an infection with Eperythrozoon suis, begins to produce cold agglutinins. Due to structural similarities between the pathogen and the erythrocyte antigen the cold agglutinin causes temperature dependent agglutination.(ABSTRACT TRUNCATED AT 250 WORDS)

Agglutinins↗

Immunolocalization of anti-agglutinin for spermatozoa in boars.

A boar "anti-agglutinin," which inhibits head-to-head agglutination of spermatozoa, has been identified as a 25-kDa sialoprotein contained in epididymal and seminal plasma. This study was conducted to determine the location of the anti-agglutinin on spermatozoa and in various organs, including epididymides, by indirect immunofluorescence and Western blotting techniques. Ejaculated boar spermatozoa were washed and subjected to immunocytochemical observation. Epididymal plasma was recovered from three different regions of epididymides and subjected to sodium dodecylsulfate (SDS)-polyacrylamide gel electrophoresis (PAGE) and Western blotting. Twelve kinds of organs (testis, epididymis, seminal vesicle, prostate, heart, liver, kidney, spleen, stomach, small intestine, lung, and muscle) were recovered from boars. The unilateral epididymides were fixed, cut into 10-microm frozen sections, and subjected to immunohistochemical observation. The other organs were homogenized and used for SDS-PAGE and Western blotting. Immunocytochemical observations revealed that the antiserum strongly recognized the acrosomal region and equatorial segment on unfixed and methanol-fixed spermatozoa. Immunohistochemical observations revealed that the epithelia of the epididymal ducts were recognized by the antiserum mainly in the corpus epididymides. Moreover, the antiserum reacted with the luminal contents of the corpus and cauda epididymides. However, no specific reaction was detected in the caput epididymides. Western blotting showed that the antiserum selectively recognized a band of the anti-agglutinin in the corpus and cauda epididymal plasma, although no band was detected in the caput epididymal plasma. In the extracts from various organs, the single band was detected in the corpus and cauda epididymides at the same mobility as the anti-agglutinin, but not in the other organs. Based on these results, the following matters concerning the anti-agglutinin are discussed: (1) the importance of its association with the acrosome of spermatozoa in inhibiting sperm head-to-head agglutination; (2) its origin in the epididymis; and (3) its tissue specificity.

Animals↗

Cell contact-dependent increase in membrane D-galactopyranosyl-like residues on normal, but not virus- or spontaneously-transformed, murine fibroblasts.

Ricinus communis agglutinin (a lectin specific for beta-D-galactopyranosyl-like oligosaccharide residues) was used to investigate differences in lectin-binding sites on normal 3T3 and transformed SV3T3 and 3T12 cells grown to various cell densities in culture. The agglutinability of SV3T3 cells by R. communis agglutinin decreased when cells were grown to confluency or to a point where the cells were in contact. The agglutinability of 3T3 cells also decreased at confluency, but this result was variable and not as dramatic as with SV3T3 cells. Saturation-binding experiments performed at 4 degrees with (125)I-labeled R. communis agglutinin were used to monitor the number of lectin-binding sites on cells grown to different densities. Transformed cells (SV3T3 and 3T12) did not show cell-culture density-dependent changes in R. communis sites; sparse, touching, and confluent transformed cells had equivalent numbers of sites. However, touching (or confluent) 3T3 cells possessed 2.5-times the number of R. communis sites per cell compared to growing, sparsely populated 3T3 cells. When growing sparse 3T3 cells are compared to growing SV3T3 or 3T12 cells, there are 5-times R. communis sites per unit surface area on the transformed cells. The change in R. communis sites during cell growth in culture is discussed in relation to membrane fluidity and topography of plasma membrane oligosaccharides and glycosyl transferases, which can modify cell surfaces at contact.

Agglutination↗

Identification of cell surface carbohydrate and antigenic changes between noninfective and infective developmental stages of Leishmania major promastigotes.

Differentiation of Leishmania major promastigotes from a noninfective to an infective stage has been demonstrated for promastigotes growing within axenic culture and within the sandfly vector. We have been attempting to identify specific biochemical or antigenic changes that are associated with the development of infective-stage promastigotes. In this report we demonstrate that during growth, cultured L. major promastigotes undergo selective changes in surface carbohydrates, determined by their agglutination by plant lectins. Thus, although all promastigotes from logarithmic (log)-phase cultures were agglutinated by the two-D-galactose-binding lectins, peanut agglutinin (PNA) and Ricinus communis, identical concentrations of these lectins failed to agglutinate approximately 50% of L. major promastigotes from the stationary-phase cultures. These changes in lectin-agglutinating properties are consistent with the fact that log-phase promastigotes represent a homogeneous population of noninfective parasites, whereas up to 50% of the stationary-phase organisms appear to be transformed into infective-stage promastigotes, as determined by their ability to survive within normal resident mouse peritoneal macrophages in vitro. The identities of the populations defined by infectivity and PNA agglutination were confirmed by the purification of PNA-unagglutinated promastigotes from stationary-phase cultures, which demonstrated that 100% of these promastigotes were able to establish intracellular infections. Lectin-purified, infective-stage promastigotes from the stationary phase were compared with noninfective promastigotes from the log phase for the purpose of identifying stage-specific antigens. On the basis of Western blot analysis and the immunoprecipitation of surface-labeled organisms, we have identified an antigen of roughly 116,000 Mr that is expressed on the surface of infective but not noninfective promastigotes.

Agglutination Tests↗

Cold agglutinins: preoperative diagnosis leads to an uneventful perfusion.

This report presents the successful use of normothermic cardiopulmonary bypass (CPB) and warm continuous retrograde cardioplegia to facilitate coronary artery bypass grafting (CABG) in a patient with cold agglutinins. As a result of their agglutinating action and resultant haemolysis, cold-reactive autoantibodies have the potential for causing morbidity and mortality when a patient is placed on hypothermic CPB and the heart is arrested with profoundly cold cardioplegia. The crux of the situation is to keep the temperature above the critical temperature of the cold agglutinin; this technique guarantees accomplishing that goal.

Aged↗

Soybean agglutinin-positive natural suppressor cells in mouse bone marrow inhibit interleukin 2 production and utilization in mixed lymphocyte reactions.

Although natural suppressor (NS) cells resident in bone marrow (BM) have been the subject of intensive study, the exact nature and mode of action of these potentially important immunoregulatory cells are still uncertain. Here we show that NS cells with potent inhibitory effects on mixed lymphocyte reactions (MLRs) can be isolated from BM of normal adult mice by agglutination with the plant lectin soybean agglutinin (SBA). Complement-dependent lysis of SBA receptor-bearing BM cells with antibodies to asialoGM1, Mac-1, Thy-1.2, J11d.2, and 2C1 phenotypic markers reveals the presence of at least two distinct populations of BM NS cells. Most of the SBA-binding BM cells with NS capacity have the null phenotype and resemble hematopoietic stem cells, and some inhibitory SBA+ BM cells express the 2C1 marker found on pregnancy-associated splenic NS cells and the J11d.2 antigen characteristic of B cells and immature T cells. Results of positive selective experiments confirmed these findings. The mechanism of natural suppression was also studied. Evidence is presented that SBA+ BM cells exert NS activity in MLRs by interfering with the production and utilization of interleukin 2. Indomethacin does not relieve natural suppression associated with SBA+ BM cells, indicating that prostaglandin synthesis is not a requirement for inhibitory function. However, neutralizing antibodies to transforming growth factor beta (TGF-beta) partially reverse the suppression mediated by SBA+ BM cells, suggesting that some BM NS cells may act through the release of an immunosuppressive molecule related to TGF beta.

Agglutination↗

Thimerosal dependent agglutination, a newly described blood bank problem.

A number of ABO grouping, Rh typing, antibody screening, and antibody identification problems are associated with chemicals in blood bank reagents. We describe a newly discovered agglutination phenomenon due to a thimerosal (Merthiolate)-dependent agglutinin found in the serum of a normal blood donor. Thimerosal is used as a preservative in several low-ionic strength reagents. This agglutination phenomenon is detected only in test systems (low-ionic-strength, albumin, saline, ficin treated test cells) in which test cells are incubated in the presence of thimerosal. Agglutination does not occur in the absence of thimerosal. The thimerosal-dependent agglutinin behaves like an IgG IgG autoantibody. There is no evidence that the thimerosal-dependent agglutinin is responsible for increased red cell destruction.

Adult↗

Differences in prostaglandin formation between thymocyte subpopulations.

The concentration of prostaglandin E and the activity of prostaglandin synthetase were determined in mature and immature mouse thymocytes. Hydrocortisone resistant thymocytes, or thymocytes separated from the immature cell population after agglutination of the latter by peanut agglutinin served as a source of mature thymocytes. It was found that mature thymocytes contain a much higher concentration of prostaglandin E and have an increased activity of prostaglandin synthetase than immature cells.

Agglutination↗

Agglutination of leukemic and 2,4-dinitrophenyl-tagged normal human lymphocytes by wheat germ agglutinin.

The present study was undertaken to determine if leukemic and 2,4-dinitrophenyl (DNP)-tagged normal human lymphocytes shared common receptors for Wheat Germ Agglutinin (WGA), a lectin capable of reacting with malignant cells. Normal peripheral blood lymphocytes were tagged with 2,4-dinitrofluorobenzene (DNFB) at a ratio of 10-11 molecules/cell. Various concentrations of WGA were added to leukemic or tagged or untagged normal lymphocytes and incubated for 20 minutes at 37 degrees C, after which agglutination was scored visually. A readily discernible quantitative difference in the agglutinability of leukemic and DNP-tagged versus untagged normal cells was seen at all concentrations of WGA in the range of 50-800 mug/ml. The reaction was maximal when a ratio of 10-11 molecules of DNFB/cell was used for tagging and decreased progressively with 10-8, 10-6, 10-4, 0r 10-2 molecules. The agglutination of leukemic and DNP-tagged normal lymphocytes by 200 mug/ml of WGA was completely blocked by 0.1 M N-acetylglucosamine (GlcNAc) while as low a concentration as 0.001 M GlcNAc inhibited the reactivity of untagged cells. Since the agglutination of leukemic and DNP-tagged normal lymphocytes was equally inhibited by GlcNAc, this suggests that the same or similar receptor sites were involved in the two reactions. On the basis of our observations we propose that the initial step in the agglutination of leukemic and DNP-tagged normal lymphocytes by WGA IS THE BINDING OF THE LECTIN TO SPECIFIC RECEPTORS RATHER Than to DNP residues on the cell surface, since leukemic cells tagged with DNFB did not show increased agglutinability.

Acetylglucosamine↗

Sperm antibodies in men from infertile couples. Analysis of sperm agglutinins and immunofluorescent antibodies in 657 men.

Sera from 657 men from infertile couples were tested for sperm agglutinins and spermatozoal antibodies detectable by the indirect immunofluorescense technique (IFT), and the results were correlated to the clinical examinations of the couples. Sperm agglutinins were found in 6.7%. Spontaneous agglutination of the ejaculated spermatozoa was observed only among these men, most commonly among those with high serum titres. IF-antibodies against the four spermatozoal antigens located beneath the cell membrane occurred in 15.2% of the patients. Antibodies against the front part of the acrosome and the postnuclear cap were mainly IgM. Antibodies against the equatorial segment of the acrosome were predominantly IgG and in a few cases IgA, whereas straining of the main tail piece was caused by IgG antibodies. Considering the clinical fertility status of the couples, sperm agglutinins in high titres (greater than or equal to 10) against the equatorial segment and the main tail piece of the spermatozoa were found significantly more often among men from couples with unexplained infertility than among clinically normal men from couples where the findings in the women could be assumed to cause infertility. These results support the view that sperm agglutinins can cause infertility, whereas the significance of the IF-antibodies is still unclarified as, in some cases, these can be found even in high titres in men with proven fertility. The possible mechanism of autosensitization were evaluated by means of an anamnestic study.

Adult↗

Functional characterization of an adhesive component from the embryonic chick neural retina.

We have developed a quantitative assay for tissue-specific adhesive components which is based on the agglutination of glutaraldehyde-fixed cells. At least 2 components are required for fixed-cell agglutination: a cell-surface ligand which is obtained from tissue culture-conditioned medium, and a soluble 'agglutinin' which accumulates in conditioned medium from monolayer cultures. Our results suggest that the surface-binding ligand and the agglutinin interact directly, resulting in tissue-specific agglutination of cells. The agglutination reaction exhibits divalent cation, temperature, and pH dependence. Several models of cell adhesion are described; the simplest of these which can account for the data is a multicomponent model in which the 2 adhesive components have structural roles.

Agglutinins↗

Comparative analysis of agglutinins from hemolymph and albumin gland of Helix pomatia.

The hemolymph of Helix pomatia contains a weak agglutinating activity. This lectin concentration was calculated to be about 1.8 micrograms.ml-1. Among the different red blood cells tested, pronase-treated sheep erythrocytes were found to be the most suitable indicator cells. Their agglutination could be inhibited by GalNAc and GlcNAc. The serum agglutinin was isolated by affinity chromatography using Sephadex G-200 as the matrix. It exhibited a single band in discontinuous PAGE. In the presence of SDS, subunits of 27,000 daltons were obtained which, after addition of 2-mercaptoethanol, partly dissociated into 13,000-dalton subunits. The biochemical properties observed were compared with those of the well-known blood group A-specific lectin from the albumin gland of H. pomatia.

Agglutinins↗

Release of cytotoxic and agglutinating molecules by Mytilus hemocytes.

Hemolymph of Mytilus edulis is known to contain cytotoxic hemocytes and a serum agglutinin. This study describes the occurrence of strong hemolytic properties as well as agglutinating activity of a hemocyte extract against different types of erythrocytes. The hemolysin purified by preparative disc-electrophoresis and subjected to PAGE reveals one band which is also visible in the electropherogram of the extract or serum, respectively. Likewise, the serum agglutinin corresponds to another distinct fraction of extract and serum. Both, hemolytic and agglutinating molecules are detectable in the supernatant of a short-term hemocyte culture indicating that these substances are actively secreted by Mytilus blood cells.

Agglutinins↗

Genetics of a-agglutunin function in Saccharomyces cerevisiae.

The Saccharomyces cerevisiae cell adhesion protein a-agglutinin is composed of an anchorage subunit (Aga1p) and an adhesion subunit (Aga2p). Although functional a-agglutinin is expressed only by a cells, previous results indicated that AGA1 RNA is expressed in both a and alpha cells after pheromone induction. Expression of the Aga2p adhesion subunit in alpha cells allowed a-agglutinability, indicating that alpha cells express the a-agglutinin anchorage subunit, although no role for Aga1p in alpha cells has been identified. Most of the a-specific agglutination-defective mutants isolated previously were defective in AGA1; a single mutant (La199) was a candidate for an aga2 mutant. Expression of AGA2 under PGK control allowed secretion of active Aga2p from control strains but did not complement the La199 agglutination defect or allow secretion of Aga2p from La199, suggesting that the La199 mutation might identify a new gene required for a-agglutinin function. However, the La199 agglutination defect showed tight linkage to aga2::URA3 and did not complement aga2::URA3 in a/a diploids. The aga2 gene cloned from La199 was nonfunctional and contained an ochre mutation. The inability of pPGK-AGA2 to express functional Aga2p in La199 was shown to result from an additional mutation(s) that reduces expression of plasmid-borne genes. AGA2 was mapped to the left arm of chromosome VII approximately 28 cM from the centromere.

Base Sequence↗

Glycosphingolipid receptors for anti-Gd and anti-p cold agglutinins.

Anti-Gd and anti-p cold agglutinins exhibit similar serological properties: neuraminidase treatment of erythrocytes greatly reduces their agglutinability by these antibodies and protease treatment enhances their agglutination. We reported previously that an anti-p cold agglutinin was inhibited by sialosyllactoneotetraosylceramide, NeuAc(alpha 2-3)Gal(beta 1-4)GlcNAc(beta 1-3)Gal(beta 1-4)Glc-Cer, the most abundant ganglioside of human erythrocytes. We now report that two less abundant gangliosides are more potent inhibitors of this antibody, and of the anti-Gd antibodies, than sialosyllactoneotetraosylceramide. These two gangliosides have the same carbohydrate chain, NeuAc(alpha 2-3)Gal(beta 1-4)GlcNAc(beta 1-3)Gal(beta 1-4)GlcNAc(beta 1-3)Gal(beta 1-4)Glc(SNH), but they differ in their ceramide moiety. The principal fatty acid of SNH-1 is C16:0, whereas SNH-2 contains a predominance of C22:0, C24:0 and C24:1. No inhibition was produced by the ganglioside, NeuAc(alpha 2-6)Gal(beta 1-4)GlcNAc(beta 1-3)Gal(beta 1-4)Glc-Cer. Another monoclonal cold agglutinin, Sa, which shares some serological properties with anti-Gd cold agglutinins, was not inhibited by any of these gangliosides.

Agglutinins↗