bluuebunny/crossref_metadata_2025 huggingface dataset:
Drug‐promoted B cell tolerance induction: a selective activity of cyclophosphamide dependent on the tolerogenicity of thymus‐independent antigens
Authors: Howard J. G. , Hale Christine
Published: February 2007

Native levan and dextran B1355 induce equivalent IgM responses, specific for β(2→6) fructosyl or α(1→3) and α(1→6) glucosyl epitopes, respectively, in congenitally athymic and euthymic BALB/c mice. These can be suppressed to a varying extent by both alkylating agents (cyclophosphamide (CY), melphalan, chlorambucil) and other immunosuppressive drugs (6‐mercaptopurine, azathioprine, A‐methopterin). In contrast, the promotion of B cell tolerance to these thymus‐independent antigens, as measured by a reduction in the minimum tolerogenic dose, was found only during suppression with CY (or related compound Asta 5122) and with none of the other drugs.

CY likewise reduced the tolerizing dose thresholds of 2,4‐dinitrophenyl (DNP)‐specific Bμ cells for feebly immunogenic dinitrophenylated pneumococcal polysaccharide type 3 and nonimmunogenic DNP‐D‐GL (D‐Glu, D‐Lys copolymer) by approximately 10‐ and 100‐fold, respectively, in CBA mice. This definitively verifies an implication from earlier variable epitope density studies (Desaymard and Howard, Eur. J. Immunol. 1975. 5: 541) that CY‐promoted tolerance with thymus‐independent antigens depends not on their immunogenicity, but on their inherent tolerogenicity. Evidence is discussed which suggests that this involves an increased susceptibility of B cells to normal tolerization by multivalent antigens.

Spleen cells from mice 14 days after CY‐promoted tolerance induction were totally unresponsive to levan and devoid of demonstrable suppressor cell activity in mixed cell transfer experiments. As B cells are usually unaffected and suppressor T cells generated during analogous tolerance with thymus‐dependent antigens (Ramshaw, Bretscher and Parish, Eur. J. Immunol. 1977. 7: 180), we conclude that the mechanisms of tolerance promotion by CY are fundamentally dissimilar for these two classes of antigen.
Phylogenetic origins of immune recognition: lymphocyte surface immunoglobulins and antigen binding in the genus Carassius (Teleostii)
Authors: Deluca D. , Warr G. W. , Marchalonis J. J.
Published: February 2007

Virtually all lymphocytes (from thymus, spleen and head nephros) of two closely related cyprinoid fish, C. auratus and C. carassius, were shown to bear surface immunoglobulin (Ig) detectable by immunofluorescence. Nonlymphoid cells (for example, those of the granulocytic and erythrocytic series) showed insignificant staining compared with lymphocytes. Rabbit antisera used in these studies were raised to purified serum IgM of C. auratus. The serum IgM of C. auratus and C. carassius expressed identical determinants as recognized by this antibody in radioimmunoassay, but with a lower level of expression on the IgM of C. carassius. Similarly, with the use of these reagents in quantitative cytofluorometry, the lymphoid cells of C. carassius stained less brightly than those of C. auratus. However, in both species, a hierarchy of fluorescence intensity could be observed, such that spleen ⩾ head nephros > thymus.

A small percentage of lymphocytes in all organs of both species bound either myoglobin, keyhole limpet hemocyanin, or horse spleen ferritin antigens. All antigen‐binding lymphocytes were also positive for membrane Ig. Analysis of the distribution of antigen and Ig patches on these cells showed that antigen patches were always coincident with Ig patches.

These results provide further evidence of lymphoid heterogeneity in the genus Carassius, and are compatible with the suggestion that lymphocyte surface Ig functions as a primary recognition molecule for all lymphocytes in Carassius species.
Requirement for antigen in lipopolysaccharidedependent induction of B cells
Authors: Bretscher P. A.
Published: February 2007

The magnitude of the IgM response to a variety of antigens, induced on the in vivo administration of lipopolysaccharide (LPS) to mice, is approximately proportional to the magnitude of the background response observed in untreated animals. This striking correlation suggests that the administration of LPS alone cannot in general induce a specific response in the absence of a background response. Such is the case for the antigen rat erythrocytes against which no LPS‐dependent or background response is found. The response to a marginally immunogenic dose of rat erythrocytes, however, can be considerably enhanced by the administration of LPS. These observations are expected on the hypothesis that both background and LPS‐induced responses are due to ongoing antigen‐dependent stimulation in normal mice. This hypothesis is further supported by evidence suggesting that the LPS‐dependent anti‐sheep erythrocyte response is due, at least in part, to a particular antigen present on degraded mouse erythrocytes.
Immune responses to weakly immunogenic virally induced tumors II. Suppressive effects of the in vivo carried tumor YAC
Authors: Devens B. , Galili Naomi , Deutsch Ofra , Naor D. , Klein Eva
Published: February 2007

Unprimed spleen cells from A and C57BL/6 mice could not produce cytotoxic responses to their syngeneic tumors: a Moloney virus‐induced in vitro subline YAC‐1 and a Rauscher virus‐induced in vitro subline RBL5, respectively. Spleen cells from A and C57BL/6 mice immunized with YAC‐1 or RBL5 (which cross‐react serologically) generated significant syngeneic cytotoxicities after cultivation in vitro.

The in vivo carried tumor of A mice, unlike the in vitro sublines, could not stimulate a priming effect. In contrast, YAC stimulated the formation of suppressor cells in both A and C57BL/6 mice. The suppressor cells abrogated the priming effect of the syngeneic tumors, but not the priming effect of the allogeneic tumors. Furthermore, YAC did not suppress normal allogeneic anti‐tumor responses. The theoretical and the practical implications of these studies are discussed.
Immune interferon II. Different cellular site for the production of murine macrophage migration inhibitory factor and interferon
Authors: Neumann Christine , Sorg C.
Published: February 2007

The production of macrophage migration inhibitory factor (MIF) and immune interferon (IF) by concanavalin A (Con A)‐stimulated cultures of thymus, lymph node and spleen cells was investigated. It was found that all cultures produced MIF activity, whereas only spleen cells produced marked IF activity. The capacity to produce IF was found to be correlated with the macrophage content of a cell preparation as evidenced by staining for esterase‐positive cells. Furthermore, column‐purified spleen T cells produced MIF but no IF. Migration inhibition caused by residual mitogen could be ruled out. On the other hand, when macrophages grown from bone marrow cells were pre‐exposed to supernatants of mitogen‐stimulated lymphocytes, IF activity was released into freshly added medium while no significant MIF activity was found. IF was also found in supernatants of macrophage cultures after exposure to conventional inducers in vitro (polyinosinic‐polycytidylic acid, Corynebacterium parvum) or in vivo (C. parvum), whereas no MIF was detected. An anti‐Type I IF serum neutralized IF in supernatants from Con A‐stimulated spleen cells but did not affect MIF in the same supernatants. This indicates that IF and MIF activity are associated with different molecules. It is, therefore, concluded that under the described conditions, IF and MIF are produced by different cells. T cells are the prime producers of MIF while IF is released by macrophages following induction by lymphokines.
Colony formation of cytolytic T cells in semisolid medium
Authors: Collavo D. , Engers H. , Nabholz M.
Published: February 2007

Addition of supernatant from concanavalin A‐stimulated spleen cells to in vitro primed cytolytic T lymphocytes in semisolid medium stimulated the growth of colonies of cytolytic lymphocytes. Optimal results were obtained using a peritoneal adherent cell underlayer where a 10% plating efficiency (⩾ 4 cells per colony) was achieved when between 5000 and 100000 cells were plated per dish.

Individual colonies were harvested and tested in a short‐term (5 h) 51Cr release microassay, employing 200 target cells. The frequency of lytic colonies varied from 46–67%. The observed lytic activities were specific for the relevant allogeneic target cells.
Studies on induction and control of cell‐mediated autoimmunity I. Induction of “autoreactive” T Iymphocytes in mice by cyclophosphamide
Authors: L'age‐Stehr Johanna , Diamantstein T.
Published: February 2007

Injection of a single dose of cyclophosphamide (CY) (125 mg/kg) or a combination of a small dose of CY (20 mg/kg) and 2.5 mg/kg lipopolysaccharide induces a transient appearance of autoreactive T lymphocytes (T‐ARC) in the spleens of mice. The T‐ARC activity reaches a peak 6 days after CY injection and could not be detected 8 days after this treatment. For testing T‐ARC activity, spleen cells were injected into the footpads of syngeneic recipients, and the resulting lymph node enlargement at the draining site of cell inoculation and the content of nucleated cells in the lymph node was determined. Possible explanations of this autoimmune phenomenon are discussed. It is postulated that CY‐resistant precursors of T‐ARC are stimulated by “new” antigenic sites present on the surface of B lymphoblasts repopulating the CY‐damaged spleen in a period of transient absence of CY‐sensitive suppressor cells.
Cell‐mediated Iympholysis: Examination of HLA genetic fine structure and complementation using cytotoxic lymphocytes
Authors: Schendel Dolores J. , Wank R. , Dupont B.
Published: February 2007

Human cytotoxic lymphocytes (CTL), sensitized in vitro in one‐way mixed lymphocyte cultures between two unrelated individuals, have been used to study target cell determinants. One pair of CTL shows strong cell‐mediated lympholysis responses against the specific target cells as well as against third‐party target cells obtained from unrelated individuals. Testing of sixty target cells shows a significant association between the two CTL with a correlation coefficient of 0.67 in the panel. The target determinant recognized by the CTL is not an HLA‐A,B,C or D specificity, as defined by standard serological and cellular reagents. Segregation studies in a large family reveal that the new specificity defined by the CTL is controlled by HLA, and its recognition may be restricted by the HLA complex.
Loss of reactivity of a BALB/c myeloma tumor with allogeneic and syngeneic cytotoxic T lymphocytes
Authors: Russel J. H. , Hale A. H. , Inbar D. , Eisen H. N.
Published: February 2007

It was previously observed that MOPC‐315EL, a subline of the BALB/c myeloma tumor MOPC‐315, varies in its ability to interact with primary anti‐H‐2d cytotoxic thymus‐derived lymphocytes (CTL) while remaining invariant in its expression of cell surface antigens recognized by anti‐H‐2d sera. This paper demonstrates (a) that secondary anti‐H‐2d CTL also fail to recognize the late tumor cells, and (b) that two other CTL systems (anti‐minor histocompatibility antigens and anti‐2,4,6‐trinitrophenyl), which require recognition of both H‐2 products and other surface antigens, also fail to react with the late tumor cells. The defect in the late tumor cells was evident when they were used as targets, inhibitors, and stimulators of CTL activity.
Nonspecific macrophage suppressor factor: its role in the inhibition of contact sensitivity to picryl chloride by specific T suppressor factor
Authors: Ptak W. , Zembala M. , Hanczakowski‐Rewicka Maria , Asherson G. L.
Published: February 2007

Anti‐picryl T suppressor factor was produced by culturing lymphoid cells from mice which were first injected with picryl sulfonic acid and then painted with picryl chloride. The supernatant was harvested at 48 h. Macrophage suppressor factor was produced by incubating peritoneal exudate cells (PEC) in T suppressor factor, washing and then adding antigen and taking the supernatant after incubation for 1 h. Immune cells incubated in the supernatant lost the ability to transfer contact sensitivity. The supernatant (macrophage suppressor factor) was nonspecific and inhibited the passive transfer of contact sensitivity to picryl chloride and oxazolone to a similar extent.

Macrophage suppressor factor was only produced when PEC were incubated in anti‐picryl T suppressor factor and then exposed to picrylated antigen. Syngeneic thymocytes picrylated in vitro were the best source of antigen. Allogeneic thymocytes and regional lymph node cells picrylated in vivo by painting with picryl chloride were less effective. Picrylated mouse red blood cells and picrylated mouse gamma globulin were least effective.

Macrophage suppressor factor differed from T suppressor factor in several ways. It was nonspecific, its molecular weight was lower (10000–20000 daltons), and it failed to bind to PEC. It also failed to bind to immune cells at 0°C.

Although macrophage suppressor factor inhibited passive transfer when the mice were tested immediately afterwards (Chase‐Landsteiner transfer), it did not affect passive transfer when testing was delayed for a week. It is proposed that macrophage suppressor factor amplifies the effect of T suppressor factor.
Cell‐mediated anti‐tumor response in the RL♂ 1 system I. T nature, H‐2 Dd involvement and antigenic specificity of the effector cells
Authors: Duprez Veronique , Gomard Elisabeth , Levy J. P.
Published: February 2007

After in vivo priming and in vitro secondary stimulation by the radio‐induced RL♂ 1 lymphoma cells, syngeneic BALB/c splenic lymphocytes evidenced a specific but very weak cytolytic activity against RL♂ 1 target cells. Under the same experimental conditions, spleen cells from (B6 x BALB/c)F1 were at least 100 times more efficient. In both cases, the effector cells were cytolytic T lymphocytes (CTL). Normal H‐2Dd antigens of the tumor cell surface were involved in the effector‐to‐target cell interaction since anti‐H‐2 or anti‐H‐2Dd antisera abolished the RL♂ 1 cytolysis by immune syngeneic CTL, whereas anti‐H‐2Kd were devoid of blocking activity. The testing of a series of lymphoma cells, either virus‐induced or not, belonging to different H‐2 haplotypes, show that the immune CTL were highly specific for RL♂ 1 target cells. Only with the P815 mastocytoma cells was a weak cross‐reactivity detected by both direct tests and competition experiments. Allogeneic (H‐2k) AKR lymphoma cells which share the X1 antigen with RL♂ 1 do not react, possibly due to an H‐2 restriction of the CTL activity. The CTL‐reacting antigen cannot be definitely identified, since several specificities, including the serologically defined X1 antigen, are possibly involved simultaneously. The Hh antigens which could have accounted for the F1 anti‐parent reaction, appear irrelevant.
Role of membrane receptors in the induction of an in vitro secondary anti‐hapten response I. Differentiation of B memory cells to plasma cells is independent of antigen‐immunoglobulin receptor interaction
Authors: Cammisuli S. , Henry Claudia , Wofsy L.
Published: February 2007

In these experiments, we show that the interaction of antigen and B cell surface immunoglobulin is not essential for the generation of an IgG in vitro response to the hapten p‐azophenyl‐lactoside (lac). In our experimental system, keyhole limpet hemocyanin (KLH) was first selectively attached either to H‐2, Ia or Ig receptors of lac‐primed B cells by a hapten sandwich technique or to Fc receptors by complexes of azophenyl arsonate (ars)‐coupled KLH and anti‐ars. The labeled cells were then cultured with KLH‐specific T cells for 5 days in the absence of antigen. Under all conditions of attachment we observed a significant anti‐lac IgG response. We have demonstrated an absolute requirement for KLH‐specific helper T cells. The results thus indicate that T helper cells are by themselves, regardless of the B cell antigen that serves to effect bridging, sufficient to activate B memory cells. We could find no evidence to support either a matrix theory or a two‐signal hypothesis as currently proposed.
Role of membrane receptors in the induction of an in vitro secondary anti‐hapten response II. Antigen‐immunoglobulin receptor interaction is not required for B memory cell proliferation
Authors: Cammisuli S. , Henry Claudia
Published: February 2007

In this study it has been investigated whether the interaction of antigen and B cell surface immunoglobulin (sIg) is required for full clonal expansion of memory B cells specific for the hapten, p‐azophenyl‐lactoside (lac). Cultures of lac‐primed B cells and keyhole limpet hemocyanin (KLH)‐specific T cells were activated in three ways: (a) by the antigen lac‐KLH, (b) in the absence of lac epitopes by attaching KLH to the H‐2 antigens of the B cells, and (c) in similar conditions where lac epitopes were supplied on carriers unrecognized by helper T cells. Dilution analyses showed that the yield of IgG anti‐lac plaques per activated precursor was identical in all situations, and that the increased responses observed in the presence of lac epitopes were due to an increase in the frequency of activated precursors. Our results thus indicate that specific interacting T cells convey both the differentiative and proliferative signals to B memory cells, and are at variance with proposals advocating that an antigeninduced proliferative phase is succeeded by at cell‐dependent differentiative event. We suggest that the effect of sIg‐antigen interaction may be to cycle some precursors into a more easily activated state.
Immune response against the β‐galactosidase enzyme of E. Coli at precursor cell level. I. Analysis of the secondary repertoire in BALB/c mice
Authors: Accolla R. S. , Celada F.
Published: February 2007

The BALB/c secondary response against the β‐galactosidase (β‐gal) enzyme of E. Coli was analyzed at the precursor cell level by using the splenic focus technique. Our results indicate that in immunized mice, one out of 18000 B cells is able to recognize β‐gal. Among the families of anti‐β‐gal monoclonal antibodies, a subset of specific antibodies was detected which is capable of protecting the enzyme from heat denaturation. The frequency of clones making protecting antibodies is 1 out of 90000 and appears to be fairly constant among different individual mice. Further, the degree of heterogeneity of protecting antibodies analyzed in one individual is very high (250‐fold difference in affinity) but comparable to other secondary repertoires.

Specific frequencies are compared with previous findings relative to secondary responses against artificial haptens. It is suggested that a different type of recognition exists between protein determinants and artificial haptens. In addition, the relatively high proportion of clones making antibodies of the protecting type suggests that only a small proportion of antigenic sites on the β‐gal is actually able to stimulate an immune response.
Functional consequences of sheep red blood cell resetting for human T cells: Gain of reactivity to mitogenic factors
Authors: Larsson Eva‐Lotta , Andersson J. , Coutinho A.
Published: February 2007

Phytohemagglutinin (PHA)‐stimulated human lymphocytes release soluble products which are mitogenic for other lymphocytes, so‐called mitogenic factors (MF). MF is highly mitogenic for peripheral T lymphocytes separated by rosetting with sheep red blood cells (SRBC), while being very poorly mitogenic for unseparated human peripheral lymphocytes. This lack of correlation between the magnitude of the responses and the number of T cells in these cell preparations was investigated.

Peripheral T cells enriched by passage through nylon wool columns do not respond to MF.

Unfractionated lymphoid preparations are strongly activated by MF once they have been exposed to SRBC, even without further enrichment for rosetteforming cells.

Red cells from species other than sheep, which do not form rosettes with human T cells, are not capable of inducing responsiveness to MF.

Lymphocytes exposed to PHA for 24 h become highly responsive to MF.

We conclude from these results that rosetting of human T cells with SRBC has functional consequences and alters the reactivity of T cells to MF. Furthermore, these factors are not directly mitogenic for resting, unmodified T cells but rather to cells which have already been activated or modified in some way.
Immune function in aged mice III. Role of macrophages and effect of 2‐mercaptoethanol in the response of spleen cells from old mice to phytohemagglutinin, lipopolysaccharide and allogeneic cells
Authors: Callard R. E.
Published: February 2007

Spleen cells from old mice responded less well to phytohemagglutinin (PHA), lipopolysaccharide (LPS), lipid A and allogeneic cells than those from young mice. The defect in each case resided with the nonadherent responding lymphocyte population rather than adherent accessary cells (macrophages). This conclusion was reached by showing that macrophages from old mice functioned normally in each of their known roles in lymphocyte responses in vitro; namely, presentation of antigen or mitogen to responding lymphocytes, support of lymphocyte responses and regulation of responses to mitogens and antigens. Normal presentation function was demonstrated by the comparable ability of peritoneal exudate cells from old and young mice to furnish the macrophage requirement for PHA responsiveness in vitro. This conclusion was confirmed by the finding that old, nonadherent cells reconstituted with macrophages from young mice, responded to PHA like unfrationated old cells. Old macrophages were also shown to be normal in their ability to provide the 2‐mercaptoethanol (2ME) replaceable support function to young lymphocytes in vitro. Furthermore, replacement of macrophage supportive activity with 2ME did not rejuvenate the response of old cells to PHA, LPS, lipid A or alloantigens. Finally, no evidence of adherent cell suppression of responses of old cells could be obtained by two different approaches. First, although depletion of adherent cells increased, to a similar degree, the responses of both old and young cells to allogeneic stimulation, this procedure did not reduce the difference in responsiveness between them. That is, the decreased response of old cells in a mixed lymphocyte culture (MLC) could not be explained by excessive adherent cell suppression. Second, no evidence for suppression could be obtained in co‐cultures of old and young cells responding to PHA, LPS or allogeneic cells. Taken together, these results suggest that macrophage function, in contrast to lymphocyte function, does not decline with age. It is suggested that this difference may result from the different half‐lives of macrophages and lymphocytes in the intact animal.

In contrast to the above results, old spleen cells acting as stimulators in an MLC were not always less effective than young cells. Furthermore, any difference that did exist between young and old cells was largely ablated by depletion of adherent cells. This result suggests that adherent cells from old mice may determine the ability of old cells to stimulate allogeneic lymphocytes in an MLC. It is not known whether this adherent cell is a macrophage or some other adherent (perhaps regulatory) cell.
Differential sensitivity of memory cell subpopulations to anti‐immunoglobulin and complement
Authors: Potash Mary Jane , Knopf P. M.
Published: February 2007

Evidence is presented for the unique sensitivity of memory cells bearing surface immunoglobulin G1 (IgG1) to functional elimination with anti‐immunoglobulin (anti‐Ig) sera and complement (C). Treatment of cells for adoptive transfer with C and anti‐γ1, anti‐K, or anti‐Ig significantly reduces the number of plaque‐forming cells (PFC) of only the IgG1 isotype found in adoptive recipients. An increase in PFC of other isotypes accompanies the decrease in IgG1 PFC; there is no net change in the total PFC response. The depletion of IgG1 PFC requires treatment of transferred cells with both specific antisera and C; antisera directed against other isotypes show no significant effects. The maintenance of the magnitude of PFC response, compensation, is discussed.
Evidence for the presence of Thy‐1 on cultured thymic epithelial cells of mice and rats
Authors: Raedler A. , Arndt R. , Raedler Elisabeth , Jablonski Dorothee , Thiele H.‐G.
Published: February 2007

Thymic tissue of C57BL/6 mice and DA rats was cultured. After 6–8 weeks, cultures were analyzed for their capacity to absorb anti‐Thy‐1 serum, and for the expression of Thy‐1 on the surface of different cell types by means of the indirect peroxidase labeling method. Three main cell types were identified: epithelium‐like cells, fibrocyte‐like cells and macrophages, but no lymphocytes were found. The presence of Thy‐1 on cultured nonlymphocytic thymus‐derived cells was demonstrated by their ability to absorb the cytotoxic activity of the appropriate anti‐Thy‐1 sera. Electron microscopical analyses of labeling experiments revealed that Thy‐1 was predominantly expressed on epithelium‐like cells with preference for their cell protrusions.

The possible role of Thy‐1 expression, both on thymocytes and thymus epithelium for cellular interaction, is discussed.
Requirement for matching T cell and B cell subsets in secondary anti‐hapten antibody responses
Authors: Gorczynski R. M. , Cunningham A. J.
Published: February 2007

The in vitro secondary anti‐hapten response to trinitrophenylated keyhole limpet hemocyanin (TNP‐KLH) has been investigated using B and T cells from the same or a pool of identically primed syngeneic individuals. The optimum antibody response obtained from B cells of any given animal was seen when the same individual's T cells were used as a helper cell source. This individual preference was lost if secondary challenge in culture was made with TNP on a heterologous carrier, with the helper cells obtained from suitably primed individuals or a pool thereof. These data are interpreted in terms of a network theory for the regulation of immune responses under physiological conditions.
Experimental allergic encephalitis: Study of cellular immunity during disease suppression
Authors: Von Muller Christine Suquet , Spitler L. E. , Lecocq J.
Published: February 2007

Administration in complete Freund's adjuvant of encephalitogenic protein (EP), derived from central nervous tissue to guinea pigs, regularly results in the development of experimental allergic encephalitis (EAE) which leads to the death of the animals. Administration of EP in incomplete Freund's adjuvant at an appropriate time will completely suppress the clinical development of disease. Results reported herein show that animals receiving suppressive injections of EP for 7 days show depression of lymphocyte DNA synthesis and macrophage migration inhibition, but not of skin reactivity, in response to EP immediately following the injections, and subsequently show recovery of lymphocyte reactivity but do not develop clinical manifestations of EAE. Humoral or other factors may prevent the development of disease in these animals. Guinea pigs receiving injections of EP for 14 days show profound and prolonged depression of lymphocyte reactivity to EP and macrophage migration inhibition. Possible mechanisms for these results include a diminished number or function of reactive cells or activity of a population of cells with the capacity to suppress cellular immune responses. Nonspecific suppression of reactivity to an unrelated antigen during the suppressive injections was not observed.
Proteolytic cleavage of human IgG molecules by neutral proteases of polymorphonuclear leukocytes
Authors: Solomon A. , Gramse Margarethe , Havemann K.
Published: February 2007

The effect on human IgG of the elastase‐like (ELP) and chymotrypsin‐like (CLP) neutral proteases derived from human polymorphonuclear leukocytes was studied. By incubating ELP with monoclonal IgG proteins, two immunochemically and electrophoretically distinct components were formed which were similar, but not identical, to the Fc and Fab fragments produced by papain digestion. When an IgG protein was incubated under similar conditions with the CLP enzyme, no proteolysis was observed. IgG proteins differed in their susceptibility to proteolysis by ELP. These differences were related to the subclasses IgG1‐IgG4. The IgG1 and IgG3 proteins were readily cleaved by ELP, but the IgG2 and IgG4 proteins were more resistant. Although free light chains differ in susceptibility to proteolysis by ELP, our studies showed that neither the type (K or λ) nor the subgroup of light chain affected the susceptibility of complete IgG molecules to cleavage by this enzyme.
Recognition of idiotypes in lymphocyte interactions I. Idiotypic selectivity in the cooperation between T and B lymphocytes
Authors: Hetzelberger Doris , Eichmann K.
Published: February 2007

Idiotypic restrictions are demonstrated in vitro for the cooperation between T and B lymphocytes with specificity for Group A streptococcal carbohydrate. T helper cells which have been primed in vivo with anti‐idiotypic antibodies to the A5A idiotype and which are therefore essentially A5A idiotype‐positive, cooperate only with A5A idiotype‐positive B cells, even when mixtures of A5A idiotype‐positive and A5A idiotype‐negative B cells are present. Essentially A5A idiotype‐negative T helper cells that have been primed in vivo with Group A streptococcal vaccine after in vivo suppression with anti‐A5A idiotypic antibody are unable to cooperate with B cells which have been primed with anti‐A5A idiotype antibody and which are therefore essentially A5A idiotype‐positive. Mixtures of A5A idiotype‐negative and A5A idiotype‐positive T cells cooperate with both A5A idiotype‐negative and A5A idiotype‐positive B cells.

Idiotypic restrictions could not be demonstrated for T and B cells recognizing carrier and hapten determinants, respectively, in experiments in which the cooperation of genetically VH‐identical T and B cells was compared to the cooperation of genetically VH‐different T and B cells. The data are discussed with respect to various models for the communication between T and B cells. It is proposed that for successful T‐B cooperation, ordinarily two types of T helper cells are required, one recognizing the antigen and the other recognizing the idiotype of the B cell.
Molecular heterogeneity and fine specificity of BALB/c antibodies elicited by isologous myeloma protein
Authors: Odermatt B. F. , Perlmutter R. , Lynch R. G.
Published: February 2007

BALB/c mice immunized with the isologous myeloma protein MOPC‐315 (M315; α, λ2) develop antibodies most of which are directed to idiotypic antigens (Id315) located in or near the CNP binding sites of M315, In order to more precisely establish the fine specificity of anti‐Id315 antibodies, and to obtain an estimate of the size of the BALB/c anti‐Id315 repertoire, we examined anti‐Id315 antibodies from individual mice by analytical isoelectric focusing followed by autoradiography. 125I‐labeled probes were prepared from purified mildly reduced and alkylated M315 protein (RA315) (7 S monomer), Fab'315, Fv315, L315, H315, DNP affinity‐labeled RA315, mildly reduced and alkylated MOPC‐460 (RA460; 7 S; α, k, Fab'460, H460, and DNP affinity‐labeled RA460. We observed that (a) the majority of BALB/c antibodies elicited by immunization with RA315 are specific for idiotypic antigens in the variable region which are rendered inaccessible in the presence of DNP‐hapten; (b) distinctly separate antibodies are specific for idiotypic antigens also located in the variable regions but which are not influenced by DNP hapten; (c) about 30 % of BALB/c mice develop antibodies which appear to be specific for a determinant located in the second or third, homology regions of the constant region of the α chain which is not influenced by DNP hapten, and which is also present in the same region of H460; (d) none of the antibodies elicited by M315 recognize free L315; (e) the total antibody response is quite restricted; (f) shared spectrotypes are common between individual mice; and (g) unique or infrequently shared spectrotypes do occur. These studies demonstrate, by a direct technique, the fine specificity and the clonal and molecular heterogeneity of the B cell response induced by immunization with RA315.
Guinea pig immunoglobulin light chain isotypes I. Separation of kappa and lambda chains and the identification of three isotypes of the lambda chain constant homology region
Authors: Brunhouse R. F. , Cebra J. J.
Published: February 2007

The separation of intact kappa chain and two fragments comprising lambda (λ) chain from immunoglobulin light chain pools isolated from strain 13 guinea pigs is achieved by cyanogen bromide digestion and gel filtration before and after reductive cleavage of disulfide bonds. The smaller λ chain fragment derives from the original carboxyl‐terminus of λ chain. The partial sequence of component tryptic and thermolytic peptides of this thirty‐nine residue fragment allowed its complete sequence to be deduced. Three isotypic forms of this λ chain constant region fragment, distinguished by four residue positions showing alternative amino acids, are found expressed by guinea pigs. Each of these three isotypes is more homologous to the other two than to λ chains of any other species. The distribution of amino acid substitutions differentiating these isotypes further supports the view that λ chain isotypes arose in guinea pigs, and in several other species, independently by gene duplication.
Anti‐peroxidase antibody‐secreting hybrid lines. I. Identification, cloning and cell characterization
Authors: Zagury Daniel , Phalente Laurent , Hollande Etienne , Buttin Gérard , Bernard Jacky
Published: February 2007

Anti‐peroxidase antibody (Ab)‐secreting hybrids have been produced by fusion of peroxidase (PO)‐immunized mouse lymph node cells and immunoglobulin (Ig)‐secreting P3‐X63‐Ag8 (X63) myeloma cells. Identification of Ab‐secreting hybrids can be performed as early as day 5 after cell fusion by the hemolytic plaque assay. Immediately after identification, hybrids were directly isolated, by means of a micropipette, into Terasaki microchambers containing nutrient medium and a thymocyte filler layer. The yield of secreting hybrids is improved by using this procedure.

All the cells of the PO 772 C2 clone show the same ultrastructural pattern and immunocytological properties; they are proplasmocytes, as are the parental X63 cells; they present intracisternae Ab and show no Ig or Fc receptors at the cell surface. Over 90% of viable PO 772 C2 cells form specific plaques. Isoelectric focusing and sodium dodecyl sulfate polyacrylamide gel electrophoresis show that the cells of this clone secrete Ab; the secreted Ig are formed with χ and γ1 chains from the parental X63 cells and specific L and H chains from the lymphoid parent. These biological investigations demonstrate the relative stability of the PO 772 C2 clone secreting anti‐peroxidase antibody.
Cooperation between subclasses of T lymphocytes in the in vitro generation of cytotoxicity against a mutant H‐2K difference An analysis with anti‐Lyt antisera
Authors: Melief Cornells J. , van der Meulen Marian Y. , Christiaans Bernard J. , de Greeve Paul
Published: February 2007

The cellular requirements for the generation of cytotoxicity in mixed lymphocyte reaction (MLR) across an H‐2K mutant difference were analyzed. Treatment of C57BL/6 lymphocytes with either anti‐Lyt‐1 or anti‐Lyt‐2 serum and complement strongly reduced their capacity to mount a cytotoxic response against the B6.C‐H‐2ba mutant. Almost complete reconstitution of the cytotoxic response occurred when a mixture of anti‐Lyt‐1 and anti‐Lyt‐2‐treated cells was allowed to respond. Once cytotoxicity was generated, only anti‐Lyt‐2 serum affected it. It is concluded that in the cytotoxic response to the ba mutant, Lyt‐1 helper cells collaborate with Lyt‐2,3 killer cell precursors in the generation of Lyt‐2,3 killer cells. Lyt‐1,2,3 cells play, if any, a minor role in the generation of cytotoxicity.

By comparison, the capacity to generate killer cells in MLR against an H‐2K + IA difference was only affected by anti‐Lyt‐2 and not by anti‐Lyt‐1 serum, indicating that this response is relatively independent of help by Lyt‐1 cells under the conditions tested.
Serologic distinction between the rabbit kappa L chain allotype b4 and an allele b4v
Authors: Smith Linda J. , Sogn John A. , Kindt Thomas J. , Mandy William J.
Published: February 2007

Rabbit kappa light (L) chain allotypes are controlled by the allelic genes b4, b5, b6, b9 and a recently described allele b4v. The product of the b4v gene differs from that of b4 by at least two amino acid substitutions in the constant region. A serologic distinction between the b4 and b4v allotypes has now been detected by a radioimmune assay using one of six anti‐b4 sera tested. The distinction was enhanced by fractionation of this antiserum on an immunoadsorbent containing cottontail rabbit IgG. IgG with L chains of the b4v type are deficient in their ability to inhibit binding of b4 IgG to the antibody preparation. L chains isolated from b4 and b4v IgG samples could not be distinguished by this assay indicating that interaction with an H chain is required for expression of the L chain determinants that differentiate b4 from b4v.
Identification of β adrenoceptors during thymocyte ontogeny in mice
Authors: Singh Upendra , Millson David S. , Owen John J. T. , Smith Pamela A.
Published: February 2007

Thymocytes have been studied at various stages during ontogeny in relation to their responsiveness to β adrenoceptor agonists and ability to bind L‐[propyl‐2,3‐3H]dihy‐droalprenolol ([3H]DHA), a specific radioligand of the β adrenoceptor. Specific [3H]DHA binding and the activity of an isoproterenol‐sensitive adenylate cyclase were compared and correlated between (14 to 20‐day) fetal mouse thymocytes and young adult thymocytes. Preliminary experiments show that [3H]DHA binding to thymocytes demonstrated the kinetics, affinity and stereospecificity expected of binding to adenylate cyclase‐coupled β adrenoceptors. Similarly, isoproterenol was shown to selectively increase intracellular adenosine 3′: 5′‐cyclic monophosphate (cAMP) levels and was antagonized by propranolol (a β adrenoceptor antagonist), but not by phentolamine (an a adrenoceptor antagonist), nor by lignocaine (a local anesthetic). The rises in fetal thymocyte cAMP levels found after stimulation with isoproterenol were of greater magnitude than in adult thymocytes. The number of [3H] DHA‐binding sites in both fetal and adult thymocytes was the same (Bmax = 50 fmol/2 × 106 cells). However, the affinity of the binding sites for [3H] DHA was less for the adult cells than the fetal cells (with KD values of 8.0 and 2.2 nM, respectively); this was reflected in the amount of [3H] DHA bound being up to 8 times greater in the embryonic cells.
Exclusion of VHa and VHy loci expression on individual B cells from normal and YH allotype‐suppressed rabbits
Authors: Knight Katherine L. , Schweizer Marianne , Pernis Benvenuto
Published: February 2007

The distribution of two heavy chain subgroups, VHa and VHy, on rabbit peripheral blood lymphocytes was examined by double membrane immunofluorescence. Fluorescent anti‐a 1 and anti‐y 33 were found to react with separate B cell populations; no doubly stained cells were observed. Further evidence for the independent expression of genes controlling the VHa and VHy subgroups was obtained by neonatal suppression of a 2 or y 33 in a2y33/a3y− heterozygous rabbits. Suppression of VHa did not affect the expression of VHy, nor did the suppression of VHy affect the expression of VHa. The expression of a single VH gene per B cell is in marked contrast to the simultaneous expression of multiple CH genes.
Maturation of B lymphocytes. II. Sequential appearance of increasing IgM and IgD in the adult bone marrow
Authors: Lala Peeyush K. , Layton Judith E. , Nossal Gustav J. V.
Published: February 2007

The relationship between surface IgM (sIgM) and surface IgD (sIgD) was examined on small lymphocytes in the adult murine bone marrow or prepubertal spleen. Cells were sorted on the basis of different sIgM levels by a fluorescence‐activated cell sorter (FACS) and relabeled for sIgD or total sIg by a sandwich technique using 125I‐labeled protein A and radioautography. For detecting sIgD, an anti‐δ allotype reagent was used in congenic mice. Cells lacking sIgM in the bone marrow or spleen were also found to be sIgD−; thus, sIgD appeared only in the presence of sIgM. Weak sIgM‐bearing cells in the bone marrow also had no sIgD indicating that sIgD appeared only after the acquisition of a significant level of sIgM. Subsequently, the incidence of sIgD+ cells increased in fractions showing increasing sIgM levels indicating the acquisition of new sIgD by “sIgM only” cells with increasing maturation levels in the bone marrow. In marrow lymphoid cells expressing both Ig isotypes, sIgM and sIgD levels increased in parallel, possibly with increasing maturation level. In the spleen, the incidence of sIgD+ cells among various cell fractions showing different sIgM levels was found constant. However, spleen cells bearing both receptors, showed a small increase in the sIgD level with increasing sIgM level.
Antibody‐independent activation of complement by human peripheral B lymphocytes
Authors: Gutiérrez Carmen , Vega Jesus , Kreisler Miguel
Published: February 2007

Normal human peripheral blood lymphocytes were shown to activate complement in normal human serum (NHS). This activation led to C3 fixation on the cell membrane, which in turn was visualized by fluorescence. The reaction occurred in the absence of detectable amounts of antibodies, since an agammaglobulinemic patient's serum also supported complement activation, and the results were unaltered by absorption of normal human serum. Trypsin treatment of lymphocytes to remove possible complement activators bound to the cell membrane, did not have any effect on the complement activation by lymphocytes. Complement membrane fluorescence was abolished in the presence of EDTA or ethyleneglycolbis(aminoethylether) tetraacetate (EGTA) supplemented by Mg++ions indicating that the classical pathway of complement activation was involved in the reaction. Experiments performed with T and B‐purifiedpopulations showed that the phenomenon was confined to the B cell fraction. Complement deposition did not diminish the number of EAC rosettes, and viability remained unchanged after exposure of lymphocytes to normal human serum.
Peanut agglutinin. II. Characterization of the Thy‐1, Tla and Ig phenotype of peanut agglutinin‐positive cells in adult, embryonic and nude mice using double immunofluorescence
Authors: Roelants Georges E. , Mayor‐Withey Kathleen S. , London Jacqueline , Serrano Beatrice
Published: February 2007

The Thy‐1, Tla and Ig phenotype of peanut agglutinin (PNA)‐binding cells was characterized in various strains of mice. In the thymus, PNA was found to bind principally but not exclusively to the Thy‐1+ Tla+ Ig− steroid‐sensitive cortical thymocytes. Thy‐1+ Tla− Tg− steroid‐resistant cells are not labeled with PNA. In other lymphoid organs, PNA bound to a minority of T or null cells but generally not to B cells.

During ontogeny, PNA+ and PNA− T lineage cells appear simultaneously in the liver at day 10 of gestation, in the thymus at day 11 and in the spleen at day 18. No evidence was found for a maturation from PNA+ to PNA− cells. Prethymocytes present in nude mice were also divided into a PNA+ and PNA− population.

The findings possibly support the proposition that cortical and medullary thymocytes develop independently. Moreover, they suggest that both populations might arise from distinct precursors and give rise to distinct functional peripheral T cells.
Clonal dominance of low‐affinity antibodies in rabbit hyperimmune anti‐streptococcal group A‐variant polysaccharide antisera
Authors: Schaich Wolfgang , Wright J. Keith , Rodkey L. Scott , Braun Dietmar G.
Published: February 2007

Intraveneous hyperimmunization of selectively bred rabbits with streptococcal group A‐variant vaccines elicits antibody responses of restricted heterogeneity at high antibody levels. In these antisera, IgG with dissociation constants KD = 10−6 M constitutes 90% and IgG with KD = 10−9 M accounts for only 10% of the group A‐variant polysaccharide‐specific antibodies. The low affinity antibody fraction represents the dominant clonotypes. Preparative isoelectric focusing in granulated (Ultrodex G‐75) gels was used to successfully purify single‐band material belonging to dominant spectrotypes. Affinity studies with these antibody fractions with the highest reported degree of purity yielded KD = 10−6 M values, thus confirming that clonal dominance is exclusively associated with low‐affinity antibodies. Since it is known from previous work (M. Cramer and D. G. Braun, Scand. J. Immunol. 1975. 4: 63) and from the rabbit antisera used here that clonal dominance of this sort is long‐lived, this work fails to support the argument of immune maturation. The data more logically relate to antibodies that emerge with different subspecificities ‐ recognized in the antigen as a function of time in immunization procedures — rather than to an inherent property of the immune system.
High nonspecific reactivity of normal lymphocytes against rnycoplasma‐infected target cells in cytotoxicity assays
Authors: Brooks C. G. , Rees R. C. , Leachn R. H.
Published: February 2007

Several rat tumor cell cultures were deliberately infected with three species of mycoplasma commonly found as contaminants of cell lines grown in vitro, and the effect of mycoplasma infection on the results of cytotoxicity assays was examined. Lymph node cells and spleen cells from normal animals showed an apparently high spontaneous cytotoxic activity against tumor cells infected with either M. arginini or M. hyorhinis, but the reactivity against cells infected with M. orale was not significantly higher than that against uninfected cells. The high reactivity towards tumor cells infected with M. arginini and M. hyorhinis bore a close resemblance to natural cell‐ mediated immunity in that spleen cells were much more reactive than lymph node cells, spleen cells from nude mice were as effective as spleen cells from normal mice, and the reaction crossed both strain and species barriers. However, closer examination revealed that the cytotoxic effects were directly caused by depletion of arginine or other essential nutrients from the medium. These findings imply that a cautious approach should be taken when interpreting certain aspects of spontaneous cell‐mediated cytotoxicity, and that the greatest care be taken to ensure that the cells used as targets in any cytotoxicity test are mycoplasma‐free.
Normal immunosuppressive protein inhibition of human and murine lymphoblastoid cell line proliferation
Authors: Nelken David , Ovadia Haim , Hanna Nabil
Published: February 2007

Normal immunosuppressive protein, prepared from human plasma by DEAE‐cellulose chromatography, inhibits DNA synthesis in human cell lines of lymphocytes of both T and B origin. It also inhibits [3H]thymidine incorporation in mouse cell lines. Normal immunosuppressive protein was able to inhibit the proliferation of these cells, although they were already transformed and had a high rate of DNA synthesis. On the other hand, it does not inhibit myeloid cells or fibroblasts.
Immune depression in trypanosome‐infected mice. II. Characterization of the spleen cell types involved
Authors: Roelants Georges E. , Pearson Terry W. , Mayor‐Withey Kathleen S. , Lundin Lena B. , Tyrer Harry W.
Published: February 2007

Spleen cells from Trypanosoma congolense‐infected mice showed a drastic depression in their capacity to respond to B and T lymphocyte mitogens and to allogeneic spleen cells in mixed lymphocyte cultures. Spleen cells from infected mice were also poor stimulators in mixed lymphocyte cultures. The poor responsiveness or stimulation capacity was not due simply to dilution of relevant B or T lymphocytes by the large number of null cells found in the spleens of infected animals. These null cells expressed approximately eight times more H‐2 antigen than spleen cells from normal (uninfected) mice and were devoid of Ia antigens.