bluuebunny/crossref_metadata_2025 huggingface dataset:
Evidence for the endogenous production of T cell receptors bearing idiotypic determinants
Authors: Julius M. H. , Cosenza H. , Augustin A. A.
Published: February 2007

Unprimed thymus‐derived (T) cells from spleens of either conventional TEPC 15+ (T15+) BALB/c mice or neonatally suppressed T15− BALB/c mice were used to reconstitute neonatally suppressed T15− BALB/c nude mice and conventional T15+ BALB/c nude mice, respectively. In so doing, the idiotypes produced by phosphorycholine (PC)‐specific bone marrow‐derived (B) cells were dissociated from idiotypes putatively produced by PC‐specific T cells. Subsequent to priming of the reconstituted BALB/c nude mice with either anti‐T15 antisera or PC‐MOPC 315, their splenic T cells were assessed for PC‐specific helper activity and expression of the T15 idiotype.

Our results indicate that expression of the T15 idiotype by T cells as determined by (a) the ability to prime PC‐specific helper cells with anti‐T15 antibodies, and (b) the ability to inhibit PC‐specific helper function with anti‐T15 antibodies, depended on the idiotype of the unprimed donor T cell source and not that of the B cells in the reconstituted recipients. We conclude that the idiotype‐bearing T cell receptor specific for PC is not a passively adsorbed B cell product.
Properties of antisera against lymphocytes of nude mice
Authors: Rudnicka Wieslawa , Długońska Henryka , Żelazowski P. , Szewczyk K. , Gościcka Teresa
Published: February 2007

The activity of rabbit antisera against nu/nu BALB/c lymphocytes was estimated in vivo and in vitro.

It was found that anti‐lymphocyte serum (ALS) against nu/nu lymph node cells suppressed the alloantigen reaction and the spontaneous rosette‐forming cell (sRFC) or plaque‐forming cell (PFC) formation for T‐dependent (sheep red blood cells) and T‐independent (lipopolysaccharide) antigens. ALS against nu/nu spleen cells affected only the sRFC and PFC for T‐independent antigen. The former serum exhibited a high cytotoxicity for the suspensions enriched or depleted in B cells, while the latter was more cytotoxic for the suspension enriched in B cells. This may indicate that ALS anti‐nu/nu spleen cells is specific for B lymphocytes, and ALS anti nu/nu lymph node cells is directed not only to B cells but also to a subpopulation of T lymphocytes. It may suggest the existence of a subpopulation of T lymphocytes in nu/nu lymph node cells.
Monoclonal xenogeneic antibodies to murine cell surface antigens: identification of novel leukocyte differentiation antigens
Authors: Springer T. , Galfrè G. , Secher D. S. , Milstein C.
Published: February 2007

Hybrid myeloma cell lines secreting monoclonal antibodies to mouse cell surface antigens have been prepared. Spleen cells from a DA rat immunized with B10 mouse spleen cells that had been enriched for T cells were fused to cells from a nonsecreting mouse myeloma line (NSI). The presence in the culture supernatants of antibodies binding to mouse spleen cells was tested by a binding assay with 125I‐labeled anti‐rat IgG. From a large number of positive cultures, ten independent hybrid clones were purified, each secreting a different antibody. Each antigenic target was analyzed by (a) gel electrophoresis of immunoprecipitated 125I‐labeled cell surface molecules, (b) heat stability, (c) strain and species distribution and (d) cross‐inhibition of binding of different monoclonal antibodies.

It was concluded that the ten monoclonal antibodies regognized four types of antigen. One was the heterophile, heat‐stable, Forssman antigen. The second (mol.wt. 210 000) appears to be a major 125I‐labeled lymphoid cell surface protein. The third, a minor component of spleen cells, was precipitated as two polypeptides of mol.wt. 190 000 and 105000. Five IgG‐secreting clones identify the fourth antigen, a heat‐stable, possibly glycolipid component expressed on mouse red blood cells and also on thymocytes. Cross‐inhibition studies suggest that these last monoclonal antibodies bind to overlapping, but not identical, determinants. The class and chain composition of the monoclonal antibodies were studied by gel electrophoresis, isoelectric focusing and ability to lyse red blood cells and thymocytes.
The macrophage, target cell of the synthetic adjuvant muramyl dipeptide
Authors: Fevrier M. , Birrien J. L. , Leclerc C. , Chedid L. , Liacopoulos P.
Published: February 2007

The mechanism of adjuvant activity of the synthetic glycopeptide N‐acetylmuramyl‐L‐alanyl‐D‐isoglutamine or muramyl dipeptide (MDP) was studied using in vitro plaque‐forming cell (PFC) response to sheep erythrocytes (SRBC). Addition of MDP to DBA/2 mouse spleen cell cultures resulted regularly in a 2 to 3‐fold increase of PFC numbers/106 recovered cells (p < 0.01). Supernates (SPN) from MDP‐stimulated cultures added to standard spleen cell + SRBC cultures brought about even more important increases of PFC numbers (p < 0.01 to p < 0.001). SPN from cultures supplemented with MDP alone (without SRBC) were more active than those of cell + MDP + SRBC cultures, and SPN removed on day 3 of culture were more active than those of day 5. This activity of SPN was maintained accross an H‐2 histocompatibility barrier. Although pretreatment of spleen cells with anti‐θ antigen serum entirely suppressed the anti‐SRBC PFC response in spite of the presence of MDP, SPN from these cultures were as active as SPN from normal spleen cell MDP‐stimulated cultures. In contrast, pretreatment of spleen cells with specific rabbit anti‐mouse macrophage serum entirely suppressed both anti‐SRBC response and SPN activity. It was concluded that the target cell for MDP is the macrophage which releases factors ultimately acting on B cells through T cell mediation.
A time study of the requirement for carrier‐specific helper cells in the response of mice to dinitrophenylated keyhole limpet hemocyanin
Authors: Segre Mariangela , Segre D.
Published: February 2007

The anti‐hapten response of spleen cells from mice primed with hapten‐carrier (dinitrophenylated keyhole limpet hemocyanin) was decreased by depletion of T cells during the first four days after secondary antigenic stimulation, but was unaffected when the T cells were depleted on day 5. The response of cultures that were depleted of T cells prior to secondary antigenic stimulation was restored by addition of carrier‐primed cells during the first two days of culture, partially restored on day 3, but not at later times. Thus, T cells were required only at about day 4 of a secondary response to a T‐dependent antigen that peaked on day 8. Autoradiography experiments showed that the frequency of antigen‐binding cells increased with time regardless of the presence of T cells in the cultures. We conclude that helper T cells are not required for B cell proliferation, but are required for the differentiation of B cells to antibody‐secreting cells.
Intrathymic pathogenesis of myasthenia gravis: transient expression of acetylcholine receptors on thymus‐derived myogenic cells
Authors: Wekerle H. , Ketelsen U.‐P. , Zurn Anne D. , Fulpius B. W.
Published: February 2007

Differentiation of myogenic stem cells from undifferentiated thymic stem cells is thought to play a critical role in the pathogenesis of myasthenia gravis. The expression of membrane acetylcholine receptor (AChR) on the membranes of developing muscle clones in cultures of murine thymus reticulum was followed and found to be transient. AChR are first expressed shortly after fusion of myotubes. In subsequent stages of myogenic development, the density of homogenously distributed AChR is strongly increased, and, in addition, concentrated “hot spot” AChR areas appear. During further maturation, membrane AChR are lost. Highly mature myotubes (3 months in culture) lack substantial amounts of homogenous AChR, as well as hot spots.
Rat macrophage‐mediated toxicity to cancer cells: effect of endotoxins and endotoxin inhibitors contained in culture media
Authors: Martin F. , Martin Monique , Jeannin J.‐F. , Lagneau Annick
Published: February 2007

The cytotoxic effect of normal or BCG‐activated rat macrophages on a syngeneic line of cancer cells was compared in media containing rat or bovine sera. Normal macrophages were usually cytotoxic to cancer cells in fetal or newborn bovine serum; however, they enhanced cancer cell growth in normal rat serum. BCG‐activated macrophages were toxic to cancer cells regardless of the serum used in the assay. Many cell culture media or sera obtained commercially were found to be contaminated by bacterial endotoxins. When endotoxin‐free reagents were used in the toxicity assay, different results were observed: normal macrophages were not cytotoxic, but rather, they often enhanced cell growth even in fetal bovine serum; toxicity of activated macrophages was significantly reduced in normal rat serum. These results suggest that endotoxin and endotoxin inhibitors play a role in the modulation of macrophage‐mediated cytotoxicity. These results emphasize the importance of monitoring endotoxin contamination in cell culture reagents used in assays involving macrophages.
The effect of colchicine and colcemid on the mitogeninduced blastogenesis of lymphocytes
Authors: Steen H. B. , Lindmo T.
Published: February 2007

The effect of colchicine and colcemid (1 × 10−6 M) on the blastogenic response of human lymphocytes to concanavalin A was studied in vitro by three different methods. (a) Measurement of [3H]thymidine ([3H]dThd) incorporation which was strongly suppressed by the drugs. (b) Volume spectroscopy showing that the growth of cellular and nuclear volume was only moderately affected by the drugs during the first two days of culture: in drug‐treated cultures, 25% of the cells responded by measureable growth of their nuclear volume as compared to 30% in untreated cultures. After two days, however, growth stagnated in drug‐treated cultures, and cell division never occurred. (c) Flow cytofluorometry, showing that in drug‐treated cultures the number of cells measurably increasing their DNA content, i.e. entering S‐phase, was about 60% of that in untreated cultures. However, the drugs caused a majority of the responding cells to stop DNA synthesis before completing S‐phase. This effect could not fully account for the strong suppression of the [3H]dThd incorporation indicating that colchicine and colcemid caused a malfunction of the [3H]dThd assay. It is concluded that colchicine and colcemid do not significantly inhibit initiation of a blastogenic response indicating that microtubuli, which are known to be affected by these drugs, are not essential for the triggering of blastogenesis.
Expression of Thy‐1 glycoprotein on lectin‐resistant lymphoma cell lines
Authors: Trowbridge I. S. , Hyman R. , Ferson Theresa , Mazauskas Catherine
Published: February 2007

Lectin‐resistant mutants with specific defects in glycosylation have been selected from the mouse lymphoma cell line, BW5147 (Thy‐1+). The quantitative expression of cell surface glycoproteins on the mutant cells has been studied. The results show that some glycosylation defects that confer resistance to the cytotoxic effects of concanavalin A block the expression of Thy‐1 glycoprotein on the cell surface. However, some changes in the oligosaccharides of Thy‐1 glycoprotein generated by glycosylation defects found in PHAR mutant cells and restricted to the termini of complex‐type oligosaccharides have no effect on the ability of Thy‐1 to reach the cell surface. No glycosylation defects were found that interfered with the expression of either gp 69,71 or H‐2 on the surface of the mutant cells. It is concluded that aberrant biosynthesis of Thy‐1 oligosaccharides can interfere with its expression on the cell surface, but that specific changes in oligosaccharide structure are necessary to block transport to the cell surface and integration into the plasma membrane.
The in vitro immune response to a T‐independent antigen I. The effect of macrophages and 2‐mercaptoethanol
Authors: Nordin A. A.
Published: February 2007

The in vitro immune response of murine spleen cells to the T cell‐independent antigen, 2,4‐dinitrophenyl‐β‐alanyl‐glycyl‐glycyl‐N(2‐aminoethyl)carbamyl‐methylated Ficoll (DAGG‐Ficoll), requires the presence of macrophages, or 24‐h culture supernates from peritoneal cells. Complete reconstitution of the response by supernates, however, is dependent on the addition of 2‐mercaptoethanol. Antigen is required to fully express the in vitro immune response, but is not required in cultures of peritoneal cells in order to obtain active supernates. Active supernates can be obtained from allogeneic or syngeneic peritoneal cell cultures. The enhancing effects of 2‐mercaptoethanol and peritoneal cell supernates appear to be synergistic nonspecific events directed toward lymphocyte activation and differentiation.
Quantitative comparison of K cell potential in human T and null cells
Authors: Caraux J. , Thierry C. , Serrou B.
Published: February 2007

Using a short‐term quantitative assay of the antibody‐dependent cell‐mediated cytotoxicity (ADCC) of human peripheral blood lymphocytes towards 51Cr‐labeled mouse lymphoma cells, it is possible to estimate the relative involvement of various lymphocyte populations in the overall ADCC potential displayed by unfractioned lymphocytes. Lymphocytes were separated by means of an anti‐F(ab')2 column combined with sedimentation of E rosette‐forming cells or EA rosette‐forming cells, and a discontinuous serum albumin gradient, and were characterized by several surface markers. ADCC results were expressed as the cytotoxic capacity of 106 cells of each population (lytic units/106 cells) as well as as the cytotoxic potential of each population by taking into account their relative numerical sizes. Although the null cells had the highest cytotoxic capacity, highly purified T cells also disclosed a cytotoxic capacity which, because of the large numerical excess of T cells over null cells, could account for closely equivalent cytotoxic potentials of these two populations. ADCC was entirely abolished by further removal of Fc receptor‐bearing cells, in all the subsets studied. Our data underline the role that the small proportion of Fc receptor‐carrying T cells might play in ADCC.
Further characterization of the effector cell responsible for natural cytotoxicity to chicken erythrocytes in man
Authors: Ranki Annamari , Saksela E. , Timonen T. , Häyry P.
Published: February 2007

Blood mononuclear leukocytes responsible for “natural killer” (NK) activity to chicken red blood cells (NK‐CRBC) and to cell line targets (NK‐CLT) were fractionated in 1 × g velocity sedimentation. The velocity distribution profile of the anti‐CRBC cytotoxicity was strikingly different from the anti‐CLT cytotoxicity indicating that these two activities were displayed by different types of effector cells. The cells responsible for the anti‐CRBC action were further isolated after rosetting with the target cells via one‐step density centrifugation over Ficoll‐Isopaque. The isolated cells resembled morphologically both large lymphocytes and small monocytes and carried a strong acid α‐naphthyl acetate esterase activity in their cytoplasm. The inhibition pattern of the esterase reaction with sodium fluoride was that of (T) lymphocytes rather than that of monocytes. The cells highly enriched for anti‐CRBC activity responded to phytohemagglutinin and concanavalin A at a rate equal to control preparations, but did not respond to Staphylococcus aureus strain Cowan I bacteria, purified protein derivative of tuberculin or oidiomycin. Taken together, the results indicate that the cells responsible for NK activity to CRBC are lymphocytes of T lineage.
The predominant heavily glycosylated glycoproteins at the surface of rat lymphoid cells are differentiation antigens
Authors: Standring Ruth , McMaster W. R. , Sunderland C. A. , Williams A. F.
Published: February 2007

Rat lymphoid cells have been labeled with sodium 3H‐borohydride after periodate oxidation. The labeled glycoproteins were solubilized in detergent and analyzed by fluorography after polyacrylamide gel electrophoresis in sodium dodecyl sulfate. Major bands were found at 150 000, 95 000 and 25 000 apparent mol.wt. for thymocytes; at 170 000 and 95 000 mol. wt. for T lymphocytes and at 200 000 mol.wt. for B lymphocytes. Bone marrow cells showed a diffuse band at 100 000 mol.wt. with relatively minor bands around 150 000 mol.wt. With the exception of the 95 000 mol. wt. bands, all these glycoproteins bound to lentil lectin.

Using monoclonal or monospecific antibodies in immunoprecipitation and on antibody affinity columns, each of these glycoprotein bands was identified as a previously defined lymphocyte differentiation antigen. The bands at 150 000 mol.wt. on thymocytes, at 170 000 on T lymphocytes, at 200 000 on B lymphocytes, and at 130 000 to 150 000 on bone marrow cells all consist of a leukocyte‐common antigen, which has previously been shown to be present on leukocytes but not on other tissues. At least a part of the 95 000 mol.wt. band on thymocytes, T lymphocytes and bone marrow cells is the W3/13 antigen previously shown to be on mature T lymphocytes, polymorphonuclear cells, and in brain. The 25 000 mol.wt. band of thymocytes is the Thy‐1 antigen.

Similar experiments were carried out on thymocytes labeled with 125I by the lactoperoxidase method. An intense band at 150 000 mol. wt. was identified as the leukocyte‐common antigen by immunoprecipitation. A labeled band, which did not bind to lentil lectin, was immunoprecipitated at 95 000 mol. wt. with W3/13 antibody. Rat Thy‐1 antigen was not labeled with 125I.
B lymphocytes contain three species of μ chains
Authors: Bergman Yehudit , Haimovich J.
Published: February 2007

The murine B cell line cloned from a single cell, 38C‐13, synthesizes three species of μ chains, that of cell surface membrane IgM (m‐μ), that of secreted IgM (s‐μ) and that of intracellular IgM (i‐μ). They differ in their mobility on sodium dodecyl sulfate polyacrylamide gel electrophoresis. Sequence analysis of the different μ chains suggests that they are identical in the N‐terminal as well as in their C‐terminal positions. The ratio between incorporated radioactive monosaccharides to radioactive amino acids into the three different μ chains was higher in s‐μ than in m‐μ, but nevertheless m‐μ migrated more slowly than s‐μ on sodium dodecyl sulfate polyacrylamide gel electrophoresis. However, since this ratio may also be influenced by the rate of synthesis, it may not represent a real molar ratio of carbohydrate to protein. Studies with normal spleen cells clearly indicated the presence of the same three types of μ chains.
Differences in the expression of histocompatibility antigens on mouse lymphocytes and tumor cells: immunochemical studies
Authors: Robinson Peter J. , Schirrmacher Volker
Published: February 2007

Immunochemical studies have shown that labeled, detergent‐solubilized extracts of SL2 (H‐2d) lymphoma cells contain components reactive with several anti‐H‐2 alloantisera of restricted specificity. Anti‐H‐2k and anti‐H‐2ja as well as anti‐H‐2d sera precipitated labeled polypeptides of a molecular weight similar to that of H‐2 heavy chains. In addition, all antisera tested precipitated a component of 70000 daltons molecular weight, which is antigenically related to gp 69/71 of Friend murine leukemia virus.

Reactions with antisera directed against haplotypes other than H‐2d could be blocked by addition of unlabeled, detergent‐solubilized extracts of H‐2d lymphocytes, or by H‐2 antigens against which the antiserum was directed. Sequential immunoprecipitations initially using antisera against the K, D, or L region gene products to remove individual known H‐2d antigens have made possible the identification of some molecules responsible for these reactions. The results show that antisera against haplotypes other than H‐2d which react with SL2 cells, cross‐react with normal H‐2d antigens. Quantitative absorption of these antisera with intact or solubilized cells has shown that lymphocytes and tumor cells differ in their expression of some H‐2 determinants. The antibodies bind only weakly to intact H‐2d lymphocytes, but strongly to the corresponding detergent‐solubilized antigens. These results do not, therefore, support the derepression hypothesis put forward earlier.
The immune response of CBA/N mice and their F1 hybrids to 2,4,6‐trinitrophenylated (TNP) antigens I. Analysis of the response to TNP‐coupled lipopoly‐saccharide in vivo and at the clonal level
Authors: Quintáns José
Published: February 2007

Plaque‐forming cell (PFC) responses to 2,4,6‐trinitrophenylated lipopolysaccharide (TNP‐LPS) were studied in normal and immunodeficient mice. In vivo immunizations with TNP‐LPS showed a 25–50% reduction in PFC responses in CBA/N mice and their (CBA/N × BALB/c)F1(NBF1) male hybrids with an X‐linked immune defect of B lymphocyte differentiation. A detailed clonal analysis of the reduced responses to TNP‐LPS revealed that CBA/N and NBF1 male mice with the X‐linked genetic defect have fewer precursor B cells engaged in the response to TNP‐LPS than the control mice. The reduction in precursor cell numbers affects selectively B cells secreting high avidity anti‐TNP antibodies as determined by PFC inhibition studies.
Changes in the population of lymphocytes and their response to mitogens during the growth of a Simian virus 40‐induced fibrosarcoma in hamsters
Authors: Chen Hana , Quan Canh P. , Zuinghedau Jaqueline , Cyr Christiane de Vaux St. , Lespinats Genevieve
Published: February 2007

Changes have been studied occurring in spleen and thymus lymphocytes, as well in their response to different mitogens, during the growth of Simian virus 40‐induced fibrosarcomas in hamsters.

During tumor growth, the spleens of tumor‐bearing animals became considerably enlarged, and their content in lymphoid cells increased by 100%. Spleen lymphocytes responded normally or slightly higher than did normal controls to concanavalin A (Con A) stimulation when tumors were small, but their response gradually decreased to 30–40% of normal in animals bearing large tumors. These same cells, when cultured with normal lymphocytes in the presence of Con A, were without effect, or were mildly suppressive of the normal cellular response to Con A. The response to Iipopoly‐saccharide (LPS) decreased slightly.

The thymus, on the other hand, became smaller and depleted of cells, and here too, the response to Con A gradually diminished.

Macrophages were found in increased numbers in the enlarged spleens of tumor‐bearing animals. It is suggested that they played a role in the suppression of lymphocyte response to mitogens. Elimination of macrophages from cultures by the addition of carageenan resulted in an enhanced response of lymphocytes from tumor‐bearing animals to Con A.

In addition, we found that carrageenan acts as a mitogen, most probably for B cells, and that when added to cultures containing LPS, a potentiation of the mitogenic response to LPS was obtained.
Influenza virus‐specific T cell‐mediated cytotoxicity: integration of the virus antigen into the target cell membrane is essential for target cell formation
Authors: Kurrle Roland , Wagner Hermann , Röllinghoff Martin , Rott Rudolf
Published: February 2007

This study deals with the requirements for target cell recognition by influenza A virus‐ specific cytotoxic T lymphocytes (CTL). H‐2‐identical cells were incubated with infectious or UV light‐inactivated influenza A virus expressing either cleaved or uncleaved hemagglutinin (HA). Thereafter, the treated cells were tested in a 4‐h 51lCr assay for susceptibility to CTL‐mediated cytolysis.

Regardless whether the influenza virus was infectious, virions expressing cleaved HA were efficient in target cell formation. In contrast, cells incubated with either active or UV‐inactivated virions expressing uncleaved HA were not lysed by virus‐ specific CTL. Yet, after mere trypsin‐mediated cleavage of the HA of cell‐absorbed viroins, strong cytolysis could be observed. On the other hand, solubilization of the envelope lipid bilayer by ethyiether abolished the capacity of the remaining HA to induce target cell formation. The results clearly suggest that mere adsorption of virions to the membrane of cells, which is performed by virus with uncleaved HA, is insufficient for target cell formation. For this, both cleaved HA and an intact envelope appear to be crucial. We conclude that fusion of the virion into the cell membrane is essential for target cell formation.
A search for hapten‐binding mouse plasmacytoma proteins
Authors: Mäkelä Olli , Kaartinen Matti , Karjalainen Klaus , Morse Herbert C. , Weigert Martin , Potter Michael
Published: February 2007

Six hundred and twelve mouse plasmacytomas were screened for hapten binding by using eleven different bacteriophage‐hapten conjugates (phage T4 conjugated with haptens NP, NIP, DIP, DNP, BOC‐ABA‐Tyr, ABA‐NP, ABA‐MIP, ABS‐HOP, PAB‐HOP, penicillin G, cloxacillin). Fifteen ascites fluids (2.4%) inactivated at least one of the phage conjugates at a high dilution indicating binding. The specificity of these reactions was studied by titrating one ascites fluid with phage conjugates carrying unrelated haptens, and by inhibiting the phage inactivation with free haptens. Of the 15 myeloma proteins, 10 had high titers (at least 30 times higher than the ascites fluid background) with the NIP‐cap phage or the NP‐cap phage or both. Four had high titers with the DNP‐cap phage and one with the ABA‐MIP phage. Thirteen of the 15 myeloma proteins were IgA, one was IgM and one IgC2b.
MLR blast cells generated in mutant‐standard strain combinations bind H‐2K and H‐2D antigens
Authors: Geib Roy W. , Klein Jan
Published: February 2007

Strains CBA (M523) ( = M523) and CBA differ by a mutation which has been mapped genetically into the K region of the H‐2 complex. Similarly, strains B 10.D2 (M504) ( = MS04) and B10.D2 differ in a mutation which occurred in the D region. The data presented in this study show that mixed lymphocyte culture in M523 anti‐ CBA and M504 anti‐B 10.D2 strain combinations leads to the release of membrane fragments from the stimulating cells and binding of these fragments by blast cells. The fragments always carry H‐2K (in the M523 anti‐CBA combination) or H‐2D (in the M504 anti‐B 10.D2 combination) antigens present in the stimulating and absent in the responding cells (antigens H‐2.60 and H‐2.40, respectively). Although Ia antigens may occasionally be present on the CBA membrane fragments, these antigens do not participate in the M523 anti‐CBA MLR stimulation. The data thus demonstrate that serologically detectable H‐2K and H‐2D antigens can induce a MLR and that a mutation can change properties of H‐2K or H‐2D molecules so that the alteration is detectable by both serological means and lymphocyte activation assays.
Purification with monoclonal antibody of a predominant leukocyte‐common antigen and glycoprotein from rat thymocytes
Authors: Sunderland Christopher A. , McMaster W. Robert , Williams Alan F.
Published: February 2007

A leukocyte‐common (L‐C) antigen which can be dominant as an immunogen in rabbit anti‐rat thoracic duct lymphocyte serum has been purified from rat thymocytes. Initially, an antigenic fragment of 100000 apparent mol. wt. was prepared at 400 to 900‐fold purification by lentil lectin affinity chromatography and gel filtration in deoxycholate. Mice were then immunized with this fraction, and a hybrid myeloma cell line secreting antibody to the L‐C antigen was prepared by cell fusion. This antibody was used for affinity chromatography and gave pure L‐C antigen at 1400‐fold puaification compared with thymocytes. The L‐C antigen is a major membrane glycoprotein of rat thymocytes and has an apparent mol. wt. of 150000 as determined by electrophoresis on polyacrylamide gels in sodium dodecyl sulfate. The antigen constitutes one of the three thymocyte glycoproteins which stain intensely for carbohydrate with periodic acid Schiff stain. It is present on > 95% of thymocytes, bone marrow cells and thoracic duct lymphocytes.
Possible role for glycosphingolipids in the control of immune responses
Authors: Ryan John L. , Shinitzky Meir
Published: February 2007

Preparations of gangliosides from bovine brain contain material which acts as a strong mitogen on murine spleen cells. This material is highly lipophilic and co‐purifies with the ganglioside fraction. It contains saccharides of a similar composition to those found in monosialogangliosides, as well as a sphinogsine base and an appreciable amount of peptide. The common brain gangliosides GM1, GD1a, and GD1b, on the other hand, are not mitogenic and act as suppressors of the mitogenic activity of bacterial lipopolysaccharide on murine spleen cells. Both the mitogenically active and suppressive fractions of bovine brain glycosphingolipid were found to act exclusively on B lymphocytes. Since gangliosides and related compounds are components of plasma membranes and of amphipathic nature, they may passively migrate between the lymphocyte subpopulations and thus act as physiological modulators of immune responses.
Cell‐mediated immunity to antigens associated with murine sarcoma virus‐induced tumors: augmentation of cytolytic T lymphocyte activity by successive specific and nonspecific stimulation in vitro
Authors: Ryser Jean‐Etienne , Brunner K. Theodor , Cerottini Jean‐Charles
Published: February 2007

It has been shown previously that lymphoid cells from mice which have rejected a tumor induced by the Moloney sarcoma virus‐leukemia virus (MSV‐MLV) complex develop high levels of specific H‐2‐restricted cytolytic T lymphocyte (CTL) activity after in vitro stimulation with syngeneic, irradiated MLV‐induced lymphoma cells in mixed leukocyte‐tumor cell cultures (MLTC). Attempts to further increase lytic activity by restimulating long‐term MLTC cells with syngeneic, irradiated lymphoma cells have met but with limited success. This report shows that, in contrast to the lack of increased activity observed after specific stimulation with lymphoma cells, nonspecific stimulation of long‐term MLTC cells either with supernatants from secondary mixed leukocyte cultures (2º MLC SN) or with supernatants from concanavalin A‐stimulated spleen cells leads, on a per cell basis, to a further 5 to 10‐fold increase in CTL activity. The stimulatory activity of 2º MLC SN is due to a factor(s) of apparent mol. wt. of 25 000 to 40 000. The activity of the CTL populations formed under these conditions is at least 100‐fold higher against syngeneic as compared to allogeneic MLV‐induced or unrelated tumor cells.
Demonstration of HLA‐DR‐like antigens on milk fat globule membranes
Authors: Wiman Klas , Curman Bengt , Trägårdh Lena , Peterson Per Artur
Published: February 2007

Milk fat globules (MFG), which are formed by exocytosis of lipid from epithelial cells of the mammary gland, are enveloped by plasma membrane from the epithelial cells. Highly purified, detergent‐solubilized MFG membranes have been shown to contain molecules reactive with a rabbit antiserum against HLA‐DR antigens. Indirect immunoprecipitation combined with polyacrylamide gel electrophoresis in sodium dodecyl sulfate demonstrated that the MFG membrane material reactive with the antiserum comprised molecules which under denaturing conditions displayed molecular weights of 28 000 and 35 000. The two types of polypeptide chains, which were both glycosylated, were held together by noncovalent forces under nondenaturing conditions. Various types of chemical and physicochemical analyses failed to reveal any significant differences between the HLA‐DR‐like antigens from MFG and from spleen cells. Since the HLA‐DR‐like antigens bound detergent in micellar form and were expressed on the outside of intact MFG, as revealed by indirect immunofluorescence, it is concluded that these antigens are embedded in the hydrocarbon matrix of the MFG and not merely passively adsorbed onto the MFG.
The distribution of HLA on human lymphoid, bone marrow and peripheral blood cells
Authors: Brown Geoffrey , Biberfeld Peter , Christensson Birger , Mason David Y.
Published: February 2007

The cellular distribution and the differential expression of HLA on cell suspensions and tissue sections has been investigated using the monoclonal antibody W6–32, which reacts with the high molecular weight chain of the major histocompatibility antigen. Lymphocytes and platelets, as assessed by autoradiographic and immunoperoxidase labeling, were the most densely labeled cells. Myeloid precursors showed more labeling than mature neutrophils. Electron microscopic immunoperoxidase labeling showed a continuous distribution of HLA antigen on lymphoid and myeloid cell membranes. Erythroid precursors (including reticulocytes), although very weakly labeled, were clearly positive, in comparison with mature erythrocytes. In the thymus, HLA‐negative, thymocyte antigen‐positive cells (85%) can be distinguished from HLA‐positive, thymocyte antigen‐negative cells (15%). By using immunofluorescence techniques on tissue sections, the former cells were shown to be cortical thymocytes and the latter medullary cells.
Lysolecithin analogs as adjuvants in delayed‐type hypersensitivity in mice. I. Characterization of the adjuvant effect
Authors: Arnold Bernd , Miller Jacques F. A. P. , Weltzien Hans U.
Published: February 2007

The adjuvant activity of 5 different lysolecithin analogs (LLA) has been studied in delayed‐type hypersensitivity (DTH) using fowl gamma globulin, bovine serum albumin and the terpolymer L‐glutamic acid 60‐L‐alanine30‐L‐tyrosine10(GAT), as antigens. Increased DTH responses, by factors of 1.8–2.0 in CBA and BALB/c mice, showed that LLA are immunopotentiators if given intraperitoneally (i.p.) or subcutaneously (s.c.) together with the antigen. The concentration range, within which LLA are active, is limited to 10–20 (μg/mouse s.c. and 100–300 μg/mouse i.p., Adjuvanticity was tested as a function of the LLA structure. The most pronounced immunopotentiation was obtained with racemic 1‐octadecyl‐2‐methylglycero‐3‐phosphorylcholine (ET18‐O‐CH3). The LLA became less active with decreasing numbers of C atoms in the alkyl chain.
Complement and Fc receptor‐mediated phagocytosis of normal and stimulated mouse peritoneal macrophages
Authors: Bar‐Shavit Zvi , Raz Avraham , Goldman Rachel
Published: February 2007

Normal and stimulated macrophage populations induced by six different stimuli were tested for their IgG and complement (C)‐mediated phagocytic capacity. A similar phagocytic capacity for sheep red cells (E) coated with IgG was exhibited by normal and stimulated macrophage populations with the exception of thioglycollate‐stimulated macrophages which exhibited a lower phagocytic potential. The extent of attachment and ingestion of E coated with IgM and C 5‐deficient mouse serum (EIgMC) was shown to depend on the concentration of IgM and serum in the opsonizing solutions. A further interaction of macrophage‐EIgMC rosettes with C5‐deficient mouse serum led to ingestion of a high proportion of the attached ElgMC. Heat‐killed yeast cells coated with C5‐deficient mouse complement were ingested to a similar extent by normal and stimulated macrophage populations except for thioglycollate‐stimulated macrophage populations which exhibited about 30% of the phagocytic response.

The data support the notion that complement receptors on macrophage surface are not limited in their function to the attachment phase but that they also are capable of mediating phagocytosis. It is suggested that the prevalent protocols of sequential opsonization of E with IgM and C5‐deficient mouse serum do not provide enough bridging moieties between the coated E and macrophages to allow for effective ingestion; the EIgMC complex formed is only capable of attachment to macrophage surfaces.
Enhanced expression of HLA antigens and β2‐microglobulin on interferon‐treated human lymphoid cells
Authors: Fellous Marc , Kamoun Malek , Bone Rosa , Gresser Ion
Published: February 2007

Human leukocyte interferon increased the expression of HLA‐A, B antigens and β2‐microglobulin on two lines of human lymphoblastoid cells and on peripheral blood lymphocytes. No effect was observed on the expression of HLA‐DR antigens.
The enumeration of rat IgE‐secreting cells using a reverse plaque‐forming cell assay
Authors: Rector Edward S. , Carter Brian G. , Kelly Ken A. , Lang Glen M. , Sehon Alec H.
Published: February 2007

A reverse hemolytic plaque assay utilizing protein A‐coated sheep red cells and a specific rabbit anti‐rat IgE preparation has been adapted for the enumeration of rat IgE‐secreting cells derived from the IR‐162 rat plasmacytoma and from rats infected with Nippostrongylus brasiliensis. Under optimal conditions, approximately 10–15% of the viable plasmacytoma cells were scored as plaque‐forming cells. In rats infected with 5000 Nippostrongylus brasiliensis larvae, a maximum of 2 × 106 IgE‐secreting cells were found in the mesenteric lymph nodes, and no IgE plaque‐forming cells in their spleens. The kinetics of the mesenteric lymph node plaque‐forming cell responses closely coincided with total serum IgE levels, with maximum responses occurring 15–16 days after infection. There was a high degree of correlation between the mesenteric lymph node IgE plaque‐forming cell responses and total serum IgE levels of individual rats. It was concluded that the IgE‐secreting cells in the mesenteric lymph nodes contributed, in a large way, to the elevated levels of IgE found in the circulation of these rats.
Detection of albumin‐secreting hepatocytes at the single cell level by a protein A plaque assay
Authors: Smith C. I. Edvard , Hammarström Lennart
Published: February 2007

In a complement‐dependent assay, using protein A‐coupled erythrocytes as target cells and anti‐albumin immunoglobulin (Ig) as a developing serum, it was possible to detect single albumin‐secreting hepatocytes as plaque‐forming cells. Plasmacytoma cells were detected using anti‐Ig antibodies and did not form plaques with anti‐albu‐ min Ig. This method can potentially be used for detecting any cell‐secreting products in sufficient amounts.
Unique lectin‐binding characteristics of cytotoxic T lymphocytes allowing their distinction from natural killer cells and “K” cells
Authors: Kimura Arthur , Örn Anders , Holmquist Göran , Wigzell Hans , Ersson Bo
Published: February 2007

Cytotoxic T lymphocytes (CTL) can be selectively depleted from in vitro or in vivo alloactivated populations of T cells on Vicia villosa lectin adsorbents through the lectin‐specific interaction with the CTLassociated surface glycoprotein T 145 (Kimura, A, Wigzell, H. and Holmquist, G., J. Exp. Med. 1979. 149: 473). Results from these and other experiments have demonstrated the general applicability of this fractionation procedure in which no constraints related to antigenic specificitiy of the CTL have been observed.

When this fractionation procedure was applied to other compartments of cytolytic cells (natural killer cells and “K” cells), no detectable impact could be seen. This differential lectin binding would appear to offer a means of dissecting the activities of CTL from other compartments of cytolytic lymphoid cells.
Composite activities on B cells of products released by T cells activated by concanavalin A
Authors: Primi Daniele , Lewis George K. , Goodman Joel W.
Published: February 2007

Supernatants from murine spleen cells cultured for 48 h in the presence of 1.0 μg of concanavalin A (Con A) induced polyclonal antibody synthesis in cultures of spleen cells from both normal and athymic mice in the absence of exogeneous antigen. Moreover, the Con A‐induced supernatant rescued B cells which had been rendered unresponsive by a tolerogen [haptenated poly(DGlu,DLys)]. The capacity of the supernatant to induce cell proliferation was studied under both high and low‐density culture conditions. In contrast to antibody secretion, proliferation was only detectable in low‐density cultures.

The Con A‐induced supernatant also contained suppressive components, since the primary anti‐sheep red blood cell (SRBC) response was markedly suppressed when the antigen added to cultures consisted of SRBC which had previously been used for absorbing the supernatants. Absorbed supernatants displayed enhanced helper activity indicating that only the suppressor component was removable by antigen. The suppressive component was eluted from erythrocytes with ammonium thiocyanate and was itself strongly suppressive when added to cultures with fresh erythrocytes. Furthermore, the suppressive component proved to be highly antigen‐specific, as the SRBC‐absorbed factor did not affect the response to horse RBC.

The results indicate that supernatants from Con A‐activated spleen cells contain both helper and suppressor factors, the latter having easily demonstrable antigen specificity. They further suggest that a nonantigen‐derived signal is sufficient to trigger both proliferation and antibody synthesis by B cells.
The production of fibrinolysis inhibitors as a parameter of the activation state in murine macrophages
Authors: Klimetzek Volker , Sorg Clemens
Published: February 2007

Macrophages from peritoneal exudates which had been induced by various irritants were cultured, and the supernatants were tested for inhibitors of fibrinolysis using the plasmin‐dependent lysis of 125I‐labeled fibrinogen as assay. Washout macrophages and casein or proteose peptone‐elicited macrophages were found to release fibrinolysis inhibitors in contrast to lipopolysaccharide or thioglycollate‐induced macrophages. The molecular weight of inhibitors was determined at 60 000, 45 000 and 15 000 by Sephadex chromatography. Whereas the inhibitors at 15 000 and 45 000 could be detected in all experiments, the inhibitor at mol. wt. 60 000 was not present in all preparations. The isoelectric point of inhibitor I (mol. wt. 15 000) and inhibitor II (mol. wt. 45 000) was determined at 4.15. The proteolytic and esterolytic activity of trypsin and chymotrypsin were both inhibited by each of the two inhibitors. On the other hand, only the proteolytic activity of plasmin could be inhibited. Evidence for the active synthesis of inhibitors by macrophages came from several experiments. Macrophages in serum‐free cultures continued to release inhibitors for at least 48 h; normal mouse serum did not contain inhibitors of the same molecular size, and [3H]leucine was incorporated into the inhibitors which were specifically detected by the absorption of plasmin inhibitor complexes to lysyl‐Sepharose. Since inhibitors and plasminogen activator could not be detected in the same macrophage culture supernatants, it appears that the production of inhibitors and plasminogen activator by the same macrophage population is mutually exclusive.
Some limits to post‐antigen generation of diversity: Failure to detect variants in clones of hapten‐specific antibody‐forming cells (AFC) developing in culture from direct AFC‐progenitor B cells
Authors: Shortman Ken , Howard Maureen , Pike Beverley L. , Marbrook John , Baker Julie
Published: February 2007

A search was made for variants in clones of hapten‐specific antibody‐forming cells (AFC) arising by stimulation of mature B cells with either thymus‐independent hapten‐POL (polymerized bacterial flagellin) conjugates, or the polyclonal activator lipopolysaccharide. Enriched, hapten‐binding B cells or unfractionated spleen cells were cultivated for 3–4 days at limiting dilution in the presence of thymus filler cells, and the AFC in each microculture well were then assayed for plaque formation on various hapten‐sheep red cell monolayers. No variants were found from (4‐hydroxy‐3‐iodo‐5‐nitrophenyl) acetyl (NIP) to 2,4‐dinitrophenyl specificity, nor from fluorescein (FLU) to NIP specificity. No variants were found in avidity for FLU hapten. All 374 clones examined, including clones of up to 300 AFC, appeared to be homogeneous in antibody specificity and plaque morphology under our conditions. These results differ from published findings using erythrocytes as antigens. Reasons for this discrepancy are discussed, including differences in sensitivity differences in immunological similarity between the test antigens, and in the particular B cell subsets involved.
Antigen‐specific stimulation and trans‐stimulation of T cells in long‐term culture
Authors: Augustin Andrei A. , Julius Michael H. , Cosenza Humberto
Published: February 2007

When T cells from antigen‐primed lymph nodes are stimulated in vitro with antigen, they give rise to a proliferative response as high as that elicited by the polyclonal T cell activator concanavalin A. It is likely that in these conditions not only antigen‐specific T cells proliferate. We have established an experimental system which demonstrates that large numbers of nonantigen‐specific T cells are induced to proliferate as a result of antigen‐specific T cells' confrontation with antigen. This phenomenon, which we call trans‐stimulation is antigen‐dependent and antigen‐specific. Although the presence of antigen‐specific T cells is required, these cells do not have to proliferate in order to induce trans‐stimulation.

In an attempt to enrich for antigen‐specific T cells in vitro, we established conditions for culturing T cells in the presence of antigen for long periods of time (up to 6 weeks). High levels of antigen reactivity were observed upon antigen restimulation of “directly” stimulated T cells from long‐term cultures. In contrast, long‐term cultures of trans‐stimulated cells were depleted of antigen reactivity. Neither type of long‐term culture contained detectable alloreactive cells indicating that trans‐stimulation is not reflected randomly upon bystander T cells.
Non‐T cell nature of the naturally occurring, spleen‐associated suppressor cells present in the newborn mouse
Authors: Rodriguez George , Andersson Gunilla , Wigzell Hans , Peck Ammon B.
Published: February 2007

Spleens from newborn mice less than 6‐7 days of age contain a “naturally occurring” suppressor cell which possesses the capacity to inhibit not only expression of alloreactivity in the newborn spleen per se, but also T‐dependent and T‐independent immune responses of third‐party adult spleen cells. Similar suppressor activity is not detectable in the newborn thymus. The effector cell of this suppressor activity is not a classical T cell: suppression is resistant to treatment with anti‐T cell reagents, is absent from purified spleen T cell populations, is present in the spleens of T‐deficient (nu/nu) mice, is Helix pomatia A hemagglutinin‐nonbinding. Furthermore, this cell appears to be distinct from classical B cells, natural killer (NK) cells and macrophages. Instead, this naturally occurring, newborn spleen‐associated suppressor cell has similar characteristics to the non‐T suppressor cell detectable during old‐age immunological senescence, described by Singhal et al. (Fed. Proc. 1978. 37: 1245). When this suppressor cell is removed from newborn spleen cell populations, the resulting T cells exhibit strong alloreactivity. Thus, these data indicate, first, that the nonresponsive state of the newborn spleen is not due to a lack of functional T cells or macrophages, and second, that the suppressor activity in the newborn spleen is not effected by a thymus‐ dependent cell as is currently hypothesized.