bluuebunny/crossref_metadata_2025 huggingface dataset:
β2 ‐Microglobulin on the cell surface Specificity of inhibition of the mixed leukocyte reaction and mitogenic properties of antibodies against the two HLA antigen polypeptide chains
Authors: Östberg L. , Lindblom J. B. , Peterson P. A.
Published: February 2007

Intact antibodies, and F(ab′)2, and Fab′ fragments thereof directed against β2‐microglobulin (β2m) and the HLA alloantigenic polypeptide chain impede the mixed leukocyte culture reaction (MLR). The Fab′ fragments are effective only when bound to the responder cell population. The kinetics of their inhibiting action suggest that they interfere with the recognition phase of the MLR. Thus, it seems possible that β2m may be part of or closely associated with those structures on the responding cells which recognize the stimulatory alloantigens.

Antibodies against β2m or the other HLA antigen polypeptide chain are mitogenic for peripheral blood lymphocytes. The antibodies against β2m caused greater stimulation than those against the HLA alloantigenic polypeptide chain. Only bivalent antibodies against β2m were mitogenic and promoted blast transformation of 1 to 2 % of the lymphocytes. Although only B lymphocytes were triggered, the mitogenic response of cultures containing various proportions of B and T cells suggests that cooperation of the two cell types is necessary to obtain optimal mitogenic stimulation.
Effect of the concentration of inducing agent on the output of lymphokines in the guinea pig
Authors: Ford W. H. , Ashworth L. A. E. , Inder S.
Published: February 2007

The production of migration inhibition (MIF) and mitogenic (MF) factors by cultured guinea pig lymph node cells was examined as a function of the concentration of antigen or concanavalin A (ConA). Maximum output of MIF was achieved at comparatively low levels of antigen and was equal to the maximum output by ConA. In contrast, MF output increased up to the highest antigen concentrations tested. Kinetic and chromatographic analysis revealed no differences between the MF produced at high and low antigen concentration.
Cell surface immunoglobulin. XV. The presence of IgM and an IgD‐like molecule on the same cell in murine lymphoid tissue
Authors: Vitetta Ellen S. , Uhr J. W.
Published: February 2007

The present studies were designed to determine whether IgM and “IgD” are on the same cell in the mouse. Thus, radioiodinated murine lymphocytes were treated with anti‐μ and complement to kill IgM‐bearing cells. The dead cells were removed by gradient centrifugation. Results indicate that a portion of the IgD is removed by depleting IgM‐bearing cells. Using cells from thoracic duct or lymph nodes but not spleen, it was evident that some of the double bearers are large lymphocytes.
Studies of the presence of membrane receptors for complement, IgG and the sheep erythrocyte rosetting capacity on the same human lymphocytes
Authors: Chiao J. W. , Good R. A.
Published: February 2007

Normal peripheral blood lymphocytes were tested by a mixed rosette method, employing different sized erythrocytes as indicators to identify lymphocytes simultaneously possessing membrane markers found commonly on B and T cells. Only small populations of these lymphocytes were detected regulary in normal lymphocyte preparations. One type of lymphocyte (ranged from 0.5%‐8%) was shown to possess the following markers: receptors for human and rabbit IgG, receptors for the third complement component C3b and C3b inactivator‐cleaved C3b (C3d), and the capacity to rosette spontaneously with uncoated sheep erythrocytes (SRBC). Another lymphocyte cell type was shown to possess both SRBC and IgG receptors but lack membrane immunoglobulins and complement receptors. This population was detected in lymphocyte preparations depleted of complement receptor cells, and an increased number of these cells was found in rosette preparations incubated with human serum. The possible presence of some lymphocytes possessing both complement and SRBC receptors and lacking other markers was considered.

The possibility that these small populations of human lymphocytes are sub‐populations of T cells with certain cytotoxic function is postulated.
Mitogen‐induced membrane changes and cell proliferation in T lymphocyte subpopulations
Authors: Resch K. , Ferber E. , Prester Marlot , Gelfand E. W.
Published: February 2007

Rabbit thymus‐dependent lymphocytes were exposed to phytohemagglutinin (PHA), concanavalin A (Con A), pokeweed mitogen (PWM) or anti‐immunoglobulin at various stages of maturation. Proliferation (induction of DNA synthesis) and early membrane events (turnover of membrane phospholipids) were measured in neonatal thymocytes, normal adult thymocytes, prednisolone‐resistant thymocytes and lymph node lymphocytes. In immature thymocytes PHA induced only a marginal increase in DNA synthesis. The mitotic response increased with maturation, but only peripheral T lymphocytes exhibited maximum stimulation. Con A and PWM were able to induce DNA synthesis in immature thymocytes and the degree of stimulation was shown to increase with maturation. In contrast to the different degree of proliferation of thymocytes induced by PHA or Con A the incorporation of [4C]oleate, [14C]choline or [14C]acetate into phospholipids was stimulated to the same degree by these lectins. Reactivity of T lymphocytes, as measured by early membrane changes at different stages of maturation, to different T cell mitogens appears to be identical. Differences in degree of cell proliferation therefore may be secondary phenomena due, in part, to tissue culture conditions. Reactivity to mitogens as measured by phospholipid turnover appears to be an early acquired function in the maturation of lymphocytes of the T cell line.
The relationship between storage and secretion of specific antibody by immune lymphoid cells: ultrastructural localization of anti‐peroxidase anti bodies in plaque‐forming cells of the rabbit popliteal lymph node
Authors: Zagury D. , Bernard J. , Lemieux S. , Mazie J. C. , Avrameas S. , Bussard A. E.
Published: February 2007

The ultrastructure of antibody‐forming cells (AFC) has been studied in the lymph node cell population from rabbits locally immunized with horseradish peroxydase (PO) incorporated in complete Freund's adjuvant, and the kinetics of AFC development followed from day 7 to day 18 after one injection of PO.

Identification of the AFC was done by local hemolysis assay, using carboxy‐methyl cellulose solidifying medium and PO‐coated sheep erythrocytes. AFC were thereafter transferred by micromanipulation into a Beem capsule, fixed, treated by PO for fine ultrastructure detection of anti‐PO antibodies, included, sectioned and studied by electron microscopy.

It was found that the AFC were essentially of three categories: lymphocytes, proplasmacytes and plasmacytes, with (+), or without (−), intracellular antibody. The proportion of these categories varies with the time elapsed since the injection of antigen and with the plaque‐forming activity of the population: lymphocytes(−) are relatively more numerous (over 30%) at the early stages of immunization (day 7). The number of plasmacytes increases with immunization. If most of them contain intracellular antibody at the early stages (up to day 9), the proportion of plasmacytes (+) decreases markedly afterwards.

The cell type distribution is compatible with the idea that the lymphocytes are the precursors of plasmacytes, proplasmacytes being transitional forms, but no direct filiation scheme can actually be deduced from these experiments.
Identification of a high molecular weight protein on the surface of murine thymus and thymus‐dependent cells
Authors: Santana Vilma , Wedderburn Nina , Abney Erika R. , Parkhouse R. M. E.
Published: February 2007

Rabbit anti‐mouse Ig reacted with mouse thymocytes resulting in the formation of caps which were shed into the medium and subsequently injected into rabbits. The antiserum from these animals (AMTP) reacted strongly with thymocytes and peripheral T cells and weakly with B cells. The antiserum did not react via the Thy‐1 antigen and could be made specific for T lymphocytes by absorption with B lymphocytes. By surface labeling of lymphocytes with 125I, it could be shown that the major T lymphocyte antigen recognized by AMTP was one, or possibly two, large, single chain molecules with a molecular weight of approximately 200 000. This molecule was not Ig and, furthermore, the AMTP did not react with cell surface Ig of B lymphocytes. The implications of this finding for previous reports on the existence of immunoglobulin on T lymphocytes are discussed.
Immunoglobulins M and D as antigen‐binding receptors on the same cell, with shared specificity
Authors: Stern C. , McConnell I.
Published: February 2007

Antigen‐binding cells specific for Type 3 pneumococcal polysaccharide were detected among normal human peripheral blood lymphocytes, tonsillar lymphocytes, and umbilical cord blood lymphocytes. By using μ and δ‐specific antiserum it was shown that some specific antigen‐binding cells simultaneously expressed both IgM and IgD on their surface. Both classes on individual cells were able to bind the same antigen, suggesting that the variable regions of each immunoglobulin class, when present on the same cell membrane, are coded by the same V gene.
Cyclicity and memory in the humoral immune response of the marine toad Bufo marinus
Authors: Azzolina L. S.
Published: February 2007

Bufo marinus toads immunized with a single dose of 100 μg of polymerized flagellin (POL) produce a longlasting cyclic humoral response at 22 °C in which the serum antibody titers rise and fall within periods of 2–3 weeks. This seems to be regulated by the catabolism of immunoglobulins, since passive 125I‐labeled IgM in the serum has a half‐life of 17 days, corresponding to the cyclicity of the titers of active antibodies. In toads injected with between 10 μg and 10 pg antigen the serum antibody titer peaks between 4 and 7 weeks, depending on the antigen dose, and declines by the 9th week. At this time a second stimulation with an equal dose of POL induces a secondary response during which higher titers of antibodies rise faster than in the primary response. A dose of 10 μg POL stimulates an optimal primary response and a second equal dose, given when the serum antibodies are disappearing, induces a secondary response enhanced in time but not in antibody titers.
Suppressor cell induction in vitro. I. Kinetics of induction of antigen‐specific suppressor cells
Authors: Kontiainen Sirkka , Feldmann Marc
Published: February 2007

The induction of antigen‐specific suppressor cells in vitro, using high concentrations (100 μg/ml) of keyhole limpet hemocyanin (KLH) in Marbrook flasks is described. Spleen and cortisone‐resistant thymocytes were the richest source of suppressor cell precursors, compared to lymph node cells, peripheral blood lymphocytes or thoracic duct lymphocytes. Suppressor cells induced with KLH only suppressed KLH‐reactive helper cells, and not B cells or helper cells of other specificity. The suppressor cells were T cells, as judged by their sensitivity to anti‐Thy‐1.2, heterologous anti‐T, but not anti‐B antisera.
Effects of Levamisole on spontaneous rosette‐forming cells in murine spleen
Authors: van Ginckel R. F. , Hoebeke J.
Published: February 2007

Levamisole, an anti‐anergic chemotherapeutic agent, is shown to depress the azathioprine sensitivity of rosette‐forming cells (RFC) in the spleen of normal mice, and to restore the azathioprine sensitivity of RFC in the spleen of adult thymectomized mice. Using the fully active dose of 1.25 mg/kg i.v., the restoration effect was present 15 h after treatment with the drug and almost disappeared after 48 h. Levamisole was ineffective on RFC in vitro. These results suggest that Levamisole might interfere with the reactivity of T lymphocytes as has been described for drugs interfering with cyclic nucleotide metabolism.
Location of light chain tyrosine peptides from the combining site of a rabbit anti‐p‐azobenzoate antibody
Authors: Friedenson B. , Roholt O. A. , Appella E. , Wright J. D. , Tissot R. , Cohen C. , Pressman D.
Published: February 2007

Peptic peptides containing a tyrosyl residue from the binding site of a rabbit anti‐p‐azobenzoate antibody were isolated by means of the paired‐iodination procedure. The peptides were from the light chain, and the tyrosyl residue is

Tyr at position 30 in the sequence ‐Val‐Tyr‐Am‐AsxLys‐Gly‐Leuand thus is in the first hypervariable region. The sequence of the N‐terminal 40 residues was determined. The major antibody‐site peptide isolated was a diiodotyrosyl (DIT) tetrapeptide representing residues 30–32A; the monoiodotyrosyl (MIT) tetrapeptide was also isolated, but in a smaller yield. By isoelectric focusing, the light chain appeared to be homogeneous. No heterogeneity was apparent in the light chain sequencing until position 32B when, in addition to the phenylthiohydantoin derivative of tyrosine present as the major residue, a significant amount of the phenylthiohydantoin derivative of glycine was obtained. The glycine presumably represents a light chain variant population and explains the source of the other antibody‐site peptides isolated, i.e. two pentapeptides, apparently of the sequence Tyr‐Asn‐Asx‐Lys‐Gly, isolated as the DIT and MIT derivatives. The tetrapeptides must have been derived from the peptic cleavage between Lys 32A and Tyr 32B in the major light chain variant and the pentapeptides from the peptic cleavage between Gly 32B and Leu 33 in the other variant.

It is interesting that position 30 is occupied by a tyrosyl residue in five out of twelve other rabbit antibody light chains of known sequence (Margolies, M.N. et al., Proc. Nat. Acad. Sci. US 1975. 72: 2180). One light chain is from another rabbit anti‐p‐azobenzoate antibody in which Tyr 30 is apparently not important in hapten binding although a tyrosyl at position 96 is clearly involved in hapten binding (Roholt, O.A. et al., J. Immunol. 1973. 111: 1367). The other four of the five light chains are from anti‐pneumococcal polysaccharide antibodies in which the role of this tyrosyl residue is not known.
Solubilization and molecular characterization of membrane‐bound antigens shared by thymocytes and brain
Authors: Arndt R. , Stark Rosemarie , Klein P. , Müller Angelika , Thiele H. G.
Published: February 2007

In order to Characterize chemically the serologically well‐defined antigens shared by thymocytes and nervous tissue of mice and rats, different solubilization procedures have been tested. Treatment of thymocyte membranes with urea‐Nonidet‐P40 (NP40) proved to be the most valuable method, since nearly 100% of the antigen was solubilized essentially without loss of the antigenicity. By gel filtration in urea‐NP4O the molecular weight was estimated to be 35 000 and the Stokes radius in sodium deoxycholate 31.8 Å. In gel filtration studies a homogenous peak was obtained, whereas isoelectric focusing yielded two peaks (isoelectric points pH 4.5–5.0 and pH 5.4). The three determinants of this antigenic system were inseparable in gel filtration and isoelectric focusing, supporting the view put forward on the basis of serological studies that they are part of the same molecule.

Extraction of murine thymocyte membranes with organic solvents yielded a considerable loss of activity of the thymocytes‐brain antigen. There was some residual activity in the protein fraction, but none in the organic phase. Correspondingly, the highly purified ganglioside GGtet 2b proved unable to absorb any rabbit anti‐ CBA brain serum. The reduced antigenic activity of the delipidated protein fraction could be restored by addition of lipids, as well as the nonionic detergent NP40. These observations suggest that interaction of protein and lipid is necessary for the antigenicity of the thymocyte‐brain antigen.
Differential cytotoxicity of activated lymphocytes on allogeneic and xenogeneic target cells. III. Species specificity of lymphocyte target cell recognition in vitro
Authors: Stejskal Vera , Perlmann P.
Published: February 2007

Cytotoxic effector lymphocytes were produced by stimulation of human peripheral blood or mouse spleen lymphocytes with PPD, PHA or PWM in vitro. The specificity of the lymphocyte target cell interaction was studied by adsorption of effector cells on various target cell monolayers. The cytotoxic activity of human lymphocytes against 51Cr‐labeled human or monkey target cells was reduced by prior incubation on primate monolayers while it was much less affected by incubation on rodent monolayers. Conversely the cytotoxicity of mouse lymphocytes against mouse L cells was strongly reduced by adsorption on mouse or rat monolayers but significantly less by that on human monolayers. This suggests that this species‐specific cytotoxicity reflects recognition by activated lymphocytes of some common surface structures present only on cells of the species of the effector cell donor, or on cells from phylogenetically closely related species.

Lymphocyte‐mediated cytotoxicity against xenogeneic target cells was studied after stimulation with PWM. The capacity of human lymphocytes to kill 51Cr‐labeled mouse cells was reduced by adsorption on either rodent or primate monolayers. Conversely, prior incubation of mouse lymphocytes on either human or mouse monolayers led to inhibition of 51Cr release from labeled Chang cells. These results suggest that the mitogen‐activated effector cells which are cytotoxic for more distantly related xenogeneic target cells have receptors for structures which are common for these cells and for target cells of the species of the lymphocyte donors.
Activation of T lymphocytes to M locus determinants in vivo.. I. Quantitation of T cell proliferation and migration into thoracic duct lymph
Authors: Sprent J. , von Boehmer H.
Published: February 2007

Proliferative responses to M locus (M1S) determinants were investigated in vivo by injecting T cell‐containing populations intravenously into irradiated H2‐identical, M1 s‐incompatible mice. Responses were studied 1–6 days later by measuring levels of radioactivity in the spleen and lymph nodes of the recipient 45 min after intravenous injection of tritiated thymidine.

High responses were observed against M1sa and M1sd determinants, i.e. determinants which give strong proliferative responses in vitro. With injection of thoracic duct lymphocytes (TDL), lymph node or thymus cells, the responses, both in the spleen and the lymph nodes, reached a peak at day 3–4 and then fell sharply. This was in marked contrast to the stimulation observed with H‐2‐incompatible mice where, with TDL or lymph node cells (though not with thymus cells), responses were low at day 3–4 but reached high levels at day 6.

Significant responses were also observed against M1sb and M1sc determinants, i.e. determinants which stimulate poorly in vitro. The kinetics of this response differed from that against M1sa or M1sd determinants in that proliferation was very low at day 4 but high at day 6. No evidence was found that the responses observed reflected “back‐stimulation” by the host. Since congenic resistant strains were not used, the possibility that the stimulation observed was in fact due to minor transplantation antigens rather than M1s determinants could not be excluded.

Large numbers of blast cells appeared in thoracic duct lymph of mice sustaining responses to M1sa or M1sd determinants. Nearly all of these cells had recently synthesized DNA and entered the lymph after day 3.
Inhibition of T cell activity in vivo: a test model for quantitative evaluation
Authors: Lemmel E.‐M. , Botzenhardt U.
Published: February 2007

A test model is presented which, in comparison with the conventional models of skin transplantation or graft‐versus‐host (GvH) reaction in mice, permits a more sensitive quantitative evaluation of T cell inhibition in viva Prospective donors (type AA) are immunized with prospective recipient material (type AB); the resulting T cell reaction of A versus B is inhibited by consecutive treatment. Extent of inhibition can be evaluated after transfer of the pretreated AA material onto AB recipients by calculation of remaining GvH reactivity, if compared to adequate control transfers. In this model the target animal for T cell reactivity (the AB recipient) remains untouched from immunosuppressive regimen.
B cell tolerance induced by polymeric antigens. VI. Kinetics and reversibility of the inhibition of antibody‐forming cells by antigen
Authors: Klaus G. G. B.
Published: February 2007

Injection of mice already making antibodies to 2,4‐dinitrophenylated (DNP) Ficoll with tolerizing doses of DNP‐pneumococcal polysaccharide (DNP‐lys‐S3) markedly inhibits the secretion of anti‐DNP antibodies by IgM antibody‐forming cells. The present study shows that the degree of inhibition depends not only on the dose of DNP‐lys‐S3 but also on the duration of exposure to antigen. DNP‐ lys‐S3 was detectable on the surface of antibody‐forming cells at a time when their rate of secretion was unimpaired, thus suggesting that the inhibition involves intracellular events subsequent to the binding of antigen to the cell membrane. The inhibition was reversible if antibody‐forming cells were exposed to antigen for 24 h, and then cultured for 18 h in its absence, but became irreversible if the treatment period was extended to 48 h. The relevance of this model of inhibition of lymphocyte function by antigen to possible mechanisms of B cell tolerance is discussed.
Immunoglobulin M receptors on memory cells of immunoglobulin G antibody‐forming cell clones
Authors: Abney E. R. , Keeler K. D. , Parkhouse R. M. E. , Willcox H. N. A.
Published: February 2007

The memory cells of two antibody‐forming cell clones had receptors of the IgM class, even though the clones had been producing IgG1 or IgG2a anti‐2,4‐dinitrophenyl antibodies for 9–15 months previously (on exposure to antigen). Thus a phenotypic switch in heavy chain constant region evidently occurred after re‐exposure of these memory cells to antigen.

To show that, we first removed the clonal cells' surface immunoglobulins by “capping” and “stripping”, with class‐ or subclass‐specific antisera. Then, to assay their remaining receptor activity, the cells were incubated with antigen in vitro, washed and transferred (together with carrier‐primed cells) to irradiated recipients, and their antibody responses to this in vitro boost were assayed by isoelectric focusing. Pretreatment with anti‐μ serum, as well as with anti‐Fab(k), prevented the responses of the IgG1 and IgG2a clones to an in vitro boost, while anti‐γ1, and anti‐γ2a antisera had no effect. An anti‐serum to the putative mouse IgD also had no effect. The anti‐μ serum failed to react with the IgG1 and IgG2a clonal serum antibodies in the test tube. Some other contaminating clones were suppressed completely only by the anti‐Fab serum.

This result strongly suggests that switching in class commitment may occur during the differentiation of memory cells to antibody producers, and may therefore be antigen‐dependent. It also implies that some apparently naïve cells with surface IgM may., in reality, be B memory cells.
Polyclonal stimulation of lymphocytes by macrophages
Authors: Opitz H. G. , Opitz Uta , Lemke H. , Huget R. , Flad H. D.
Published: February 2007

To analyze the interaction between macrophages and splenic lymphocytes with reference to time and concentration, the Mishell‐Dutton system was divided into two experimental steps. Step 1 consisted of the cocultivation of spleen cells with various doses of macrophages for different periods of time, while in step 2 macrophages were removed, spleen cells transferred to fresh petri dishes and cultivated until plaque assay. Cocultivation of spleen cells with high doses of macrophages for 4–8 h markedly enhanced the DNA synthesis and plaque‐forming cell (PFC) response of sheep red blood cell‐stimulated and unstimulated cultures. A cocultivation longer than 24 h resulted in an inhibition of both DNA synthesis and PFC response of spleen cells. These studies suggest a nonspecific function of macrophages on proliferation and differentiation processes in‐antibody formation.
Isolation of a murine liver‐specific alloantigen, F antigen, and examination of its immunogenic properties by radioimmunoassay
Authors: Lane D. P. , Silver D. M.
Published: February 2007

The autoantibody response induced in mice by alloimmunization with liver‐specific F antigen is an example of the circumvention of humoral self‐tolerance. The F molecule has been isolated and shown to be a protein with a mol. wt. of 40 000 Daltons which migrated as a β‐globulin. The purified antigen retains both the immunogenic and antibody‐combining properties of crude liver homogenate. Successful iodination of the protein allowed the establishment of a radioimmunoassay which demonstrated high titers of antibodies in responder strains. At the same time it was clearly shown that no antibody could be detected, either as a result of syngeneic immunization or as a result of alloimmunization in nonresponder strains. The characteristics of the F antigen immune response distinguish it from that induced by other proteins.
Amino acid sequence studies on the branched, synthetic polypeptide antigens of the immune response‐1 gene system
Authors: Seaver Sally S. , Ohms J. I. , Freed J. H.
Published: February 2007

Three immunogens with side chains of random amino acid sequence, poly (L Phe, L Glu)‐poly (DL Ala)–poly(L Lys) [(Phe, G)‐A–L 223], poly(L Tyr, L Glu)‐ poly(DL Ala)– poly(L Lys) [(T, G)‐A–L 509] and (T, G)‐A–L 52, as well as two immunogens with side chains of defined amino acid sequences, GGT‐A–L and TG‐A–L, were sequenced using a Beckman automated sequenator. Despite the lack of a unique amino acid sequence for the amino terminus, reasonable results for the sequence studies were obtained using the Edman reaction. GGT‐A–L and TG‐A–L had 70 % and 80 % of their side chains, respectively, with the desired sequence. The three compounds of random amino acid sequence were found to contain a large proportion of their A–L side chains unsubstituted. The side chains had a much greater probability of terminating in the aromatic amino acid than in the glutamic acid. The distribution of the length of side chains and their amino acid sequences was completely heterogeneous.
Many cells in rat bone marrow have cell‐surface Thy‐1 antigen
Authors: Williams A. F.
Published: February 2007

Thy‐1.1 and Thy‐1 xenoantigenic determinants were detected at the cell surface of many rat bone marrow cells. The absorptive capacity of bone marrow cells was 6–10 % of that of thymocytes for Thy‐1 antigenic determinants, and 30–45 % of rat bone marrow cells were specifically labeled with anti‐Thy‐1 antibody as detected by autoradiography. Thus, while mice and rats are similar in having large amounts of Thy‐1 in brain and thymocytes, they differ in that the rat lacks the antigen in most peripheral T cells and expresses it in a large number of bone marrow cells; the opposite is true in the mouse.
Receptors for immune complexes on cells within a polyoma virus‐induced murine sarcoma
Authors: Braslawsky G. R. , Serban D. , Witz I. P.
Published: February 2007

Cells present in the polyoma virus‐induced murine ascites tumor SEYF‐a showed the capacity to fix soluble immune complexes of ovalbumin anti‐ovalbumin. The fixation could be inhibited by preincubating the cells with antisera directed against H‐2 antigens and with syngeneic anti‐tumor antibodies. The latter did not react with normal cells. Depletion of phagocytes from the ascites cell population, thus enriching for tumor cells, increased the inhibition of complex fixation by the syngeneic anti‐tumor antiserum. The inhibition of complex fixation by the anti‐tumor antibodies was not mediated by “third‐party” complexes. Pepsin‐treated globulin derived from the syngeneic anti‐tumor antiserum could still inhibit complex fixation by SEYF‐a cells. These results raise the possibility that tumor cells, per se, expressed receptors for immune complexes. Macrophages, apparently of host origin, residing in the SEYF‐a tumor, also expressed such receptors.
Stimulation and suppression of rat mast cell functions by alloantibodies
Authors: Mossmann H. , Lauer W. , Vortisch Uta , Günther E. , Hammer D. K. , Bazin H.
Published: February 2007

The stimulatory as well as the inhibitory capacity of alloantisera has been investigated with respect to rat mast cell functions. Alloantibody against alloantigens coded for by the major histocompatibility (H‐1) gene region promoted histamine release from purified LEW mast cells. This process was found to be complement‐independent but demonstrated an absolute requirement for calcium.

Pretreatment of mast cells with anti‐H‐1 antisera in the absence of calcium markedly suppressed the IgE‐dependent histamine release challenged either by antigen or by anti‐IgE antibody. The alloantisera, however, did not interfere with the ability of compound 48/80‐associated histamine liberation. Additionally, antibodies specific for H‐1 antigens were highly effective in inhibiting the binding of IgE to the mast cell surface. Alloantisera absorbed with erythrocytes lost their capacity to block mast cell functions.

Based on these data the possible relationship between H‐1 alloantigens and the IgE receptor on the mast cell surface is discussed.
Naturally‐occurring double‐stranded RNA and immune responses. IV. Influence of molecular size on antigenicity and adjuvant activity
Authors: Butlin Pamela M. , Cunnington P. G.
Published: February 2007

The immunological properties of a naturally‐occurring double‐stranded ribonucleic acid (ds‐RNA), obtained from a mycophage of Penicillium chrysogenum, have been studied in relation to molecular size. Materials of reduced size, as reflected by molecular weight measurements, produced by ultrasonication of native ds‐RNA, exhibited progressively lowered ability to induce an anti‐ds‐RNA response in mice. Adjuvant and immunosuppressive activities were of similar magnitude in both high and low molecular weight fractions. Evidence was also obtained of increased toxicity in materials of reduced size.
Shared determinants between virus‐infected and trinitrophenyl‐conjugated H‐2‐identical target cells detected in cell‐mediated lympholysis
Authors: Starzinski‐Powitz A. , Pfizenmaier K. , Röllinghoff M. , Wagner H. , Koszinowski U.
Published: February 2007

Infection of H‐2‐identical mice with either lymphocytic choriomeningitis (LCM) virus, vaccinia virus, or paramyxo (Sendai) virus resulted in the generation of specifically sensitized cytotoxic T lymphocytes (CTL). CTL generated in vitro against 2,4,6‐trinitrophenyl (TNP)‐conjugated syngeneic stimulator cells were specifically cytotoxic for TNP‐conjugated H‐2K(D) region identical targets. Both LCM and vaccinia‐induced CTL, however, were found to be strongly cytotoxic towards TNP‐conjugated, H‐2K(D) region‐identical target cells. In contrast, Sendai virus‐induced CTL did not lyse TNP‐conjugated, syngeneic target cells. Inhibition experiments using cold targets suggested that shared antigenic determinants can be detected on either LCM virus‐infected and TNP‐conjugated targets, which are not present on the cell surface 6f normal target cells.
Control mechanism of lymphocyte traffic Altered migration of 51Cr‐labeled mouse lymph node cells pretreated in vitro with phospholipases
Authors: Freitas A. A. , de Sousa Maria
Published: February 2007

Glycoproteins have so far been the only surface components thought to be of importance in the process of recognition between circulating lymphocytes and endothelial cells of the lymph node post‐capillary venules and thus in the control of lymphocyte traffic. In this paper the effect of in vitro treatment of 51Cr‐labeled mouse lymph node cells with phospholipases (PL) (A and C) on their migration into syngeneic recipients was investigated. PL‐A and PL‐C‐treated cells migrated differently from control (untreated) cells. Diminished numbers of PL‐A‐treated lymphocytes were found in the lymph nodes at 1, 6 and 24 h after cell transfer with a simultaneous increase in the lungs at 1 h, and spleen at 6 h after transfer. PL‐C‐treated cells remained in the blood longer than untreated cells.

We conclude that factors other than the integrity of surface glycoproteins are involved in the control of lymphocyte traffic. The roles played by cell adhesion, in particular cell‐to‐cell interactions in regulating the rate of cell migration, are discussed.
Specific loss of stimulator activity following mixed lymphocyte reactions is due to cytotoxic cells
Authors: Janeway C. A. , Mosier D. E. , Tigelaar R. E.
Published: February 2007

Experiments were performed to test the hypothesis that stimulating antigens in the mixed lymphocyte reaction (MLR) are expressed in a restricted fashion on lymphocytes. Thus one‐way MLR between spleen cells from congenic mouse strains differing at H‐2 were treated with 5‐bromo‐2‐deoxyuridine (BrdUrd) and light to inactivate dividing cells. The ability of the residual cells to act as responder or stimulator cells in a subsequent MLR was assessed. AS expected, a specific loss of responder cell activity occurred under these conditions. Furthermore, such cells, following irradiation, would not stimulate fresh spleen cells from the strain against which they initially responded, but would stimulate spleen cells of unrelated mouse strains. This was shown to be due to the generation of cytotoxic T cells detectable in 51Cr release assays in the primary MLR, despite BrdUrd and light treatment and irradiation. Furthermore, loss of stimulator activity mapped to the H‐2K region of the H‐2 complex rather than the strong MLR‐stimulating I‐A or I‐B subregions. These experiments provide no evidence of restricted expression of MLR‐stimulating antigens on lymphocytes.
Effect of sera from immunologically altered mice on phytohemagglutinin‐induced mouse lymphocyte transformation
Authors: Nelson D. S. , Penrose Jean M. , Shneider Cynthia N.
Published: February 2007

The DNA‐synthetic response of mouse spleen cells to phytohemagglutinin in vitro is depressed by the addition of normal mouse serum. The effects of sera from mice that had been modified immunologically were examined. Increased depressive activity was found in sera from nude mice and from mice recently treated with anti‐thymocyte globulin, but no change was found in sera from thymectomized, irradiated, bone marrow‐reconstituted mice, nor from lethally or sublethally irradiated or cyclophosphamide‐treated mice. Base line DNA synthesis was, however, less inhibited by sera from irradiated or cyclophosphamide‐treated mice. Increased depressive activity was found in sera from mice with graft‐versus‐host reaction and from mice injected with Salmonella enteritidis 11RX, in which macrophage stimulation occurred. Increased depressive activity was also found in the sera of mice injected with sheep erythrocytes. T cells do not appear to be a source of depressive activity but B cells, macrophages and nonlymphoid cells may be sources.
Surface molecules of cultured human lymphoid cells
Authors: Trowbridge I. S. , Hyman R. , Mazauskas Catherine
Published: February 2007

Cell surface molecules of cultured human lymphoid cells were selectively labeled by lactoperoxidase‐catalyzed iodination and examined by polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate. Two major iodinated species with apparent mol. wts. of 27 000 and 35 000 daltons were detected on autoradiographs of the labeled proteins of human lymphoid cell lines believed to be of thymus‐independent (B) cell origin. Neither molecule was detected on putative thymus‐dependent (T) lymphoid cell lines. Metabolic labeling studies showed that both molecules are glycoproteins. Rabbit antisera against cultured B lymphoid cells made specific by absorption for B cells reacted with several labeled species from iodinated B cells including the 27 000 and 35 000 mol. wt. glycoproteins. These molecules were also detected on tonsillar lymphocytes but not on peripheral blood lymphocytes. Reciprocal absorption with B cells of rabbit antisera against cultured T cells gave antisera specifically cytotoxic for T cells. However, these sera did not precipitate iodinated proteins from Nonidet P‐40 lysates of T cells.
Studies on the relationships between the immunogenicity and catabolism of antigens and their binding to the surface of macrophages
Authors: Gallily Ruth , Bar‐Eli M.
Published: February 2007

The relationship between immunogenicity of Shigella paradysenteriae, the branched synthetic polypeptide poly‐L (Tyr, Glu)‐polyLPro‐polyLLys [(T, G)‐Pro–L] and human serum albumin (HSA) interacting with macrophages and the kinetics of antigen degradation and degree of binding to the cell surface was studied. Following thioglycollate inoculation into C57BL/6 mice, the peritoneal‐stimulated macrophages had higher levels of hydrolases as compared to unstimulated cells. The lysates of the stimulated macrophages catabolized the three labeled antigens faster than did the lysates of unstimulated cells. However, when degradation of labeled antigens by macrophage cells was assessed, no direct correlation could be demonstrated between the level of cell hydrolases and rate of (T, G)‐Pro–L or HSA catabolism.

The immunogenicity of the antigens following their uptake by unstimulated and stimulated macrophages was determined by transfer of the antigen‐bearing cells into irradiated and nonirradiated syngeneic recipients. No correlation was apparent between the rate of antigen degradation and the capacity to evoke a humoral response. Similarly, no correlation could be demonstrated between the amount of antigen bound to the macrophage cell surface and the immunogenicity of the antigen.

It is suggested that neither the rate of antigen catabolism by macrophages nor the amount of antigen bound to the macrophage membrane is the sole factor which determines the immunogenicity of antigens interacting with macrophages.
In vivo sensitization of T cells to hapten‐conjugated syngeneic structures of major histocompatibility complex. I. Effect of in vitro culture upon generation of cytotoxic T lymphocytes
Authors: Starzinski‐Powitz A. , Pfizenmaier K. , Röllinghoff M. , Wagner H.
Published: February 2007

Murine T cells were sensitized in vitro towards fluorescein isothiocyanate (FITC)‐conjugated syngeneic spleen cells. The lytic activity of the effector cells generated was restricted to FITC‐conjugated, H‐2‐compatible target cells. 2,4,6‐Trinitrophenyl (TNP)‐conjugated syngeneic targets were not lysed.

A method is described for the in vivo sensitization of murine T cells towards TNP (or FITC)‐conjugated syngeneic spleen cells. The procedure is based on the observation that a local graft of hapten‐conjugated syngeneic spleen cells results in the development of sensitized prekiller T cells within the draining lymph node (LN). By mere in vitro incubation of such LN cells immunological specific anti TNP (or anti‐FITC)‐reactive cytotoxic T lymphocytes (CTL) are generated. The in vitro differentiation of CTL requires 48‐72 h; it is dependent on cell proliferation and is abolished by treatment of the LN cells with mitomycin C. Thus there is a separation between the sensitization of CTL precursors (which effectively takes place in vivo) and the phase of cell differentiation into CTL (which effectively takes place only in vitro). Similar to in vitro‐sensitized CTL, the specificity of in vivo‐sensitized CTL is dictated by the hapten used for the induction of the immune response and is restricted to hapten‐conjugated syngeneic target cells.
Active heterologous chain recombinants of monoclonal antibodies raised in related rabbits
Authors: Braun D. G. , Riesen W. F. , Huser H.
Published: February 2007

Heterologous chain recombinants of homogeneous anti‐streptococcal group A‐variant polysaccharide antibodies produced by pedigreed rabbits regain in certain pairs the same antigen‐binding capacity as the homologous pairs. In contrast, chain recombinants with antibodies from nonrelated rabbits are much less active. This data suggests random pairing of immunoglobulin heavy and light chains coded for in the germ line and subsequent selection.
Binding of immune complexes of guinea pig IgG2 to homologous peritoneal exudate cells
Authors: Leslie R. G. Q. , Alexander M. D. , Cohen S.
Published: February 2007

A quantitative study has been performed to correlate the macrophage‐binding activity of immune complexes of guinea pig IgG2 with the antigen‐antibody composition and size of the immune complex. Binding, measured as (a) uptake at a single IgG concentration, (b) resistance to IgG2 monomer inhibition and (c) mean binding avidity of the complex, was maximum at the antigen‐antibody ratio optimum for immune precipitation. All three parameters declined in value with increasing proportions of antigen in the complex. Gel filtration of immune complexes revealed that complex size and binding avidity declined with increase in antigen excess. The relationship of binding activity to complex size and the similar inhibitory patterns of IgG2 and its fragments for binding of monomer and complexed IgG2 suggest that binding enhancement results from the cooperative action of multiple Fc sites in the immune oligomer, rather than from conformational change.
The helper cell function of primed T cells. I. Marked amplification of antibody formation by antigen‐educated T cells carrying surface Ig 6 h after priming
Authors: Paraskevas F. , Lee S. T.
Published: February 2007

These experiments deal with a subpopulation of T cells bearing adsorbed Ig, thus considered to be Fc‐receptor positive. Such cells were collected from spleens of lethally irradiated mice reconstituted with thymocytes 6 h after priming with heterologous erythrocytes (sheep or horse red blood cells). The helper cell function of such cells was examined upon transfer to secondary hosts with normal bone marrow cells. Such educated thymocytes upon challenge generated a 2–3‐fold increase of 19 S plaque‐forming cells (PFC) and a 6–7‐fold increase of 7 S PFC above the level given by unprimed thymocytes. Such amplification of antibody formation is highly specific. No helper cell function was detected in cells obtained similarly from nonreconstituted animals or from mice reconstituted with bone marrow cells. Carrier‐primed thymocytes collected 6 h after priming are also able to enhance the primary 7 S anti‐hapten response but only when the hapten is provided on the same carrier used for priming. The helper cell function of 6 h primed thymocytes was compared to that of more conventionally educated thymocytes collected 5 days after priming. Although both cell preparations induced similar enhancements of 19 S PFC, the 6 h primed cells gave more than twice the number of 7 S PFC as compared to 5 day primed cells. This difference is statistically highly significant (p < 0.001).

Since the 6 h primed thymocytes contain a subpopulation which has acquired surface Ig, as shown by our previous work, their role in the mechanism of the enhancement of the helper cell function is discussed.
Characterization of suppressor cells involved in regulation of experimental allergic encephalomyelitis
Authors: Welch A. M. , Swanborg R. H.
Published: February 2007

This report describes studies carried out in an effort to identify the suppressor cells involved in the regulation of experimental allergic encephalomyelitis (EAE) in the Lewis rat. Viable lymph node cells (LNC) from donors rendered tolerant to clinical EAE by pretreatment with myelin basic protein antigen in nonencephalitogenic form are capable of transferring unresponsiveness to syngeneic recipients. Adoptive transfer of unresponsiveness was abrogated if LNC were treated in vitro with anti‐thymocyte serum and complement.

In further experiments, it was shown that suppressor cells are among the LNC subpopulations that do not adhere to glass wool. These findings suggest that the immunoregulatory cells in EAE are suppressor T lymphocytes.
Tolerance in differentiating B lymphocytes
Authors: Elson C. J.
Published: February 2007

These experiments demonstrate that the response of B lymphocytes to particulate antigen in vivo can depend on their stage of differentiation: B lymphocytes differentiating from stem cells were rendered tolerant, while mature B lymphocytes were primed under the same conditions. Lethally irradiated mice of one allotype were repopulated with 13–15 day fetal liver cells from congenic mice bearing another allotype and the effect of antigen on the emergence of responsive B cells determined. B cells, descended from the fetal liver inoculum (identified by their allotype) produced an antibody response to antigen in the presence of additional T cells, 15 days after transfer. Such a response could be prevented by injecting the recipient with alum‐precipitated antigen (but not with deaggregated antigen) shortly after irradiation and reconstitution. This unresponsive state was specific and independent of afferent suppressor mechanisms. Mature B cells, on the other hand, were shown to be primed by alum precipitated antigen in irradiated reconstituted hosts. It was concluded that a fundamental difference exists between the responsiveness of mature and differentiating B lymphocytes. Tolerance in differentiating B lymphocytes is discussed in relation to the acquisition of self‐tolerance.
Evidence for quasi‐silent germline genes coding for phylogenetically ancient determinants of the rabbit a locus allotypes
Authors: Van Der Loo W. , De Baetseliei P. , Hamers‐Casterman Cécile , Hamers R.
Published: February 2007

Anti‐a 2 sera raised in a3 rabbits are shown to detect determinants on a2 molecules which are different from those detected by anti‐a 2 sera raised in al animals.

The former determinants are occasionally observed at a low level in rabbits of the al allotype and at a high level in sera of Leporidae of different genera. The two types of anti‐a 2 sera are shown to compete for the same sterical region of the a2 molecules. All homogeneous a2 molecules which have been tested show both types of determinants.
The expression and relation of HLA, β2 ‐microglobulin and receptor for marmoset red blood cells on man/mouse and man/Chinese hamster hybrid cells
Authors: Fellous M. , Wiels J. , Hors M. C. , Rebourcet R. , Finaz C. , Weil D. , Heuertz S. , Mahouy G. , Fridman W. H.
Published: February 2007

The expression of HLA, human and mouse β2‐microglobulin (β2m), P red blood cell antigen and a receptor for marmoset red blood cells (MaRBC) were studied on 18 man/mouse and man/Chinese hamster hybrids. A positive correlation was found between the expression of HLA, P, and the receptor for MaRBC, which we interpret as a possible synteny between these different loci. We studied 3 hybrid clones where HLA antigens are still expressed despite the absence of human β2m and where redistribution experiments demonstrate that HLA is associated with mouse β2m. Synteny between HLA and the receptor for MaRBC can be a useful tool to select HLA‐positive hybrid clones.
Inhibition of human mixed lymphocyte culture stimulation by anti‐HLA‐D ‐associated antisera: studies with primed responding cells
Authors: Hirschberg H. , Albrechtsen D. , Solheim B. G. , Thorsby E.
Published: February 2007

The inhibitory effects of HLA‐D ‐associated antisera on stimulating lymphocytes when cultured together with allogeneic primed responding lymphocytes were investigated. The responding lymphocytes were primed for either the HLA‐Dw2 or Dw3 determinants. The presence of HLA‐D ‐associated (la‐like) antibodies during the culture period specifically inhibited the stimulatory capability of lymphocytes possessing the HLA‐D determinants with which the antisera were apparently reacting, as long as the stimulating cells carried the determinant for which the responding cells were primed. HLA‐D ‐associated antisera of other specificities caused no decrease in the stimulatory capability. These antisera, therefore, apparently contain antibodies which are reactive with determinants closely associated or identical to the HLA‐D determinants and may be human analogues to the mouse Ia antigens.