bluuebunny/crossref_metadata_2025 huggingface dataset:
A cross‐reacting human idiotype (B17) associated with antibodies to N‐acetyl‐D‐glucosamine Specificity, immunoglobulin class association, and distribution in the population
Authors: Emmrich Frank , Greger Bernd , Eichmann Klaus
Published: February 2007

This report describes the study of the expression of an idiotype in the human population which is associated with antibodies to N‐acetyl‐D‐glucosamine (GlcNAc) present in most human sera presumably due to streptococcal infections. The idiotype is identified with antisera and monoclonal antibodies prepared against the IgM (χ) antibody secreted by the Epstein‐Barr virus‐transformed human B cell line B17.

At least 90% of 207 individuals tested had immunoglobulin with B17 idiotypic determinants in their sera, as demonstrated with conventional and one monoclonal anti‐idiotypic antibody. Another monoclonal anti‐idiotypic antibody reacted with antibodies in only a few of the sera. No correlation was found between the level of expression of different idiotopes in individual human sera, suggesting molecular heterogeneity of the B17‐positive antibody population.

B17‐positive immunoglobulins are to a large extent specific for GlcNAc but represent only a minor population of all GlcNAc‐specific antibodies in human sera. B17 determinants are on IgM (χ) in all human sera and on IgG and IgA in some. In addition, some λ‐bearing Ig was found to react with anti‐B17 antisera, suggesting the detection of VH‐associated idiotypic determinants in this experimental system.
Complement inhibits immune responses: C3 preparations inhibit the generation of human cytotoxic T lymphocytes
Authors: Ballas Zuhair K. , Feldbush Thomas L. , Needleman Barbara W. , Weiler John M.
Published: February 2007

C3 fragments have been shown to inhibit mitogen‐ and antigen‐induced human lymphocyte blastogenesis. In this study, C3 preparations and a small fragment of C3 (contained in a preparation called Fraction 2) were examined for their capacity to regulate cytotoxic T lymphocytes (CTL) and proliferative mixed lymphocyte responses (MLR). We found that both preparations inhibited the generation of allogeneic human CTL as well as MLR in a dose‐related manner. In contrast, Fraction 1, which contained native C3 and C3b, did not inhibit the generation of CTL nor did it inhibit the MLR. The kinetics of inhibition of proliferation were divergent from the kinetics of inhibition of CTL generation; the active preparations inhibited proliferation significantly when added as late as day 5 of a 6‐day culture, whereas no inhibition of CTL generation was seen when these preparations were added after day 3 of culture.

Cultures in which C3 preparations caused complete inhibition of CTL generation had normal levels of the nonspecific, anomalous killer cell activity, as assayed on K 562 target cells. Furthermore, C3 preparations and Fraction 2 had no effect on the lytic function of differentiated CTL, on “spontaneous” natural killer cell activity or on interferon‐induced augmentation of natural killer cell activity. These findings indicate that C3 fragments may play a negative role in the regulation of CTL responses.
Strong histocompatibility and cell‐mediated cytotoxic effects of a single Mls difference demonstrated using a new congenic mouse strain
Authors: Berumen Luis , Halle‐Pannenko Olga , Festenstein Hilliard
Published: February 2007

In vivo and in vitro effects of incompatibility at the Mls locus have been studied utilizing a recently created congenic mouse strain. Results obtained with skin grafts were compared to those obtained in the mixed lymphocyte reaction (MLR) and cell‐mediated cytotoxicity assays. The in vitro responsiveness of cells from skin‐grafted mice was compared to that of cells from corresponding ungrafted mice. The results showed that: (a) Mlsa, strongly stimulatory in primary MLR, has a weak effect on skin graft rejection; specific in vivo preimmunization against Mlsa increases and accelerates the rejection of skin grafts, but abrogates the responsiveness in MLR; and (b) incompatibility for Mlsb, nonstimulatory in primary MLR, induces relatively rapid rejection of 100% of skin grafts; this rejection is dramatically accelerated by specific in vivo preimmunization and is followed by activation of helper and cytotoxic cells. Results obtained in the cell‐mediated cytotoxicity assay suggest that the recognition of Mlsb determinants is H‐2‐restricted. Finally, the rejection of skin grafts incompatible for numerous non‐H‐2 loci is delayed by an additional incompatibility for Mlsb, suggesting that Mlsb decreases the response to other non‐H‐2 antigens, thus acting as a suppressor and/or competitor antigen. We conclude that, in contrast with previous findings, Mls incompatibility may have a strong effect on skin graft rejection, depending on the allelic combination involved, and, after in vivo immunization, Mlsb activates cell‐mediated proliferative and cytotoxic responses and definitely is not “silent”. The importance of the histocompatibility effects of Mls determinants and the variety of its biological functions are much in favor of the existence of a polymorphic and complex system capable of activating different cell subsets.
Genetic polymorphism of λ1 and λ3 immunoglobulin light chains in the Mus subgenus
Authors: Amor Mounira , Guenet Jean‐Louis , Bonhomme François , Cazenave Pierre‐André
Published: February 2007

Several inbred or partially inbred mouse strains derived from wild mice of different Mus subgroups were surveyed for expression of λ1 light chain. One strain, SPE, expressed little or no λ1 chains. Two populations of antibodies were obtained by immunization of SPE mice with λ1 light chain isolated from the BALB/c J558 (α,λ1) myeloma protein. One population of antibodies recognized λ1 allotypic determinants located on the C terminal fragment beginning at the residue 176. A second population was directed against epitopes present on both λ1 and λ3 chains. These determinants, which were detected in all strains tested with the exception of SPE, were located in the V region. This result is in concordance with recent DNA studies showing that the λ1 and λ3 isotype use the same Vλ1 genes (Blomberg, B. et al., Proc. Natl. Acad. Sci. USA 1981. 78: 3765). Whether the V epitopes recognized by SPE antibodies are allotypic or isotypic in nature is not certain.
The selection and maintenance of the V region determinant repertoire is germ‐line encoded and T cell‐independent
Authors: Juy Dominique , Primi Daniélé , Sanchez Pierre , Cazenave Pierre‐André
Published: February 2007

The number of lipopolysaccharide‐sensitive precursor cells synthesizing immunoglobulin (Ig) which reacts with the monoclonal anti‐M460 antibody F6(51) has been determined in the spleen and in the bone marrow of different strains of mice. These precursor frequencies fall into two quantitatively different groups. The first group includes mice with the same Igh haplotype as BALB/c animals (Igh3). In this group, spleen cells contained between 1:104 to 1:5 × 104 B cell precursors secreting Ig which bound F6(51). The second level of precursor was obtained with animals with allotypic haplotypes other than Igh3. These values were too low to allow accurate frequency determinations. The frequency of these cells in mice of the latter group, however, increased dramatically when these animals were hyperimmunized with the monoclonal anti‐M460 antibody. Similar results were obtained when the frequencies were determined using the Ig− fraction of bone marrow cells.

Surprisingly, the numbers of lipopolysaccharide‐sensitive B cell precursors secreting F6(51)‐binding Ig in spleen cells of nude mice was found to be similar to the one in splenocytes of normal mice, and even in this case, the frequencies reflected the genetic background of the animals tested. Taken together these data support the notion that the establishment and the maintenance of the M460 idiotypic repertoire is germ‐line encoded and independent of regulatory T cells.
The mechanism of SiO2 (Aerosil)‐mediated enhancement of the proliferative response of mouse spleen lymphocytes to antigen and mitogens in a serum‐free system
Authors: Burger Mikulas , Hess Max W. , Cottier Hans
Published: February 2007

SiO2 particles enhanced the in vitro proliferation of splenic B cells obtained from BALB/c mice immunized with sheep erythrocytes. T cells from immunized animals were capable of replacing SiO2 with regard to the enhancement of both in vitro proliferation and the primary immune response. In addition, the stimulating effect of IgG, phytohemagglutinin (PHA) and concanavalin A (Con A) on spleen lymphocytes was also augmented by SiO2. The enhancing effect of SiO2 was higher at suboptimal than at supraoptimal concentrations of Con A. SiO2 is capable of binding Con A. The SiO2‐bound lectin retained its mitogenic effect on spleen cells and, under certain conditions, SiO2‐bound Con A was considerably more active in this respect than the free substance.
Prevention of complement activation on the homologous cell membrane of nucleated cells as well as erythrocytes
Authors: Okada Hidechika , Tanaka Hiroko , Okada Noriko
Published: February 2007

A C3b receptor, a glycoprotein with a molecular weight of 205 kDa (gp205) on human erythrocytes (Ehu), has been claimed to restrict the activation of human complement via the alternative complement pathway (ACP), thereby inhibiting the activation of the ACP even on neuraminidase (Nase)‐treated Ehu. However, the Nase‐treated Ehu were sensitive to hemolysis by guinea pig complement via ACP activation, although the C3b receptors on Ehu can react with guinea pig C3b. Furthermore, HeLa cells which had no detectable C3b receptor did not became reactive with guinea pig ACP. On the contrary, Nase treatment of guinea pig erythrocytes (Egp) as well as guinea pig line 10 tumor cells, which have no detectable C3b receptor, could not make those cells reactive with the homologous guinea pig ACP although they became reactive with human and rabbit ACP. Similarly, rabbit E did not become reactive with the homologous rabbit ACP following Nase treatment. Nase‐treated Egp preincubated with human serum in the presence of EDTA were also not lysed by guinea pig serum. Therefore the unreactiveness of Nase‐treated cell membrane with homologous ACP was not merely due to the absence of antibody to cell membrane in the homologous serum. There may be a membrane inhibitor which preferentially interacts with homologous complement to circumvent undesirable complement activation on the homologous cell membrane.
T lymphocyte surface antigens in primates
Authors: Letvin Norman L. , King Norval W. , Reinherz Ellis L. , Hunt Ronald D. , Lane Heather , Schlossman Stuart F.
Published: February 2007

We examined the binding of peripheral blood mononuclear cells from various primate species to a panel of monoclonal antibodies with specificity for human T lymphocytes. A remarkable structural conservation of the erythrocyte rosette receptor on T cells between such phylogenetically distant primates as lemurs and man was found. Furthermore, it was demonstrated that the degree of sharing of other T cell‐specific surface determinants between man and other primates reflects the phylogenetic distance between them. Moreover, these studies suggest the potential use of monoclonal antibodies for further structural and functional elucidation of T lymphocyte‐specific surface structures.
The origin of human B and T cells from multipotent stem cells: a study of the Tn syndrome
Authors: Brouet Jean‐Claude , Vainchenker William , Blanchard Dominique , Testa Ugo , Cartron Jean‐Pierre
Published: February 2007

The Tn (or polyagglutinability) syndrome corresponds to a human nonmalignant acquired condition which results from a somatic mutation occurring at the level of bone marrow stem cells. This model offers therefore a unique opportunity to study the contribution of multipotential stem cells to the maintenance of cells from the lymphoid lineage. We found that the Tn mutation is expressed by both myeloid and lymphoid mature blood cells. Whereas a large proportion of surface IgM‐bearing B cells carry the Tn mutation, only a small percentage of T cells and IgA‐ or IgG‐bearing B cells are defective, showing that under physiological conditions the penetration of stem cells into the various myeloid and lymphoid compartments is variable.
Recognition of λ1 and λ2 murine light chains by carrierspecific isologous T helper cells; effect of L‐H chain assembly
Authors: Bogen Bjarne , Jørgensen Trond , Hannestad Kristian
Published: February 2007

Previous studies from this laboratory have revealed an antigenic site located on the variable domain of the λ2 light chain of BALB/c myeloma protein 315 (the Vλ2315 site). This site is recognized by conventional carrier‐specific T helper cells (Th) of BALB/c mice and is expressed on both the free and assembled Vλ2315 domain. The present work defines two new antigenic sites associated with murine λ chains. The first site was associated with free λ1‐chain of myeloma protein J558. It was recognized by splenic Th from animals that had been primed with free λ1J558 in complete Freund's adjuvant; when transferred to irradiated animals the primed Th responded to a boost with (4‐hydroxy‐5‐iodo‐3‐nitro‐phenyl)acetate (NIP)‐free λ1J558 in saline, but did not respond to NIP‐complete J558 or NIP‐free λ2315. Priming with complete J558 failed to elicit Th that responded to NIP‐free λ1J558. This determinant was therefore only expressed on the free (as opposed to the assembled) form of λ1J558, and it was not shared with free λ2315. The second antigenic site was shared between free λ1J558 and free λ2315. It was defined by free λ2315‐primed Th which responded to a boost with NIP‐free λ1J558. Since priming with free λ1J558 did not elicit Th that recognized NIP‐free λ2315, the cross‐reaction was undirectional. The free λ2315‐primed Th failed to respond to the complete J558, and M315‐primed Th failed to respond to NIP‐free λ1J558, indicating that the second (cross‐reactive) antigenic site, like the first, was only expressed on free λ chains. Completely reduced and alkylated (unfolded) free λ1J558 and free λ2315 chains elicited Th that recognized native (folded) free chains.

Thus, free λ1J558 bears two antigenic determinants recognized by Th, one private and a second shared with free λ2315. λ2315 also bears two determinants, a cross‐reactive one on free λ2315 shared with free λ1J558, and a private one located on the Vλ2315 domain of the complete M315.

The discussion is focused on possible explanations for the quenching of the two new λ chain determinants upon light‐heavy chain assembly and why, by contrast, the private Vλ2315 site is maintained in the complete M315.
Inhibition of lymphocyte proliferation and antibody production in vitro by silica, talc, bentonite or Corynebacterium parvum: involvement of peroxidative processes
Authors: Hoffeld J. Terrell
Published: February 2007

This study was undertaken to determine whether and by what means particles which induce granulomata in vivo can affect murine spleen lymphoproliferative and antibody responses in vitro. Particles of silica, talc, Bentonite or C. parvum cells inhibited lipopolysaccharide‐ or concanavalin A‐stimulated proliferation and sheep red blood cell‐induced antibody response in vitro. The inhibition required at least 48 hours exposure of the cells to the particles. The late onset of inhibition and its reproducibility at different cell or mitogen concentrations implicated particle‐induced injury to both phagocytes and lymphocytes. Either α‐tocopherol or 2‐mercaptoethanol prevented the particle‐induced inhibition of spleen cell responses. α‐Tocopherol and 2‐mercaptoethanol have in common the capacity to protect cells against membrane lipid peroxidation. The inhibitory peroxidative process(es) implicated by these studies are most likely attributable to: (a) stimulation of oxidative metabolism of phagocytic cells by particles; and (b) iron‐catalyzed peroxidation directly by the particles. These data may be relevant in understanding the pathogenesis of and devising therapeutic approaches toward various granulomatous conditions.
Antigen‐binding human T suppressor cells and their association with the HLA‐DR locus
Authors: Lehner Thomas
Published: February 2007

The ability of human lymphocytes to bind antigen was studied by direct binding of 125I‐labeled streptococcal protein antigen, followed by autoradiography. T‐enriched lymphocytes depleted of adherent cells and B cells showed specific binding of 125I‐labeled streptococcal antigen (SA) at 4°C and in the presence of sodium azide. Further depletions of the T‐enriched population by the monoclonal T4 or T8 antiserum and complement revealed that the antigen‐binding T cell is T4−, T8+. This was confirmed by positive selection of T8 cells, by rosetting with ox red blood cells and by the binding of SA by in vitro induced suppressor but not helper cells. Antigen specificity of binding to the suppressor cells was established by complete inhibition with the SA but no inhibition with keyhole limpet hemocyanin. A characteristic dose‐response of binding 1 or 10 ng SA to HLA‐DRw6 lymphocytes and 1000 ng SA to DR4,1,2,3 or 5 lymphocytes was found. A comparison of the dose‐responses of antigen‐binding T+ suppressor cells with those of helper and suppressor functions showed that the dose of SA which binds to suppressor cells is similar to the dose required to induce helper but not suppressor function. A plausible interpretation of these observations is that the T8+ antigen‐binding suppressor cells might function as “contrasuppressor cells” which compete successfully for the membrane receptors of helper cells, thereby preventing suppression by the major subset of suppressor cells.
Antigen‐specific plaque‐forming cell response of human cord blood lymphocytes after in vitro stimulation by T cell‐dependent antigens
Authors: Van Tol Maarten J. D. , Zijlstra Jitske , Heijnen Cobi J. , Kuis Wietse , Zegers Ben J. M. , Ballieux Rudy E.
Published: February 2007

Mononuclear cells isolated from human cord blood (CBL) of full‐term neonates were stimulated in vitro with a dose range of T cell‐dependent antigens, i.e. ovalbumin or sheep erythrocytes, and tested for the capacity to mount an antigen‐specific plaque‐forming cell (PFC) response. Both of the antigens used induced in CBL a PFC response with the same kinetics of PFC formation and of the same magnitude as found in cultures of adult peripheral blood lymphocytes (PBL).

However, optimal PFC responses in CBL were obtained at a hundredfold lower concentration of the antigens compared with the optimal antigen doses for the induction of a PFC response in adult PBL. This phenomenon was further investigated with respect to the antigen dose dependency of the activation of neonatal B cells and neonatal regulatory T cells. The induction of a PFC response in CBL at antigen concentrations that were suboptimal for adult PBL showed a correlation with the particular antigen dose requirements for the activation of B cells and T helper cells in neonates. Furthermore, the findings suggest that the decrease of the PFC response in CBL stimulated with supraoptimal doses of antigen was not caused by the induction of unresponsiveness at the B cell level or by interference of pregnancy‐associated substances with the PFC response, but was rather the result of the activation of antigen‐specific T suppressor cells. Neonatal T suppressor cells were activated at antigen concentrations that generated T helper activity in the adult. Thus, although neonatal B cells possess the intrinsic capacity to mature into antigen‐specific PFC, the conditions for effective activation of neonatal T cells regulating the B cell response differ from those for the activation of adult regulatory T cells.
Quantitative and qualitative differences in the distribution of HLA class I antigenic determinants in the human thymic compartments
Authors: Stein Harald , Müller Claudia , Ziegler Andreas , Wernet Peter
Published: February 2007

The topographical distribution of HLA class I antigens has been investigated by the immunoperoxidase technique on normal frozen thymic tissue sections with a panel of mono‐ and polymorphic monoclonal anti‐HLA antibodies. HLA class I framework determinants detected by the monoclonal antibody W6/32. HL were present on 80–90% of cortical thymocytes, as well as on all cortical epithelial and medullary cells. However the staining intensity of cortical thymocytes with this reagent was about threefold weaker than that of the medullary thymocytes. Labeling patterns of selected monoclonal antibodies against matching HLA‐A/B allospecificities revealed striking variations in the quantitative expression of certain HLA‐A vs. HLA‐B locus alloantigenic determinants on cortical thymocytes compared to a consistent staining on almost all medullary cells.
Evidence that cytotoxic T cells and natural cytotoxic cells use different lytic mechanisms to lyse the same targets
Authors: Patek Paul Q. , Collins John Leslie , Cohn Melvin
Published: February 2007

There is evidence that natural cytotoxic (NC) cells are in the T cell lineage. To lyse targets, cytotoxic T cells (TK) must recognize any of the myriad antigens plus syngeneic major histocompatibility complex (MHC) determinants. In spite of the evidence which indicates TK and NC are in the same lineage, NC cells can recognize few determinants (perhaps only one) and do not require recognition of MHC determinants.

In addition to differences in the requirement for target recognition, in this report we show that TK cells and NC cells also use different lytic mechanisms to lyse the same targets. NC effectors initiate a lytic mechanism in NC‐sensitive and NC‐resistant targets. This lytic mechanism requires approximately 4 h before target lysis is apparent in NC‐sensitive targets; it is inactivated by a protein synthesis‐dependent counterlytic mechanism in NC‐resistant targets. In contrast the TK lytic mechanism causes a rapid release of 51Cr from both NC‐sensitive and NC‐resistant targets and is not inhibited by the NC counterlytic mechanism present in NC‐resistant cells. These findings lead to the conclusion that the mechanism used by NC cells to lyse targets is fundamentally different from that used by TK cells.
Induction of cytolytic T lymphocytes by mitogenic lectins is specifically inhibited by anti‐Lyt‐2 antibodies
Authors: Gullberg Martin , Larsson Eva‐Lotta
Published: February 2007

The effects of anti‐Lyt‐2 antibodies at different levels of lectin‐induced cytotoxic T lymphocyte (CTL) responses have been analyzed. Induction of interleukin 2 (T cell growth factor) reactivity (“step 1”) by three different lectins was profoundly inhibited by anti‐Lyt‐2 antibodies. Also lectin‐dependent cytotoxicity of polyclonally induced CTL was significantly inhibited by anti‐Lyt‐2 antibodies, whereas the interjacent IL2‐dependent proliferation of “step 1”‐induced CTL precursors was unaffected by these antibodies. The anti‐Lyt‐2‐mediated inhibition was selective and specific to the target cell determinants and limited to the events in CTL responses which require interactions with the lectins. These results parallel those obtained in antigen‐induced responses and indicate that antigens and lectins induce CTL responses by interacting with the same type of membrane receptor complex containing Lyt‐2 molecules and antigen‐specific receptors. It follows that T cell mitogenic lectins do not appear to deliver triggering signals through “mitogen” receptors.
HLA class I genes integrated into murine cells are inducible by interferon
Authors: Rosa Frédéric , Le Bouteiller Philippe P. , Abadie Annie , Mishal Zohair , Lemonnier François A. , Bourrel Dominique , Lamotte Michel , Kalil Jorge , Jordan Bertrand , Fellous Marc
Published: February 2007

In human cells treated with interferon, there is an increase in the amount of HLA‐A, B, C mRNA and, to a lower extent, membrane‐bound antigen. However, the mechanism of this mRNA enhancement is still unknown. Using mouse L cells transfected with a unique class I HLA gene, we were able to show that both the related HLA mRNA and protein are increased after murine but not human interferon treatment. Moreover, the discrepancy between interferon‐directed HLA mRNA and protein enhancement is also observed. The mouse transfected cells allowed us to study more precisely the origin of this discrepancy.
Prevention and therapy with electrolectin of experimental autoimmune myasthenia gravis in rabbits
Authors: Levi Giovanni , Tarrab‐Hazdai Rebecca , Teichberg Vivian I.
Published: February 2007

Electrolectin (EL), an endogenous β‐D‐galactoside‐binding lectin from Electrophorus electricus, was found to have a prophylactic and therapeutic action on the experimental autoimmune myasthenia gravis (EAMG) in rabbits. EAMG is an autoimmune disease induced by immunization with the purified acetylcholine receptor protein (AChR) and is considered to be a good model for the human disease myasthenia gravis. Simultaneous immunization with AChR and EL completely prevented the onset of myasthenic symptoms. This preventive effect was accompanied by a decrease in the recognition of AChR by anti‐AChR antibodies. The administration of EL to myasthenic rabbits led, in most cases, to a complete recovery which was not accompanied by any significant change in the level of circulating anti‐AChR antibodies. No evidence for an action of EL at the muscular level could be obtained. EL, however, was found to bind to rabbit lymphocytes and to stimulate their mitosis. These results suggest that EL produces its effects on EAMG by acting at the level of the immune system. It is proposed that EL may play a role in the immunological regulation of the response to self‐antigen, which could be one of the biological functions of this animal lectin.
Myeloma class switch variant X63.2aRI‐16 secretes IgG2a and IgG1 with identical VDJ sequence
Authors: Zaiss Siegfried , Beyreuther Konrad
Published: February 2007

The myeloma line X63.2aRI‐16 isolated in vitro as spontaneous tertiary class switch variant (γ1 → γ2b → γ2a → γ2a,γ1) of X63 (IgG1,x) by fluorescence‐activated cell sorting using class‐specific antisera expresses two heavy chains. X63.2aRI‐16 secretes IgG2a,x as does the parental cell line X63.2a‐25, a hybrid molecule containing γ2a and γ1 heavy chains and IgG1,x. The chain of the latter protein is the product of a reverse class switch in regard to the embryonic order of the CH genes. We purified the immunoglobulins of X63.2aRI‐16, isolated the CNBr fragments of both heavy chains and determined the complete amino acid sequence of the VH domains and of the CH domains up to the first subclass‐specific residues. The remaining CNBr fragments of the CH domains were characterized by amino acid analyses. It was found that both heavy chains of the double producer possess identical VH domains and CH domains characteristic for the subclasses γ2a and γ1, respectively. The identities of the two VDJ sequences expressed in X63.2aRI‐16 cells suggest that the reverse class switch event to γ1 cannot simply be explained on the basis of a deletion model involving only a single CH locus.
The chemiluminescence response of human natural killer cells. II. Association of a decreased response with low natural killer activity
Authors: Werkmeister Jerome , Helfand Stephen , Roder John , Pross Hugh
Published: February 2007

Low natural killer (NK) responders selected from a panel of 600 normal, healthy volunteers exhibited 5‐ to 10‐fold less cytotoxicity against the human erythroleukemic cell line K562, compared with high NK responders. Antibody‐dependent cellular cytotoxicity against tumor cells, which is mediated by similar or identical effectors, was also depressed in low NK donors whereas lectin‐dependent T cell killing and monocyte‐mediated cytolysis of tumor cells was normal. Low NK donors exhibited normal frequencies of cells expressing the HNK‐1 marker of human NK cells and highly enriched NK fractions were not impaired in their ability to recognize and bind to NK‐sensitive target cells. Interferon partially activated low responder NK cells but did not restore the response to normal levels. The burst of chemiluminescence that is generated by NK cells within seconds of target cell contact was markedly impaired in low NK responder donors. We have previously shown that chemiluminescence detects reactive oxygen intermediates which are necessary but not sufficient for the activation of the NK cytolytic pathway.
Lymphocyte heterogeneity in the trout, Salmo gairdneri, defined with monoclonal antibodies to IgM
Authors: Deluca Dominick , Wilson Melanie , Warr Gregory W.
Published: February 2007

A monoclonal antibody to trout serum IgM was tested by immunofluorescence analysis with lymphocytes from thymus, spleen and head kidney. By visual examination, the antibody reacted with only a subpopulation of lymphocytes. The mean values ± SE for positive cells were 5.2 ± 2.3% in the thymus, 30.3 ± 7.9% in the spleen and 12.4 ± 3.0% in the head kidney. Flow cytofluorometric analysis revealed evidence of heterogeneity by size among the membrane IgM‐positive cells of the head kidney and spleen. Depletion of head kidney cells positive for surface IgM by an immune affinity adherence technique of panning, using monoclonal anti‐IgM, significantly reduced the mitogenic response to lipopolysaccharide but not to concanavalin A. It is suggested that this information supports the existence of distinct subpopulations of fish lymphocytes that may be homologous in certain respects to mammalian T and B type cells.
Internalized membrane immunoglobulin meets intracytoplasmic DR antigen in human B lymphoblastoid cells
Authors: Pletscher Martin , Pernis Benvenuto
Published: February 2007

The important role of type II antigens of the major histocompatibility complex (Ia and DR) in the antigen presentation and in the antigen‐specific cooperation between T and B cells is by now firmly established. Human B lymphoblastoid lines MWE and BL were stained with different fluoresceinated anti‐DR antibodies. Not only surface but intracytoplasmic DR structures were brightly stained. The intracellular stain accumulated in a cluster close to the nucleus. Different specificity controls were performed. MWE and BL cells quickly internalize membrane IgM if cross‐linked by corresponding antibodies. The intracellular location of the vesicles containing these complexes showed substantial coincidence with DR‐positive structures in the paranuclear location. It is speculated that IgM‐ligand complexes meet internal DR molecules and are both reexpressed on the plasma membrane to be recognized by primed T cells.
Erythrocyte‐rosette receptor expression by chronic lymphocytic leukemia B lymphocytes
Authors: Guglielmi Paul , Preud'homme Jean‐Louis , Brouet Jean‐Claude
Published: February 2007

Erythrocyte (E) rosette‐forming cells have been investigated in three patients with B chronic lymphocytic leukemia whose leukemic lymphocytes were easily identifiable. A small percentage of fresh neoplastic cells formed E rosettes in two patients. In every patient, most unstimulated, cultured leukemic lymphocytes became E+ and this was further enhanced by phytohemagglutinin and pokeweed mitogen stimulation or neuraminidase treatment. These E+ B cells lacked detectable T cell antigens (except for a weak expression of an antigen associated with the helper T cell subpopulation in one case). They were unreactive or weakly reactive by immunofluorescence with a monoclonal antibody to the E receptor. However, this antibody completely inhibited E‐rosette formation. The enhanced expression of E‐rosette receptors by in vitro cultured cells appeared to be dependent upon the presence of a small number of E‐rosetting cells at the beginning of the culture. E‐rosette receptor expression by leukemic lymphocytes was most likely in a fourth case (out of 9 patients studied). This finding may account for some of the discrepancies in the study of so‐called T cells in B chronic lymphocytic leukemia.
Constitutive secretion of interleukin 1 by human monocytes
Authors: Treves Abraham J. , Barak Vivian , Tal Tova , Fuks Zvi
Published: February 2007

The constitutive and lipopolysaccharide (LPS)‐induced secretion of interleukin 1 (IL1) by cultured human monocytes and macrophages has been studied. Both freshly obtained monocytes and their culture‐derived macrophages were induced by LPS to secrete similar amounts of IL1. Such induction, however, was accompanied by the secretion of dialyzed inhibitory activity. Constitutive secretion of IL1 was detected in concentrated supernatants of monocyte cultures. The factor obtained constitutively did not manifest significant inhibitory activity. A method is described for the recovery of IL1‐containing supernatants in serum‐ and other stimulant‐free medium. The biological activities of the constitutively secreted IL1 were similar to the LPS‐induced activities.

The constitutive secretion of IL1 was not equally distributed in the entire monocyte population. We found that a small fraction of loosely adherent monocytes secreted higher amounts of IL1 than the strongly adherent monocytes. However, the property of higher secretion of IL1 was not stable and disappeared following monocyte cultivation. Thus, constitutive activity of IL1 could be recovered either by concentrating the culture supernatants or by enriching a subset of monocytes with higher IL1 activity.
Different repertoires of mouse T cells for bovine insulin presented by syngeneic and allogeneic cells
Authors: Ishii Norishisa , Klein Jan , Nagy Zoltan A.
Published: February 2007

Splenic T cells were primed, after removal of alloreactive cells, to beef insulin on allogeneic antigen‐presenting cells (APC). The fine specificity of in vitro secondary response was tested in combinations H‐2b (responder) T cell‐H‐2k (nonresponder) APC, and vice versa, using separated chains of beef and pork insulin. The response in both combinations exhibited identical specificity patterns demonstrating that both responder and nonresponder APC could present the same array of insulin epitopes to allogeneic T cells. The determinants presented to allogeneic T cells include the A‐chain loop epitope and the B‐chain determinant(s) that were found to be immunogenic for H‐2b and H‐2d T cells, respectively, in the context of syngeneic major histocompatibility complex (HC) molecules. In addition, minor determinants were detected in the A chain outside the loop that are not immunogenic in syngeneic T cell‐APC combinations. Inhibition of T cell proliferation with monoclonal antibodies has shown that class II MHC molecules of the nonresponder (AαkAβk, EαkEβk) as well as those of the responder APC (AαbAβb) are equally capable of presenting virtually all insulin epitopes recognizable by T cells. The data, therefore, demonstrate that the selective recognition of different insulin epitopes observed in syngeneic or semisyngeneic T cell‐APC combinations does not result from determinant selection at the level of APC.
Evidence that the Thy‐1 molecule is the target for T cell mitogenic antibody against brain‐associated antigens
Authors: Jones Barry
Published: February 2007

Rabbit anti‐mouse brain (RaMBr) antiserum can induce Lyt‐1+, Lyt‐2−, T cells to proliferate and stimulates the same T cell subset to induce B cell proliferation. The aim of this report is to demonstrate that the mitogenic determinant recognized on the T cell surface by RaMBr antiserum is located on the Thy‐1 molecule expressing the products of the Thy‐1a and Thy‐1b alleles. Evidence is drawn from serological and genetic experiments. The brain T cell cross‐reactive, mitogenic determinant is not expressed on Thy‐1− mutants of the BW5147 T cell lymphoma that fail to express the Thy‐1 molecule but do express other T cell surface proteins such as T‐200 and gp 69, 71. Monoclonal anti‐Thy‐1.1 and anti‐Thy‐1.2 antibodies block the binding to the appropriate T cells of the majority of the serum antibody from RaMBr antiserum. The absorption of mitogenic antibody was blocked in a similar fashion, thus demonstrating the close association of the determinant and the Thy‐1 antigen defined by monoclonal alloantibodies. The mitogenic and Thy‐1.1 determinants are probably located on the same molecule because of the data obtained with the BW5147 Thy‐1− mutants and the observation that Thy‐1a T cells, which express a lower level of surface Thy‐1 than Thy‐1b T cells, also express lower levels of the determinant recognized by RaMBr antiserum. Furthermore, in (AKR × DBA/2)F1 mice (Thy‐1a/b) which express less Thy‐1.1 antigen than Thy‐1.2 at the surface, the mitogenic determinant was found to be prefentially associated with Thy‐1.2. The coordinated genetic control of the surface levels of the Thy‐1 determinant and the mitogenic determinant suggests that both determinants are situated on the same molecule in the T cell membrane.
Activation of human B lymphocytes: frequency of antigen‐specific B cells triggered by alloreactive or by antigen‐specific T cell clones
Authors: Lanzavecchia Antonio , Parodi Barbara , Celada Franco
Published: February 2007

Human T cell clones specific for tetanus toxoid (TT) or for alloantigens were isolated and expanded in culture using antigen stimulation and soluble growth factors. When stimulated by the specific antigen, the clones were able to proliferate in the absence of exogenous growth factors and to provide help to B cells. The alloreactive and TT‐specific clones were compared for their capacity to help an anti‐TT as well as a polyclonal antibody response. The frequency of the B cells activated to the production of specific antibody was determined by limiting dilution analysis in cultures containing limiting numbers of responding B cells and optimal numbers of cloned T helper cells. In these conditions a single activated B cell was able to produce about 10 ng of antibody. TT‐specific clones, in the presence of low TT concentrations, selectively induced a number of TT‐specific B cells to produce IgG antibody in the absence of a detectable polyclonal B cell activation. On the other hand the alloreactive clones activated higher numbers of TT‐specific B cells as a part of a strong polyspecific B cell activation. In this case the antibody production did not require the presence of TT in culture; furthermore cells producing antibodies of unrelated specificities were also activated in allostimulated cultures. IgG anti‐TT were produced only by immune donors, while IgM anti‐TT were produced by immune and nonimmune donors, providing the B cells were activated by alloreactive clones.

These data demonstrate that human memory B cells can be triggered by both antigenspecific and alloreactive T cells to antibody production. The alloreactive clones can therefore be used to analyze at the clonal level the repertoire of a pool of B cells that contain most, if not all, the memory antibody specificities.
Recirculating and sessile B cell populations in normal and CBA/N mice
Authors: Chaudhuri Monisha , Wallis Valerie J. , Connell Dorothea I.
Published: February 2007

Chromosomally distinguishable syngeneic mice were parabiosed and the resultant chimerism was followed for 6 weeks in the lymphoid organs, by culturing their cells with polyclonal mitogens, lipopolysaccharide (LPS) for B cells and phytohemagglutinin (PHA) for T cells. As expected of a recirculating population, the T cells equilibrated completely. The B cells in lymph nodes (LN) and Peyer's patches (PP) also equilibrated completely, suggesting that they too are recirculating. B cells in the spleen and blood, however, did not equilibrate over this period. After separation of parabiosed mice, the percentage of partner cells in both the recirculating T and B lymphocyte populations declined steadily, but it continued to rise in the LPS‐responsive populations in spleen and peripheral blood suggesting that they were derived from precursor populations which were themselves chimeric. Injection of lymphocytes into CBA/Ca or CBA/N mice showed that LPS‐responsive populations in LN and spleen localized differently.

These results have been interpreted as demonstrating two major populations of LPS‐responsive B lymphocytes in the mouse, one recirculating and the other sessile. The recirculating population appears to be the only LPS‐responsive population in LN and PP. In the spleen, however, the recirculating cells constitute about a quarter of the LPS‐responsive cells, while the rest are sessile cells. The relationship between these two populations has yet to be clarified. CBA/N mice are deficient in both populations but the sessile one appears to be more severely depleted.
The HLA proteins and a related protein of 28 kDa are preferentially induced by interferon‐γ in human WISH cells
Authors: Wallach David
Published: February 2007

The HLA‐A,B,C proteins are preferentially induced by interferon (IFN)‐γ. An increase in their synthesis and of their expression on the cell surface can be observed at concentrations of IFN‐γ which are lower than those inducing an antiviral effect. On the other hand, with IFN‐α and β, induction of these proteins can be observed only in the antiviral range of IFN concentrations. In human WISH cells, IFN also induces a protein with a molecular mass of 28 kDa (28K). The efficiency of IFN‐β and γ in inducing this protein is correlated to the efficiency with which they induce the HLA‐A,B,C proteins. The 28K protein can be immunoprecipitated with antibodies against β2‐microglobulin, just as the HLA proteins; yet it can be clearly distinguished from the HLA proteins in several respects: (a) it is not a cell surface protein but rather an intracellular one, with a relatively short half‐life, (b) partial peptide mapping suggests that it contains sequences distinct from those of which the HLA α chains or β2‐microglobulin are comprised and (c) the extent of its induction by IFN is much larger than that observed for the HLA proteins.
Relationship between mouse lymphocyte receptors for peanut agglutinin (PNA) and Helix pomatia agglutinin (HPA)
Authors: De Petris Stefanello , Takacs Béla
Published: February 2007

The relationship between mouse lymphocyte receptors for peanut agglutinin (PNA) and Helix pomatia agglutinin (HPA) has been investigated by immunofluorescence (cocapping) and radiolabeling. In neuraminidase‐treated and untreated thymocytes there are two groups of glycoproteins which bind roughly equivalent amounts of PNA. One group also carries all the detectable receptors for HPA, the other binds only PNA. Binding inhibition experiments suggest that PNA and HPA receptors are in close proximity on the shared glycoproteins. The same two groups of receptors are present on 35–10% of neuraminidase‐treated spleen lymphoid cells, mainly immunoglobulin (Ig)‐negative lymphocytes. Almost all B cells have only PNA‐specific receptors. Five–12% of the untreated spleen cells appreciably bind PNA and only a few bind HPA.

Solubilized glycoproteins specific for PNA or HPA were compared by sodium dodecyl sulfate polyacrylamide gel electrophoresis and autoradiography. The major PNA‐specific radioiodinated glycoproteins of neuraminidase‐treated thymocytes, as isolated by affinity chromatography, consist of the 185‐kDa and 195‐kDa components of the T200 antigen and of two (diffuse) components of about 140 and 120–125 kDa. All these molecules also bind to HPA‐Sepharose, with the exception of the 185 kDa component, which is probably the main constituent of the “pure” PNA receptors on the intact thymocytes. In gels directly labeled with radioactive lectins, the only band strongly labeled by PNA and HPA is the diffuse 140‐kDa band. The band at 120 kDa is well labeled by PNA, but all the other components are weakly labeled. The mobility of the 140‐ and 120‐kDa bands depends strongly on neuraminidase‐treatment. These bands cannot be detected in gels of untreated thymocytes, but a major HPA‐and PNA‐specific band of lower molecular weight can be labeled after treating the gels with neuraminidase. The factors determining the differences in labeling pattern obtained by different methods as well as the nature of PNA and HPA binding sites are discussed.

The same major PNA‐ and HPA‐binding glycoproteins (apart from minor differences) are present on neuraminidase‐treated Ig‐negative spleen lymphocytes. The major PNA‐binding protein of B lymphocytes appears to correspond to the 225‐kDa (“B220”) antigen specific for these cells.
In vitro and in vivo histamine‐producing cell‐stimulating factor (or IL3) production during Nippostrongylus brasiliensis infection: coincidence with self‐cure phenomenon
Authors: Filho Mario Abbud , Dy Michel , Lebel Bernard , Luffau Gérard , Hamburger Jean
Published: February 2007

Spleen cells from Nippostrongylus brasiliensis‐infected mice produce large amounts of histamine in response to adult worm antigen. This phenomenon results from the production of HCSF (histamine‐producing cell‐stimulating factor, probably related to IL3) by sensitized lymphocytes. This factor acts on its target cells (presumably mast cell precursors) by inducing a rapid increase in histamine synthesis. Similarly, parasite infection generates enhanced histamine production by spleen cells in response to concanavalin A (Con A). This results from increases in both HCSF production and the HCSF sensitivity of its target cells. In all cases, maximal histamine and HCSF productions are obtained on day 8 after infection and coincide with parasite rejection. Methyl prednisolone suppresses HCSF production by infected mouse spleen cells in response to worm antigen or Con A. HCSF activity is found in vivo on day 8 in the sera of infected mice, 4 h after they are challenged with an i. v. injection of adult worm antigen. No activity is detected in the sera of normal mice with or without antigen injection. Sera from infected mice that did not receive the antigen exhibit a slight HCSF activity on day 8. Our data bring the first evidence of the existence of an in vivo production of HCSF.
Somatic H‐2Kk variants reveal nonidentity of serological and cytotoxic T cell‐defined Kk determinants
Authors: Vohr Hans‐werner , Holtkamp Bodo , Rajewsky Klaus
Published: February 2007

The relationship of serologically defined determinants to determinants recognized by cytotoxic T cells on molecules encoded by the Kk gene of the murine major histocompatibility complex (H‐2) has been analyzed. For this purpose we used three somatic variants of a Kk‐expressing lymphoma line lacking individual determinants of the Kk molecule, as defined by monoclonal antibodies (mAb), as target cells for Kk‐specific alloreactive and Kk‐restricted cytotoxic T lymphocytes (CTL) cloned by limiting dilution. Neither alloreactive nor fluorescein isothiocyanate, influenza‐ or Newcastle disease virus‐specific Kk‐restricted CTL clones were found to distinguish between variants and wild type cells, indicating that the serologically defined determinants lost by the variants were not essential for antigen recognition of CTL with these specificities. On the other hand, two of the variants lacking either one of a pair of serological determinants were discriminated from Kk wild type cells by about 40% of Kk‐restricted, trinitrophenol (TNP)‐specific CTL clones. The third variant, lacking both of the determinants, however, was lysed by all CTL clones to the same extent as wild type cells. From these results we conclude that the determinants restricting the TNP‐specific CTL were also not identical with those defined by mAb.

In experiments performed to optimize the conditions for the limiting dilution analysis we found that the specificity of the CTL stimulation was strongly dependent on the concentration of T cell growth factor (interleukin 2) in the cultures during CTL stimulation. High concentrations of IL2 resulted in a drastic increase in the frequency of CTL clones. Part of these clones, however, were found not to be specific for antigens present on the stimulator cells.