bluuebunny/crossref_metadata_2025 huggingface dataset:
Regulatory circuits and antibody responses
Authors: Herzenberg Leonore A. , Black Samuel J. , Herzenberg Leonard A.
Published: February 2007

Consideration of the interactions among cells and cell products involved in regulating antibody responses leads us to suggest that such interactions are organized into several discrete circular series (circuits) integrated with one another by virtue of shared circuit components. We see these circuits as individually concerned with particular aspects of regulation (carrier‐specific, idiotype‐specific, etc.), but together constituting an integrated, self‐governing system capable of regulating all aspects of antibody production and assuring the ordedy progress of the response (sequential idiotype representation, affinity maturation, isotype representation, overall or selective non‐ responsiveness, etc.).

To illustrate how a circuit‐based regulatory system could be constructed and expected to operate, we describe four integrated circuits here: a core regulatory circuit that determines whether a given idiotype will or will not be produced and three auxiliary regulatory circuits that respond to antigen and serum antibody (idiotype) levels by switching the core regulatory circuit into a suppression or “help” mode. These circuits incorporate the idiotype‐anti‐idiotype recognition system basic to the Jerne network theory but also provide for the operation of other cognitive systems that enable specific interactions between individual circuit elements (B cells, antibody, the various suppressor and helper T cells, macrophages and soluble regulatory products). As an integrated unit, the circuits constitute a detailed “working” model that depends on relatively few assumptions and is consistent with the known interactions between elements and the known properties of responses.
Immunochemical study of the β chain of Escherichia coli tryptophan synthetase and its proteolytic fragments
Authors: Zakin Mario M. , Boulot Ginette , Goldberg Michel E.
Published: February 2007

It has been previously reported that a limited proteolysis by trypsin of the β2 subunit of Escherichiiz coli tryptophan synthetase produces a nearly functional dimeric protein, the protomer of which consists of two large, nonoverlapping, polypeptide fragments, F1 and F2. In the study reported here, an immunochemical comparison between the native protein, the nicked protein and its two isolated proteolytic fragments was performed, leading to the following conclusions:

The β2 subunit and the nicked protein, regardless of the presence or absence of the coenzyme pyridoxal phosphate and of the reduction of the Schiff base between the cofactor and the protein, are immunologically indistinguishable. This confirms the strong structural similarity between the intact and nicked protein.

The failure to detect a change in the immunological reactivity of intact or nicked β2 upon removal or reduction of the coenzyme suggests that pyridoxal phosphate does not play a major role as an antigenic determinant in β2 or in modification of the conformation of the apoprotein.

When the two proteolytic fragments are separated, they still cross‐react with native β2, and all the antigenic determinants of β2 are recognized either on isolated Flor on isolated F2 by antibodies directed against native β2. However, the average affinity of the antibodies for the isolated fragments is much lower than for the native or nicked protein.

The results are discussed in terms of formation and arrangement of globular intermediates during the folding of the intact protein.
Cell‐mediated anti‐tumor response in the RL♂61 system II. Control of the T killer cells by an H‐2‐linked Ir gene interfering with non‐H‐2 factors
Authors: Duprez Veronique , Belucchi Sylvia , Lévy Jean Paul
Published: February 2007

The generation of cytolytic T lymphocytes (CTL) during the immune response directed against the syngeneic X‐ray‐induced BALB/c RL♂ 1 leukemia has been described previously: T killer cells react with a tumor antigen of RL♂ 1 cells, and the H‐2Dd molecules of the target cells play some role in the interaction. The study of anti‐RL♂ 1 responses of [(C57BL/6 × BALB/c) × BALB/c] mice shows that the major histocompatibility complex controls the anti‐RL♂ 1 CTL reaction at a second level, through an Ir gene, with dominant responsiveness, probably mapping to the right of I‐B and controlling the high or low‐CTL responder phenotype. Another non‐ H‐Associated gene interferes with the H‐2‐linked Ir gene, a responder allele at the non‐H‐2 locus, being necessary for the expression of the high‐responder phenotype at the Ir gene locus.
Capping revisited: I. Inhibition by some thiols
Authors: Loor Francis
Published: February 2007

The capping, but not the clustering (spotting), of membrane immunoglobulins and of other lymphocyte membrane macromolecules is inhibited when the medium contains some reducing agents, principally cysteine. The inhibition is easily reversible, being rather a retardation of capping than its blockage. The mechanism of inhibition is still unclear, but it definitely depends on the sulfhydryl moiety of the thiols.
Studies on the immunobiology of rnu/rnu “nude” rats with congenital aplasia of the thymus
Authors: Brooks Colin G. , Webb Peter J. , Robins R. Adrian , Robinson Graham , Baldwin Robert W. , Festing Michael F. W.
Published: February 2007

A detailed study of the recently described “nude” rat, which suffers from congenital aplasia of the thymus, has shown that this animal is grossly deficient in functional mature T cells.

Histological investigation revealed that those areas of lymph node, spleen and Peyer's patches, which are considered to be thymus‐dependent, were markedly depleted of lymphocytes. The areas of lymph node and Peyer's patches, which are normally considered to be thymus‐independent, were also partially depleted of lymphocytes, whereas the thymus‐independent areas of splenic white pulp showed greater activity than in control animals.

Indirect immunofluorescence with a monoclonal anti‐T cell antibody showed that lymph node and spleen cells were severely depleted of mature T cells, whereas staining with anti‐immunoglobulin antisera revealed an increased percentage of B cells in these organs. The nature of the residual anti‐T+ cells in rnu/rnu lymph node and spleen is not clear, but at least some of these may be precursor T cells. Spleen cells from rnu/rnu rats gave no response to phytohemagglutinin (PHA), and only occasional small responses to concanavalin A (Con A), but showed normal responses to Staphylococcus aureus bacteria. The absence of responses to PHA and Con A was not caused by suppressor cells nor by any defect in helper cell activity. In so far as PHA and Con A are considered to be T cell‐dependent mitogens and S. aureus a T cell‐independent mitogen, these results indicate that rnu/rnu rats lack functional T cells.
Synthesis of the mouse complement component C 4 (Ss‐protein) by peritoneal macrophages: kinetics of secretion and glycosylation of the subunits
Authors: Fey George , Odink Karel , Chapuis Rose Marie
Published: February 2007

Ss antigen was partially purified from mouse EDTA plasma, and a highly specific antiserum was prepared. Peritoneal exudate cells from Ss‐high mouse strains were labeled in primary tissue culture with [35S]methionine. Ss protein was found to be synthesized by macrophages and to be secreted into the culture medium as shown by indirect immunoprecipitations performed with this antiserum. The unreduced precipitated Ss molecule coelectrophoresed with human C4 at an apparent mol. wt. of 200000. Upon reduction, Ss protein dissociated into three subunits α, β and γ of mol. wts. 98000, 70000 and 32000. This pattern was almost identical to the one obtained for human C4. The Ss a subunit was converted by human Cls into an α subunit of approximately 85 Kdalton. This conversion is a characteristic property of C4. A single‐chain intracellular precursor for the Ss protein (pre‐Ss: 200 Kdalton) was also immunoprecipitated. In pulse‐chase experiments, it disappeared from the cytoplasmic extract within less than 10 h in a reciprocal manner to the appearance of extracellular mature Ss protein. No significant amounts of high‐mol. wt. extracellular precursors were detected. A group of four single‐chain molecules of mol. wt. between 160000 and 220 000 was immunoprecipitated from the tissue culture supernatant with anti‐Ss antiserum. These molecules could not be chased into mature Ss protein. The α, α′ and β subunits of Ss and the α chain of C3 incorporated [3H]mannose and [3H]glucosamine, the Ss α and C3 β chains did not.
Development of cytotoxic T lymphocyte precursors in the absence of the thymus
Authors: Galli Peter , Dröge Wulf
Published: February 2007

Reconstitution of adult thymectomized and lethally irradiated C3H or (C 3 H × DBA/2) F1 mice with syngeneic adult bone marrow cells or 18 to 20‐day‐old fetal liver cells resulted almost regularly in the generation of large numbers of cytotoxic T lymphocyte precursors (CTLP) against trinitrophenylated C3H cells and three types of allogeneic stimulator and target cells. The responses against 2,4,6‐ trinitrophenylated cells were restricted and in so far typical for cytotoxic T lymphocytes.

The failure of bone marrow cells from athymic C 3 H mice to reconstitute significant cytotoxic activity indicated that the CTLP had developed from “cytotoxic T lymphocyte preprogenitors” (CTLPP) which were derived from the donor and which had already been under thymic influence. The stem cell preparations in themselves contained frequencies of mature CTLP far too low to account for the reactivity and CTLP frequencies in the reconstituted mice. This fact implied that the CTLPP proliferated extensively and/or matured in the recipient in the absence of the thymus.

Individual mice failed to respond to one or more of these stimulator cells. The failure of individual mice to respond was randomly expressed for the four specificities even when the mice were reconstituted with the same stem cell preparation suggesting that CTLPP with defined specificity and low frequency (about 1/108 in fetal liver) were contained in the stem cell preparation and transferred randomly into the irradiated recipients. This would imply that one CTLPP gives rise to 5 × 103–20 × 103 CTLP within 5 weeks.

The data suggest that the peripheral pools, at least of certain T cell subclasses, may be maintained largely by post‐thymic proliferation of CTLPP.
Prostaglandin (PG) release in the mixed lymphocyte culture; effect of presensitization by a skin allograft; nature of the PG‐producing cell
Authors: Dy Michel , Astoin Monique , Rigaud Michel , Hamburger Jean
Published: February 2007

A release of prostaglandin (PG) has been demonstrated in lymphocyte culture supernatants. The amount of PG produced is strikingly increased in mixed cultures between allograft donor and recipient. This phenomenon is not yet detectable after 6 h of culture, appears at 24 h and reaches its maximum at 48 h. Little or no increase in PG production is found in the supernatant of primary mixed lymphocyte cultures (i.e. without previous allograft) at least in the first two days of culture. The difference between allografted and control animals begins at day 6 after grafting, reaches a maximum at day 12, remains high until day 20 and decreases thereafter.

This increased amount of PG in mixed cultures between donor and recipient spleen cells is probably, at least to a large extent, produced by macrophages. Evidence for this interpretation includes the following observations: (a) cells responsible for the increase are adherent cells and (b) the phenomenon is no longer found following a treatment of spleen cells with silica.

When mouse peritoneal macrophages (or adherent spleen cells) are incubated in vitro with supernatants of mixed cultures between allograft donor and recipient, their PG production is considerably increased. Hence, it is suggested that the above‐described phenomenon could result from the stimulation of macrophages by lymphokines released in mixed cultures following allografts.

If such a release of PG takes place within the graft, it may play a regulatory role in the control of the magnitude of the anti‐allograft immune response.
Antibody‐dependent, cell‐mediated cytotoxicity against human red blood cells: correlation of effector cell type with enzymatic alteration of the target cell surface
Authors: Yust Israel , Frisch Bertha , Goldsher Naomi
Published: February 2007

Target cell factors, which contribute to the determination of the effector cell type in an antibody‐dependent, cell‐mediated cytotoxicity system were studied. Human red blood cells (RBC) were treated with papain and investigated by transmission and scanning electron microscopy (TEM and SEM). Both untreated (native) and treated 0 Rh+ RBC were labeled with 51Cr, sensitized with anti‐D immunoglobulin and incubated with unfractionated autologous peripheral blood mononuclear cells. With native RBC, immune lysis was proportional to the number of phagocytes: enrichment of effectors in phagocytes increased lysis, while depletion of phagocytes from effectors decreased lysis. Following papain treatment of target RBC, lysis by unfractionated mononuclear effectors was markedly augmented; since this effect was not diminished by decrease of phagocytes to less than 2%, the augmented lysis was not due to the number of phagocytic effectors. TEM and SEM of enzyme‐treated RBC showed spherocytosis with varying degrees of creation and blurring and irregularities of the cellular membranes. The results suggest that papain‐induced alterations in the target RBC rendered them susceptible to lysis by interaction between anti‐D antibody and peripheral blood lymphocytes.
Structure of Ia antigens from the rat. Mouse alloantisera demonstrate at least two distinct molecular species
Authors: Blankenhorn Elizabeth P. , Cecka J. Michael , Frelinger John , Götze Dietrich , Hood Leroy
Published: February 2007

Ia antigens isolated from spleen cells of rats and mice are composed of two polypeptide chains, designated α and β. Mouse alloantisera specific for the I‐Ak and I‐Ek subregions react with two distinct groups of rat Ia antigens, designated A‐like and E‐ like, respectively. Two‐dimensional gel electrophoresis and peptide map analysis demonstrate that the A‐like antigens of rat are distinct from the E‐like antigens. Both rat Ia antigens react with alloantiserum produced in rats congenic for the major histocompatibility complex (MHC). These results demonstrate for the first time that two distinct Ia antigens are present in the rat. Accordingly, the rat, like the mouse, may have Ia antigens encoded by at least two sub regions of the rat MHC. The existence of multiple Ia gene products in rats is revealed by chemical techniques even in the absence of formal genetic evidence of more than one I subregion in the rat.
H‐2 gene products influence susceptibility of target thyroid gland to damage in experimental autoimmune thyroiditis
Authors: Ben‐Nun Avraham , Maron Ruth , Ron Yacov , Cohen Irun R.
Published: February 2007

The restriction of the pathogenesis of experimental autoimmune thyroiditis (EAT) by H‐2 gene products was investigated. EAT was induced by injecting thyroglobulin extract plus adjuvant into F1, hybrid mice that had been implanted under the kidney capsules with thyroid glands originating from either the EAT‐susceptible or ‐resistant parental strain mice. We found relative H‐2 restriction of thyroid damage to those glands originating from the H‐2‐susceptible parental strain. H‐2 restriction of damage at the level of the target thyroid gland implicates cytotoxic effector T lymphocytes as a pathogenic agent of EAT.
A glycolipid on the surface of mouse natural killer cells
Authors: Kasai Masataka , Iwamod Masao , Nagai Yoshitaka , Okumura Ko , Tada Tomio
Published: February 2007

Cytotoxic treatment with rabbit antiserum raised against purified glycosphingolipid “asialo GM1” was capable of eliminating natural killer (NK) activity of spleen cells from different inbred mouse strains including CBA/J, C57BL/6, BALB/c, AKR, and athymic nude mice. The anti‐asialo GM 1 antiserum showed little cross‐reactivity with structurally related glycolipids, e.g. GM 1, GD 1 b and asialo GM 2 in the microflocculation test. The specific reactivity of this antiserum with NK cells was confirmed by the quantitative absorption of anti‐NK activity with graded amounts of asialo GM 1 but not with other glycosphingolipids. The absorption of anti‐brain‐associated T cell antigen (anti‐BAT) with asialo GM 1 also effectively diminished its anti‐NK activity, leaving the ability to kill T cells intact. This suggests that the antibody to asialo GM 1 is responsible for the anti‐NK activity contained in the anti‐BAT antiserum. In contrast to the extreme sensitivity of NK cells to anti‐asialo GM 1, alloreactive cytotoxic T killer cells generated in the mixed lymphocyte culture were not killed by anti‐asialo GM 1 and complement. These results indicate that asialo GM 1 is expressed on mouse NK cells in a high concentration.
Cell surface immunoglobulin μ and γ chains of human lymphoid cells are of higher apparent molecular weight than their secreted counterparts
Authors: Singer Paul A. , Williamson Alan R.
Published: February 2007

Selected human lymphoma‐derived and lymphoblastoid cell lines have been characterized and shown to be useful model systems for the expression of either cell surface Ig, or secretory Ig, or both simultaneously. Daudi and Raji cell lines were shown to express surface IgM with no secretion of IgM. The lymphoblastoid cell lines Tay‐3 and RPMI 1788 are high‐rate secretors of IgM. The lymphoma cell line BJAB synthesizes both cell surface IgM and secretory IgM. In the secreting cells, we have identified an intracellular μ chain with an apparent molecular weight approximately 2000 less than secreted μ chain. In cells synthesizing surface IgM, a surface μ chain has been identified which has an apparent mol. wt. of approximately 2000 more than secreted μ chain. The intracellular μ chain in these cells is indistinguishable in size from the mature surface μ chain; the Daudi cell line is exceptional in that surface deposition of the intracellular μ chain is preceded, or accompanied, by an increase in apparent mol. wt. The lymphoblastoid cell line Bec‐11 synthesizes both cell surface IgG and secretory IgG. In Bec‐11 cells, a surface form of μ chain, having a higher apparent mol. wt. than secreted γ chain, has been resolved. There is no detectable difference between L chains associated with any of the different forms of H chain. A biosynthetic relationship between the different forms of H chain is proposed.
Cell cooperation during in vivo anti‐hapten antibody responses: V. Two synergistic Ly‐1+23− helper T cells with distinctive specificities
Authors: Janeway Charles A. , Bert Deborah L. , Shen Fung‐Win
Published: February 2007

Experiments were carried out to determine the antigen specificity of two distinct helper T cells (Th) that act synergistically in adoptive secondary in vivo anti‐hapten antibody responses. Both Th were present in anti‐Ly‐2 and complement‐treated spleen T cell populations, implying that both Th are Ly‐1+,23−. Adding normal T cells or T cells primed to other carriers to specific carrier‐primed T cells, using a variety of different protocols did not affect the helper activity of the specifically primed Th. Thus, both Th apparently are antigen‐specific. Furthermore, Th primed with one carrier and boosted with that carrier plus hapten linked to a noncross‐ reactive carrier cannot help B cells. However, if a mixture of Ly‐1 T cells from mice primed with two different carriers is transferred along with B cells, and the mice are boosted with hapten coupled to one of the two priming carriers, then giving the other carrier induces a significant increase in antibody production. Thus, only one of the two Th (Th1) requires a hapten‐carrier bridge, while the other does not (Th2). However, both Th 1 and Th2 are clearly antigen‐specific and require stimulation with antigen to exert helper activity. Furthermore, these experiments strongly suggest that Th 2 cannot express helper function in vivo in the absence of Th 1. These findings, and the absence of Th2‐like cells in agammaglobulinemic mice, were correlated with other studies in which two helper activities have been described. It was concluded that in vivo responses require an effective Th 1‐B cell interaction, whereas Th2, if stimulated with antigen, will augment certain portions of the antibody response, such as idiotype or allotype, and thus influence the quality of the antibody response directly.
Cell cooperation during in vivo anti‐hapten antibody responses: VI. Evidence for an allogeneic effect replacing one of two helper T cells
Authors: Janeway Charles A. , Bert Deborah L. , Mosier Donald E.
Published: February 2007

T and B lymphocyte activity in adoptive secondary antibody responses was assessed by cell titration in mice of the X‐linked immune defective CBA/N strain and mice of their normal partner strain CBA/CaJ. No quantitative differences could be detected in either T or B cell activity in these experiments, in which 2,4‐dinitrophenyl was used as the hapten. Both of the helper T cells detected in such assays were present in both strains. During these experiments, it was found that a subline of CBAN maintained at Yale may have diverged from the CBA/N NIH stock. This was detected by an ability of irradiated mice of the Yale subline to increase the antibody response of B cells from the NIH subline, provided specific helper T cells were also present. This allogeneic effect apparently replaced the activity of one helper T cell, but did not replace the requirement for a carrier‐specific helper T cell.
Studies on transplantation immunity. IV. Murine natural immunity to lymphoid cells in vivo
Authors: Pincott Christine E. , Bainbridge Douglas R.
Published: February 2007

A natural response acting to discriminate between allogeneic and syngeneic lymphocytes in vivo is described for normal mice. Eighteen to 24 h after systemic injections of low doses of 51Cr‐labeled cells, less radioactivity is found in the lymph nodes after allogeneic transfer. The spleen but not the liver participates in the response. It can be abolished by neonatal induction of transplantation tolerance, is shown to be immunologically specific, and is resistant to irradiation up to 1000 rd, although a radiosensitive phase occurs during recovery from sublethal irradiation. The response is cell‐mediated but depends upon cooperation from a factor present in normal serum. It is thymus‐independent: this clearly distinguishes it from the superficially similar immune response acquired by immunization and aligns it with the class of responses to which the hybrid histocompatibility response and natural killer‐like phenomena belong. Unlike these, however, it is present at birth and directed primarily against H‐2 antigens. It appears to follow the classical transplantation rules in a limited range of strains. Some of the difficulties inherent in this type of study are discussed.
The role of vesicular stomatitis Virus major glycoprotein in determining the specificity of virus‐ specific and H‐2‐restricted cytolytic T cells
Authors: Sethi Krishan K. , Brandis Henning
Published: February 2007

Possible involvement of the major glycoprotein (G protein) of vesicular stomatitis virus (VSV), which is expressed on infected cell surfaces, in the virus‐specific and H‐2‐restricted lysis of targets by cytotoxic T lymphocytes (CTL) was sought by examining the effect of monoclonal antibody directed against the G protein of Indiana (VSVInd) or New Jersey (VSVNJ) serotypes. Evidence is presented that hybridoma supernatants containing monoclonal antibody of the IgG class directed against the G protein of VSVNJ could specifically block the lytic activity of primary CTL obtained from BALB/c mice infected with UV‐inactivated VSVNJ, but not VSVInd for homotypic but not heterotypic VSV‐infected P815 Y cells. Likewise, monoclonal anti‐VSVIndand anti‐G protein antibody proved effective in blocking the lysis mediated by VSVInd‐ but not VSVNJ‐primed CTL against targets infected with VSVInd, but not those infected with VSVNj. The results of blocking assays are consistent with the interpretation that UV‐inactivated VSVNJ or VSVInd could generate, during the primary in vivo response, CTL subsets which were able to distinguish between serologically distinct VSV G proteins and those which were cross‐reactive for both serotypes. Purified G protein derived from either of the 2 VSV serotypes could in in vitro culture trigger the generation of completely serotype‐specific and H‐2‐restricted secondary CTL from nonlytic precursors primed in vivo with homologous VSV serotype. The lytic activity of secondary VSVNJ‐ and VSVInd‐specific CTL could be blocked by incubation of infected targets with monoclonal anti‐VSVNJ and anti‐VSVInd G protein antibodies, respectively. The data obtained are taken as suggestive evidence for the specific recognition of VSV G protein expressed on target cells by virus‐specific CTL.
Mechanism of antigen binding by T cells: H‐2 (I‐A)‐restricted binding of antigen plus Ia by helper cells
Authors: Puri Joseph , Lonai Peter
Published: February 2007

The binding of a complex containing self Ia and antigen (IAC) to T cells was investigated. Poly‐L (Tyr, Glu)‐poly‐DLAla—poly‐LLys [(T, G)‐A—L], bovine serum albumin, ovalbumin or fowl gamma‐globulin were used as antigen. The effect of this complex was investigated in three experimental systems: autoradiographic antigen binding, in vivo immunization, and in vitro radioactive suicide of helper T cells. Autoradiographic experiments have shown that antigen binding to T cell‐enriched spleen cells is a slow process with a half‐life period of 20 min. It was found that during this time, antigen which can bind to Lyt‐1+ T cells with much faster kinetics (half‐life period = 2 min), is liberated from adherent cells. This “processed” antigen was retained by anti‐Ia or lentil lectin affinity columns, and its binding to T cells was restricted by the I‐A subregion of H‐2. IAC was 100 to 1000‐fold more immunogenic in vivo than the same amount of untreated antigen. This immunogenicity could be removed on anti‐Ia columns, and was found to be under similar H‐2 restriction as was its binding to T cells. The functional T cells, to which IAC binds, were identified by radioactive antigen suicide. It was found that the IAC killed syngeneic but not allogeneic, helper T cells. For the binding of processed antigen, helper cells required metabolic energy and a nonspecific soluble factor of adherent cells. These data are interpreted to suggest that H‐2 restriction is directly determined by the interaction of the helper cell receptor with self Ia and foreign antigen. It also appears that the Ia‐containing antigen may be a potent, cell type‐directed immunogen.
Qed‐1 – a target for unrestricted killing by T cells
Authors: Lindahl Kirsten Fischer , Hausmann Barbara
Published: February 2007

Two prototype target determinants for unrestricted killing by T cells are defined: Qed‐la, detected on B6.Tlaa targets by C3H/HeJ lymphocytes primed in vivo and restimulated in vitro by B 10.BR spleen cells; and Qed‐1b, detected on C57BL/6J lymphocytes by B 10.BR anti‐C 3 HiHeJ effector cells generated in the same manner. Other mouse strains can be typed for Qed‐1 by the ability of their lymphocytes to inhibit one of these lytic reactions. Of 55 inbred strains, 52 expressed either Qed‐1a or Qed‐1b, which thus behaved as products of alleles of a single locus, Qed‐1. The remaining three strains, all H‐2r, did not compete against specific lysis of Qed‐1a, but inhibited Qed‐1b‐specific lysis only in part; it is proposed that these strains carry a third allele or haplotype, Qed‐1c. The Qed‐1 locus was mapped distal to Qa‐2. Qed‐1h was found on both normal and mitogen‐activated lymphocytes and did not appear confined to any lymphoid subpopulation. Cytotoxic responses, not restricted by H‐2 and specific for antigens controlled by the Tla region, could be induced in several combinations of H‐Zidentical strains differing at Qed‐1. Cells of some strains, like B 10.BR, NZB, and SWR, responded directly in culture, even without priming in vivo.
Major histocompatibility gene complex (MHC)‐coded determinants on antigen‐specific suppressor factor for delayed‐type hypersensitivity and surface phenotypes of cells producing the factor
Authors: Liew Foo Y. , Sia Dwo Y. , Parish Chris R. , McKenzie Ian F. C.
Published: February 2007

Antigen‐specific suppressor factor for delayed‐type hypersensitivity (DTH) to sheep red blood cells (SRBC) was obtained by incubating in vitro spleen cells from CBA mice (H‐2k) injected intravenously 3 days previously with 1 × 109 SRBC. The suppressor factor was characterized for major histocompatibility gene complex (MHC)‐coded antigenic determinants by passing the factor through immunosorbents coupled with appropriate alloantisera. The suppressor factor was absorbed by anti‐H‐2k, anti‐Iakand anti‐I‐Jk immunosorbents but was not retained by anti‐IaS, anti‐I‐JS, anti‐I‐Ak, anti‐I‐E/C′ or anti‐H‐2Kk immunosorbents. In addition, the factor bound to an immunosorbent coupled with rabbit antibodies against carbohydrate‐defined Ia antigens. Furthermore, the suppressive activity that was absorbed was quantitatively recovered in the acid eluates from the immunosorbents. Treatment of the spleen cells with anti‐Lyt‐1.1 antiserum and complement completely abrogated their ability to elaborate the suppressor factor in vitro. In contrast, treatment with anti‐Lyt‐2.1 or anti‐Iak antiserum and complement had no effect. Thus, it appears that the suppressor factor for DTH to SRBC bears I‐J subregion‐coded determinants, and its production is dependent on cells which have the Lyt‐1 +,2− and Ia− phenotype.
Accelerated age‐dependent decline in the T suppressor capacity of SJL mice
Authors: Nakano Katsuji , Cinader Bernhard
Published: February 2007

Tolerance induction with rabbit gamma‐globulin was employed as a probe for age‐ dependent changes in suppressor capacity of SJL lymphoid cells. The tolerant state was assessed by loss of cooperative capacity and by infectious tolerance. The supply of precursor cells was assessed by thymectomy and by treatment with colchicine and cyclophosphamide, which have been reported to eliminate suppressor cells. Thymectomy, 16–18 days before tolerance induction, did not affect antibody responses or tolerance inducibility; thymectomy, 33 days before tolerance induction, reduced both antibody response and tolerance inducibility. Colchicine, injected together with aggregate‐freed rabbit gamma‐globulin, inhibited tolerance induction partially in 35‐ day‐old mice and completely in 106‐day‐old mice. Colchicine, given to younger mice, thymectomized 17 days before tolerance induction, prevented tolerance induction completely. A low dose of cyclophosphamide interfered with tolerance induction in older, but not in younger mice. A high dose of cyclophosphamide interfered with tolerance induction in thymus cells of younger and older mice. After thymectomy, there was a much more profound interference of a low dose of cyclophosphamide with tolerance induction. Results were discussed in terms of an age‐dependent decline of thymus progenitors and of peripheral progenitors of suppressor cells.
Macrophage requirement for in vitro generation of specific, secondary cell‐mediated cytotoxicity against SV40‐induced tumor‐associated antigens in mice
Authors: Glaser Moshe
Published: February 2007

The role of adherent phagocytic cells in an in vitro secondary cytotoxic response against Simian virus 40 (SV40)‐induced tumor‐associated antigens was investigated. Spleen cells (responder cells), from mice primed with syngeneic SV40‐transformed cells, extensively depleted of macrophages by filtration through a Sephadex G–10 column followed by iron carbonyl treatment, had a markedly decreased capacity to generate in vitro secondary cytotoxic reactivity against syngeneic SV 40‐transformed cells when cultured with the relevant stimulator cells. The secondary response was restored by the addition of adherent peritoneal cells from normal mice syngeneic to those immunized with the antigen. Within a certain dose range, small numbers of peritoneal cells completely reconstituted the response, whereas large numbers inhibited the reactivity. The restored cultures maintained specific cytotoxic reactivity against SV40‐induced tumor‐associated antigens which was mediated by effector T cells as shown by sensitivity to anti‐Thy‐1.2 antiserum and complement. These results suggested a requirement for adherent phagocytic cells (accessory cells) in in vitro generation of a secondary, cytotoxic response to tumor‐associated antigens.
Solubilization of complexes between tumor‐associated and H‐2 antigens from a tumor cell plasma membrane
Authors: Honeycutt Pamela J. , Gooding Linda R.
Published: February 2007

The tumor‐associated cell surface antigens (TAA) gp71 and AgI cocap H‐2, but are not associated with H‐2 following solubilization of membranes with detergent. We have attempted to solubilize intact TAAIH‐2 complexes from surface‐labeled L cells using decreasing concentrations of the nonionic detergent Nonidet‐P40 (NP40). Associations between gp71 and H‐2 and between AgI and H‐2 in solution were detected using sequential immunoprecipitation. gp7UH‐2 and AgI/H‐2 complexes were solubilized at the lowest detergent concentration used, 0.01% NP40. No co‐ precipitation of these antigen pairs was seen at any higher NP 40 concentration tested. Sodium dodecyl sulfate polyacrylamide gel electrophoresis revealed that precipitation of antigens solublized in 0.01% NP40 leads to co precipitation of a small number of other protein peaks and does not appear to involve wholesale inclusion of labeled membrane proteins. These results, together with previous observations of cocapping between TAA and H‐2 antigens, suggest that the molecules are associated with one another in the membrane. Detergent solubilization of membranes with all but the most gentle conditions leads to disruption of these complexes.
Hapten‐specific helper T cells. I. Collaboration with B cells to which the hapten has been directly coupled
Authors: Martinez‐Alonso Carlos , Coutinho António , Bernabé Rosa R. , Augustin Andrei , Haas Werner , Pohlit Helmut
Published: February 2007

A new system to obtain large numbers of functionally competent hapten‐specific effector helper T cells has been developed. Mice were primed in the tail with syngeneic spleen cells derivatized with one of three different haptens: 2,4,6‐trinitrophenyl, fluorescein isothiocyanate and 3‐(p‐sulfophenyldiazo)‐4‐hydroxyphenyl. Draining lymph node cells were subsequently restimulated in culture with the homologous antigen for periods up to 6 weeks. More than 99% and 90% of the cells recovered from these preparative cultures, expressed Thy‐1 and Lyt‐1 antigens, respectively. These cells proliferated specifically in response to the homologous stimulation by haptenated syngeneic spleen cells, and they were found to display very high levels of hapten‐specific helper activity, as assayed in a new, universal method for testing T ‐ B cell cooperation, where every B cell can potentially respond to specific T cell help. Coculture of hapten‐derivatized, functionally competent B cells with hapten‐specific T cells obtained from the preparative cultures, resulted in the appearance, and exponential increase with time, of very large numbers of IgM and IgG plaque‐forming cells. This helper activity could be shown to be: specific for the immunizing hapten and to increase with the time of in vitro helper cell enrichment, which also resulted in higher average avidities expressed by the helper cell populations. This methodology appears valuable for structural studies on hapten‐specific helper cells, as well as for the functional analysis of effector helper ‐ B cell interactions.
Hapten‐specific helper T cells. II. Genetic determination of functional recognition
Authors: Martinez‐Alonso Carlos , Coutinho António , Bernabé Rosa R. , Haas Werner , Pohlit Helmut
Published: February 2007

Helper T cells can be raised in CBA mice with specificity for syngeneic spleen cells derivatized with each of the three haptens, trinitrophenyl (TNP), fluorescein isothiocyanate (FITC) and 3‐(p‐sulfophenyldiazo)‐4‐hydroxyphenyl (SP). These helper cells are exquisitely specific for the homologous antigens, since they express helper activity on target B cells derivatized with hapten concentrations 100‐fold lower than those used for priming, while being totally unable to recognize the heterologous hapten modifications. Expression of helper activity, i.e. induction of target B cells, requires the simultaneous recognition of antigen and I‐A‐ or I‐E/C‐encoded determinants directly on the responding B cell surfaces.

Helper T cells raised in DBA/2 mice with specificity for the same hapten modifications, while functionally recognizing as efficiently as CBA helper cells densely coupled target cells, fail to interact with syngeneic cells derivatized with low concentrations of any of the three haptens. Furthermore, DBA/2 helper cells show a unique “fine specificity” pattern in that anti‐FITC DBA/2 helpers cross‐react with TNP‐DBA/2 targets.
Natural killer cells are responsible for the interferon production induced in human lymphocytes by tumor cell contact
Authors: Timonen Tuomo , Saksela Eero , Virtanen Ismo , Cantell Kari
Published: February 2007

The identity of cells producing interferon among human peripheral blood lymphocytes in contact with tumor cells was investigated. The producer cells were target cell‐adherent lymphocytic cells morphologically similar to natural killer (NK) cells. As interferon is known to augment the cytotoxic activity of initially inactive “pre‐NK” cells, the results suggest an internal positive feedback mechanism in the activation of NK cells.
Interaction of lectins with human T lymphocytes mitogenic properties, inhibitory effects, binding to the cell membrane and to isolated surface glycopeptides
Authors: Dillner‐Centerlind Marie‐Louise , Axelsson Bernt , Hammarstrom Sten , Hellström Ulla , Perlmann Peter
Published: February 2007

The mode of interaction of twelve lectins with human T lymphocytes was investigated. In order to establish possible differences between mitogenic and nonmitogenic lectins, they were studied for their capacity to induce or inhibit DNA synthesis. Their interaction with intact T cells was studied by immunofluorescence and 51Cr release. Further, lectins conjugated to Sepharose were investigated with regard to their capacity to bind surface glycopeptides from T cell lysates. Operationally, the lectins could be divided into three groups: (a) mitogenic lectins; (b) lectins inhibitory for lymphocyte mitogenesis as induced by leucoagglutinin (La) from Phaseolus vulgaris; and (c) nonmitogenic lectins which were noninhibitory in this La system. Six lectins were nonmitogenic. For two or possibly three of these, lack of mitogenicity was due to complete or partial failure to bind to the lymphocytes. This explanation could not account for lack of mitogenicity of the other three nonmitogenic lectins. Only two of the lectins utilized inhibited La‐induced mitogenesis. However, when the lectins were compared with regard to their capacity to bind surface glycopeptides from T cell lysates, important differences between mitogenic and nonmitogenic lectins were seen. As revealed by polyacrylamide gel electrophoresis in sodium dodecyl sulfate and autoradiography, the mitogenic lectins bound a larger number of surface glycopeptides (15–20) than the nonmitogenic lectins (3–10). More importantly, five distinct glycopeptides (gp 135 K, 125 K, 105 K, 95 K and 43 K) were bound by all mitogenic lectins but not by the nonmitogenic lectins. It remains to be established whether these glycopeptides are present on the T cells which are susceptible to the mitogenic action of the lectins and whether it is the interaction of the lectins with one or several of them which triggers mitogenicity.
Cellular requirements for the in vitro induction of specific suppression of antibody responses by immune spleen cells
Authors: Calkins Catherine E. , Stanton Thomas A. , Stutman Osias
Published: February 2007

Feedback regulatory signals to an intermediary suppressor cell may provide the mechanism of the suppression of antibody responses which has been described in cocultures of primed (immune) and unprimed (normal) spleen cells. The active cell(s) in the unprimed spleen population is nonadherent to nylon wool, Sephadex G‐10 and glass beads. Lymph node cells and cortisone‐resistant thymocytes from normal animals act similarly to normal spleen cells in this coculture system. Spleen cells from homozygous nude mice, unlike their heterozygous thymus‐bearing littermates, do not produce a high degree of suppression in coculture with immune spleen cells. These data strongly suggest that the normal cell which interacts with primed cells in the cocultures to produce suppression is of thymic origin. However, spleen cells from neonatally thymectomized mice are suppressive in the presence of spleen cells immune to sheep red blood cells. The unprimed cell(s) active in the suppression are sensitive (in the presence of complement) to antisera directed against the surface markers, Thy‐1, Qa‐1, Lyt‐1, Lyt‐2, and Ia. Most of the antiserum treatments abrogated the suppressive capacity of the normal spleen cells only partially. Only treatment with anti‐Qa‐1 and complement routinely eliminated the ability of these cells to suppress in the cocultures suggesting either low concentration of or inaccessible surface alloantigen on the active cells. Alternatively, more than one Qa‐1‐positive cell set from the unprimed population may be involved. It is postulated that there is at least one subset of Qa‐1‐positive T lymphocytes present in unprimed spleen and lymph node cell populations capable of participating in the suppression of specific secondary antibody responses when cocultured with spleen cells from specifically primed animals.
Interactions between a novel cell surface glycoprotein and the H‐2K and H‐2D antigens on myeloma tumor cells
Authors: Celis Esteban , Eisen Heman N.
Published: February 2007

Previous studies have shown that when a subline of plasmacytoma LPC‐1 is grown in ascites form, the tumor cells harvested after 10–12 days (“late” cells) are resistant to lysis by cytotoxic T lymphocytes (CTL), apparently because the cell surface H‐2‐encoded molecules are blocked by a trypsin‐sensitive glycoprotein of approximately 160 kdaltons. The glycoprotein (gp 160) is produced, and accumulates on the cell surface, as the growing cells enter the stationary phase. In contrast, LPC‐1 cells harvested from the peritoneal cavity early in the transplantation cycle (ca. 4 days), while in exponential growth (“early” cells), have far less gp 160 and are susceptible to lysis by CTL. It is shown that, compared with early cells, the late LPC‐1 cells are far less effective in adsorbing antibodies to products of the H‐2 Kd and H‐2 Dd alleles, but only slightly less effective in adsorbing antibodies to la antigen, and fully effective in adsorbing antibodies to several antigens not related to H‐2 (e.g. PC.1, gp70, gp100, B220). The differences suggest that gp160 might preferentially block H‐2‐encoded molecules (especially K and D)

Gp160 was also detected on another myeloma, MOPC 315 OPEC, a subline of MOPC 315, where it also appeared to block H‐2 molecules but not PC.1. Additional evidence for an interaction between gp160 and H‐2 molecules was obtained when sonicated membrane fragments were used to elicit secondary CTL responses to H‐2 in culture. The response could be elicited by fragments from early but not from late LPC‐1 cells, unless the late cells were treated with subtilisin (to remove gp 160) before sonication.
Analysis of immunoglobulin chain secretion using hybrid myelomas
Authors: Wilde C. Deborah , Milstein Cesar
Published: February 2007

Three different approaches have been used to study nonsecreting variants of myeloma and hybrid myeloma lines. Hemolytic plaque assays were used to screen nonsecreting and light (L) chain‐secreting anti‐sheep red blood cell hybrid myeloma variants for reversion to specific antibody or immunoglobulin (Ig) production. No revert ants were detected from among 1.5 × 107−4.2 × 107 cells of each line studied. In the absence of a heavy (H) chain, the P3 (MOPC 21) x chain is not secreted but degraded intracellularly. The nature of this secretion defect was investigated in a hybrid myeloma line that produces the P3 x chain and another L chain which is secreted without an H chain, by biochemical studies of the relative distribution of mRNA activity for the two L chains between membrane‐bound and free polysomal fractions. The mutant P3 H chain (H*) produced by the line P3‐NSII/1 is also degraded intracellularly rather than secreted. This defect was complemented by cell fusion of P 3‐NSII/1 to P1, a different Ig‐secreting myeloma line. Mutant H* chains were only secreted as part of hybrid Ig molecules with P1 L chains indicating that the defect in their secretion in the P 3‐ NSII/l line was due to lack of a complementary Ig chain. Additionally, the preferential recovery of P1 H chain loss variants from these hybrids that are producing two H chains and only one L chain, supports the idea that free intracellular H chains have an effect on cell viability and influence the type of variants recovered from hybrid myeloma lines.
Differential sensitivity to cyclophosphamide of helper T cells for humoral responses and suppressor T cells for delayed‐type hypersensitivity
Authors: Shand Frank L. , Liew Foo Y.
Published: February 2007

The relative sensitivity to cyclophosphamide (CY) of helper T cells in antibody responses and of suppressor T cells in delayed‐type hypersensitivity (DTH) responses against sheep red blood cells (SRBC) was measured by pretreating cell suspensions in vitro with the microsomally activated form of CY and evaluating their subsequent function in transfer experiments. It was found that suppressor T cells involved in DTH responses were sensitive to much lower concentrations of activated CY than were helper T cells for anti‐SRBC antibody responses. Since the cytotoxic activity of CY is thought to be dependent on its ability to alkylate nuclear DNA, the differential sensitivity observed may be more easily explicable in terms of additional secondary enzyme‐mediated degradation or DNA repair mechanisms.
Possible mechanism of target cell resistance in antibody‐dependent cellular cytotoxicity
Authors: Lavrovsky Vadim A. , Viksler Victor K.
Published: February 2007

The rate of disappearance of anti‐H‐2 antibodies from the surface of target cells varies in different cell types. It sharply increases in the presence of spleen cells, i.e. of cells which effect the antibody‐dependent cellular cytotoxicity (ADCC). Xenogeneic serum produces a stronger ADCC reaction than does aliogeneic serum, aid the antibodies of the former are lost by the target cells at a slower rate than those of the allogeneic serum. The rate of disappearance of the antigen‐antibody complexes from the target cells may limit the efficiency of the ADCC.