bluuebunny/crossref_metadata_2025 huggingface dataset:
Bursal and postbursal cells in chicken. Occurrence of postbursal cells in bone marrow, thymus and spleen
Authors: Toivanen P. , Toivanen A. , Tamminen P.
Published: February 2007

To study the postbursal nature of lymphoid cells found in the bone marrow, thymus and spleen, their capacity for a long‐term restoration of bursa‐dependent immune functions and of bursal and splenic morphology was evaluated using cyclophosphamide‐treated chicks as cell recipients. The results reveal that postbursal cells appear in significant numbers, first in the spleen and then in the bone marrow and thymus. This observation is interpreted to indicate that migration of postbursal cells from the bursa to bone marrow and thymus most probably occurs through the spleen. The findings also indicate that in the development of the B cell line an early postbursal cell and a mature postbursal cell can be distinguished. Both of these cell types are capable of further function without the influence of a bursal microenvironment. The mature postbursal cell does not have a capacity for formation of germinal centers in significant numbers in the spleen, but the early postbursal cell still shares this potential with its precursor, the bursal stem cell. They are also distinguishable by a slight proliferation of the early postbursal cells in the bursa when transferred into cyclophosphamide‐treated newly‐hatched recipients. Both of these cell types represent distinct entities in the stepwise development of the B cell line.
The gut‐associated lymphoid system: nature and properties of the large dividing cells
Authors: Guy‐Grand Delphine , Griscelli C. , Vassali P.
Published: February 2007

The nature of the lymphoid cells and blasts (i.e. cells labeled in vitro with [3H]‐thymidine) of the Peyer's patches (PP), mesenteric lymph nodes (MLN) and thoracic duct lymph (TDL) has been studied by combined immunofluorescence and radioautography, using antisera directed against T (MSLA) or B (MBLA) cell antigenic determinants, or against various Ig chains. The migration pattern of these various cell populations after transfer to syngeneic mice or rats was determined by radioactivity counting and radioautography and the nature of the homed cells was studied by combined immunofluorescence and radioautography. B and T blasts from MLN and TDL have, in contrast to blasts from the peripheral lymph nodes, a marked tendancy to home in the gut, and migrate as well in a graft of fetal intestine as in the recipient's own gut, indicating that this selective accumulation is not the result of a mechanism recognizing antigen absorbed from the gut lumen.

The gut‐homing B blasts are cells bearing surface IgA (sIgA) and containing intracellular IgA, which transform into IgA plasam cells in the lamina propria. Evidence is discussed that the progenitors of the intestinal IgA plasma cells are proliferating sIgA cells from the PP geerminal centers, which migrate via lymphatics to MLN and TDL and mature during this migration, acquiring intracellular IgA chains as well as a gut‐homing mechanism which might be related to this increased IgA synthesis.

The gut‐homing T blasts migrate both in the lamina propria and the intestinal epithelium. Most, if not all, the intraepithelial lymphocytes of the gut mucosa appear to be T lymphocytes derived from rapidly dividing cells. Evidence is presented for the existence in the lymphoid system of two types of T blasts, one that is circulating and has a marked tendancy to home to the gut, and a second that does not home to the gut and may be sessile.
Allotypic markers of rhesus monkey immunoglobulin G
Authors: Kruisbeek Ada M. , Rádl J. , Swart A. C. W.
Published: February 2007

An allotypic specificity, Ma(1) (Ma as an abbreviation of Macaca), of rhesus monkey IgG is described; it was identified by an alloantiserum, anti‐Ma(1). Ma(1) is located on Fc fragments of IgG molecules.

Family studies showed that the allotype Ma(1) is inherited; it occurs in 25 percent of the rhesus monkeys from a random population.

Immunization with slightly polymerized IgG proved to be a suitable way to raise anti‐allotype antisera.
The genetic control of the immune response to different antigenic determinants within the synthetic polypeptide poly (His,Glu)‐polyPro–poly Lys
Authors: Mozes Edna , Shaltiel S. , Sela M.
Published: February 2007

The development of a new method for the protection of histidine residues during synthesis of polyamino acids has made it possible to prepare a histidine‐containing polymer built on multichain polyproline. The new polypeptide, poly(LHis, LGlu)‐polyLPro–polyLLys, designated (H,G)‐Pro–L, was used for studying the genetic control of the immune response in inbred mouse strains. The new polymer appeared to be a potent immunogen, provoking high antibody titers already at the primary response. Although most of the mouse strains studied responded well to (H,G)‐Pro–L, differences were observed in the specificity of the antibodies elicited in the various strains. Some of the responding strains (C3H/HeJ, AKR/Cu) produced antibodies mainly to the (H,G) determinant, whereas another high responding strain, SJL/J, elicited antibodies specific to the Pro–L moiety exclusively. A third group of strains responded to determinants that are characterized by the very combination of the above specificities. The response potential to the (H,G) part of the immunogen was found to be linked to the major histocompatibility (H‐2) locus of the mouse, whereas the capacity to produce antibodies to the polyproline region of (H,G)‐Pro–L or to determinants in which the (H,G) and Pro‐L moieties participate was found not to be linked to H‐2. Thus, the ability to respond to (H,G)‐Pro–L is controlled by at least three immune response genes.
Detection and quantitation of IgG on the surface of human lymphoid cells by rosette formation with protein A‐coated sheep red blood cells
Authors: Ghetie V. , Nilsson K. , Sjöquist J.
Published: February 2007

Sheep red blood cells coated with protein A of Staphylococcus aureus (SpA) form rosettes with human lymphoid cells with surface‐associated IgG and with cells treated with antibodies of the IgG class against some of the cell membrane antigens. Inhibition of rosette formation by SpA was used for quantitation of immunoglobulins on the cell surface.

The sensitivity of the method permits the quantitation of 104 – 105 molecules of IgG receptors and detected less than 104 antibody molecules of the IgG class bound to the surface of IgM‐producing cells.

This method seems to be suitable for detection and quantitation of membrane‐associated antigens including immunoglobulins.
Estimation of the amount and tissue distribution of rat Thy‐1.1 antigen
Authors: Acton R. T. , Morris R. J. , Williams A. F.
Published: February 2007

The distribution and amount of Thy‐1.1 antigen expressed in rat and mouse tissues have been studied. When anti‐Thy‐1.1 antisera were absorbed with various tissues and assayed by cytotoxicity or radioactive binding assays, it was found that antigen was expressed in similar amounts on thymocytes and brain of both species. Lymphocytic leukemia cells from PVG/c rats also expressed as much Thy‐1.1 as rat thymocytes. In contrast, Thy‐1.1 was only detected in very small amounts on rat lymph node cells or thoracic duct lymphocytes; the level was 20‐fold less than the AKR mouse equivalent. Rat spleen cells had larger amounts than other peripheral rat lymphocytes, and had only 2–3 times less antigen than AKR spleen cells.

These results were confirmed by direct binding assays which showed that AKR mouse and PVG/c rat thymocytes bound more than 500000 molecules of anti‐Thy‐1.1 antibody per cell. Autoradiographic analysis showed 90 % of thymocytes, 12 % of spleen cells, and 2 % of lymph node or thoracic duct lymphocytes of the rat to be specifically labeled.
Clones of antibody‐forming cells in pokeweed mitogen stimulated microcultures. II. Estimation of the frequency of precursor cells and the average clone size
Authors: Quintáns J. , Lefkovits I.
Published: February 2007

In allogeneically complemented microcultures of nude spleen cells, the frequency of B precursor cells engaged in the anti‐SRC response is considerably higher in the presence of pokeweed mitogen (PWM) (3 × 10−5 – 1 × 10−4) than in the absence of PWM (1.1 × 10−5 – 5 × 10−5). These precursor cells, in the absence of PWM, give rise to clones of plaque‐forming cells (PFC) with an average clone size of 30–70 at the peak of the response. The addition of PWM results in a smaller average clone size (20–40 PFC/clone) as well as an early decline of the response. It is proposed that in this system at least, PWM does not act mainly as a mitogen but rather as an agent that in the presence of T cells, induces the maturation of B cells.
Resistance to hydrocortisone conferred upon thymocytes by a thymic humoral factor
Authors: Trainin N. , Levo Y. , Rotter Varda
Published: February 2007

Treatment of thymic cells with thymus humoral factor (THF) increased their capacity to elicit a graft‐versus‐host (GVH) reaction in vitro. Similarly, it was shown that in vitro THF treatment of thymic cells increased the resistance of these cells to hydrocortisone (HC) succinate. These results suggest that THF can increase the HC‐resistant compartment of the thymus cell population by transforming the HC‐sensitive cells into resistant ones.
The role of thymus‐derived lymphocytes in an antibody‐mediated hapten‐specific helper effect
Authors: Janeway C. A. , Koren H. S. , Paul W. E.
Published: February 2007

The cellular basis of the antibody‐mediated, hapten‐specific anti‐idiotype antibody response of CBA/J mice to a hapten conjugate of the BALB/c myeloma protein LPC‐1 was examined. Previous studies have shown that anti‐idiotype antibody is produced if the mice are given anti‐2,4‐dinitrophenyl (DNP) antibody and then immunized with DNP‐LPC‐1; immunization with DNP‐LPC‐1 or LPC‐1 alone does not lead to the production of this antibody. In the present experiments, mice depleted of thymus‐derived lymphocytes by two different techniques failed to make anti‐idiotype antibody after transfer of anti‐DNP antibody and immunization with DNP‐LPC‐1. However, thymus‐deprived mice given anti‐DNP antibody in response to DNP‐LPC‐1. Thymocytes could not reconstitute such mice for this response. The possible mechanisms for this hapten‐specific, antibody‐mediated, T cell‐dependent helper effect are discussed. It is felt that such helper effects represent an alernate pathway to conventional specific, T cell‐mediated cooperation. Further examples of antibody‐mediated helper effects which support this hypothesis are also presented.
Spontaneous release of T cell receptors for alloantigens. II. Induction of antibodies of T cell receptors
Authors: Ramseier H.
Published: February 2007

Spleen cells from normal mice, when cultivated in vitro, released receptors or recognition structures (RS) for alloantigens into the surrounding medium. The spontaneous shedding of receptors was revealed by their ability to induce the formation of anti‐recognition structure (anti‐RS) antibodies upon injection into appropriate F1 hybrid recipients. Cell suspensions containing T and B lymphocytes and those containing T lymphocytes wer capable of inducing anti‐RS antibody formation, whereas supensions devoid of T cells were incapable of doing so. Receptors shed from such cell suspensions during a 24‐hour cultivation period gave exactly the same results. Cell‐free culture supernatants, however, incited higher anti‐RS antibody titers, presumably because of an accumulation of RS. The capacity of released T cell receptors to recognize alloantigens as determined in the PAR assay and their ability to induce anti‐RS antibodies went roughly parallel.
Similar specificity fo IgG1 and IgG2a antibodies in individumice
Authors: Kolb H. , Trissl Dorothesa
Published: February 2007

In this study the previous finding of similar variable regions in individual IgG1 and IgG2a antibody populations is extended by the demonstrations of similar fine specificity of IgG1 and IgG2a combining sites. Antibody populations form individual mice directed against oligo‐D‐alanine determinants were analyzed in their cross‐reactivityb towards 5 heterologous dipeptides. This was done by mixing antibody and hapten followed by determination of free antibodies in a kinetic red cells sensitization assay. The comparison of hyperimmune sera fror 10 mice showed that genetically identical mice can differ significantly in their cross‐reaction pattern. Within each serum the cross‐reaction pattern was determinated for IgG1 and IgG2a. With a few exceptions the same individual pattern was found in both IgG1 and IgG2a antibody populations. This was taken as evidence that the combining sites of IgG1 and IgG2a anti‐oligo‐D‐alanine antibody populations in an individual mouse are similar.
Denaturing effect of x‐irradation on deoxyribonucleic acid aqueous solutions. An immunochemical study
Authors: Natali Pier G.
Published: February 2007

The denaturation of calf thymus DNA aqueous solution following x‐ray radiation (x‐DNA) has been investigated with the help of a rabbit anti‐denatured DNA antiserum. These antibodies were shown to recognize exclusively single‐stranded DNA determinants on DNA molecule in double immunodiffusion analysis. By means of this method it was possible to demonstrate that increasing numbers of single‐stranded DNA determinants wer formed in DNA solutions exposed to increasing doses of radiation. The rabbit serum appeared to be a highly sensitive reagent (0.5 μg/ml of single‐stranded DNA) capable of detecting DNA denaturation when low ionizing doses were used and when only minor changes in DNA physico‐chemical parameters were measurable. Antigenic comparison between x‐DNA and heat‐denatured DNA demonstrated that antigenic determinants are shared by the two molecules. The possible application of immunochemical methods to the study of nucleic acid denaturation of different physical and chemical agents is discussed.
Radioactive antigen suicide of an anti‐DNP (2,4‐dinitrophenyl) clone. I. Recovery and escape from clonal dominance by suici resistant precursors
Authors: McMichael A. J. , Willcox N.
Published: February 2007

An anti‐2,4‐dinitrophenyl (DNP) clone line, maintained in vivo by serial pasage through irradiated syngenic recipients, was exposed to 125I‐labeled dinitrophenylated L‐Tyr‐L‐Glu‐L‐Lys copolymer antigen of high specific a Hapten‐specific suicide was obtained, though with more difficulty than for a heterogeneous secondary response.

The recovery was followed and was shown to occur either with the same clones or with new clones, depending on conditions. After suicide at a late passage of the clone, recovery by new clones occured very rapidly. This indicated that there was a background heterogeneity in the clone system, nor suppresed by clonal dominance and that some of these new clones were suicide resistant.
Lymphocyte membrane receptors in human lymphoid leukemias
Authors: Ferrarini M. , Tonda G. P. , Risso Angela , Viale Giovanna
Published: February 2007

Membrane‐bound immunoglobulins, receptors for the Fc fragment of IgG and receptors for the third component of human or murine complement were used as B cell membrane markers to study eripheral blood lymphocytes from twentytwo patients with chronic lymphatic leukemia (CLL), five patients with acute lymphoblastic leukemia (ALL) and one patient with Sézary syndrome. The capacity of human T cells of forming „spontaneous rosettes”︁ with sheep erythrocytes was employed as T cell membrane marker.

In nineteen out of twenty‐seven CLL or ALL cases tested a larger percentage of cells than that found in normal individuals expressed at least one of the three B cell membrane markers studied. In the patient with Sézary syndrome the percentage of cells forming „spontaneous rosettes”︁ with sheep erythrocytes was larger than the normal, while cells bearing B cells markers were below the normal values.
„Natural”︁ killer cells in the mouse. II. Cytotoxic cells with specificity for mouse Moloney leukemia cells. Characteristics of the killer cell
Authors: Kiessling R. , Klein Eva , Pross H. , Wigzell H.
Published: February 2007

Normal mice contain cytolytic cells with specificity for in vitro grown mouse Moloney leukemia cells. Such killer cells are most frequent in the spleens; lymph node and bone marrow contain less and thymus virtually no killer activity. Peak activity is found around one to three months of age. Spleen cells from genetically athymic mice are as active killer cells as those from normal mice of the same strain. Treatment with anti‐theta serum plus complement followed by removal of adherent and surface Ig positive cells by filtration through anti‐Ig columns will leave between 1–5 % of the original spleen cell population from a normal mouse. These cells have the morphology of small lymphocytes and perhaps contain all of the total original killer activity of the spleen against the Moloney leukemia cells. Such killer enriched cells are devoid of T and B lymphocytes and largely fail to function in antibody induced, cell‐mediated lysis against antibody‐coated chicken erythrocytes. It is concluded that the spontaneous selective cytotoxic activity of normal mouse spleen cells against Moloney leukemia cells is exerted by small lymphocytes of yet undefined nature.
Decrease in microviscosity of lymphocyte surface membrar associated with stimulation induced by concanavalin A
Authors: Inbar M. , Shinitzky M.
Published: February 2007

Microviscosity in the surface membrane lipid core of rat lymph node lymphocytes was determined by fluorescence polarization analysis of the fluorescent hydrocarbon probe 1,6‐diphenyl‐1,3,5‐hexatriene when embedded in the membrane of intact cells, in relation to in vitro stimulation induced by concanavalin A. The apparent microviscosity in the stimulated cell population was found to be distinctively lower than in the nonstimulated cell population, based on which the membrane microviscosity of the blast cells was estimated. For each of the six experiments which were carried out the estimated microviscosity in the blast cell membranes falls between the upper and the lower limits represented by freshly drawn intact lymphocytes and leukemic cells, respectively. In accord with this observation it is suggested that a controlled reduction in the microviscosity of the surface membrane is one of the processes which take place during the stimulation of lymphocytes by antigens in vivo.
Immunological memory function of the T and B cell types: distribution over mouse spleen and lymph nodes
Authors: Romano T. J. , Mond J. J. , Thorbecke G. J.
Published: February 2007

Spleens from LAF1 mice injected intravenously with sheep erythrocytes (SE) are relatively rich in memory T cells early in the immune response (1 to 3 days) and rich in memory B cells as the response progresses (2 weeks or more). Marked cooperation for the secondary immune response in vitro was obtained by combining 106 spleen cells from LAF1 mice, taken 2 days after intravenous priming with SE, with 107 spleen cells from day 14 primed mice. The results indicate relative deficiencies in the spleen for B memory cells on days 1 to 2 and for T memory cells on day 14 after priming. Day – 14, but not day – 2, immune lymph node (LN) cells could replace the day – 2 spleen cells (anti‐Thy 1.2 sensitive) in the in vitro cooperation with day – 14 immune spleen cells.

Immune spleen cells taken 4 to 7 days after priming contain more equivalent numbers of B and T memory cells, but 10 to 7 days after transfer of such immune spleen cells without SE into irradiated recipients the T memory cells were again more prominent in lymph node and the B memory cells in spleen as shown by in vitro cooperation studies. These results suggest that during the second week after intravenous injection of SE relatively more T than B memory cells migrate from spleen to lymph node, resulting in an imbalance in the splenic memory cell population favoring B memory cell function.
Production of migration inhibitory factor and lympl toxin by non‐T cells
Authors: Bloom B. R. , Stoner G. , Gaffney Judith , Shevach E. , Green I.
Published: February 2007

Treatment of tuberculin‐sensitive guinea pig spleen or lymph node cells with a burro anti‐T cell serum plus complement diminished markedly number of functionally detectable T cells, but did not affect the amount of migration inhibitory factor (MIF) or lymphotoxin produced by the residual T cell‐depleted populations.
Primary and secondary in vitro generation of cytolytic T lymphocytes in the murine sarcoma virus system
Authors: Plata F. , Cerottini J.‐C. , Brunner K. T.
Published: February 2007

Cell‐mediated cytotoxic responses in vitro to surface antigens associated with murine sarcoma virus (MSV)‐induced tumors were investigated using mixed leukocyte‐tumor cell cultures (MLTC). The source of responding cells was either spleens from normal C57BL/6 mice (primary MLTC) or spleens of C57BL/6 mice carrying or having rejected a MSV‐induced tumor (secondary MLTC). Graffi virus‐induced GiL‐4 leukemia cells, Rauscher virus‐induced RBl‐5 leukemia cells, and MSV‐induced MSV‐B16 sarcoma cells were used as stimultating syngeneic tumor cells and/or target cells.

Under appropriate culture conditions, cytolytic T lymphocytes (CTL) were generated in both primary and secondary MLTC. As assessed by a quantitative short‐term 51Cr release assay system, CTL activity in secondary MLTC populations was at least 10‐fold higher than that in primary MLTC populations, and 100‐fold higher than that in spleen cells taken at the peak of the in vivo response of MSV‐infected mice. The ability of spleen cells to mount a secondary CTL response in vitro could be observed as early as 5 days after virus injection, increased up to the time of maximum tumor size and persisted long after tumor regression. This suggests the development of increased numbers of CTL progenitors and/or the formation of “memory” CTL in spleens of MSV‐injected mice.
Nonspecific acid esterase activity: A criterion for differentation of T and B lymphocytes in mouse lymph nodes
Authors: Mueller J. , del Re G. Brun , Buerki H. , Keller H.‐U. , Hess M. W. , Cottier H.
Published: February 2007

A modified technique was used to demonstrate lymphocytic acid α‐napth acetate esterase activity in frozen sections of mouse lymphoid tissue or smears. Positive, dot‐like reaction products were noticed in more than 94 % of the lymphocytes located in the diffuse cortical (“paracortical”, “thymus‐dependent”) area of mesenteric lymph nodes of young adult ICR mice. Almost identical values were found for lymphocytes in the cisterna chyli. In contrast, the follicular cortex, which is predominantly occupied by B cells, contained less than 7 esterase‐positive lymphocytes. In vitro, cytotoxic anti‐θ serum destroyed vast majority of esterase‐positive lymphocytes while esterase‐negative lymphocytes were resistent to this treatment. In mesenteric nodes of nude BALB/(nu/nu) mice, follicular cortex and paracortex together contained approximately 16 times less esterase‐positive lymphocytes than in the immunologically competen hybrid BALB/c (nu/+) animals. These findings indicate that non‐specific acid esterase activity may serve as a criterion to differentiate peripheral T B lymphocytes in lymphocytes in lymph node sections and smears of mice by light microscopy Possible implications of this enzyme activity in thymus‐derived lymphocytes are discussed.
Analysis in deoxycholate of three antigenic specificities associated with the rat Thy‐1 molecule
Authors: Morris R. J. , Letarte‐Muirhead Michelle , Williams A. F.
Published: February 2007

Three antigens similar in tissue distribution can be identified on rat thymocytes; the Thy‐1.1 antigen, a rat specific xenoantigen, and a rat‐mouse cross‐reacting xenoantigen. To determine if these three antigens were on the same molecule their behavior in detergent‐solubilized extracts from thymocytes was studied. Membrane fragments containing Thy‐1.1 activity were prepared by a rapid method involving the use of Tween‐40 detergent, and were solubilized in deoxycholate. The 150 000 × g supernatant from this extract contained aproximately 50 % of the original Thy‐1.1 and xenoantigen activity. The supernatant was chromatographed on Sephadex G‐200, and subjected to zone sedimentation on sucrose gradients in H2O and 2H2O to determine the hydrodynamic properties of the antigens. The three antigens migrated in identical fashion in all cases, and behaved as a molecule of 28 000 daltons molecular weight. When the antigenically active fraction, recovered after chromatography on Sephadex G‐200, was passed through an immunoabsorbent consisting of rabbit antibody to one of the xenoantigens, all three antigens were equally depleted compared with passage through a control column.

The results of these experiments suggested that Thy‐1.1 antigen and the two xenoantigens were closely associated and most probably all on the Thy‐1 molecule.
Studies on the effect of various agents on the maturation of thymus stem cells
Authors: Singh U. , Owen J. J. T.
Published: February 2007

Experiments were carried out on 14‐day fetal mouse thymic stem cells which were treated with agents known to increase cellular cAMP levels for a period of 90 min at 37 °C. When compared to controls, a high proportion of treated stem cells were found to develop Thy‐1 (θ) antigen as indicated by dye exclusion tests using anti‐Thy‐1 serum and complement.
Regulation of the immune response by subclasses of T lymphocytes. I. Interactions between pre‐killer T cells and regulatory T cells obtained from peripheral lymphoid tissues of mice
Authors: Cantor H , Simpson Elizabeth
Published: February 2007

The generation of killer cells to alloantigens in vitro depends upon an interaction between two subclasses of peripheral T cells: “pre‐killer” T cells and “regulatory” T cells.

The pre‐killer T cell, found in highest concentrations in peripheral lymph nodes of mice, is sensitive in vivo to the administration of small doses of anti‐thymocyte serum (ATS) and is depleted in vitro by treatment with (a) anti‐Thy‐1.2 + C, (b) low doses (600 r) of x‐irradiation. Specificity of pre‐killer cells is supported by adsorption of pre‐killer activity on appropriate allogeneic monolyers and by the specific absence of this activity from lymphoid tissues of mice rendered tolerant in neonatal life.

Although T cells remaining in the spleen 2 days after a small dose of ATS (SPA−T) did not generate killer cells, this subset exerted substantial regulatory effects upon the generation of killer activity by pre‐killer T cells. The addition of this population of regulatory T cells to small numbers of lymph node T cells (LN‐T) resulted in substantial enhancement in the generationof killer cells from the LN‐T pre‐killers. The addition ofSPA−T to larger numbers of LN‐T (which produce strong responses alone), failed to enhance the response, and insome cases resulted in significant suppression which could not easily beaccounted for by alteration in cell numbers in culture. Although amplifier activity was relatively radioresistant, “suppressor” activity was sensitive to relatively small doses of irradiation. The significance of this T‐T interaction is discussed.
A network theory of the immune system
Authors: Richter P. H.
Published: February 2007

The face that every antibody also had antigenic properties leads to the existence of a functional network of interacting antibodies and lymphocytes in the immune system. With a minimum set of assumptions about thenature of these interactions some of the principal features of the immune response such as normal primary and secondary response, low and highzone tolerance induction, and memory can be reproduced. The low zone tolerance phenomenon plays a central role in our theory, as it is the simplest nontrivial mode of response to an antigenic stimulus. It may be understood as the defeat of the stimulated lymphocyte species against their internal adversaries. The normal response and high zone tolerance induction may be characterized as low zone tolerance on a second and third level of a hierarchy of lymphocyte populations. In particular, the weakness of the primary response in explained in terms of internal struggles whichlead to a final suppression of the aggressors, thereby opening the way for an unhindered secondary response.
Analysis of antibody populations to oligo‐D‐alanine. VIII. Sequential studies on properties of antibody subpopulations: rate constant, affinity, and isoelectric focusing spectrum
Authors: Weiler Ivan Jeanne , Bosma G , Dittrich B , Weiler E
Published: February 2007

Allotypically marked antisera to the hapten oligo‐D‐alanine were studied over periods up to 10 months in individual mice and in serial transfers of both nonimmune and memory cells to irradiated recipients. Parameters observed were divalent association rate constants, affinity and autoradiography of isoelectric focusing (IEF) spectra.

The two allotypic subpopulations of heterozygous mice are shown to be independent with respect to affinity. Association rate constant, affinity, and IEF spectra of the antibody populations remain largely stable in most mice over prolonged periods. There is an occasional isolated dramatic change in a single property of one allotypic subpopulation; this may be in the direction of either lower or higher rate constant or affinity.

While different recipients of naive spleen cells from a single donor, when immunized, differ one from the other in the measured antibody properties, the characteristics now established in each recipient persist in a lineage of transferred memory cells up to 4 generations, with infrequent changes in isolated properties of only one allotypic subpopulation. The limited changes observed would be in agreement with a model of moderate somatic variability superimposed on a small spectrum of germ line genes.
Antibody production to lipopolysaccharide in thymectomized Xenopus
Authors: Collie Madeleine H. , Turner R. J. , Manning Margaret J.
Published: February 2007

Xenopus toadlets, some of which had been thymectomized as larvae, were immunized with E. coli lipopolysaccharide. Antibody titers were similar in thymectomized and intact toadlets. Antibody was exclusively IgM. The results suggest that a division into thymus‐dependent and thymus‐independent antibody responses extends at least as far back in phylogeny as the amphibians.
A simple rosette assay for demonstration of complement receptor sites using complement‐coated zymosan beads
Authors: Huber CH , Wigzell H
Published: February 2007

In the present article we describe a simple rosette assay for detection of C3 receptor‐bearing B lymphocytes with complement (C)‐coated zymosan (Zy) beads. Zy coated with murine or human C bound to a distinct population of human and mouse lymphocytes as well as to the majority of lymphoblastoid cells of several human established cell lines. Rosette formation was also observed with human red blood cells, with human monocytes and neutrophils. Experiments with anti‐immunoglobulin sera, with other B and T cell markers and with mouse thymocytes proved that the capacity to bind C‐coated Zy is primarily a feature of B lymphocytes. The following findings suggested that C‐coated Zy is bound via receptor sites for the activated components of C3: (a) Zy coated with C3‐deficient serum failed to bind, (b) comparable percentages of various lymphoid and nonlymphoid cells formed rosettes with C‐coated Zy as well as with antibody and C‐coated sheep red bloodcells, and (c) antibodies against human or murine C3 inhibited the binding of C‐coated Zy.
Suppression of immune response to sheep red blood cells in mice treated with preparations of a tumor cell component and in tumor‐bearing mice
Authors: Pikovski Mary A. , Ziffroni‐Gallon Y. , Witz I. P.
Published: February 2007

The frequency of rosette‐forming cells (RFC) in spleens of mice immunized with sheep red blood cells (SRBC) was significantly reduced by pretreatment with preparations obtained from tumor extracts. This effect was not produced by preparations obtained by similar methods from normal tissue extracts. Significant suppression of RFC frequency was also found in spleens of mice immunized with SRBC at late stages of tumor growth, as compared to that in immunized controls and in mice bearing tumors at early stages.

The results suggest that at late stages, a tumor cell component is released by tumor cells which may be similar to the nondialyzable immune suppressive factor(s) separated by us from tumor extracts, factors found in ascites fluid of tumor‐bearing mice and those known to be released from tumor cells in vitro.
Graft‐versus‐host reaction induced by Peyer's patches
Authors: Eloy Rosy , Vuitton D. , Vaultier J.‐P. , Grenier J. F.
Published: February 2007

Parental Peyer's patches were implanted into the anterior hepatic lobe of F1 hybrid rats. Using conventional histological techniques, phenomena typical of a graft‐versus‐host reaction were observed, such as paravascular lymphoid infiltration in the liver, cellular depletion of the thymus‐dependent areas of spleen, and diffuse reticuloendothelial cell proliferation in various lymphoid tissues. Based on these findings and other observations it is concluded that a thymus‐dependent cell population is present in the Peyer's patches.
A human lymphoid cell line with an IgG‐like membrane component
Authors: Nilsson K. , Ghetie V. , Sjöquist J.
Published: February 2007

A human lymphoid cell line (S95) with surface‐located IgG is described. The line was derived from a patient with Hodgkin's disease and is aneuploid. Its characterstics are suggestive of a malignant B lymphocyte derivation, but no ultimate proof of malignancy can be forwarded. The line produces immunoglobulin (IgG) which appears to be devoid of light chain. The amount of IgG detectable at the cell surface by inhibition of the rosette formation by protein A‐coated sheep red blood cells with protein A was 5–10 ng/106 cells corresponding to 70 000 – 140 000 molecules/cell. The immunoglobulin is membrane bound. Partial characterization of the IgG‐like protein shows that it has a molecular weight of 50 000 Daltons and that the molecule lacks some of the normal γ‐chain determinants.
The nature of active and passive thyroglobulin binding lymphoid cells in Obese strain (OS) chickens
Authors: Richter E. , Wick G. , Schauenstein K.
Published: February 2007

Thyroglobulin‐binding lymphoid cells were identified in the spleen of Obese strain (OS) chickens by their capacity to form rosettes with thyroglobulin‐coated chicken red blood cells. The nature of these cells was studied in inhibition experiments using turkey anti‐chicken bursa or thymus cell sera and rabbit antisera specific for chicken Ig, γ, μ, α, Fabγ or Fcγ. Spleen cells actively synthesizing surface receptors for thyroglobulin were identified as B cells and the receptors found to be complete IgM molecules. Normal T cells became thyroglobulin‐rosette‐forming cells via passive adsorption of thyroglobulin antibodies, a phenomenon which could be inhibited competitively by the addition of normal chicken serum to the incubation medium. Thyroglobulin antibodies passively adsorbed onto the surface of normal T cells also belong to the IgM class as verified both by inhibition experiments and studies employing IgM and IgG fractions of a high titered OS serum for the preincubation of the cell suspension. Only preincubation with the IgM fraction of the anti‐thyroglobulin antibodies resulted in the formation of significant numbers of passive rosette‐forming cells.
Expression of a receptor for IgM by human T cells in vitro
Authors: Moretta L. , Ferrarini M. , Durante Maria Laura , Mingari Maria Cristina
Published: February 2007

The capacity of human peripheral blood lymphocytes (PBL) to bind antigen‐IgG antibody (EA(IgG)) and antigen‐IgM antibody (EA(IgM)) complexes was investigated using a rosette technique with ox erythrocytes coated with rabbit IgG or IgM antibody. It was found that while EA(IgG)‐rosette‐forming cells (RFC) were detected on PBL freshly drawn from normal individuals, EA(IgM)‐RFC were present only in suspensions kept in culture for 24 h in mediá supplemented with sera containing very low or no amounts of IgM. Experiments of simultaneous detection of EA(IgG)‐RFC or EA(IgM)‐RFC and other membrane markers for human T or B cells together with experiments on purified T or B cell populations indicated that EA(IgG)‐RFC were formed by both T and B cells, while T cells only were capable of EA(IgM) rosette formation.

The specificity of the receptors for IgG and IgM was determined by studying the inhibitory capacity of purified human IgM and IgG in the rosette assay. The receptor for IgG was inhibited by IgG and not by IgM, while the reverse was true for the receptor for IgM.
The role of thymus on autosensitization against syngeneic normal and malignant cells
Authors: Carnaud C. , Ilfeld D. , Petranyi G. , Klein Eva
Published: February 2007

Mouse lymphocytes were exposed to syngeneic fibroblasts and tumor cells in Millipore chambers inserted into the peritoneal cavity of intact and thymectomized mice. Autosensitization to fibroblasts occured only if the chambers were carried by thymectomized mice. Sensitization to tumor‐specific antigens also took place in intact mice. If thymic extract was administered to thymectomized mice autosensitization in the chambers was inhibited.
Antibody‐dependent human lymphocytotoxicity: a micro assay system
Authors: Zeijlemaker W. P. , Roos M. Th. L. , Schellekens P. Th. A. , Eijsvoogel V. P.
Published: February 2007

A micro assay system is described for measuring antibody‐dependent lymphocytotoxicity with human effector cells. The target cells were mouse mastocytoma cells sensitized with rabbit antibody. The tests were performed in microtiter plates, each well containing 5 × 103 51Cr‐labeled target cells, together with varying numbers of effector cells. Whereas highly purified lymphocyte suspensions induced lysis, purified monocyte and granulocyte suspensions had virtually no effect.

In parallel experiments it was shown that the latter cell suspensions were very active in lysing sensitized human erythrocytes, which in turn were not lysed by purified lymphocytes.

Finally, it was shown that the lytic capacity of lymphocytes was not affected by preservation of the cells at liquid nitrogen temperature. It is concluded that the system described can be used for the clinical analysis of antibody‐dependent lymphocytotoxicity in lymphocyte suspensions.
Participation of immunoglobulin‐bearing lymphocytes in the production of macrophage migration inhibitory factor
Authors: Pick E. , Godny Y. , Gold E. F.
Published: February 2007

The role of immunoglobulin‐bearing cells in the production of macrophage migration inhibitory factor (MIF) by tuberculin‐stimulated lymphocytes of guinea pigs, immunized with complete Freund's adjuvant, was studied. It was found that: (1) pretreatment of lymphocytes with rabbit anti‐guinea pig IgG (anti‐IgG) does not block antigen‐induced MIF production. (2) Passage of lymphocytes through double layer IgG‐anti‐IgG gelatin bead columns (the preparation of which is described) abolishes MIF formation by the eluted cells. Cells retained on the columns can be recovered and where shown to produce MIF, when stimulated by antigen. (3) Pulsing of lymphocytes with anti‐IgG, for 2 h at 37°C, results in MIF synthesis by the cells cultured in medium, in the absence of specific antigen. These findings indicate that cells bearing Ig or Ig fragments are either able to secrete MIF themselves, upon stimulation with antigen or anti‐IgG, or are required for MIF production by a different cell type.
Bursa lymphocytes and IgM‐containing cells in chicken embryos bursectomized at 52–64 hours of incubation
Authors: Janković B. D. , Knežević Z. , Isaković Katarina , Mitrović Kosana , Marković B. M. , Rajčević Miroslava
Published: February 2007

A technique of surgical removal of the bursal primordium (“bursectomy”) of chicken embryos at stage 17, approximately 52–64 hours and 29–32 somites, is described. The survival rate of bursectomized (Bx) embryos approached a level of 50% on the 21 st day. About 20% of correctly Bx embryos exhibited malformations of the anal sphincter and the large intestine. Using a rabbit anti‐bursacyte serum, which did not react with thymocytes, the specific bursa‐derived cell (Bu) marker was detected on the surface of bursa, spleen, bone marrow and thymus lymphocytes. Early embryonic bursectomy caused a moderate depletion of Bu marker‐bearing and IgM‐containing cells. It has been postulated that embryonic Bu cells can be recruited from sites other than the bursa and in the absence of the bursa.
The analysis of the monoclonal immune response to influenza virus. I. Production of monoclonal anti‐viral antibodiesin vitro
Authors: Gerhard W. , Braciale T. J. , Klinman N. R.
Published: February 2007

Limiting numbers of spleen cells from mice primed with influenza virus were transferred into lethally irradiated syngeneic recipients. Upon antigenic stimulation of fragment cultures of the recipient spleens it was observed that a linear relationship existed between the number of transferred spleen cells and the number of responding fragments. The antibody product of individual fragments exhibited a highly restricted heterogeneity in isoelectric focusing as well as in its reactivity against various viral antigenic determinants. It was concluded that the limiting cell type in this adoptive transfer system corresponds to the virus‐primed B cell which, upon antigenic stimulation, gives rise to a clone of antibody‐producing cells. PR8‐specific precursor B cells occurred at a frequency of at least 1/4000 splenic B cells in PR8‐primed BALB/c mice. Approximately 25% of the stimulated cell clones produced sufficient quantities of antibody (200 ng) to render feasible an analysis of closely related viral antigens.
A leukocyte migration inhibition assay technique using blood clot fragmentsin vitro
Authors: Sandru G.
Published: February 2007

Concomitantly with the capillary tube method, anin vitroleukocyte migration inhibition assay technique using blood clot fragments was performed in chicken egg albumin, Bacillus Calmette Guérin and complete Freund's adjuvant‐treated immune guinea pigs. Results of both methods were concordant.
Neonatally induced transplantation tolerance: in vitro evidence supporting a clonal inactivation mechanism
Authors: Brooks C. G.
Published: February 2007

Mixed lymphocyte culture (MLC) tests on the cells of mice made fully tolerant to allogeneic tissues in neonatal life showed an absence of specific antigenreactive cells. Similarly, no cells cytotoxic in a chromium release test could be detected. The absence of reactivity in the tolerant populations could not be accounted for by either suppressor cell activity or serum blocking factors. By contrast, mice in which partial tolerance had been deliberately or inadvertently induced often possessed detectable numbers of MLC‐reactive cells and, after grafting, their sera inhibited the MLC reactivity of normal cells. These results are discussed in terms of possible mechanisms of self tolerance.
The specific blocking of humoral immune cytolysis mediated by anti‐tumor antibodies degraded by lysosomal enzymes of tumor origin
Authors: Keisari Yona , Witz I. P.
Published: February 2007

The IgG fraction from rabbit antisera against a mouse plasmacytoma (RaPCT‐IgG) was incubated, under acidic conditions, with lysosomal extracts (LE) derived from the corresponding tumors. The LE‐treated IgG demonstrated a significant decrease in its complement‐dependent cytotoxic potential when compared to RaPCT‐IgG incubated without LE under the same conditions (control IgG).

Ammonium sulfate (AS) precipitation of the control IgG and the LE‐treated IgG preparations at 40% saturation of AS revealed that some of the IgG lost its precipitability at this AS concentration after LE treatment, but could be precipitated at 60% or 70% saturation. The LE‐treated IgG and control IgG fractions that precipitated by 40% saturated AS showed similar gel filtration profiles. The LE‐treated IgG fraction precipitating at 70% saturation of AS (but not at 40%) showed a different gel filtration profile. This fraction was separated into several subfractions, some with an apparent lower molecular weight. Some of these subfractions which still contained antigenic IgG lacked any expression of antigenic Fc, and were not cytotoxic to tumor cells. They could, however, rebind to tumor cells and block the complement‐dependent cytotoxic activity of native RaPCT‐IgG.

Lysosomal enzymes of tumor origin seem, therefore, to convert cytotoxic antitumor antibodies into molecules devoid of Fc but still retaining their antigen binding activity. Such an activity, if occurring in vivo might enhance tumor growth.
Effector‐cell blockade. II. A demonstration of the reversible masking of an immune response by blockade of antibody‐forming cells
Authors: Schrader J. W.
Published: February 2007

Previously we showed that multivalent forms of antigen could specifically block the effective secretion of antibody by binding to the antibody‐forming cell (AFC). We termed this inhibition of antibody‐secretion at the level of the AFC “effector cell blockade” (ECB). The present paper shows that dinitrophenylated gelatin, (DNP‐GEL), can induce ECB in vitro. Thus, portions of a suspension of spleen cells from DNP‐immune mice were incubated for 30 min with DNP‐GEL, washed and then assayed for anti‐DNP‐plaque‐forming cells. The resultant plaques were much fewer and smaller than those in assays of control portions of the spleen cell suspension. This DNP‐GEL‐induced ECB was shown to be reversible by treatment of the DNP‐GEL‐incubated cells with the specific enzyme collagenase. The reversibility of ECB by removal of extracellular antigen was confirmed using the multivalent antigen DNP‐glucan, together with the enzyme β‐lichenase, an enzyme with no action on mammalian carbohydrates.

The in vitro response to dinitrophenylated polymerized flagellin could be inhibited by the addition of DNP‐GEL at any time during the culture period. However, after the early hours of culture, the inhibition caused by the addition of DNP‐GEL was totally reversible by treatment of the cells with collagenase after harvest and immediately prior to assay. This demonstrated that B cells could divide and differentiate to AFC, despite the presence of multivalent forms of specific antigen in concentrations sufficient to block, by ECB, the detection of a response using a hemolytic plaque method.

The demonstration that persistent, multivalent antigen can produce a state of apparent unresponsiveness in spite of the presence of an ongoing immune‐response suggests that the importance of a reversible masking of an immune response by ECB should be evaluated in all models of tolerance using this class of antigen.
Effect of polyamines on the proliferative response of T cells stimulated with antigen
Authors: Ballet J. J. , Preisig E. , Merler E.
Published: February 2007

Presence of polyamines in cultures of human lymphocytes amplifies the proliferative response of sensitized T cells to antigens in vitro. Similar effects of aminoguanidine, an inhibitor of diamine oxydase, suggests a role of endogenous polyamines in normal proliferative events. This effect may have practical application in the amplification of low in vitro responses to antigens and in mixed lymphocyte cultures.