bluuebunny/crossref_metadata_2025_split huggingface dataset:
Differential induction of anti‐trinitrophenyl plaque‐forming cell responses to lightly and heavily conjugated trinitrophenylated heterologous and autologous erythrocytes in mice
Authors: Naor D. , Morecki Shoshana , Mitchell G. F. 
Published: February 2007

AbstractVarious anti‐TNP PFC (2,4,6‐trinitrophenyl plaque‐forming cell) responses were obtained by injecting C3H mice with different conjugates of trinitrophenylated sheep red cells (TNP‐SRC). Mice which were injected with lightly conjugated TNP‐SRC (TNP0.14SRC) produced indirect anti‐TNP PFC 4 days after injection, while mice which were injected with heavily conjugated TNP‐SRC (TNP14SRC) produced both direct and indirect anti‐TNP PFC or direct anti TNP PFC only.Heavily conjugated trinitrophenylated autologous mouse red cells elicited a low direct anti‐TNP PFC response 4 days after injection. The system is another example of the capacity to modify antibody responses by modification of the antigen.
In vitro antibody response of primed rabbit peripheral blood lymphocytes to Group A variant streptococcal polysaccharide
Authors: Read S. E. , Braun D. G. 
Published: February 2007

AbstractPeripheral blood lymphocytes obtained from rabbits at various times after a primary course of immunization with streptococcal Group A‐variant vaccines were successfully stimulated in vitro with this vaccine. Day 5 cultures contained about 81 % IgM and only 19 % IgG plaque‐forming cells, day 10 cultures contained only 38 % IgM and 62 % IgG plaques, and day 15 cultures contained predominantly IgG plaques (83 %) and far fewer IgM plaques (17 %). Concomitantly, IgM and IgG secretion into the media was shown. Analysis of the secreted IgG antibodies by isoelectric focusing showed in principle that the clones stimulated in vitro were those that had determined the in vivo response. These data demonstrate the circulation of clonal progenitor cells in the rabbit peripheral blood.
Equivalent responsiveness to branched polysaccharides and their dinitrophenyl conjugates in the Biozzi high and low responder lines of mice
Authors: Howard J. G. , Courtenay Barbara M. , Desaymard Catherine 
Published: February 2007

AbstractDose response curves for two thymus‐independent branched polysaccharides, levan and dextran B 1355, have been compared by direct plaque‐forming cell assays in the Biozzi high (Ab/H) and low (Ab/L) responder lines of mice. In contrast with all of many other antigens so far tested, equivalent IgM responses were elicited by native levan (mol. wt. 2 × 107), Pseudomonas levanicum vaccine and native dextran (mol. wt. 4 × 107). Partially depolymerized levan (mol. wt. 5 × 104 − 7 × 104) was surprisingly more immunogenic in Ab/L than in Ab/H mice. Furthermore, the tolerance threshold dose of both native and depolymerized levans was lower in the Ab/H line, the converse of previous findings with the linear polysaccharide SIII. Equivalent anti‐DNP responses were obtained in the two lines when they were immunized with the hapten conjugated with levan, whereas conventional high/low separation was obtained when polymerized flagellin was used as carrier.It is concluded that nonspecific “high” and “low” responsiveness in Ab/H and Ab/L mice results not from an intrinsic difference in their B cells, but from selective involvement of an extrinsic regulation mechanism. Evidence which implicates divergence in antigen handling by macrophages as a primary factor, and the exceptional behavior of the branched polysaccharides in evading this difference are discussed.
Changes in affinity of IgM antibodies in amphibian larvae
Authors: Du Pasquier L. , Haimovich J. 
Published: February 2007

AbstractThe increase in affinity of anti‐2, 4‐dinitrophenyl (DNP) antibodies of IgM class in tadpoles was followed as a function of time after administration of antigen by the inhibition of inactivation of DNP‐bacteriophage T4. A 10‐fold increase in binding affinity was observed over a period of 3–4 weeks after injection.
Surface morphology of murine B and T lymphocytes: A comparative study by scanning electron microscopy
Authors: Polliack A. , Hämmerling U. , Lampen N. , de Harven E. 
Published: February 2007

AbstractA variety of murine lymphocytes of known B or T derivation obtained from different lymphoid organs were prepared for scanning electron microscopy (SEM) by the critical point drying method after collecting the cells by aspiration onto silver membranes. Comparison of SEM appearances of cells prepared by this technique and serological classification accoding to surface antigens showed that most T cells had smooth surfaces with few micorvilli, while many B lymphocytes were moderately to markedly villous.Further evidence for the above correlation was obtained by examining thymic cells and enriched B or T cells populations. Thymic cell suspensions containing less than 5 % B cells showed over 80 % generally smooth cells bye SEM. Enriched T cell populations, obtained by mass cytolysis of lymph node preparations with anti‐Ia or anti‐Ig sera or by purification through nylon fibern columns, contained over 85 % T cells, and more than 75 % of them were of the were of the smooth cell type.A similar correlation was noted for enriched B cell populations obtained by cytolysis of lymph node cells with anti‐Thy‐1 serum, and by lysis of EAC‐rosettes. Over 90 % of these cells were identified as B cells by immunologic methods and approximately 75 % had moderate to markedly villous surfaces. The 15 % difference can be accounted for by the existence of a subpopulation of smooth B cells. Direct observation of EAC‐rosettes confirmed that most B cells had moderate to large numbers of the smooth cells seen in enriched B cell populations may represent precursors or B lymphocytes at different stages of differentiation.These result indicate that murine T and B lymphocytes, like their human counterparts, can be recognized in many cases under the SEM on the basis of their surface mophology. Smoother B and more villous T cells are difficult to classify to SEM without parallel immunologic identification.
Immunoglobulin heavy chain mRNA in mitogen‐stimulate B cells
Authors: Stevens R. H. , Askonas Brigitte A. , Welstead Jacqueline L. 
Published: February 2007

AbstractThis paper relates the synthesis of DNA, immunoglobulin and heavy chain (H) MRNA in murine spleen cells following activation of B cells with lipopolysaccharide from E. Coli (LPS).Spleen cells (CBA/H mice) were cultivated with 10 % FCS and 10 μg LPS/ml. 4 h pulses with [3H]thymidine showed that DNA synthesis was stimulated within the firstb day following LPS activation and exhibited a sharp peak at 24 h. The shape of the DNA synthesis curve suggests that the cells susceptible to LPS stimulation are activated in a synchronous manner.Stimulation of H‐chain mRNA (H‐mRNA) synthesis proceeded raidly (within 6 h of LPS addition) and peaked around 24 h, in parallel to DNA synthesis. The H‐mRNA was isolated and quantitated by making use of its interaction with IgG [1, 2]. The actual level of H‐mRNA in the culture increased three‐fold during the first 24 h and then doubled within the next 48 h. Estimates of the actual number of H‐mRNA were approximately 200 molecules H‐m‐RNA/cell on day 0 rising to 1800/cell on day 3. In such a mixed cell populations these figures will be accurate only within a factor of 2–3 (at least 35 % B cells in spleen cell suspensions at the commencement of the culture, with up to 35–60 % of plasma blasts by day 3 and 4 of LPS treatment).Translation of the lymphoid cell mRNA in oocytes from Xenopus laevis demonstrated that stimulation of H‐mRNA synthesis was restricted to μ‐mRNA, although some γ‐mRNA was present in the original spleen cells.High levels of synthesis of immunoglobulin followed after a lag period of about 24 h following LPS addition peaking after 48 h adn 72 h; the proportional Ig production relative to total protein synthesis reached 26 % on days 3 and 4. Stimulation of Ig production was limited to IgM.Rapid stimulation of mitosis and H‐mRNA synthesis thus precedes the maximum synthesis of Ig molecules, suggesting a translational block on the transport of H‐mRNA from the nucleus during early stages of activation.
Soluble HL‐A antigens in serum. I. Isolation and Purification
Authors: Oh S. K. , Pellegrino M. A. , Ferrone S. , Sevier E. D. , Reisfeld R. A. 
Published: February 2007

AbstractA new method was developed which utilizes fractional salting out, gel filtration, ion exchange chromatography and polyacrylamide gel electrophoresis for the isolation and purification of soluble HL‐A antigens from serum. The method produced purified antigens possessing HL‐A 5,9 specificities with yield up to 60 % of that detected in the original serum. Up to 150‐fold increase in specific HL‐A antigenic activity above that in the starting material could be achieved as measured by the ability of the purified antigens to specifically inhibit the cytotoxic activity of HL‐A alloantisera against selected target cells. Electrophoretically purified HL‐A antigens with different specificities appear to have a similar molecular size, i.e. 33 000, but differ in their electric charge properties. β2‐microglobulin (β2m) seems to be noncovalently associated with HL‐A antigens present in serum, but during purification β2m is progressively lost until at the final purification by polyacrylamide gel electrophoresis, the material is completely devoid of β2m.
Turnover of radioiodinated and of leucine‐labeled immunoglobulin M in murine splenic lymphocytes
Authors: Melchers F. , Cone R. E. 
Published: February 2007

AbstractLactoperoxidase‐catalyzed radioiodination of cell surface proteins and biosynthetic incorporation of tritiated leucine were used to study the size and turnover of cell‐associated immunoglobulins in splenic lymphocytes of different size from BALB/c, C3H, and nu/nu mice.Small spleen cells, separated from large cells by velocity sedimentation, showed a single slow rate of turnover (t1/2= 10–30 h) of surface radioiodinated or leucine‐labeled IgM released as the monomeric 7–8 S subunit of IgM. Mitogen‐activated large B cells and nonstimulated large spleen cells, separated by velocity sedimentation, released leucine‐labeled IgM in an initial rapid phase (t1/2= 2–4 h) as 19 S IgM, and later released 7–8 S IgM slowly (t1/2= 10–30 h). The iodination reaction changed neither the biphasic mode of turnover, nor, even at higher concentration of H2O2, the size of the actively secreted 19 S IgM. Radioiodination of mitogen‐activated large cells or of unstimulated large cells labeled only the slowly released 7–8 S IgM, not the actively secreted 19 S IgM. Large cells of nonstimulated spleen, however, released radioiodinated as well as leucine‐labeled IgM also rapidly (t1/2= 1–3 h). These rapidly released IgM molecules were found to be 7–8 S IgM subunits.Our results indicate that these turnover rate and size differences of radioiodinated and of leucine‐labeled IgM released from murine spleen cells are in part resulting from the differences in the methodology of labeling and are in other parts due to different small and large splenic lymphocytes releasing IgM of different size at different rates.
B cell tolerance induced by polymeric antigens. I. Comparison of thedose and epitope density requirement for inactivation of primed and unprimed B cells in vivo
Authors: Klaus G. G. B. , Humphrey J. H. 
Published: February 2007

AbstractHapten [2,4‐dinitrophenyl (DNP)]‐specific tolerance was induced in nonimmun or DNP‐hemocyanin (DNP‐KLH) primed mice by administering hapten‐conjugated type 3 pneumococcal polysaccharide (DNP‐lys‐S3). The dose of DNP‐lys2.5−S3 required to suppress the primary anti‐DNP antibody responses was appaprox‐imately ten times higher than that required to suppress the secondary response Large doses of lightly substituted antigen (DNP‐lys0.6−S3) had no effect on prim‐ary antibody responses, while small doses of this conjugate suppressed 90—95 % of the secondary response. The conclusion from this (presumably B cell) tolerance model is that B lymphocytes “mature” in their susceptibility to tolerization following primary contact with immunogen, since primed cells are inactivated by lower doses of tolerogen, and by tolerogen with lower epitope density, than no immune B cells. These and other data suggest that the tolerance threshold of B lymphocytes is related to their state of differentiation, and especially to their antigen‐binding characteristics.
Stimulation of mixed lymphocyte cultures and cytotoxic responses: evidence that T cells express SD but not LD antigens, whereas B cells express both
Authors: Simpson Elizabeth 
Published: February 2007

AbstractBy separating T and B cells from stimulator spleens it has been found that mixed lymphocyte response (MLR) and cytotoxic cells are generated in responder T cell populations by B but not by T stimulator cells in a wide variety of strain combinations.It is suggested that MLR‐stimulating or LD antigens are expressed on B but not T cells, and that their presence is necessary in order to generate cototoxic responses to H‐2K and/or H‐2D (or SD) antigens which are present on both T and B cells. The finding that B cells and macrophages stimulate MLR is consistent with the hypothesis that Ia antigens, expressed on both these cell types but not on nylon column purified peripheral T cells, are the MLR‐stimulating or LD determinants.
The development of the thymus in the nude mouse
Authors: Owen J. J. T. , Jordan R. K. , Raff M. C. 
Published: February 2007

AbstractThe developing thymus of nude mouse embryos (derived from homozygous, nu/nu × nu/nu, matings) has been examined from 13 days' gestation onwards for the presence of large basophilic stem cells or their lymphoid progeny. No trace of either stem cells or lymphocytes has been found at any stage, indicating that from the earliest stages of thymic development lymphopoiesis is defective. However, histological evidence alone is not sufficient to rule out the possibility that small numbers of lymphocytes may be present in the nude thymus. Recent evidence that nude mice born of heterozygous (nu/+) females possess some T lymphocytes and “T lineage” cells is discussed in relation to these findings. A series of morphological changes have been defined within the epithelial component of the developing nude thymus, further analysis of which may help to determine the nature of the thymic defect.
Kinetics of the reactive cell clones after immunosuppression and induction of tolerance. II. Different recovery of 19 S and 7 S plaque‐forming cells after induction of tolerance
Authors: Botzenhardt U. , Lemmel E.‐M. 
Published: February 2007

AbstractBy the aid of two alkylating agents (cyclophosphamide (CP) and 036.5122, (Asta), applied after a single dose of antigen, tolerance to sheep red blood cells (SRBC), has been induced in NMRI mice. Duration and characteristics of recovery were followed by a second antigenic challenge at various time intervals and by determination of 19 S and 7 S plaque‐forming cells (PFC) 4 days later. During recovery from the tolerant state two phases of responsiveness could be differentiated: an early phase with no or markedly reduced numbers of total PFC, all of them being of the IgM type; a later phase with a steady increase in total PFC up to normal values, paralleled by an increase in the proportion of 7 S PFC finally reaching 90% of total PFC. In comparison with CP, recovery from tolerance induced by equitoxic doses of 5122 were delayed and modified. Even after 8 weeks, total PFC to SRBC were still depressed, and the ratio 19 S/7 S PFC resembled neither a typical primary nor secondary pattern.It is concluded that CP‐mediated immunological tolerance is followed spontaneously by the establishment of a memory state. This observation, in agreement with findings of other authors, is interpreted as the expression of an established B cell memory compartment during the period of deficient T cell activity. The long‐lasting modification of specific responsiveness after 5122 indicates a profound disturbance of the potency to recover from the impact of this alkylating agent, the biological base of which is as yet unidentified.It is suggested that observation of the characteristic features during the recovery phase from tolerance may help to clarify the nature of the defect in specific responsiveness.
Histocompatibility antigens and genetic control of the immune response in guinea pigs. II. Specific inhibition of antigen‐induced lymphocyte proliferation by anti‐receptor alloantisera
Authors: Geczy A. F. , Geczy C. L. , de Weck A. L. 
Published: February 2007

AbstractThe in vitro recognition of acetylsalicilyl ovalbumin, penicilloylated bovine IgG (BPO‐BGG) and the multichain copolymer poly‐L‐(Tyr, Glu)‐poly‐DL‐Ala‐poly‐L‐Lys [(T, G)‐A‐L] by primed (2 × 13) F1 cells could be markedly and specifically blocked by alloantisera directed against “receptors” (R) or recognition structures for these antigens. The antisera were raised against lymphoid cells from various F2 hybrid guinea pigs of (2 × 13) histocompatibility type in which responsiveness to low doses of acetylsalicylic acid anhydride, BPO‐BGG and (T, G)‐A‐L segregated independently of each other. One of the genes required for the expression of high responsiveness appears to be linked to the 13 MHC genes. The anti‐R antisera did not contain antibodies capable of interacting directly with the stimulating antigen since passage of the sera through antigen‐immunoadsorbent columns did not remove antibodies capable of suppressing in vitro recognition. Furthermore, the antisera did not appear to contain cytotoxic antibodies directed against specific antigen‐sensitive cells. The activity of the anti‐R sera was highly specific: their inhibitory activity could only be absorbed by lymphoid cells bearing the specific recognition structures for the appropriate antigen. Preliminary experiments yield no indication that the anti‐R antisera are specific for immunoglobulin idiotypes.
A general method for enumerating single cells secreting antigen: albumin‐secreting hepatocytes detected as plaque‐forming cells
Authors: Molinaro G. A. , Maron E. , Eby W. C. , Dray S. 
Published: February 2007

AbstractSheep erythrocytes, artificially coated with purified antibody specific for mouse serum albumin (anti‐MSA Ab‐E) were agglutinated and lysed by mouse serum albumin. Mouse liver cells, plated with anti‐MSA Ab‐E formed hemolytic plaques in a modified plaque in a modified plaque‐forming cell (PFC) assay. The same cells tested with anti‐MSA Ab‐E did not rosette in a modified immunocytoadhesion assay. Thus, liver cells secreted molecules (albumin) which were not detectable on the cell membrane. This PFC assay with Ab‐E is probably a general method for enumerating antigen‐secreting cells.
Immunological maturation in cell‐mediated immunity: progressive increase with time after sensitization in the ability of guinea pig peritoneal cells to discriminate between cross‐reacting determinants
Authors: Jokipii Liisa , Jokipii A. M. M. , Leskowitz S. , Kosunen T. U. 
Published: February 2007

AbstractGuinea pigs were sensitized with the azobenzenearsonate (ABA) conjugates of the N‐acetyl derivatives of L‐tyrosine, L‐histidine and L‐tryptophan in complete Freund's adjuvant. After 4, 9 or 14 weeks, pertioneal cell migration inhibition was tested with each conjugate separately. The ABA‐specific reactivity was strongest at four weeks, but at that time there was no detectable immunological specificity beyond the ABA moiety. The ability to discriminate between the homologous and heterologous conjugates appeared between 4 and 9 weeks, and was also found at 14 weeks. Increasing fine specificity discrimination between cross‐reacting immunogenic determinants was interpreted as increasing average affinity of the recognition structures involved in peritoneal cell migration inhibition, i.e. the recognition structures of thymus‐dependent lymphocytes.
Dual pathway of B lymphocyte differentiation in vitro
Authors: Askonas Brigitte A. , Roelants G. E. , Mayor‐Withey Kathleen S. , Welstead Jacqueline L. 
Published: February 2007

AbstractDirect visualization of the events resulting from LPS stimulation of mouse spleen cells in vitro was achieved by characterizing the cells during four days of culture for morphology, Ig and Θ surface markers and autoradiography after [3H] thymidine uptake. The changes observed were related to biochemical parameters such as incorporation of [3H] thymidine into DNA, Ig biosynthesis and secretion.Two pathways of B lymphocyte differentiation were observed: a) the generation of a large number of small B lymphocytes with high density of surface Ig but no internal pool detectable by immunofluorescence, and b) the maturation of a very small proportion of cells with a large intracellular pool and the ability to secrete Ig. Both cell types arise from dividing blast cells, either physically separated or traced by pulse chase experiments with [3H] thymidine.We discuss whether this duality is caused by the triggering of different B cell subpopulations at different developmental stages, preprogramed to one or the other pathway or whether the final direction of development depends on the microenvironment of individual dividing cells.
Modifications of the thymocyte membrane during redistribution of concanavalin A receptors
Authors: Wioland M. , Dormer M. , Neauport‐Sautes C. 
Published: February 2007

AbstractThe modifications of the thymocyte membrane which are induced by concanavalin A (Con A) were studied by means of the variation of electro phoretic mobility which the lectin induces on the cell. The electrophoretic mobility of thymocytes is increased when Con A is used under conditions expected to induce a cap formation and the subsequent endocytosis. This increase persists as long as the lectin is present in the medium and disappears as soon as the lectin is eliminated. The redistribution of the Con A receptors into spots and caps may partially explain this electrical modification. The ionized groups of the thymocyte membrane are drastically modified during these phenomena with: 1) a diminution by 61% in the density of the sialic carboxyl groups, 2) a decrease of 40% in the density of phosphate groups and of 60% in the density of amino groups, 3) a 20 times higher density of unidentified negatively charged groups.The electrophoretic mobility of normal human blood lymphocytes is similarly increased by Con A. A marginal difference exists in the shape of the dose response curves obtained when normal and cancerous thymocytes react with increasing doses of Con A. No measurable electrical modification was observed during redistribution of H‐2 and Thy‐1.2 antigens on EL4 cells.Some experiments suggest a possible correlation between the mitogenicity of the lectin and a measurable modification of the cell electrophoretic mobility.