bluuebunny/crossref_metadata_2025 huggingface dataset:
Human lymphoblast cell lines: Antibody‐dependent cytotoxicity
Authors: Lefebre J.‐C. , Petitprez A. , Juy D. , Bona C.
Published: February 2007

Five cell lines were isolated after prolonged culture of human buffy coat leukocytes. The cells consisted for the most part of lymphoblasts morphologically similar to those produced by in vivo or in vitro stimulation of small lymphocytes by antigens or mitogens. One of the lines possessed virus‐like particles of the Epstein‐Barr type. All the established lines were capable of mediating antibody‐dependent cytotoxicity (LADC) quantitatively at a level not significantly different from that mediated by freshly isolated, normal human peripheral blood lymphocytes (PBL). The LADC of the lymphoblasts was inhibited by all the human IgG subclasses tested (IgG1, IgG2, IgG3, IgG4) as was the LADC of PBL. It is concluded that, at least so far, the lymphoblasts have retained the properties of the lymphocytes from which they were originally derived as regards their ability to mediate LADC.
Recruitment of effector lymphocytes by initiator lymphocytes: role of a trypsin‐sensitive membrane component
Authors: Livnat S , Cohen I. R.
Published: February 2007

In earlier studies we found that initiator T lymphocytes sensitized in vitro against fibroblasts were able to recruit immunospecific effector T lymphocytes in vivo in syngeneic mice. In the present study, to investigate the possible function in effector cell recruitmentof sensitizing antigens passively adsorbed onto the initiator cell membrane, we treated the initiator lymphocytes with trypsin. We found that trypsin inhibited recruitment. However, the initiator cells spontaneously recovered their recruiting ability after incubation in vitro for 4 h in the absence of contact with sensitizing antigens. Recovery could be blocked by cycloheximide. Hence, it appears that recruitment depends on the intrinsic metabolic function of the initiator lymphocytes and is not due merely to passively‐adsorbed antigen carried over into the recipient mouse.
X‐ray enhancement of splenic rosette‐forming cells in nonimmune mice
Authors: Watanabe S. , Kajiwara H. , Minowada J. , Yamamura Y.
Published: February 2007

The formation of rosettes between spleen cells from nonimmune mice and sheep red blood cells (SRBC) has been investigated. The number of splenic rosette‐forming cells (RFC) in the intact spleen was very low but greatly increased after sublethal whole body x‐irradiation. These cells were inhibited by pretreatment of the cells with AKR anti‐C3 H‐Θ antigen antiserum, in the presence of fresh guinea pig serum, but not with rabbit anti‐mouse immunoglobulin antiserum. The splenic RFC also increased after cortisone acetate administration into mice. These results suggest that the RFC are a T cell subpopulation having x‐ray resistant and cortisone‐insensitive characteristics. The x‐irradiation of mice in vivo selectively increased the number of splenic RFC in consequence of reduction in the number of cells having non‐T cell characteristics. These RFC are presumably antigen‐specific sheep red blood cell rosettes, a quite different situation as in the case of human T lymphocyte rosette formation.
Role of epitope density in the induction of immunity and tolerance with thymus‐independent antigens. I. Studies with 2,4‐dinitrophenyl conjugates in vitro
Authors: Desaymard Catherine , Feldmann Marc
Published: February 2007

The effect of different degrees of conjugation of levan, dextran, pneumococcal polysaccharide SIII and the copolymer of D‐glutamic acid and D‐lysine with the 2,4‐dinitrophenyl determinant (DNP) on the immunogenic and tolerogenic capacity of its haptenic conjugates was investigated in vitro. A strikingly uniform effect of hapten conjugation was observed despite the marked difference in the mol. wt. and structure (branched or linear) of the carrier molecules. Regarding the anti‐DNP response, low density conjugates were immunogenic but not tolerogenic (even at high doses), higher conjugates were both, depending on concentration, while very high density conjugates were only tolerogenic. These results confirm and extend earlier findings made with DNP conjugates of polymeric flagellin and indicate the probable generality of this principle. Together with parallel in vivo studies (Eur. J. Immunol. 1975. 5: 541), they reaffirm the importance of epitope density in the discrimination between immunity and tolerance.
The effect of the thymus‐independent antigens, collagen and synthetic collagen‐like polypeptide, on the requirement of cell cooperation in the immune response to thymusdependent antigens
Authors: Mozes Edna , Schmitt‐Verhulst Anne‐Marie , Fuchs Sara
Published: February 2007

The effect of thymus‐independent antigens on the need for cell cooperation in the immune response to thymus‐dependent antigens was investigated. Irradiated recipient mice transplanted with either bone marrow cells or a mixture of bone marrow and thymus cells, were immunized with the thymus‐independent antigen (Pro‐Gly‐Pro)n covalently conjugated to the thymus‐dependent ovalbumin, or with a mixture of (Pro‐Gly‐Pro)n and ovalbumin. In both cases an effective response towards ovalbumin was observed in the absence of thymus cells as was found for the thymus‐independent (Pro‐Gly‐Pro)n. The same effect on ovalbumin was demonstrated when a mixture of the thymus‐independent collagen and ovalbumin was used for immunization. On the other hand, when irradiated reconstituted mice were immunized with a mixture of ovalbumin and the thymus‐dependent gelatin, which is the denatured product of collagen, cell‐to‐cell cooperation was required for an immune response to both immunogens.

The effect of (Pro‐Gly‐Pro)n and collagen on the response to the thymus‐dependent ovalbumin in vivo was observed in in vitro experiments using sheep red blood cells (SRBC) as the immunogen as well. In the presence of reduced and carboxymethylated (RCM) Ascaris collagen and (Pro‐Gly‐Pro)n, nude spleen cells could produce significant numbers of plaque‐forming cells towards SRBC. Thus, (Pro‐Gly‐Pro)n and collagen can deliver the signal required to stimulate B cells to produce antibody towards thymus‐dependent antigens in the absence of T cells.

In contrast to the results with (Pro‐Gly‐Pro)n and collagen, the thymus‐independent synthetic polypeptide poly (DTyr, DGlu)‐poly(DPro)‐‐poly(DLys) did not affect the requirement for cell cooperation of the thymus‐dependent immunogens, ovalbumin and SRBC. It thus appears that the ability to substitute for T cells for antibody production towards thymus‐dependent immunogens is not a general characteristic of thymus‐independent antigens.
Studies on sperm antigenicity. IV. Lymphocyte cytotoxicity in cell‐mediated response to homologous spermatozoa
Authors: Toder V. , Marcus Z. H. , Nebel L.
Published: February 2007

In the presence of specific antigen, lymph node cells from Rockefeller strain guinea pigs with delayed hypersensitivity to homologous spermatozoal antigen produced progressive destruction of L929 cell monolayers. This effect was measured by counting surviving target cells removed from Leighton tubes by trypsin treatment as well as by standard cell counts in microplates. The cytotoxic effect was immunologically specific since neither sperm‐sensitized lymphocytes in presence of unspecific antigen nor normal lymph node cells with guinea pig sperm, induced target cell destruction. The effect required an antigen concentration equal to, or greater than, 70 μg protein/ml. A ratio of 100 : 1 of sensitized lymphoid cells to target cell was found to be optimal. L‐cell lysis could be demonstrated at day 14 and reached its peak on day 21 after immunization. A high level of correlation between lymphocyte cytotoxicity and macrophage migration inhibition was found.

The role of lymphocyte cytotoxicity in cell‐mediated immunity to spermatozoa is discussed as one of the possible mechanisms leading to destructive changes in the testes.
Enrichment of effector T lymphocytes specific to H‐2 antigens by elution from allogeneic target cells and characterization of the eluted lymphocyte population
Authors: Brondz B. D. , Egorova S. G. , Kotomina I. F.
Published: February 2007

The technique of elution by pronase of murine immune lymph node cells adherent to relevant allogeneic target cells has been developed for enrichment of effector T cell population. A fraction of killer cells has been obtained possessing cytotoxic activity which exceeds that of the initial immune lymphocyte population by a factor of 6–8 as judged by a number of lymphocytes required for 50% cytotoxic effect (CE). The gain in CE is fairly reproducible in different H‐2 systems and under various lymphocyte‐target incubation conditions. It appears to be due to the quantitative enrichment of the population in cells bearing receptors to the particular H‐2 antigens and giving rise to specific CE rather than to an increase in cytotoxic activity per cell resulting from treatment with the target monolayer and pronase. The eluted killer cell fraction is characterized by a twofold increase in percentage of cells killed by anti‐Θ antibody, a 4–5‐fold increase in the number of DNA‐synthesizing cells and by an increase in medium and large lymphocyte content. A further enrichment in effector lymphocytes is reached by depletion of B cells at the expense of their receptors to Fc fragment of Ig. Macrophage monolayer fixed by glutaraldehyde lost its capacity to absorb effector lymphocytes. The implications of the data obtained for further studies on cell‐mediated immunity are discussed.
Antibody synthesis by chicken spleen cells in vitro. I. Requirements of B cells at various stages after immunization for T cells, macrophages and antigen
Authors: Evans G. , Ivanyi J.
Published: February 2007

The requirements for T cells, macrophages and antigen during the induction of in vitro antibody responses were ascertained with chicken spleen cells obtained at various times after immunization with sheep red blood cells (SRBC). The IgM plaque‐forming cell (PFC) response was T cell independent exclusively in cultures initiated 3 days after priming, but macrophage dependent at all time intervals tested. In cultures started 4 to 10 days after priming the IgG response was both T cell and macrophage independent and PFC numbers remained at a high plateau level throughout the culture period. In contrast, IgG responses initiated more than 15 days after priming showed a reversal to complete T cell and macrophage dependence and were characterized by a sharp increase in PFC numbers between days 2 and 4 of culture. Formaldehyde‐fixed SRBC were immunogenic for IgG PFC 4 to 10 days after priming but failed to stimulate later IgG memory and all IgM responses. Contrasting antigen dose requirements for IgM and IgG responses were found in cultures initiated at various periods after priming.

The results suggest that direct contact with fixed antigen was sufficient to maintain IgG antibody synthesizing PFC in vitro, while native antigen and cell co‐operation were required for late secondary IgG and all IgM responses. These results are interpreted in terms of separate pathways of differentiation for IgM and IgG antibody‐producing cells. A distinct 3rd day stage of T cell‐independent but macrophage‐dependent responsiveness for both classes of antibody was also defined.
The dominant role of la antibodies in the passive enhancement of H‐2 incompatible skin grafts
Authors: Staines N. A. , Guy K. , Davies D. A. L.
Published: February 2007

The ability of H‐2 antisera and their constituent K and la antibodies to enhance the survival of skin allografts was investigated. Ia sera were prepared from H‐2 alloantisera by exhaustive absorption with donor‐strain RBC and the absorbed K antibodies were also recovered by acid elution of the RBC. The removal of conventional K/D antibody in no way diminished the activity of enhancing sera over wide dose ranges in two different incompatibility systems. The recovered K/D antibodies in the doses used had at best a trivial enhancing effect. The dominant role of Ia antibodies in enhancement was confirmed by showing significant prolongation of graft survival in third‐party systems where the sera covered only some of the Ia antigens in incompatibilities involving K,D and Ia differences and in homologous systems using Ia sera fractionated into their constituent mono‐specificities. It is concluded that enhancement is a function of antibodies directed against Ia antigens (I region products) and that antibody against conventional histocompatibility antigens such as H‐2.K, D, and by homology HL‐A and Ag‐B has only a minor role in passive enhancement.
Macrophage inhibiting activity in serum and central lymph of Listeria‐immune mice
Authors: Kaufmann S. , Weber L. , Hahn H.
Published: February 2007

Serum and central lymph from mice immunized with live Listeria monocytogenes six days previously and boostered four hours before collection exerted significant inhibition of macrophage migration in vitro. It is concluded that lymphokines or lymphokine‐like products of the cellular immune reaction are released in vivo and are possibly instrumental in the generation of acquired cellular antibacterial immunity.
Ir gene control of carrier recognition. I. Immunogenicity of bovine insulin derivatives
Authors: Keck K.
Published: February 2007

2,4‐Dinitrophenyl‐lysin B29 ‐bovine insulin was used as immunogen to investigate the carrier function of insulin in the induction of immune response. Experiments with backcross mice suggest that this is controlled by autosomal Ir genes. The response pattern shown by congenic mice demonstrate the linkage of these genes to the H‐2 complex. With a standard dose of 20 μg per mouse, strains with the H‐2 haplotypes d,b,v respond to this carrier. All other strains tested, with the H‐2 haplotypes a,k,u,r,s,q, are nonresponders.

The two Ir genes, Ir‐insulinBov (H‐2d) and Ir‐insulinBov (H‐2b), which are associated with H‐2d and H‐2b respectively, can be distinguished from one another on a functional basis. Only H‐2d mice respond to an appreciable extent when B. pertussis organisms are the adjuvant. With complete Freund's adjuvant, H‐2d and H‐2b mice give high antibody titers, but with low doses of antigen only H‐2d mice respond. In contrast to H‐2d mice, H‐2b mice do not respond to trifluoresceinthiocarbamyl insulin, suggesting that the dimeric insulin might be the immunogenic form in these mice. Furthermore, as has been shown earlier (Nature, 1975. 254: 78.), the A‐chain loop is needed as a carrier determinant only in H‐2b mice.

Experiments with recombinant strains localize Ir‐insulinBov (H‐2b) to the left of Ir‐1B, probably in Ir‐1A.

H‐2k mice are strict nonresponders, even when other proteins such as bovine IgG, methylated bovine serum albumin or rabbit IgG are provided as carriers complexed with insulin. However, if proinsulin is used as the antigen, anti‐insulin antibody can easily be raised in these strains.
The frequency of effector cells in populations containing cytotoxic T lymphocytes
Authors: Berke G. , Gabison D. , Feldman M.
Published: February 2007

A new approach for the direct enumeration of effector cells in populations containing cytotoxic T lymphocytes is described. Stable lymphocyte‐target cell conjugates are formed during centrigugation at room temperature of mixtures containg cytotoxic lymphocytes and target tumor cells. Various types of lymphocyte‐target cell conjugates can be formed, the composition of the conjugate being dependent upon the ratio of lymphocytes to target cells during the conjugation process. The number of conjugates formed is highest at equal lymphocyte and target cell concentrations. At least 35% of the BALB/c anti‐EL4 peritoneal exudate lymphoid cells can conjugate to target cells and the majority of the conjugated lymphocytes are also killer cells. The variation in cytolytic activity of lymphoid cells with time following immunization and the differences in the lytic activity of immune lymphoid cells from various lymphoid organs are due to differences in the actual number of effector cells capable of conjugating with target cells.
The modulation of microprojections on the lymphocyte membrane and the redistribution of membrane‐bound ligands, a correlation
Authors: Loor F. , Hägg Lena‐Britt
Published: February 2007

Immunofluorescence microscopy allows one to detect microprojections on the lymphocyte surface and to follow their modulation by various environmental conditions. Both T and B cells express villi similarly. Among other factors, the expression of villi is decreased after cell chilling, is enhanced in the presence of metabolic inhibitor, is decreased in the presence of an agent affecting microfilament integrity, is relatively insensitive to agents affecting microtubule integrity, is sensitive to the pH, is inhibited by high does of lectins and is dependent on the lack of detectable crosslinking of membrane antigens by the ligand.

Striking similarities suggest a correlation between the ring → spots → cap transition phenomenon and the villi dynamics on the cell surface.

The possible function of lymphocyte villi is discussed.
A characterization of human B and T lymphocytes by their lactate dehydrogenase isoenzyme pattern
Authors: Plum J. , Ringoir S.
Published: February 2007

Human lymphocytes have been separated by two different techniques: the rosette sedimentation technique and the nylon wool column filtration method. The unseparated lymphocytes and each B and T fraction obtained, were examined according to their capacity to form E and erythrocyte antibody‐complement complex (EAC) rosettes. The lactate dehydrogenase (LDH) isoenzyme pattern was studied on each cell population after agar gel electrophoresis.

The T lymphocytes showed a significantly higher activity in the LDH‐1 band compared to the B lymphocytes. Previous contradictory reports on the LDH isoenzyme pattern of unseparated lymphocytes and the characterstic decrease of the LDH‐1 band observed in chronic lymphocytic leukemia cells are discussed.

A possible application of the isoenzyme distribution in B and T cells, i.e. a criterion for characterization of human B and T lymphocytes, is proposed.
IgG2 and other immunoglobulin classes on the cell surface of rat lymphoid cells
Authors: Williams A. F.
Published: February 2007

The binding to rat lymphoid cells of the F(ab′)2 fragments of purified rabbit antibodies specific for the Fc or Fd part of rat IgG2 was studied. Both reagents heavily labeled about 15 % and 6 % of cells from spleen and cervical lymph nodes respectively of rats kept in a conventional animal house. In contrast to this there were very few IgG2 positive cells in the thoracic duct lymph of any animals, or in the spleen of rats from an SPF animal house.

Results on the quantitative binding of rabbit antibodies against rat Fab, IgM and IgA to rat lymphoid cells are also reported. IgM positive cells in the spleen bound much more anti‐IgM relative to their binding of anti‐Fab antibody, than IgM positive cells from thoracic duct lymph or cervical lymph node.
Relationship between the enhanced expression of histocompatibility antigens on interferon‐treated L 1210 cells and their position in the cell cycle
Authors: Killander D. , Lindahl Pernilla , Lundin Lena , Leary Patricia , Gresser I.
Published: February 2007

We have determined the cell cycle position of individual mouse leukemia L 1210 cells by cytophotometric and autoradiographic techniques and simultaneously determined the amount of histocompatibility antigens expressed on the surface of individual cells by quantitative immunofluorescence. Interferon treatment of L 1210 cells was accompanied by an enhanced expression of histocompatibility surface antigens. The distribution of interferon‐treated cells in the various phases of the cell cycle was similar to that for control cells and the enhanced expression of histocompatibility antigens was observed on interferon‐treated cells in all phases of the cell cycle. We conclude, therefore, that this enhancement is not due to a preferential concentration of these cells in any one particular phase of the cell cycle.
Ontogeny of adherent cells. I. Distribution and ontogeny of A cells participating in the response to sheep erythrocytes in vitro
Authors: Landahl Carol Ann
Published: February 2007

An adherent (A) cell function required for the in vitro antibody‐forming response to sheep erythrocyte (SRBC) antigen has been demonstrated in a culture medium enriched with nucleic acid precursors and 2‐mercapto‐ethanol. The essential function is fulfilled best by adult adherent cells of the spleen, to some extent by bone marrow and perhaps lymph node A cells, and poorly or not at all by peritoneal or lung A cells. Ontogenetic studies reveal the absence or inhibition of neonatal A cell synergistic function in the in vitro response to SRBC. The capacity of splenic adherent cells to collaborate with column‐separated nonadherent cells appears only from the third or fourth day after birth, with ratio indices reaching levels significantly greater than nonsynergistic background by the fifth day and showing little further increase until the second week of age.
Fc‐rosetting and nonrosetting T cells are killer cells
Authors: Krammer P. H. , Elliott B. E. , von Boehmer H.
Published: February 2007

A fraction of T cells activated to H‐2 determinants in vivo (ATC) express Fc receptors (FcR) on the cell surface. Those FcR can be detected by antibody coated red blood cells (EA rosettes). Nonrosetting and EA rosetting ATC could be obtained in highly enriched form (more than 99 % pure) by separation by velocity sedimentation at unit gravity. Separately tested, both fractions of ATC showed killer cell activity against specific target cells. Possible explanations why only one population of T killer cells expressed FcR are discussed.
The effect of short‐term culture on the sensitivity of MDAY murine tumor cells to lysis mediated by normal rabbit serum
Authors: Caspi Rachel , Witz I. P.
Published: February 2007

Freshly explanted MDAY murine tumor cells are sensitive to lysis mediated by fresh normal rabbit serum. The sensitivity, which increases with the age of the tumor, is rapidly lost upon short‐term culture, and takes place at 37 °C but not at 4 °C.

Cellular components released into the medium during short‐term culture are capable of eliciting xenogeneic antibodies that mediate complement‐dependent lysis of such cells.
Isolation of antigen‐binding cells from unprimed mice. II. Evidence for monospecificity of antigen‐binding cells
Authors: Julius M. H. , Janeway C. A. , Herzenberg L. A.
Published: February 2007

Spleen cells from unimmunized mice were exposed to two contrastingly fluorescent antigens simultaneously. Antigen‐binding cells of either specificity were isolated using a fluorescence‐activated cell sorter (FACS). Purified cells binding one or the other of the antigens were then examined by fluorescence microscopy for the presence of bound antigen of the alternate specificity.

No double binding cells were seen. If cells bear receptors of two or more specificities and these receptors are randomly distributed among antigen‐binding cells, then of the 13 000 binding cells examined 82 were expected to bind both antigens. These results strongly suggest that antigen‐binding cells bear receptors of only one specificity. In addition, by inference from the functional correlation between antigen‐binding cells and precursor cells, the data support the contention that precursors of antibody‐forming cells are monospecific.
Detection of immunologically active zones in equine growth hormone
Authors: Poskus E. , Zakin M. M. , Fernández H. N. , Paladini A. C.
Published: February 2007

Peptide fragments, obtained from equine growth hormone by cyanogen bromide cleavage and further chemical treatment, were isolated and identified. Their immunological reactivities were tested by hemagglutination and complement fixation methods using rabbit antisera against native hormone.

Antigenic determinants were detected in the fragments comprising amino acid sequences 5–72 and 73–123, this last one being predominant. Fragment 124–178 had very low reactivity. Nitration of peptide 73–123 did not modify its immunological properties, but oxidation diminished them.

Comparison of the antigenicity of equine growth hormone fragment 73–123 with that of the homologous ovine growth hormone fragment 86–123 lent support to the hypothesis that at least one antigenic determinant area in the horse hormone fragment is dependent on sequence 86–123.
Long‐term immunoglobulin G production by transplanted thymus cells
Authors: Micklem H. S. , Anderson N. , Ure Janice , Jones Helen Parry
Published: February 2007

Two sublines of CBA/H mice congenic for the Igl allotype locus were used to study donor‐allotype IgG2a concentrations in the serum of mice injected intravenously with thymus cells. High concentrations (up to several mg/ml) were found in x‐irradiated recipients(exposed to 650 rad, or to 900 rad with a restorative injection of fetal liver cells). The highest concentrations were seen 1–2 months after injection, but detectable quantities were still present in most individuals after 377 days. No donor‐allotype Ig was detected in non‐irradiated recipients. Cell for cell, lymph node cells were about as efficient as thymus cells at transferring IgG production. Although pluripotent hema‐ topoietic stem cells were found in the thymus, their concentration (about 10−8) was too low to account for the results. It is suggested that the thymus contains B lymphocytes, or their precursors, with considerably greater powers of self‐maintenance and expansion than are possessed, on average, by the B lymphocytes in lymph nodes.
Suppression of local graft‐versus‐host reactions by mouse fetal and newborn spleen cells
Authors: Skowron‐Cendrzak Anna , Ptak W.
Published: February 2007

Fetal splenic but not thymic lymphocytes significantly reduce the ability of parental adult spleen cells to elicit local graft‐versus‐host reactions in F1 recipients. This suppressive activity wanes early after birth. There is no requirement for histocompatibility between reacting and suppressor cells.
Reduction of trapping of aggregated human IgG in germinal centers by mitogens
Authors: Papamichail M. , Gutierrez Carmen , Embling P. , Holborow E. J.
Published: February 2007

The effect of nonspecific mitogens on the trapping of 125I‐labeled aggregated human IgG (125I‐AHGG) in germinal centers (GC) of mouse spleens has been investigated by both radioactivity uptake and immunofluorescence. Phytohemagglutinin and concanavalin A (Con A) significantly decreased trapping. Lipopolysaccharide produced less inhibition, and pokeweed mitogen had no significant effect. The maximum inhibition occurred with 250–500 μg Con A. This had no effect on 125I‐AHGG uptake in liver, kidney and blood. No differences were found between i.p. and i.v. routes of Con A injection.

The effect of mitogens on the 125I‐AHGG trapping in GC is due more likely to modification of the migratory properties of lymphocytes brought about by surface binding, than to their mitogenic properties, since Con A decreased 125I‐AHGG localization in thymectomized, x‐irradiated and bone marrow‐ reconstituted animals.
Lack of neonatal susceptibility to induction of tolerance by polysaccharide antigens
Authors: Howard J. G. , Hale Christine
Published: February 2007

Susceptibility to tolerance induction by polysaccharides during the neonatal period has been studied with the α‐1.3 and α‐1.6 glucosyl epitopes of dextran B 1355 in BALB/c mice and the β‐2.6 fructosyl epitope of levan in CBA mice.

Acquisition of responsiveness, as measured by plaque‐forming cell (PFC) assays, is relatively late – taking more than 14 days to appear and 2–3 months to attain maturity in the case of α‐1.6 glucosyl and β‐2.6 fructosyl. The mice responded well to sheep red blood cells and 2,4‐dinitrophenylated (DNP) keyhole limpet hemocyanin (KLH) by 14 days, but were refractory to another thymus‐independent antigen DNP‐Ficoll. Nonresponsiveness of 2‐week‐old spleen cells to the polysaccharides was stable on transfer and could not be attributed to suppressor cells.

Despite this long post‐natal phase of immaturity, no evidence was obtained of concomitant susceptibility to tolerance induction by dextran and levan. Response curves in mice injected at birth with weight‐adjusted doses revealed similar or even higher “high‐zone” thresholds to those tolerized at 3 months. Only partial α‐1.3 glucosyl tolerance is inducible in adults but this was no greater after neonatal exposure, which led also to short‐lived α‐1.6 tolerance. Repeated injections of B 1355 and levan during the first 10 days was no more tolerogenic, and PFC appeared spontaneously with maturity in mice given these antigens neonatally.

Thus, the recognized neonatal susceptibility to thymus‐dependent antigens does not extend to these thymus‐independent antigens. It is therefore considered that tolerance studied with polysaccharides has little relevance to the mechanism of self‐tolerance acquired in the embryo and, in vivo, is determined by interaction with a relatively mature B cell rather than by “clonal abortion” of a tolerance‐sensitive precursor stage.
Production of xenogeneic and allogeneic antisera specific for mouse thymus‐derived lymphocytes
Authors: Bron C. , Anckers C. , Sauser D.
Published: February 2007

Xenogeneic and allogeneic antisera were raised in rabbits and mice using purified mouse T cell‐specific antigens. These antisera were shown to be reactive in complement and antibody‐dependent cell‐mediated cytotoxicity tests as well as in immunofluorescence, with 30 % of mouse spleen cells, 80 % of lymph node cells and 100 % of thymocytes or various T lymphoblastoid cell lines labeled.

No reaction could be detected with bone marrow cells or non‐T cell lines. Both types of reagents bound to the same spleen lymphocyte subpopulations and competed for the same antigenic sites as anti‐Thy‐1.2 alloantiserum. These antisera raised with small amounts of immunogens did not require any absorption to be rendered specific for mouse T cells.
Identification of the murine leukemia viral antigens detected on mouse cells by H‐2 alloantisera
Authors: Milner R. J. , Henning R. , Edelman G. M.
Published: February 2007

H‐2 alloantisera have been previously reported to contain antibodies against murine leukemia viral antigens, but the nature of the viral antigens on mouse cells which interact with these antibodies has not been established. We have found that H‐2 alloantisera recognize components of molecular weight 70 000 – 80 000 on mouse lymphocytes and leukemia cells. These components were also detected by a goat antiserum against the murine leukemia virus (MuLV) glycoprotein (gp70) and are therefore closely related to or identical with that viral protein.

Although most H‐2 alloantisera detected gp70‐like molecules on lymphocytes and leukemia cells from a great variety of mouse strains, only one H‐2 alloantiserum was found to interact with a gp70 component on cells from C57BL/10 and C57BL/6 mice. Animals such as C57BL/10 mice that lacked the component reacting with most H‐2 alloantisera showed increased serum levels of anti‐MuLV antibodies after injection of B10.A spleen cells having a gp70 component detectable by other H‐2 alloantisera. In contrast, strains with cells reactive to antiviral antibodies in the H‐2 alloantisera had low responses to MuLV antigens after a similar immunization procedure. Serum levels of anti‐MuLV antibodies in both groups of mice, however, were increased after injection of Freund's adjuvant. These observations suggest that anti‐MuLV antibodies in mouse alloantisera may arise from a response to viral antigens on the immunizing cells and general stimulation of the immune system.
Uniformity in the clonal repertoire for the immune response to phosphorylcholine in mice
Authors: Claflin J. L.
Published: February 2007

A comparison of the clonal nature of the immune response to phosphorylcholine (PC) was made in nine different inbred mouse strains. Quantitative idiotypic analysis showed that anti‐PC antibodies from each strain were composed of antibodies bearing binding‐site idiotypic determinants indistinguishable from two different BALB/c myeloma proteins, T15 and M511. Idiotypic determinants of two other PC‐binding proteins, M167 and M603, were not detected. Isoelectric focusing of the light (L) chains verified the presence of antibodies similar to T15 and M511 in each strain and indicated the presence of two additional antibodies, one of which has an L chain which cofocuses with M603. Fractionation of anti‐PC antibody with anti‐idiotypic antibody showed that immunoglobulins bearing T15 and M511 idiotypic determinants are separate and contain L chains that are uniform and resemble those of T15 and M511, respectively.

Thus, these mice which differ genetically at multiple loci including the heavy chain allotype complex locus each possess, at least in part, an equivalent set of clonotypes specific for PC. This indicates that the genes encoding these antibodies must be contained in the germ line.
Effect of carrier‐specific tolerance on the generation of helper cell function
Authors: Sanfilippo F. , Cohn Marjorie L. , Scott D. W.
Published: February 2007

The effect of carrier‐specific tolerance on the development of helper cell function was studied in irradiated rats reconstituted with normal or carrier‐tolerant bone marrow. Bone marrow (BM) from normal rats or rats tolerant to sheep IgG (SGG) was transferred to lethally irradiated syngeneic recipients, which were challenged 3 to 5 weeks later when immunocompetence to T‐dependent antigens was shown to have recovered. When recipients were challenged with the 2,4,6‐trinitrophenyl (TNP) hapten coupled to SGG in adjuvant, groups which received SGG‐tolerant BM were 70–80 % unresponsive in terms of anti‐TNP plaque‐forming cells compared to recipients of normal BM. This effect was carrier (SGG)‐specific and was reversed when normal thymocytes were transferred with tolerant BM. Moreover, neither tolerant BM nor tolerant thymocytes were able to suppress the responsiveness of normal BM at a 1:1 ratio. These cell‐mixing experiments imply that the reduction in helper cell function is due neither to suppressor cells nor antigen carryover in the tolerant BM. It is suggested that a BM precursor of the helper T cell may be rendered tolerant and therefore already possesses antigen specificity prior to thymic migration.
Immune conservation: a possible consequence of the mechanism of interferon‐induced antibody suppression
Authors: Booth R. J. , Booth Joan M. , Marbrook J.
Published: February 2007

The effect of interferon preparations on the development of single clones of antibody‐forming cells generated against sheep red blood cells in mouse spleen cell cultures has been studied. It was found that the presence of interferon had no effect on either the number or the size of clones which developed early in the in vitro antibody response. At the peak of the response (day 3), a decrease in the number but not in the size of clones was observed in interferon‐treated compared to control cultures, while by day 4 both the size and number of clones were significantly decreased. These findings indicate that interferon appears to affect only nonactivated B cell precursors by preventing them from becoming activated and commencing clonal expansion. Early responding precursors, which are in cell cycle, presumably having been previously activated in vivo, are refractory to interferon‐induced suppression in vitro. The way in which this immunosuppressive activity of interferon might be of great advantage to an animal as a means of “immune conservation” during viral infections is discussed.
Antigen, host and adjuvant requirements for induction of hyperacute experimental autoimmune encephalomyelitis
Authors: Lennon Vanda A. , Westall F. C. , Thompson Millie , Ward Elsie
Published: February 2007

A hyperacute form of experimental autoimmune encephalomyelitis (HEAE) was induced in Lewis rats using small doses (3.2 μg) of guinea pig myelin basic protein as immunogen and B. pertussis vaccine as adjuvant. Myelin basic proteins from species other than guinea pig (rat, man, monkey, pig, ox, rabbit and sheep) induced only ordinary EAE with this adjuvant. HEAE was more readily distinguished from ordinary EAE by clinical criteria (early onset, with a rapid and severe course, and high incidence of cerebral signs and mortality) than by histologic signs which, although characteristic of HEAE, were not pathognomonic for HEAE. HEAE was transferred to x‐irradiated syngeneic recipient rats with lymph node cells from appropriately immunized donors. The Brown Norway (BN) strain of rat was found susceptible to induction of ordinary EAE, but not HEAE, using large doses of either rat or guinea pig myelin basic proteins. The unique immunogenicity of the guinea pig basic protein must be due to a different antigenic determinant from the determinant(s) which is shared by rat and guinea pig myelin basic proteins and which without B. pertussis induces ordinary EAE. The adjuvant action of B. pertussis in inducing HEAE in the Lewis rat is most likely mediated through an immunocompetent T lymphocyte.
Differences in effect of isoproterenol stimulation on levels of cyclic AMP in human B and T lymphocytes
Authors: Niaudet P. , Beaurain Geneviève , Bach Marie‐Anne
Published: February 2007

The level of cyclic AMP (CAMP) in human lymphocytes in the presence or absence of isoproterenol stimulation was studied in various lymphocyte subpopulations containing different proportions of B and T lymphocytes.

Lymphocytes from thymus and peripheral blood (which contain a majority of T cells) were more sensitive to isoproterenol action than lymphocytes from tonsils or adenoids (where B cells are predominant). Using purified B or T lymphocytes from peripheral blood, tonsils or adenoids, we observed an absence of B lymphocyte response to isoproterenol, whereas T lymphocytes, which had a lower basal cAMP level than B cells, exhibited in all experiments a significant increase in cAMP content after isoproterenol stimulation. The intensity of the response varied in the different T lymphocyte subpopulations.
The ontogeny of B lymphocytes. III. Opposite signals transmitted to B lymphocyte precursor cells by inducing agents and hormones
Authors: Hämmerling U. , Chin Ann F. , Abbott Joan , Goldstein G. , Sonenberg M. , Hoffmann M. K.
Published: February 2007

Present evidence supports the idea that agents inducing phenotype conversion in B and T precursor cells can be obtained from many sources (e.g. LPS, cate‐cholamines, prostaglandin E1, and DB cyclic AMP). They share the feature of raising intracellular cyclic AMP in some systems. Our experiments have demonstrated another class of components (carbamyl choline, insulin, human growth hormone, 8‐bromo‐cyclic GMP) which inhibit induction of phenotype conversion in early B lymphocyte precursor cells. All of these substances are known or suspected to raise levels of intracellular cyclic GMP. The blocking effect is transient as precursor cells regain inducibility after removal of the inhibitor within 2 to 4 h. Thymopoietin (TP), which is a selective inducing agent for conversion of prothymocytes (Thy‐1 −) to thymocytes (Thy‐1+), inhibited the induction of expression of B cell markers, Ig and Ia. Conversely, tumor necrotizing serum (TNS), which selectively induces B precursor cells (Ig− → Ig+ and Ia− → Ia+), inhibited the inducing effect of TP on prothymocytes. We propose that induction requires interaction of a specific inducing hormone with a receptor associated with adenylate cyclase, whereas inhibition of induction requires interaction with a receptor which activates guanylate cyclase. Our data indicate that prothymocytes and pro‐B cells have receptors for both TP and TNS, which are, however, associated with different signal mechanisms in B and T precursor cells. The manner in which a given precursor cell responds depends less on the specificity of hormone receptor interaction than on pre‐set receptor associations to deliver stop or go signals. This system can be regarded as a model for regulation of T and B cell differentiation by pairs of hormones with opposing effects.
Search for the physiological function of H‐2 gene products
Authors: Lengerová Alena , Zelený V. , Haškovec C. , Hilgert I.
Published: February 2007

The previously demonstrated role of H‐2 gene products in nonimmune cell interactions was further analyzed. As model of such interactions served the erythropoietic performance (in terms of 59Fe uptake) of bone marrow cell (BMC) inocula in the cellular environment of the spleen of massively irradiated hosts. When the performance in syngeneic hosts is taken as standard, the performance of cells from the same pool in H‐2 disparate (congenic) hosts is subnormal. The inhibition was also observed in two congenic strain combinations where the H‐2 disparity did not involve the I region. The capacity of BMC to distinguish H‐2 ‐identical and H‐2 ‐disparate hosts could be greatly reduced or virtually abolished by enzymatic digestion of certain cell surface carbohydrates. An essential effect of neuraminidase was further increased by emulsin. When the digested cells were left for 6 h in an enzyme‐free medium, their capacity to dinstinguish H‐2 disparities recovered. A pretreatment with papain, which cleaves a large fragment of the H‐2 protein carrying both the antigenic site and the carbohydrate chain, had an effect comparable with but no greater than the sugar‐removing enzymes. The enzymatic effect was largely due to the impairment of the performance of BMC in H‐2 ‐identical hosts rather than to an improvement in H‐2 ‐disparate ones. The neuraminidase‐ and emulsin‐sensitive groupings thus seem to be essential for the cells to recognize “self” rather than “non‐self” and to interact with H‐2 ‐identical cells in physiological processes. A hypothesis is proposed that in H‐2 glycoproteins, the antigenically and physiologically active sites are distinct, being located in the protein and carbohydrate parts of the molecules, respectively. It is further suggested that the normal function of the H‐2 products might consist in providing the cell surface with structures which are complementary to similar structures on other cells; the carbohydrate moiety seems to be essential for this type of physiological interaction in contrast to the key and lock‐type of complementarity in immune interactions which is based on protein structures.
Enhancement of Lewis lung carcinoma in a syngeneic host by spleen cells of C57BL/6 old mice
Authors: Gozes Y. , Trainin N.
Published: February 2007

The development and growth of transplanted syngeneic Lewis lung carcinoma and their relation to aging was investigated. The Lewis lung carcinoma (3LL) is a metastasizing tumor which developed spontaneously in a C57BL/6J mouse. We found that the frequency and rate of tumor growth were increased when the tumors were implanted in aged as compared to young mice. In order to determine whether this finding involves the participation of the immunological system of the host, spleen cells of mice at various ages were mixed with tumor cells at a ratio of 100:1 and injected into one footpad of syngeneic recipient mice. Spleen cells from older mice were found to strikingly enhance tumor growth in the recipient. Only living T cells were responsible for this enhancement, since in vitro irradiation of donor spleen cells or use of spleen cells from thymectomized donors abolished this enhancement. The quantitative distribution of various cell populations in the spleen did not vary greatly with age, these results suggesting that a change occurs in the intrinsic properties of lymphoid cells during aging. It is suggested that the tumor‐enhancing properties of aged lymphoid cells are due to autoimmune activity of the cells. Indeed, cellular autoimmune activity was detected when these cells were injected into adequate animals.

Various other features of cell‐mediated immunity were analyzed in groups of young and old mice.
Nonspecific genetic regulation of antibody responsiveness in the mouse
Authors: Siqueira Maria , Esteves Maria B. , Ibanez Olga M. , Ferreira Vera C.A. , Sant'Anna O.A. , Reis Moema H. , Biozzi G.
Published: February 2007

Four lines of mice were produced by selective breeding for quantitative agglutinin responsiveness to flagellar (f) or somatic (s) antigens (Ags) of Salmonellae: high (H) or low (L) responder lines to f Ag and H and L responder lines to sAg.

The Salmonellae contained both f and sAgs, the Ag used to perform the selection was the Selection Ag and the other was the Associated Ag. The selective breeding produced a progressive interline separation with an equivalent effect for both Ags. After 15 generations (F15) the level of agglutinin response was about 60 times higher in H than in L responders. About 50 % of the phenotypic variation of the character investigated is determined by a group of immune response genes, the rest is due to environmental factors. The nonspecific effect of this group of immune response genes was investigated by measuring the responses to three independent antigens: Sheep erythrocytes (SE), dinitrophenyl‐conjugated human IgG (DNP‐HGG) and bovine IgG (BGG).

The selection for fAg response produced an equivalent modification in the responsiveness to the Associated Ag (97 %) and to BGG (130 %). This nonspecific effect was smaller for responsiveness to SE and DNP‐HGG, 58 % and 41 % of the Selection Ag response, respectively.

The selection for sAg response produced a nonspecific modification of responsiveness of 94 % for the Associated Ag of 74 % for BGG and 63 % for DNP‐HGG. An important exception concerned SE to which an equal antibody response is produced in high and low lines of sAg selection.
Limulin (Limulus polyphemus lectin): mitogenic effect on human peripheral lymphocytes
Authors: Roche Annie‐Claude , Perrodon Yolaine , Halpern B. , Monsigny M.
Published: February 2007

The lectin from hemolymph of Limulus polyphemus was purified by affinity chromatography on insolubilized bovine submaxillary mucin. The purity of the protein was checked by crossed immunoelectrophoresis. Agglutination of human red blood cells was completely abolished after neuraminidase treatment, while other cells were still agglutinable after the same treatment but required a higher concentration of lectin. Limulin was able to stimulate about 50 % of human peripheral lymphocytes. This mitogenic effect could be inhibited by bovine submaxillary mucin but not by the desialylated mucin. Related to the known oligosaccharide‐binding specificity of limulin and of the other nonspecific activators of lymphocytes, the authors suggest that lymphocyte stimulation is triggered by binding to a glyco‐conjugate bearing the following carbohydrate chains: