bluuebunny/crossref_metadata_2025 huggingface dataset:
Distribution of immunoglobulin on the surface of mouse lymphoid cells as determined by immunoferritin electron microscopy, Antibody‐induced, temperature‐dependent redistribution and its implications for membrane structure
Authors: De Petris S. , Raff M. C.
Published: February 2007

The ultrastructural distribution of membrane‐bound immunoglobulin (Ig) on mouse spleen lymphocytes has been studied by labeling the surface Ig with anti‐mouse Ig antibody conjugated to ferritin (FT). The distribution is temperature‐dependent. At 0 °C – 4 °C FT appears distributed in small clusters over the entire surface, whereas at 20 °C – 22 °C, in the great majority of the labeled cells, it is concentrated over one pole. This pole corresponds to that part of the cell which contains the Golgi complex and most of the cellular organelles, and which forms the uropod in moving lymphocytes. This polar redistribution is accompanied by endocytosis of part of the labeled membrane.

The redistribution of label occurring at room temperature indicates that labeled and unlabeled components of the plasma membrane can segregate from each other and suggests that plasma membrane is fluid at room temperature. The diffuse distribution found at 0 °C – 4 °C is probably close (although not identical) to the distribution in vivo before labeling, while the polar distribution at higher temperature is probably induced by the cross‐linking of the surface Ig molecules by the antibody‐FT conjugate and by a metabolically‐dependent flow of the aggregates towards the “tail” of the lymphocyte. The mechanism involved is considered to be the same mechanism responsible for membrane flow during cell movement. A detailed model of the structure and rheological properties of the lymphocyte membrane is proposed, which can explain the present results and those of others concerning the behavior of surface components of lymphocytes and other cells.
Migration inhibition experiments with mixtures of human peripheral blood lymphocytes and guinea pig peritoneal exudate cells
Authors: Marsman A. J. W. , Van Der Hart Mia , Walig C. , Eijsvoogel V. P.
Published: February 2007

Migration inhibition using mixtures of human peripheral blood lymphocytes and non‐sensitized guinea pig peritoneal exudate cells was demonstrable with purified protein derivative of tuberculin (PPD) and Candida albicans extract (CAE) when lymphocytes were obtained from individuals with a delayed type skin reaction to these antigens. No migration inhibition occurred when lymphocytes were used from skin test negative individuals.

Furthermore it was found that lymphocytes from some skin test negative persons, which did not induce migration inhibition, showed, however, an increased DNA synthesis when cultured in vitro with PPD. This indicates that a dissociation between the results of migration inhibition, skin test and lymphocyte transformation can occur not only in patients with immune disorders, as has been described by other investigators, but also in healthy individuals.
The enhancement of a primary in vitro anti‐hapten response by carrier priming
Authors: Trowbridge I. S.
Published: February 2007

The primary in vitro antibody response of mouse spleen cell suspensions to the hapten 4‐hydroxy‐3‐iodo‐5‐nitrophenacetyl (NIP) coupled to heterologous red blood cells (RBC) was enhanced by preimmunization of the spleen cell donors with the carrier RBC. The enhancement of the anti‐NIP response by carrier priming was specific and in order to stimulate an in vitro anti‐NIP response, the hapten had to be coupled to the same RBC which was used for priming.

The capacity for an enhanced anti‐NIP response developed rapidly after the priming immunization, arising earlier than the anti‐carrier RBC antibody response. There was a close correlation between the priming dose of carrier RBC required to enhance the anti‐NIP response and that required to prime for an enhanced secondary in vitro RBC response. No inhibition of the anti‐NIP response of spleen cell suspensions stimulated by NIP‐SRBC was observed by the addition of excess intact or lysed SRBC.

The requirement for a carrier‐specific cell which participates in the anti‐NIP response was demonstrated. The function of this cell in the anti‐NIP response was more resistant to irradiation and treatment with mitomycin C than that of the anti‐NIP precursor cell. From these and other studies in which spleen cell suspensions were treated with high specific activity [3H]d Thd it was concluded that cell division is necessary for the development of the anti‐NIP response, but that the carrier‐specific cell does not have to divide in vitro to execute its role in this response.
The thymus origin of the carrier‐specific cell in an anti‐hapten response in vitro
Authors: Trowbridge I. S. , Anderson H. R.
Published: February 2007

The primary in vitro response of spleen cells to 4‐hydroxy‐5‐iodo‐3‐nitrophenacetyl‐(NIP)‐ hapten was markedly reduced by procedures which depleted the spleen cell population of T cells. One approach was to use adult thymectomized, irradiated, bone marrow restored (TxBM) mice. The anti‐NIP response of spleen cells from carrier (SRBC)‐primed TxBM mice was significantly reduced compared to that of primed sham‐TxBM or primed normal spleen cells, and correlated with a deficient secondary anti‐SRBC response in vitro.

Two criteria were used for T cell depletion of TxBM mice: their impaired ability to mount a primary response to SRBC in vivo and the lower proportion of their spleen and lymph node cells susceptible to the cytotoxic action of anti‐Θ serum.

Using a second approach, the anti‐NIP response of normal carrier‐primed spleen cells was reduced by pretreatment of the cells with anti‐Θ serum and complement. The anti‐NIP response of anti‐Θ treated cells and cells from TxBM mice was enhanced by the addition of irradiated spleen cells from primed normal mice.

The requirement for carrier‐priming to induce a good primary in vitro antihapten response was not abrogated by injecting donor mice with allogeneic lymphoid cells at various times before the preparation of cell cultures.
Mitogen‐induced lymphocyte‐mediated cytotoxicity in vitro: Effect of mitogens selectively activating T or B cells
Authors: Möller G. , Sjöberg O. , Anderson J.
Published: February 2007

Concanavalin A (Con A) and phytohemagglutinin (PHA) are selective T cell mitogens, whereas lipopolysaccharide (LPS) and purified protein derivative of tuberculin (PPD) are selective B cell mitogens. Con A and PHA induced mouse lymphocyte‐mediated cytotoxicity in vitro, which was equally expressed on autologous, allogeneic and heterologous target fibroblasts, as measured by thymidine release from prelabeled targets. The dose response curves of Con A‐induced lymphocyte‐mediated cytotoxicity and DNA synthesis were parallel, 5 μg/ml being optimal, both higher and lower concentrations being less effective. Con A pretreated mouse lymphocytes failed to express cytotoxicity even though they were irreversibly activated with regard to DNA synthesis and were morphologically transformed. However, when Con A pretreated lymphocytes were added to target fibroblasts in the presence of soluble Con A, the cytotoxic effect markedly exceeded that induced by Con A in non‐pretreated lymphocytes. It is suggested that cytotoxicity not only requires close contact between target and aggressor lymphocyte, but actual binding of the lymphocyte to the target, in this case effectuated by Con A.

Con A and PHA failed to induce lymphocyte‐mediated cytotoxicity in B lymphocytes. LPS and PPD did not induce cytotoxicity in normal or in B lymphccytes. Even LPS or PPD pretreated B lymphocytes failed to exert cytotoxicity when aggregated to the targets by Con A. It is suggested that the lymphocytes responsive to LPS and PPD are not the non‐T cells responsible for cell‐mediated cytotoxicity on antibody‐coated target cells.

Con A and PHA, but not LPS and PPD, induced lymphocyte‐mediated cytotoxicity in human lymphocytes on allogeneic and heterologous target fibroblasts. The dose response curves for induction of cytotoxicity and DNA synthesis by Con A were not always identical in this case, cytotoxicity persisting at low Con A concentrations, which failed to activate DNA synthesis.
Lymphocyte activation: Rapid changes in the phospholipid metabolism of plasma membranes during stimulation
Authors: Resch K. , Gelfand E. W. , Hansen Käthe , Ferber E.
Published: February 2007

Lymph node lymphocytes from normal or BCG‐sensitized rabbits were stimulated by phytohemagglutinin (PHA) or purified protein derivative of tuberculin (PPD). After incubation of intact lymphocytes with [14C]oleate, the cells were disrupted and microsomes (consisting of plasma membrane and endoplasmic reticulum) were isolated. In some experiments the microsomal fraction was separated into plasma membrane and endoplasmic reticulum by dextran gradient centrifugation.

After 10 min microsomes from PHA‐stimulated lymphocytes had incorporated 3 times more [14C]oleate into lecithin than microsomes from controls. With PPD as antigen, after 1 h incubation a significant increase in the incorporation of [14C]oleate into microsomal lecithin was detected. The stimulation index with respect to [14C]oleate uptake remained constant in both cases when the lymphocytes were cultured for longer times. Approximately 90 % of the [14C]oleate incorporated into microsomal lecithin was recovered in the plasma membrane which exhibited the highest stimulation. The results are discussed in relation to possible biochemical events underlying the triggering process of lymphocytes.
Plant agglutinins used to distinguish between different classes of mouse lymphocytes
Authors: Schnebli H. P. , Dukor P.
Published: February 2007

Cortisone‐resistant thymocytes and thoracic duct cells from nu/+ mice and lymph node cells from athymic nu/nu mice were used as highly enriched populations of T and B cells, respectively.

The agglutinin from wheat germ agglutinated B cells more strongly (by factors of 5 and 14) than both cortisone resistant thymocytes and thoracic duct cells. Wheat germ agglutinin may thus provide a new B cell‐specific marker.

Soy bean agglutinins from two different sources agglutinated B cells and cortisone‐resistant thymus cells equally well, but failed to agglutinate thoracic duct cells. The different behavior of the two T cell preparations is taken as further evidence of the existence of subpopulations of thymus‐derived lymphocytes.
Rosette formation by human T and B lymphocytes
Authors: Brain P. , Marston R. H.
Published: February 2007

Human peripheral lymphocytes, identified as T or B cells with a fluorescent anti‐globulin serum, were studied in two varieties of rosette formation: (1) with sheep red corpuscles, a phenomenon shown by a large proportion of human lymphocytes and totally different from that observed in the mouse; and (2) with human red cells sensitized with incomplete anti‐Rh. Lymphocytes forming sheep cell rosettes were never fluorescent; i.e. they were T cells. 73 % of lymphocytes forming sensitized‐cell rosettes were fluorescent B cells. Horse anti‐human lymphocyte serum inhibits the first but not the second variety of rosette formation.
The avian bursa‐independent humoral immune system: serologic and morphologic studies
Authors: Bryant B. J. , Adler H. E. , Cordy D. R. , Shifrine M. , Damassa A. J.
Published: February 2007

Chickens injected variously with Mycoplasma gallisepticum organisms or sheep erythrocytes and assayed for specific serum agglutinins were individually evaluated with respect to lymphoid development in spleen, thymus, cecal tonsils, cloaca, and bursa of Fabricius. The examinations were carried out during the period of normal maximal bursa size on chickens which had been chemically bursectomized (CBx) at the 7‐day‐embryo stage and on intact controls. The embryonic genesis of bursal epithelium was completely prevented in 41 of 43 CBx birds. These bursaless birds nonetheless collectively formed agglutinins in 1 of 30 cases at 10 – 12 days after primary stimulation, in 6 of 26 cases at 22 – 23 days after primary stimulation, and in 15 of 32 cases after secondary stimulation. The titers compared favorably with controls. Agglutinin responsive bursaless birds had secondary follicles in spleen and cecal tonsils and an impressive, if variably subnormal, development of lymphoepithelial tissue. By contrast, agglutinin negative bursaless birds lacked germinal centers and had only moderately to sparsely populated lymphoepithelia. This lymphocyte deficit was especially marked in the proctodeal and urodeal roofs and cecal tonsils. Plasmacytes in bursaless birds were rarely found in spleen but were always found in gut lymphoepithelia in numbers correlating with regional lymphoid cell content.
Studies on the effect of a thymic humoral factor on differentiation of thymus‐derived lymphocytes
Authors: Lonai P. , Mogilner B. , Rotter Varda , Trainin N.
Published: February 2007

The effect of a thymic humoral factor (THF) on differentiation of thymus‐derived (T) lymphocytes was studied in various graft‐versus‐host models. It was demonstrated that THF, which is known to be capable of restoring immunocompetence of cells from neonatally thymectomized mice, does not act on lymphoid populations devoid of T cells. Immunologically defective lymphoid cells such as spleen cells obtained from mice treated with anti‐lymphocyte serum could be activated by THF by in vivo or in vitro interaction. These experiments indicate that the target cell acted upon by THF is a T cell with a low level of immunocompetence. It is suggested that THF acts on young T cells and transforms them into mature T cells active in cell‐mediated immune reactions, presumably without substantial multiplication.
Morphological observations on the contact‐induced lysis of target cells
Authors: Koren H. S. , Ax W. , Freund‐Moelbert Elisabeth
Published: February 2007

Interactions in tissue culture of sensitized C57BL spleen and DBA/2 mastocytoma cells have been studied by microcinematography, electronmicroscopy and light microscopy. Motile lymphocytes with their characteristic hand mirror shape move on the surface membrane of the target cells, establishing a close contact within a few minutes. As seen by electron microscopy and equidensitometry, the contact between the cells is very firm, leading to damage of the target cell membrane while leaving the effector cell intact. Analysis of time‐lapse cinematography shows that one motile lymphocyte has the capacity to lyse more than one target cell, a phenomenon which may account for the highly efficient surveillance mechanism in vivo. The role of soluble factors and the importance of the lymphocytic uropod in cellular interactions are discussed.
Immunofluorescent detection of surface antigens specific to T and B lymphocytes in the chicken
Authors: Hudson L. , Roitt I. M.
Published: February 2007

Rabbit antisera specific for chicken T and B cells as judged by surface immunofluorescent staining have been raised. Specificity was established by the staining of thymus and bursal cell suspension and by the effects of thymectomy and bursectomy on the staining of peripheralized lymphocytes. Furthermore, double labeling experiments showed that anti‐T and anti‐B sera reacted with different populations of blood lymphocytes. Comparable numbers of cells in blood and spleen stained for B and light chain determinants. No evidence for “null cells” was obtained. There was little change in the percentage of cells staining in the various lymphoid organs from 4 days to 12 months of age.

The thymus contained approximately 7 % B cells, although no T cells were demonstrable in the bursa. One antiserum showed only thymocyte specific antibodies not reacting with peripheral T cells. The specific B and T markers seem to be acquired during differentiation within the appropriate central lymphoid organ. Demonstrable surface immunoglobulins appear later in ontogeny than the B antigens. The majority of cells bearing the B marker in bone marrow were large cells lacking surface light chain determinants.
Studies on sperm antigenicity. I. Delayed hypersensitivity to spermatozoa
Authors: Marcus Z. H. , Soffer Y. , Ben‐David A. , Peleg Sarah , Nebel L.
Published: February 2007

Delayed hypersensitivity to human and guinea pig sperm was demonstrated in guinea pigs of the Rockefeller strain by immunization with H37Ra adjuvant. The reaction in vivo was demonstrated by skin testing the animals and in vitro by the capillary method. It was found that the sensitivity is not only directed towards the sensitizing antigen, but also shows cross‐reactivity. Thus, peritoneal exudate cells derived from guinea pigs sensitized to human sperm were inhibited by guinea pig sperm. This cross‐reactivity revealed the possibility of a tissue specific antigen. In addition, supernatants obtained after incubation of the sensitized lymph node cells with the specific antigen were found to be spermatotoxic.
Cytotoxicity of adenovirus‐antibody complexes. Specificity of antibody and virus‐antibody ratio at which cytotoxicity is induced
Authors: Kjellén L. , Ankerst J.
Published: February 2007

Adenoviruses aggregate in the presence of type‐specific antibodies against whole virus particles. These aggregates were found to damage human cells in vitro in far higher order of magnitude than virus alone, when virus and type‐specific antibodies were mixed at a certain virus‐antibody ratio. No cytotoxicity occurred when the virus was mixed with type‐specific antibodies in higher or lower dilutions or when the virus was incubated with antisera against another adenovirus serotype. Furthermore, it was found that the cytotoxicity could be prevented by type‐specific anti‐hexon sera and that type‐specific anti‐fiber sera produced cytotoxic aggregates out of subtoxic ones. The presence of the cytotoxic aggregates was demonstrated by electron microscopy and by 51Cr release cytotoxicity tests.
An improved method for the production of antiserum directed against weakly immunogenic tumor antigens
Authors: Kurth R. , Bauer H.
Published: February 2007

An immunization procedure is presented which enhances the immune respons to weakly immunogenic tumor‐specific cell surface antigens by coupling new helper antigens to tumor cells. Mice were immunized with lyophilized tumor cell membranes to which helper antigen was coupled. Only animals which were so primed against the helper antigen as to induce delayed hypersensitivity showed an increased in vitro immune response. This was not found in mice which were not primed or which exhibited immediate hypersensitivity.

The possibility is discussed of enhancing immune response by introducing additional helper determinants linked to the original antigens.
The nature of the transforming lymphocyte in chronic lymphocytic leukemia
Authors: Schweitzer Marjan , Melief C. J. M. , Eijsvoogel V. P.
Published: February 2007

Lymphocyte transformation in vitro was studied with lymphocytes from patients with chronic lymphocytic leukemia (CLL). The responding capacity to phytohemagglutinin (PHA), pokeweed mitogen (PWM) and allogeneic lymphocytes, as well as the stimulating capacity in mixed lymphocyte cultures (MLC), were assessed.

Lymphocytes of CLL patients display a depressed and delayed reaction to PHA. In MLC experiments a decreased responding and stimulating capacity could be demonstrated, the latter being reduced to a smaller extent. However, reduced numbers of lymphocytes from normal individuals show a similar reaction pattern with regard to these parameters. By albumin gradient centrifugation the lymphocytes from CLL patients could be separated into a nonresponsive population and other fractions, containing lymphocytes with increased reactivity in comparison with unfractionated cells.

It was concluded that the leukemic cells in CLL are completely unresponsive to PHA and PWM and have no MLC activities. All observed in vitro reactivity can be attributed to the small proportion of normal lymphocytes among the leukemic cell population.
The specificity of cellular immunity: studies in guinea pigs using defined tetrapeptides containing p‐azobenzenearsonate‐L‐tyrosine
Authors: Becker M. J. , Levin H. , Sela M.
Published: February 2007

The specificity of the cellular immune response to p‐azobenzenearsonate(ABA)‐L‐Tyr, ABA‐L‐Tyr(L‐Tyr)3, ABA‐L‐Tyr(L‐Ala)3, and (L‐Tyr)3 ABA‐L‐Tyr was investigated. None of these immunogens was able to lead to the formation of anti‐ABA antibodies in guinea pigs as measured by a sensitive hapten‐modified bacteriophage inactivation assay. Using antigen‐induced [2‐14C] thymidine incorporation in lymph node lymphocyte cultures in vitro and delayed hypersensitive skin tests as indicators of cellular immunity, a maximal response was elicited by the homologous immunizing antigen. This indicates that the receptor for the cellular immune response exhibits a high degree of specificity for more than just the ABA or ABA‐Tyr moieties.
Effect in vitro of anti‐immunoglobulin sera on proliferative responses of lymphoid cells to antigen+
Authors: Mond J. , Kaplan R. E. , Thorbecke G. J.
Published: February 2007

Experiments were designed to determine the effects, if any, of anti‐immunoglobulin (anti‐Ig) sera on T cell‐dependent proliferative responses in vitro. Using rabbit lymphoid cells there was no inhibition of the proliferative response, but instead, an additive effect of anti‐Ig and either antigen or phytohemagglutinin added together, suggesting stimulation of two different cell populations. Pretreatment of mouse lymphoid cells with anti‐Ig and complement caused a detectable inhibition of the proliferative response, which was probably due to the removal of B cells. Pretreatment with anti‐Θ and complement resulted in a much stronger inhibition.
Properties of educated T cells. The ability of educated T cells to facilitate the immune response to non‐cross‐reacting antigens in vitro
Authors: Waldmann H. , Munro A. , Hunter Phillipa
Published: February 2007

Thymus‐derived cells educated to either keyhole limpet hemocyanin or fowl IgG can reconstitute the response of T cell‐depleted spleen cell cultures to other non‐cross‐reacting antigens. This response can only be obtained if the initial educating antigen is present in culture.
Affinity of T and B lymphocyte receptors for hapten determinants
Authors: Möller Erna , Bullock W. W. , Mäkelä O.
Published: February 2007

The affinity of anti‐hapten antibodies, produced by single cells, was studied by hapten inhibition of plaque‐forming cells using the local hemolysis in gel assay. The shift in affinity of anti‐hapten antibodies, that occurs with time after immunization, was parallelled by an analogous shift, at the cellular level, with regard to indirect plaque‐forming cells (PFC). Thus, there was a gradual decrease of the hapten concentration which was needed to suppress indirect plaque formation with time after immunization, indicating a gradual increase in the number of high affinity cells. No such shift was observed with cells causing direct plaque formation.

Analogous studies were performed with hapten‐specific antigen‐binding cells of T and B origin by using hapten‐inhibition of rosette‐forming cells. Hapten‐specific antigen‐binding cells were present in both cell populations. Lymphocyte binding of haptenated red cells could be specifically inhibited by free hapten. It was found that antigen‐binding B lymphoid cells became gradually more susceptible to hapten inhibition with time after immunization, whereas no such change was observed in antigen‐binding T lymphoid cells. Possible reasons for this discrepancy are discussed, as well as the implications for these findings regarding the specificity and structure of the T cell receptors.
Cellular events in protein tolerant inbred rats. II. Antibody avidity maturation during induction and loss of tolerance
Authors: Bell E. B.
Published: February 2007

Complete and partial states of tolerance were induced in (AS2 x AS)F1 hybrid rats after single or repeated injections of high, medium and low doses of fluid HSA (100 mg to 10 μg). Changes in antibody avidity, following challenge with HSA plus adjuvant, were used to detect those affinity subclasses of HSA‐specific cells which were not eliminated by tolerogenic antigen.

Rats undergoing prolonged low dose treatments of fluid HSA induced an appreciable quantity of high avidity antibody before challenge. The avidity decreased significantly following challenge, indicating a progressive loss of high affinity cells, but only after the synthesis of antibody. Rats made partially tolerant against large and medium doses of fluid HSA when challenged, synthesized antibody which failed to mature to a high level, indicating again that high affinity cells were among the first to be deleted. The higher affinity cells in primed rats (including partially unresponsive rats) were the first to disappear during the memory response which was also triggered by fluid HSA. It is proposed that protein antigens induce a state of tolerance by eliminating B cells, but only after driving them through a stage of antibody synthesis.

Avidity of antibody was measured following restoration of HSA responsiveness. Antibody failed to mature to a high level in previously tolerant rats that were allowed to recover naturally (stem cell replacement) or were given normal thoracic duct lymphocytes after the tolerance inducing treatment.
Suppression by several synthetic polypeptides of experimental allergic encephalomyelitis induced in guinea pigs and rabbits with bovine and human basic encephalitogen
Authors: Teitelbaum Dvora , Webb Cynthia , Meshorer A. , Arnon Ruth , Sela M.
Published: February 2007

The basic copolymer of alanine, glutamic acid, lysine and tyrosine, denoted Cop 1, is an efficient suppressor of experimental allergic encephalomyelitis (EAE) induced with the bovine basic encephalitogen in guinea pigs and rabbits. The suppression was very effective also when the experimental disease was induced with the basic protein from human source. Two related polymers, one in which glutamic acid was replaced with aspartic acid, and one devoid of tyrosine, were less effective in the suppression of the experimentally induced disease.

The route of administration of Cop 1 plays an important role in its suppressive effectiveness, with intravenous injections being the most efficient. The injection schedule and dose of injection are also of great importance; thus, repeated doses of Cop 1 starting five days after the administration of the basic protein are suppressive, whereas a single dose of 5 mg given 72 h after challenging with the basic protein does not suppress EAE. Cop 1 is not a nonspecific immunosuppressant, as it does not affect the immune response towards a variety of antigens, including the rejection of a skin graft.

When EAE was induced with the human encephalitogen, the histological changes observed included demyelination and fibrosis in the guinea pig brain.
Antigenic determinants on bovine encephalitogenic protein. Localization of regions that induce transformation of lymph node cells from immunized rabbits
Authors: Bergstrand H. , Källén B.
Published: February 2007

With the aid of a lymph node cell transformation test and several fragments of the bovine encephalitogenic protein, attempts have been made to examine more closely various parts of the protein that stimulate DNA‐synthesis of lymph node cells from immunized rabbits. Evidence was obtained for the presence of at least two strongly stimulating regions within residues 44–170: one resides in peptide 44–89 and the other in peptide 93–170. When parts of these regions and other oligopeptide derivatives of region 44–170 were tested, only a slight or no stimulating effect was observed, and a closer localization of all reactive sites – corresponding to that made in guinea pigs with the macrophage migration inhibition technique – could not be made unequivocally. However, peptides 44–68 and 154–170 were shown to have transformation‐inducing effects.

Further evidence for the nonreactivity of the tryptophan region was obtained in accordance with previous findings. For at least one region of the encephalitogenic protein – the tryptophan region – there is thus no correlation between disease‐inducing activity and ability to stimulate lymph node cells from immunized rabbits to transform in vitro.
The influence of the net charge of antigen on the distribution of bovine IgG class antibodies
Authors: Mossmann H. , Bartsch K. , Rüde E. , Kickhöfen B. , Hammer D. K.
Published: February 2007

It has previously been shown that bovine immunoglobulins of the more positively charged IgG2 class are confined exclusively to the serum and are incapable of being transferred to the colostrum by the dry mammary gland. Since recent studies have demonstrated that antigens with a negative net charge preferentially provoke the synthesis of more positively charged antibodies, it could be expected that antibodies against such antigens would not be transferred to the colostrum. In the present study, however, acidic antigens (p‐azobenzenearsonate edestin and its maleylated derivative) failed to stimulate predominantly the synthesis of precipitating, binding and phage neutralizing antibodies of the positively charged IgG2 class. As expected, immunization of cattle with lysozyme, (a basic antigen), resulted in the production of antibodies almost exclusively confined to the more negatively charged IgGs fraction. In analyzing the precipitin reaction of IgGs class antibodies, it could be shown that maximum precipitation was achieved at pH 5.0 and decreased significantly at higher pH values.
Induction of tolerance to dinitrophenylated bovine IgG in pigs
Authors: Franěk F. , Šimek L.
Published: February 2007

Intraveneous administration of soluble 2,4‐dinitrophenyl(DNP)‐conjugated bovine IgG to pigs led to induction of tolerance to this antigen. A single dose of 100 mg soluble conjugate per animal resulted in complete tolerance which lasted at least 80 days. Lower doses led to partial tolerance. Induction of tolerance in pigs was shown to be a process taking several days to complete. Animals exhibiting tolerance when challenged by the homologous conjugate still synthesized significant amounts of antibody when challenged by the carrier protein or by a conjugate of the 2,4‐dinitrophenyl group with a different carrier.
Strain differences in the fine specificity of mouse antihapten antibodies
Authors: Imanishi Thereza , Mäukelä O.
Published: February 2007

Mice of six strains were immunized with (4‐hydroxy‐3‐nitrophenyl)acetyl (NP) groups coupled to chicken globulin. The fine specificities of these antibodies were characterized by estimating relative affinities for related compounds, (4‐hydroxy‐3, 5‐dinitro‐phenyl)acetyl (NNP), (5‐bromo‐4‐hydroxy‐3‐nitrophenyl)acetyl (NBrP) and (4‐hydroxy‐5‐iodo‐3‐nitrophenyl)acetyl (NIP) groups. These measurements were carried out on both serum and single plaque‐forming cell antibodies. At least three patterns of fine specificity could be recognized among these strains.

C57BL/6 produced 7 S (IgG) anti‐NP that consistently had 3–10 times higher affinity for NIP than for NP, and higher affinity for NNP and NBrP than for NP (heteroclitic). By doing affinity measurements on serum and plaque‐forming cell antibodies, we could demonstrate that the majority of the 7 S (IgG) anti‐NP produced by C57BL/6 mice was heteroclitic at both early and later stages of immunization. Moreover, the antibody from this strain exhibited only a slight change in affinity during the immune response, while the other strains underwent clearcut maturation (progressively increased affinity for NP and increased discrimination between NP and the related compound).

Nine F1 hybrid mice between C57BL/6 and CBA produced anti‐NP antibody that was very similar to C57BL/6 anti‐NP.
Antigenic differences between spleen‐seeking and lymph node‐seeking thymus cells
Authors: Schlesinger M. , Shlomai‐Korzash Zipora , Israèl Evelyne
Published: February 2007

Thymus cells of mice of the C3H and A strains were labeled with 41Cr and exposed in vitro to either normal mouse serum or to various antisera and the cells injected intravenously into syngeneic recipients. Exposure of thymus cells to various sera was found to have different effects on the cell subpopulations migrating to either the lymph nodes or the spleen. Anti‐H‐2 serum had a marked inhibitory effect on the migration of thymus cells to lymph nodes, and a much weaker effect on their migration to the spleen. Anti‐TH serum had a slightly stronger inhibitory effect on spleen‐seeking, as compared to lymph node‐seeking thymus cells. Anti‐Ly serum had a strong inhibitory effect on both migration streams. Anti‐TL serum had a stronger inhibitory effect on spleen‐seeking thymus cells than on lymph node‐seeking cells, a difference which became even more pronounced in cells exposed to Anti‐TL serum and complement. Normal guinea pig serum had a marked inhibitory effect on thymus cells migrating to the spleen, but hardly affected the lymph node‐seeking thymus cells.

These results indicate that the thymus contains two major subpopulations of cells of differing antigenicity, which migrate to either the spleen or the lymph nodes. It is suggested that the different properties of T cells found in the spleen and in the lymph nodes result from the migration of different subpopulations of thymus cells to these organs.
Immunoglobulins in the intestinal content of the human fetus with special reference to IgA
Authors: Petit J. C. , Galinha Annie , Salomon J. C.
Published: February 2007

The gut walls and gut contents of 27 fetuses were analyzed for the presence of immunoglobulins. Secretory IgA was detected in 16 samples, IgM in 22 samples, IgG in 25 samples, while all three classes were detected in 16 samples. No IgA was found in the meconia of neonates; this suggests a transient synthesis during fetal life. The assumption is made that the fetal environment is antigen‐free and the possibility that early immunoglobulin production may be independent of antigenic stimulation is discussed.
Immune responses in vitro. iii. enhancement of the mouse mixed lymphocyte interaction by isologous and homologous sera
Authors: Peck A. B. , Click R. E.
Published: February 2007

This report describes the enhancement of the mouse mixed lymphocyte interaction which results from supplementing a protein‐free medium with either isologous or homologous sera. The degree of stimulation is affected by several variables which include serum preparation and concentration, the genetic relationship of the responder and stimulator cells to the source of sera, and the composition of the medium.
Immunoglobulins on the surface of sheep lymphocytes. ii. class, size and fate during incubation of lymphocytes at 37 °c
Authors: Ey P. L.
Published: February 2007

Sheep lymphocytes possessing surface Ig were labeled with 125I‐labeled anti‐Ig antibodies. The radioactive complexes thus formed were dissolved from the cell membrane by treatment with the detergent Nonidet‐P40 and their molecular sizes estimated by sedimentation centrifugation. IgG and IgM (20–40 % as 19 S IgM) were shown to be present on the cell surface.

Cells labeled with anti‐Ig antibodies and incubated at 37 °C lost 30–40 % of their radioactivity within 30–45 min, after which time the rate of loss decreased. By 3–4 h, approximately 50 % had been released and loss had almost stopped. Label associated with surface‐bound anti‐sheep lymphocyte globulin was also lost rapidly (20–30 % in 30 min), but unlike anti‐Ig antibodies, no further loss occurred. Anti‐Ig complexes retained by labeled cells during incubation at 37 °C were steadily degraded to a 3–4 S component. Sodium azide (0.015 M) significantly reduced the rate at which this degradation occurred (e.g. inhibition relative to degradation in the absence of azide was 94 % after 2 h and 67 % after 4 h incubation, respectively).

When unlabeled lymphocytes were incubated at 37 °C for up to 20 h and then reacted with labeled anti‐Ig, the following was observed. The proportions of lymphocytes able to bind anti‐γ or anti‐μ‐chain antibody (as judged by autoradiography) decreased from 17 % to 3 % and 28 % to 18 %, respectively, during 20 h incubation. From measurements of Ig released during incubation, it was concluded that most of the IgG initially on cells binding anti‐γ‐chain antibody was probably cytophilic. IgM initially on the surface of cells binding anti‐μ‐chain antibody seemed to be released and replaced by the cells, although a small proportion may have been cytophilic.
Involvement of more than a single polypeptide chain in the helical antigenic determinants of collagen
Authors: Hahn E. , Timpl R.
Published: February 2007

Rat antibodies to native triple helical calf collagen were used to study the structural requirements of helical antigenic determinants revealed in this particular model. Renaturation of random‐coiled chains of collagen in the original proportion of two α1‐chains and one α2‐chain to triple‐helical structures is accompanied by complete recovery of antigenic activity. Although physically similar to native collagen, triple‐helical structures prepared from individual chains alone were inactive or exhibited a strongly reduced activity. These results were interpreted as to the involvement of parts of the α1 and α2‐chains in several dinstinct helical antigenic determinants of collagen.

Further studies with collagenase‐derived, triple helical fragments of variable length revealed successive loss of antigenic activity upon reduction in size. However, the smallest fragment, having a length of 78 nm, still contained some of the original antigenic determinants. The antibodies to helical antigenic determinants also showed rather limited interspecies cross‐reactions as opposed to the very strong cross‐reactions found previously between antigenic determinations of sequential nature in random‐coiled α‐chains. Helix formation of two different types of α‐chains essentially masks these cross‐reacting structures.
Isolation and characterization of a molecular complex containing thy‐1 antigen from the surface of murine thymocytes and t cells
Authors: Vitetta Ellen S. , Boyse E. A. , Uhr J. W.
Published: February 2007

A complex containing the Thy‐1 (θ) antigen has been isolated from the surface of murine thymocytes and T cells by cell surface radioiodination, lysis by freezing and thawing, and immunoprecipitation. The specificity of the immunoprecipitation was firmly established using both congenic and noncongenic anti‐Thy‐1 sera and thymocytes from congenic and noncongenic mice.

Unlike cell surface Ig and the TL and H‐2 alloantigens, the antigenicity of Thy‐1 was abolished by treatment with nonionic detergent. Thy‐1 was localized exclusively in a complex of cell surface molecules which has a density lower than that of protein. Moreover, Thy‐1 could be readily labeled by incubating thymocytes with [3H]galactose, but not 3H‐labeled amino acids. These observations suggest that the antigenicity of Thy‐1 may reside in a glycolipid.
Assignment of a tyrosyl residue from the site of a rabbit anti‐p‐azophenyl‐trimethylammonium antibody to position 102 of the heavy chain
Authors: Takeda Y. , Friedenson B. , Roholt O. A. , Pressman D.
Published: February 2007

The isolation of two chymotryptic peptides, each containing a tyrosyl residue considered to be derived from the hapten‐binding site of a rabbit anti‐p‐azophenyltrimethylammonium antibody preparation, was achieved by the paired‐iodination procedure. One peptide, from a heavy chain, corresponded to the sequence ‐Cys‐Ala‐Arg‐Asp‐Pro‐Tyr‐ which, on the basis of comparison with other sequences, represents positions 97–102 of the heavy chain. The other peptide, from a light chain, corresponded to the sequence ‐Ser‐Ser‐Glu‐Tyr and apparently represents a hypervariable region of the light chain.
Study of the thymic‐derived or ‐independent nature of mouse spleen cells induced to proliferate in culture by various mitogens and antigens
Authors: Piguet P.‐F. , Vassalli P.
Published: February 2007

The nature of mouse lymphoid cells induced to proliferate in vitro by a number of stimulating agents has been explored by 1) karyotypic analysis of the mitoses observed in stimulated spleen cell cultures (arrested on sequential days) of chimaeras bearing chromosomally marked T cells; 2) comparison between the response in DNA synthesis of total spleen cells and of spleen cells depleted of thymus‐dependent lymphocytes by treatment with anti‐MSLA (anti‐mouse‐specific lymphocyte antigen) + C, and 3) study of the response of cortisone‐resistant thymocytes (CRT) to some of these agents. Pokeweed mitogen stimulated both B and T cells equally and simultaneously. Rabbit anti‐mouse Ig induced moderate proliferation of B cells exclusively. The response to lipopolysaccharide was entirely B cell‐dependent, but evidence was found of some T cell proliferation following or accompanying the stimulation of B cells. A similar observation was made in the case of “primary” or “secondary” in vitro response to bacteriophage T4. Good stimulation with sheep red blood cell stromas or mitogen‐treated xenogenic spleen cells were observed only in cultures from primed animals, and consisted of a mixed B and T cell proliferation with a majority of B mitoses, even at the earlier stages of the response. That this “secondary” response was not totally T cell‐dependent was suggested by the observation of a stimulatory effect of these antigens on T‐depleted spleen cell cultures which were found in parallel experiments to be totally unresponsive to PHA. Finally, using chimeric mice treated in vivo with vinblastine prior to establishment of the spleen cell cultures, evidence was obtained that part of the B cells stimulated to divide in vitro by several of these mitogens belong to a rapidly dividing cell population in vivo.
Specific cytostatic effect of lymph node cells from normal and T cell‐deficient mice on syngeneic tumor target cells in vitro and its specific abrogation by body fluids from syngeneic tumor‐bearing mice
Authors: Chia Eunice , Festenstein H.
Published: February 2007

Lymphoid cells from tumor‐bearing animals were shown to be cytostatic for syngeneic tumor target cells in vitro using a post labeling radioactive assay. The specific decrease or removal of this cytostatic activity was possible using a “blocking” serum or ascitic fluid from syngeneic tumor‐bearing animals. Further lymphoid cells from chronically irradiated, thymectomized mice, which were shown to be extensively deprived of T cells by reduced PHA responsiveness and anti‐θ cytotoxicity tests, were also found to cause cytostasis of target tumor cells and to a greater extent than with nondeprived lymphoid cells.
Normal development of the thymus‐dependent limb of humoral immune responses in mice
Authors: Arrenbrecht S.
Published: February 2007

The capacity of mice to produce antibody‐forming cells (AFC) to sheep erythrocytes and to low doses of two haptenated proteins increases logarithmically with age in the postnatal period. This increase is prevented by thymectomy. These findings, together with those on the ability of suckling mice to make high numbers of AFC to high doses of at least one of the antigens used, indicate that T cells are the limiting cell type in neonatal humoral immune responses. An analysis of variance of the number of AFC in individual spleens as a measure for T cells showed that the data are in agreement with random generation and subsequent proliferation of these cells during ontogenesis. Different antigen reactivities carried by these cells seem to arise at different times during fetal life.
Development of host plasma cells during graft‐versus‐host reactions in mice
Authors: Lindholm L. , Rydberg L. , Strannegård Ö.
Published: February 2007

Graft‐versus‐host (GVH) reactions induced by thymus or spleen cells in newborn mice were found to trigger the development of plasma cells in the medullary areas of lymph nodes. No germinal centers were found. The plasma cells were found from the fourth day of the GVH reactions and increased in numbers over the next few days. On the 14th day the plasma cells were still present, although in lower numbers.

Results of immunodiffusion experiments indicated that during GVH reactions induced by spleen cells, donor as well as host plasma cells develop. In contrast, induction of GVH reactions by thymus cells leads to the development of plasma cells, which probably originate exclusively from the host.

Positive Coombs' reactions were detected 15–20 days after induction of GVH reactions and host immunoglobulins were found to contribute to the Coombs' positivity.

The GVH reactions stimulated the formation of antibodies to sheep erythrocytes. This effect was more marked on 7 S than on 19 S antibody production.
Density gradient separation of chicken thymus cells
Authors: Tamminen Pekka , Toivanen Auli , Toivanen P.
Published: February 2007

Chicken thymus cells were separated into six fractions by a discontinuous albumin gradient centrifugation. When 10 or 16‐week old cell donors were used, thymus cells responding with antibody formation to Brucella abortus were clearly separated from those active in graft‐vs.‐host assays. The former were found in low and the latter in high density fractions. The results suggest that B and T cells in chicken thymus may be preferentially concentrated into separate fractions according to density.
in vitro induction of specific immune responses in the absence of serum: requirement for nonspecific t or b cell mitogens
Authors: Coutinho A. , Möller G.
Published: February 2007

A mixed lymphocyte culture reaction (MLC) between histoincompatible mouse lymphocytes could be induced in the absence of serum in vitro. There was a steady increase of DNA synthesis for 7 days in the absence of serum, whereas peak activity occurred on day 4 in the presence of serum. Analogous results were obtained when the secondary responses to SRC were determined by stimulation of DNA synthesis.

It was not possible to induce a primary humoral antibody response to SRC in the absence of serum. However, if the serum‐free cultures were supplemented with optimal concentrations of T (concanavalin A) or B (lipopolysaccharide, LPS) cell mitogens, a primary specific antibody response to sheep red cells (SRC) could be induced and increased in magnitude for 4 days in culture. Also, a MLC reaction permitted the induction of primary antibody responses to SRC. In the presence of fetal calf serum (FCS), optimal concentrations of T cell mitogens, as well as a MLC reaction, suppressed the induction of a primary antibody response to SRC, whereas suboptimal doses of the mitogen stimulated it.

It was possible to induce specific secondary IgM and IgG antibody responses to SRC in the absence of serum.

In contrast to the findings with SRC, a primary – as well as secondary – antibody response could be induced to LPS, which is a relatively thymus‐independent antigen.

Taken together the results suggest that:

a) FCS is necessary for the induction of primary antibody responses, because it contains B and possibly T cell mitogens.

b) Primary antibody responses to SRC can be induced in the absence of FCS if nonspecific B cell activation is provided by the addition of either B cell mitogens or B cell activating factors, obtained by activating T cells by specific mitogens or by a MLC reaction.

c) Secondary responses to T cell‐dependent antigens are possible in the absence of FCS because of the large number of specifically activated T cells present in the culture system.

d) Primary antibody responses to LPS are possible in the absence of FCS because LPS by itself is a B cell mitogen.