bluuebunny/crossref_metadata_2025 huggingface dataset:
Induction of neonatal tolerance to H-2k in B6 mice does not allow the emergence of T cells specific for H-2k plus vaccinia virus.
Authors: Schwartz D H , Doherty P C
Published: June 2004

Thymocytes and spleen cells from C57BL/6 mice (H-2b) neonatally tolerized to H-2k alloantigens do not generate an anti-vaccinia response restricted to H-2Kk when adoptively transferred to appropriate irradiated hosts. This is in sharp contrast to the case for negatively selected C57BL/6 spleen cells acutely depleted of alloreactivity. No evidence for suppression was found in cell mixture experiments. We have shown elsewhere that our neonatally tolerized animals have a centrally induced delection-type tolerance in the absence of obvious suppression.2 We now suggest that in the neonatally tolerized mouse, chronic, central delection of anti-H-2k clones during early T cell ontogeny eliminates the major source of cells able to give rise, via somatic mutation and expansion, to anti-H-2Kk + vaccinia specific cytotoxic T lymphocyte precursors (CTL-P) in the adult. A similar mechanism may operate in the (k + b) leads to b chimera; however, the presence of H-2kxb accessory and presenting cells may permit the eventual generation (via cross-stimulation) of an H-2k-restricted vaccinia-specific repertoire. This would account for our observation of such "aberrant recognition" CTL-P emerging in the spleens of older (k x b) leads to b chimeras.
BALB- and Harvey-murine sarcoma virus transformation of a novel lymphoid progenitor cell.
Authors: Pierce J H , Aaronson S A
Published: June 2004

BALB- and Harvey-murine sarcoma viruses (MSV) comprise a family of retroviruses whose mouse- and rat-derived onc genes are closely related. These viruses induce sarcomas and erythroleukemias in susceptible animals. An in vitro colony assay that detects transformation of lymphoid cells by Abelson-murine leukemia virus was used to demonstrate that BALB- and Harvey-MSV transform a novel hematopoietic cell both in culture and in vivo. Bone marrow colony formation was sarcoma virus dependent, followed single-hit kinetics, and required the presence of mercaptoethanol in the agar medium. BALB- and Harvey-MSV-induced colonies could be established in culture as continuous cell lines that demonstrated unrestricted self-renewal capacity and leukemogenicity in vivo. The cells had a blast cell morphology and lacked detectable markers of mature cells within the myeloid or erythroid series. They also lacked detectable immunoglobulin mu chain or Thy-1 antigen, markers normally associated with committed cells of the B and T lymphoid lineages, respectively. However, the transformants contained very high levels of terminal deoxynucleotidyl transferase (TdT), an enzyme believed to be specific to early stages within the lymphoid differentiation pathway. This phenotype distinguishes these BALB- and Harvey-MSV transformants from any previously reported hematopoietic targets of transforming retroviruses, including the pre-B lymphoid cell transformed by Abelson-MuLV under identical assay conditions. These newly identified lymphoid progenitor cell transformants may provide an important means of studying early stages of lymphoid ontogeny and the possible role of TdT in lymphoid development.
Monoclonal alloantibodies specific for the constant region of T cell antigen receptors.
Authors: Tokuhisa T , Komatsu Y , Uchida Y , Taniguchi M
Published: June 2004

We established three distinct monoclonal antibodies (7C5, 7D1; IgM and 6A4; IgG1) by the fusion of P3U1 and BALB/c (Igh-1a) spleen cells hyperimmunized with T cell blasts from the immunoglobulin heavy chain (Igh) allotype congenic CB-20 (Igh-1b) mice. The 7C5 or 6A4 antibody reacts with the constant region determinants on the antigen-binding molecule (Ct) of the antigen-specific suppressor T cell factor (TsF) or augmenting T cell factor (TaF), respectively. The 7D1 antibody, however, recognizes the shared determinants on the Ct molecules of TsF and TaF. Genetic studies of determinants recognized by these monoclonal antibodies have also suggested that the distinct Ct molecules of TsF and TaF are encoded by two discrete genes linked to the Igh-1b genes, which are located on the right side of the variable genes of Igh on the 12th chromosome. By using the immunoadsorbent columns of 6A4 antibody and anti-I-Ab, TaF, in a manner similar to TsF, was demonstrated to be composed of two chains, i.e., the Ct molecules and the I-A-encoded products. Furthermore, the Ct-bearing molecules were shown to possess the antigen-binding moiety.
Deregulation of idiotype expression. Induction of tolerance in an anti-idiotypic response.
Authors: Ortiz-Ortiz L , Weigle W O , Parks D E
Published: June 2004

The induction of tolerance in an anti-idiotypic response was attempted by in vivo exposure to excess idiotype. Monoclonal immunoglobulin from the anti-p-azobenzenearsonate (ABA) hybridoma R16.7 was used as a representative of cross-reactive idiotype-positive (CRI+) antibodies because this hybridoma protein (HP) shares one or more closely related public idiotypic determinants with the serum CRI in A/J mice. Immunologic unresponsiveness was established by a single injection of the R16.7 idiotype and persisted for at least 6 wk. The level of circulating anti-idiotypic antibodies in tolerized A/J mice was significantly depressed after immunogenic challenge with eigher antigen, ABA-keyhole limpet hemocyanin (KLH), or the idiotype R16.7 HP. Experimental depletion of anti-idiotypic antibodies by tolerization allowed assessment of immunoregulation within this altered idiotype-anti-idiotype network. Deregulation of idiotype expression in tolerized mice challenged with ABA-KLH was manifest with up to 96% of the anti-ABA antibodies cross-reacting with the R16.7 idiotype. This selective enhancement of a major idiotype was accomplished without substantial alteration of the level of the overall anti-hapten response. Both the unresponsiveness established in anti-idiotypic antibody-producing cells and the enhanced synthesis in idiotype-producing cells were stable upon adoptive transfer into lethally irradiated, syngeneic recipients. Finally, previous immunization with the antigen ABA-KLH interfered with the induction of unresponsiveness to the idiotype. This interference is presumed to be mediated by prior activation of anti-idiotypic cells and/or antibody because injection of antigen with tolerogenic idiotype did not abrogate tolerance induction.
Use of Epstein-Barr virus-transformed B cell lines for the generation of immunoglobulin-producing human B cell hybridomas.
Authors: Chiorazzi N , Wasserman R L , Kunkel H G
Published: June 2004

HGPRTase-deficient EBV-transformed B cell lines were shown to be effective fusion partners with mitogen-activated human B cells for the construction of Ig-producing human B cell hybridomas. In a series of experiments using these lines and B cells from several tissue sources, approximatley 20% of the cultures plated were consistently positive for growth after hypoxanthine-aminopterin-thymidine selection and approximatley 30% of these synthesized significant new Ig. A marked increase in Ig secretion was observed after hybridization, which was due to new Ig; Ig from the parental lime was shown to disappear in several instances. Special analyses were carried out on a human hybridoma secreting antibody specific for tetanus toxoid and tetanus toxin and stable subclones were derived. These studies suggest that EBV-transformed lines will prove useful in human hybridization studies, thus making a large library of B cell lines available for the generation of human monoclonal antibodies.
Redistribution of renal allograft-responding leukocytes during rejection. II. Kinetics and specificity.
Authors: Nemlander A , Soots A , von Willebrand E , Husberg B , Hayry P
Published: June 2004

We investigated the traffic of allograft-responding leukocytes between the host and graft without handling of these cells in vitro. The blood flow between the host and graft was disconnected, the proliferating cells were labeled with [3H]thymidine selectively in the graft or in the host, the label was chased with cold thymidine, and the circulation was reestablished. The localization of labeled cells was quantitated by autoradiography. The first host-derived labeled cells appeared in the graft and graft-derived labeled cells in the host, already on the 1st d after transplantation. This was followed by an exponential increase in the labeled cell traffic in both directions. The peak of traffic was observed on day 4 after transplantation, whereafter the traffic rapidly declined and tapered off. This decline was not due to exhaustion of supply, as the labeled cells continued to proliferate in their original compartments, nor to a slowdown of blood circulation, which took place 2-3 d later. We consider the decline to indicate that the rejection has proceeded to a (irreversible) stage autonomous of the host lymphatic and hematopoietic system. During the exponential increase, nearly one-third of the graft-infiltrating inflammatory cells were replaced as a consequence of relocalization during each 18-h-period. All mononuclear white cell types, with the exception of granulocytes, participated in the traffic. Most lymphoid cells entrapped in the graft were descendents of recent cell divisions; most of the mononuclear phagocytes derived from a preexisting phagocyte pool. The entrapment of labeled leukocytes in a relevant graft was specific: when an allograft and an autograft were simultaneously transplanted, a more than 50-fold entrapment was observed in the allograft, compared with the autograft. Very few of the cells localized in irrelevant positions, such as the liver and lung, of the recipient.
In vitro differentiation of human monocytes. Differences in monocyte phenotypes induced by cultivation on glass or on collagen.
Authors: Kaplan G , Gaudernack G
Published: June 2004

We demonstrated that the in vitro differentiation of human peripheral blood monocytes to macrophages is dependent on the environment and conditions of monocyte culture. Cultivation of monocytes on glass or microexudate-coated glass gave rise to cells resembling foreign body granuloma macrophages. After an initial rise in Fc receptor- and C3 receptor-mediated phagocytosis, a progressive loss of Fc receptor expression and C3-mediated ingestion were observed. The monocyte surface antigens recognized by the anti-human monocyte monoclonal antibodies 1D5 and 63D3 were lost from the surface of the majority of cells cultured on glass and microexudates. A subpopulation of Fc receptor-positive cells that were 1D5 and 63D3 positive was retained in fully differentiated cell populations. In comparison, monocytes cultivated on collagen matrices gave rise to highly phagocytic cells resembling human resident tissue macrophages. Both Fc- and C3-mediated phagocytosis were enhanced and remained so during the entire length of culture. The surface antigens recognized by the 1D5 antibody, expressed on all freshly seeded monocytes, was maintained on the macrophages. The antigen recognized by the 63D3 antibody was not expressed on mature cells. The present evidence would indicate that variations in expression of phagocytic receptors and the surface antigens 1D5 and 63D3 can be ascribed to the stage of development of the macrophage or its stage of activation, rather than to independent subsets of mononuclear phagocytes.
Tumor-promoting phorbol esters stimulate C3b and C3b' receptor-mediated phagocytosis in cultured human monocytes.
Authors: Wright S D , Silverstein S C
Published: June 2004

Monocytes were isolated in high yield (approximately 80%) and purity (greater than 90%) by Percoll gradient centrifugation and incubated in Teflon culture vessels. Using this culture method, we routinely recovered 80% of the cells originally placed into culture. Studies of the C3b and C3b' receptors of these monocytes showed that the function of both receptors could be dramatically altered by treating the cells with tumor-promoting phorbol esters. Both C3b and C3b' receptors of human monocytes efficiently mediate attachment of erythrocytes coated with the corresponding ligands, but do not promote their ingestion. However, monocytes treated with phorbol myristate acetate (PMA) or phorbol didecanoate ingest C3b- and C3b'-coated erythrocytes. Phorbol esters that are inactive as tumor promoters do not stimulate C3 receptor-mediated phagocytosis. The ability of monocytes to respond to PMA by activation of C3 receptors is developmentally regulated. Freshly isolated monocytes do not take up C3b- or C3b'-coated erythrocytes in response to PMA, but after 3 d of culture they show strong PMA-stimulated uptake. The stimulatory effect of PMA on monocyte C3b and C3b' receptor function occurs within minutes, is stable for hours, is cycloheximide insensitive, and can be inhibited with colchicine. Several lines of evidence indicates that phagocytosis of C3b or C3b'-coated erythrocytes is specifically mediated by the monocytes' C3b and C3b' receptors. First, erythrocytes attached to monocytes with concanavalin A are not ingested when the monocytes are treated with PMA. Second, monocytes plated on IgG-bearing substrates lose Fc receptor activity on their nonadherent surfaces but retain the capacity to ingest C3b- or C3b'-coated erythrocytes after PMA treatment. Third, PMA-treated monocytes plated on C3b-coated surfaces lose C3b receptor activity on their nonadherent surfaces but retain the capacity to ingest C3b'-coated erythrocytes. Conversely, PMA-treated monocytes plated on C3b'-coated surfaces show reduced C3b' receptors activity on their nonadherent surfaces but retain the capacity to ingest C3b-coated erythrocytes.
Protective antigenic determinant of streptococcal M protein shared with sarcolemmal membrane protein of human heart.
Authors: Dale J B , Beachey E H
Published: June 2004

We present definitive evidence that at least one protective antigenic determinant on type 5 M protein of group A streptococci evokes antibody that is cross-reactive with human heart tissue. One of nine rabbits immunized with a peptide fragment of type 5 M protein (pep M5) produced antibody that cross-reacted by immunofluorescence with sarcolemmal membranes of human heart. The cross-reactive antibody could be removed by absorbing the antiserum with sarcolemmal membranes, types 5 and 19 streptococci, or their pepsin-extracted M proteins, but with no other serotypes tested. Although each of the pep M5 immune sera was opsonic for type 5 streptococci, only the heart-reactive antiserum opsonized type 19 streptococci. The opsonization of type 19 streptococci was abolished by absorbing the antiserum with sarcolemmal membranes isolated from human heart tissue. Purified heart-reactive antibodies eluted from sarcolemmal membranes opsonized both types 5 and 19 streptococci, indicating that the heart cross-reactive determinant of type 5 M protein is cross-protective. The cross-reactive antigen was purified by affinity chromatography from detergent extracts of sarcolemmal membranes and determined to be a complex protein composed of four subunits apparently linked by disulfide bonds.
Activation of complement by serum-resistant Neisseria gonorrhoeae. Assembly of the membrane attack complex without subsequent cell death.
Authors: Harriman G R , Podack E R , Braude A I , Corbeil L C , Esser A F , Curd J G
Published: June 2004

Interaction of the human complement system in normal human serum (NHS) with serum-resistant and -sensitive Neisseria gonorrhoeae was evaluated to better understand the mechanism of serum-resistance. Complement activity (CH50) was depleted from NHS in a dose-dependent fashion by both serum-resistant and -sensitive N. gonorrhoeae. No detectable CH50 remained in NHS incubated with 10(9) colony-forming units (CFU)/ml serum of either resistant or sensitive strains. When smaller numbers of bacteria were incubated with NHS, lesser, yet comparable, amounts of CH50 were depleted by both resistant and sensitive strains. Hemolytic C2 activity was diminished by 33% in the case of resistant N. gonorrhoeae (10(8) CFU/ml serum) and by 48% in the case of a sensitive strain. No detectable decreases in hemolytic C4 or C7 activities were found with either sensitive or resistant strains at this concentration. Both resistant and sensitive strains activated C1s in NHS. Resistant strains specifically activated 19-21% of radiolabeled C1s in NHS, whereas sensitive strains activated 18-32%. Both resistant and sensitive strains also activated C5 in NHS. In binding assays using radiolabeled C5 and C9 in NHS, resistant and sensitive strains bound comparable amounts of C5 and C9. The number of bound C5 and C9 molecules varied according to the number of bacteria or amount of serum used in the assay. The ratio of C9/C5 bound to a sensitive strain was 6.8, and to a resistant strain was 8.2, suggesting that C5 and C9 were incorporated into membrane attack complexes (MAC). Electron microscopic examination of resistant and sensitive strains incubated with NHS revealed that MAC is bound to the surfaces of the resistant strain as well as the sensitive strain.
Acquisition of mitogenic responsiveness by nonresponding lymphocytes upon insertion of appropriate membrane components.
Authors: Jakobovits A , Sharon N , Zan-Bar I
Published: June 2004

The effect of insertion of plasma membrane components from lymphocytes responding to mitogens into the membranes of nonresponding cells using Sendai virus envelopes as vehicles was examined. T cells modified by B membranes were stimulated by lipopolysaccharide (LPS) to proliferate as well as to produce interleukin-2 activity. B cells modified by T membranes were stimulated by concanavalin A to proliferate and to produce interleukin-2 activity. B cells derived from C3H/HeJ LPS-nonresponder strain of mice, when modified by B membranes derived from the LPS-responder C3H/eb strain, acquired LPS responsiveness. These findings indicate that the inability of either T or B cells to respond to specific mitogens is due to the lack of suitable plasma membrane constituents and that by changing the membrane composition the lymphocytes can be endowed with new functions.
Suppressor T cells activated in a primary in vitro response to non-major histocompatibility alloantigens.
Authors: Macphail S , Stutman O
Published: June 2004

Normal mouse spleen cells are not capable of mounting a primary cytotoxic T lymphocyte (Tc) response to non-H-2 alloantigens in vitro, although a good secondary H-2-restricted response is observable after in vivo immunization of the responder animals. Suppressor cells are generated in such a primary responses provided a Mls incompatibility exists between the responder and stimulator. These suppressors are not antigen specific, are Thy-1+, Lyt-1+, 2-, I-J-, and are highly radiosensitive. The suppressor cell precursors in normal spleen express the same phenotype. These suppressor cells are probably implicated in the lack of a primary Tc response in a primary mixed lymphocyte reaction across non-H-2 incompatibilities that include an Mls difference.
Structure and expression of endogenous ecotropic murine leukemia viruses in RF/J mice.
Authors: McCubrey J , Horowitz J M , Risser R
Published: June 2004

High leukemic mouse strains possess proviral genomes that are more inducible for virus expression by halogenated pyrimidines than the proviral genomes harbored by low leukemic mice. We investigated the induction and arrangement of ecotropic proviruses in RF mice, a strain of mouse that develops a moderate incidence of leukemia late in life. We found that RF mice, unlike either high or low leukemic inbred strains, carried both a gene for high efficiency virus induction (Rjv-1) and a gene for low efficiency virus induction (Rjv-2). Virus induction from mice that contained Rjf-2 alone was observed only in crosses with two other strains that carried ecotropic proviruses, i.e., DBA/2 and C57BL/6, and not in crosses performed with mice that lacked ecotropic proviruses, i.e., 129, SWR, and NFS. Inheritance of the Rjv-1 gene frequently resulted in viremia when a virus-suppressive gene(s) of RF (most likely Fv-1) was not present in the same individual. Rjv-1 and Rjv-2 virus induction genes co-segregated with ecotropic proviruses integrated in different cellular DNA sequences. Rjv-2, the less inducible ecotropic provirus in RF mice, is located in cellular DNA sequences very similar to those found adjacent to the ecotropic provirus of BALB/c. These results document a second system of virus interaction or complementation and demonstrate that ecotropic proviruses of different phenotypes can be found within an individual mouse strain.
Study on cellular events in postthymectomy autoimmune oophoritis in mice. I. Requirement of Lyt-1 effector cells for oocytes damage after adoptive transfer.
Authors: Sakaguchi S , Takahashi T , Nishizuka Y
Published: June 2004

Neonatal thymectomy during the critical period, 2-4 d after birth, can induce various organ-specific autoimmune diseases including oophoritis in A/J mice. The oophoritis thus induced was passively transferred into neonatal mice by injection of spleen cells obtained from syngeneic donors with the disease. Recipient ovaries were rapidly damaged with remarkable mononuclear cell infiltration and destruction of follicular structures. The phenotype of effector cells responsible for successful adoptive transfer was found to be Thy-1+, Lyt-1+,23-, Ia-, Qa-1-, and was sensitive to antithymocyte serum treatment but resistant to cyclophosphamide treatment or in vitro X-ray irradiation. The compatibility between donor and recipient at the major histocompatibility complex was not required for the effector phase of transfer. The oophoritis induced in BALB/c (nu/+ or +/+) was also shown to be transferred into athymic BALB/c nude mice with resulting ovarian lesion and circulating autoantibodies against oocytes. In this transfer system, the effector cells were also demonstrated to be T cells with the Lyt-1+,23- phenotype. Adoptive transfer experiments in both systems revealed that the destruction of ovaries in postthymectomy autoimmune oophoritis was mediated by Lyt-1 T cells. Whether these T cells can be distinguished from other Lyt-1 cells, such as T helper cells and effector T cells in delayed-type hypersensitivity (DTH), is not clear at present, but the results suggest that the effector mechanisms may be closely related to a DTH reaction.
Isolation of the receptor for IgG from a human monocyte cell line (U937) and from human peripheral blood monocytes.
Authors: Anderson C L
Published: June 2004

The Fc receptors for IgG from a human monocyte line (U937) and from highly purified human peripheral blood monocytes were solubilized, purified, and partially characterized. Both sources of cells gave indistinguishable results. Two molecules (or sets of molecules), one of about 72,000 mol wt and the other of 40,000-43,000 mol wt were discerned on autoradiograms of sodium dodecyl sulfate (SDS)-polyacrylamide gels analyzing acid eluates from Sepharose-IgG columns over which detergent lysates of radioiodinated cells had been passed. The larger of the two molecules, p72, accounted for greater than or equal to 90% of the radioactivity. This component was noted to be heterodisperse both by size on SDS gels and by charge on isoelectric focusing gels. The charge heterogeneity, being virtually eliminated by neuraminidase and tunicamycin, was probably due to variable glycosylation. Several lines of evidence indicated that p72 is probably all or part of the Fc receptor: (a) radiolabeling of this molecule using chloroglycouril was blocked by IgG of the Fc receptor; (b) in soluble form this molecule expressed ligand specificity identical to the in situ receptor; (c) the molecule was not recovered from affinity adsorbants bearing proteins that do not bind to the Fc receptors, nor (d) from a human T cell line that does not bear Fc receptors. The smaller of the two molecules isolated, p40-43, is at least in part actin. Its relationship to p72 is not understood.
A search for messenger RNA molecules bearing immunoglobulin VH nucleotide sequences in T cells.
Authors: Kemp D J , Adams J M , Mottram P L , Thomas W R , Walker I D , Miller J F
Published: June 2004

Expression of VH-coded mRNA molecules in T cells, antigen-specific T cell lines, or T cell hybridomas was not detected using four different VH DNA probes under conditions that permitted cross-hybridization between distantly related VH genes. In contrast, VH gene expression was readily detected in two B cell lymphomas and in splenic B cells. Less than one molecule per cell of RNA, exactly complementary to the DNA probes used, would have been detected in these T cell populations. The results thus seriously question the proposition that T cells use the B cell VH repertoire to code for antigen receptors.
Helper cell-independent cytotoxic clones in man.
Authors: Wee S L , Chen L K , Strassmann G , Bach F H
Published: June 2004

We report here a class of helper cell-independent cytotoxic T cell (HITc) clones in man that can proliferate in response to antigenic stimulation as well as mediate cytotoxicity. HITc appear to be rare among clones derived from primary in vitro allosensitized culture, but constitute the majority of clones derived from cells sensitized to autologous Epstein-Barr virus-transformed lymphoblastoid cell lines. The implications of the derivation and function of HITc clones are discussed.
Suppression of hyperbilirubinemia in the rat neonate by chromium-protoporphyrin. Interactions of metalloporphyrins with microsomal heme oxygenase of human spleen.
Authors: Drummond G S , Kappas A
Published: June 2004

The synthetic metalloporphyrin, Cr-protoporphyrin, as a potent competitive inhibitor of heme oxygenase activity in rat spleen, liver, and kidney. When administered to neonatal animals in a single dose immediately after birth, Cr-protoporphyrin suppresses postnatal hyperbilirubinemia and produces a marked and sustained lowering of heme oxidation activity in liver, spleen, and kidney. The metalloporphyrin also potently inhibited the rate of heme degradation to bile pigment in human spleen.
Alterations in collagen production in mixed mononuclear leukocyte-fibroblast cultures.
Authors: Hibbs M S , Postlethwaite A E , Mainardi C L , Seyer J M , Kang A H
Published: June 2004

The cell-cell interactions between fibroblasts and mononuclear leukocytes (MNL) which promote alterations in collagen accumulation were examined using a system of co-culture of human fibroblasts and peripheral blood MNL. The stimulation of collagen production was optimal after 48 h of co-culture and the increase in collagen correlated directly with the number of MNL added. The enhancement of collagen production was seen in both autologous and allogeneic co-cultures. Stimulation of non-collagenous protein was also noted. Co-culture supernatants contained soluble substances that were capable of stimulating collagen production, although they stimulated collagen production to a lesser degree than direct co-culture. Fractionation of these supernatants on Sephadex G-200 revealed a predominant area of stimulatory activity at 160,000 mol wt. Lesser areas of activity were noted at molecular weights of 80,000 and 25,000. Determination of the types of collagen produced by fibroblasts during co-culture with MNL showed that the ratio of type I:III collagen was decreased. These alterations in both the quantitative and qualitative accumulation of collagen mimic the changes often seen in wound healing and early inflammation suggesting that cellular interactions between fibroblasts and MNL may be important in the modulation of collagen production in normal and pathologic states.
Dendritic cells are the principal stimulators of the primary mixed leukocyte reaction in mice
Authors: Steinman RM , Gutchinov B , Witmer MD , Nussenzweig MC
Published: June 2004

Clone 33D1 is a mouse-rat hybridoma that secretes a specific anti-dendritic cell (DC) monoclonal antibody (14). Because the antibody kills DC in the presence of rabbit complement, it can be used to study the functional consequences of selective DC depletion. Previous data on the cell specificity of 33D1 were first extended. By cytotoxicity (rabbit complement) and indirect immunofluorescence (biotin-avidin technique), 33D1 reacted with DC but not with macrophages nor other splenocytes. In contrast, the monoclonal antibody, F4/80 (15), reacted with macrophages but not DC.

The functional assay evaluated in this paper was stimulation of the primary mixed leukocyte reaction (MLR). 33D1 antibody itself did not inhibit stimulation by enriched populations of DC. In the presence of complement, 33D1 killed DC and ablated stimulatory function.

The effect of 33D1 and complement on MLR stimulation by heterogenous cell mixtures was then evaluated. Removal of DC from unfractionated spleen suspensions reduced stimulatory capacity 75-90 percent, comparable to that produced with specific anti-Ia antibody and complement. Stimulation of both proliferative and cytotoxic responses was reduced. DC depletion had similar effects on MLR generated across full strain differences, or across selected subregions (H2I, H-2K/D) of the major histocompatibility complex.

To further compare the functional properties of spleen DC and macrophages, MLR stimulation by adherent and nonadherent fractions of spleen were tested separately. 62 +/- 8 percent of the total stimulatory capacity of spleen was in the plastic adherent population. Activity was ablated greater than 90 percent after elimination of DC. MLR stimulation by 24-h cultures of spleen adherent cells, which contained a three- to sixfold excess of Ia(+) macrophages, was also ablated when DC were removed. Stimulation by nonadherent spleen was more resistant, but was reduced 50-75 percent by 33D1 and complement.

The function of spleen cells treated with 33D1 or anti-Ia antibody and complement was restored with a small inoculum of purified DC. The latter corresponded to 0.5 percent of total stimulator cells and were enriched by previously described techniques that did not require the 33D1 antibody.

We conclude that the DC, a trace component of mouse spleen, is the principal cell type required for stimulation of the primary MLR. Because other cells are not immunogenic, but do express Ia and H-2 alloantigens, DC likely represent the critical accessory cell required for the induction of lymphocyte responses.
Clonotypic structures involved in antigen-specific human T cell function. Relationship to the T3 molecular complex.
Authors: Meuer S C , Fitzgerald K A , Hussey R E , Hodgdon J C , Schlossman S F , Reinherz E L
Published: June 2004

Monoclonal antibodies were produced against a human cytotoxic T cell clone, CT8III (specificity: HLA-A3), with the view of defining clonally restricted (clonotypic) surface molecules involved in its antigen recognition function. Two individual antibodies, termed anti-Ti1A and anti-Ti1B, reacted exclusively with the CT8III clone when tested on a panel of 80 additional clones from the same donor, resting or activated T cells, B cells, macrophages, thymocytes, or other hematopoietic cells. More importantly, the two antibodies inhibited cell-mediated killing and antigen-specific proliferation of the CT8III clone but did not affect the functions of any other clone tested. This inhibition was not secondary to generalized abrogation of the CT8III clone's function, because interleukin 2 responsiveness was enhanced. To examine the relationship of the structures defined by anti-clonotypic antibodies with known T cell surface molecules, antibody-induced modulation studies and competitive binding assays were performed. The results indicated that the clonotypic structures were associated with, but distinct from, the 20,000-mol wt T3 molecule expressed on all mature T lymphocytes. Moreover, in contrast to anti-T3, anti-Ti1A and anti-Ti1B each immunoprecipitated two molecules of 49,000 and 43,000-mol wt from 131I-labeled CT8III cells under reducing conditions. The development of monoclonal antibodies to such polymorphic T cell surface structures should provide important probes to further define the surface receptor for antigen.
Evidence for a mature B cell subpopulation in Peyer's patches of young adult xid mice.
Authors: Eldridge J H , Kiyono H , Michalek S M , McGhee J R
Published: June 2004

Peyer's patch (PP) and mesenteric lymph node (MLN) cell cultures from young adult X-linked immunodeficient (xid) CBA/N and (CBA/N X DBA/2) F1 male mice support primary anti-sheep erythrocyte (SRBC) plaque-forming cell (PFC) responses, which suggests that gut-associated lymphoreticular tissue (GALT) contains a normal B lymphocyte subpopulation. Further support for this was provided by the observation that PP cells from xid mice gave responses to both TI-1 and TI-2 antigens that were similar to the responses of PP cell cultures from normal mice. Spleen cell cultures from xid mice were unresponsive to SRBC and TI-2 antigens. Proof that GALT of xid mice contain mature B lymphocytes was provided by the demonstration of PP B cells that bear a low density of surface immunoglobulin M. When these cells were separated by flow cytometry and immunized with trinitrophenyl (TNP)-Ficoll in vitro, good anti-TNP PFC responses were observed. These results suggest that GALT of young adult xid mice contain mature B cells and may represent the origin for the mature B cell responses seen in aged xid mice.
Interleukin 1 stimulation of collagenase production by cultured fibroblasts.
Authors: Postlethwaite A E , Lachman L B , Mainardi C L , Kang A H
Published: June 2004

Interleukin 1 is a monokine that exerts biological effects on a variety of target cells in vitro. In this report, interleukin 1 has been found to be capable of stimulating collagenase production by cultured dermal fibroblasts. The concentrations of interleukin 1 that stimulate fibroblast collagenase production are similar to those that stimulate mouse thymocyte proliferation. Analyses by high performance liquid chromatography indicate that interleukin 1, rather than a contaminating monokine, is responsible for this effect on fibroblasts. Interleukin 1, released in vivo by macrophages infiltrating sites of tissue damage or inflammation, may function to stimulate the release of collagenase by connective tissue fibroblasts.
Isotypic and allotypic specificity of mouse rheumatoid factors.
Authors: Van Snick J L , Stassin V , de Lestré B
Published: June 2004

The specificity of polyclonal mouse rheumatoid factors (RF) was analyzed by competition experiments with heat-aggregated mouse IgG subclasses. The RF spontaneously produced by three normal mouse strains (129/Sv, CBA/Ht, and C57Bl/6) and by two strains with autoimmune diseases (MRL/l and NZB) were found to consist of distinct non-cross-reactive antibody subpopulations each specific for one IgG subclass. The sera of the normal strains contained IgG1- and IgG2a-specific RF. The autoimmune strains produced an additional variety of RF that was specific for The autoimmune strains produced an additional variety of RF that was specific for IgG2b. Also, the RF secreted by spleen cells of various normal strains after in vitro polyclonal activation with lipopolysaccharide could be resolved into distinct subpopulations specific for IgG1 or IgG2a. These results were confirmed by the analysis of monoclonal RF derived from BALB/c, C57Bl/6, CBA/Ht, and 129/Sv mice: of 73 hybridomas with RF activity, 71 displayed a strict subclass specificity. The subclass predominantly recognized depended on the origin of the spleen cells used to generate the hybridomas. After polyclonal activation in vitro, a broad spectrum of different specificities was obtained with 16 RF specific for IgG1, 13 for IgG2a, and 4 for IgG2b. In contrast, 27 of 28 monoclonal RF derived from 129/Sv and BALB/c mice without prior polyclonal activation were specific for IgG2a, and of these 75% were allotype specific since they failed to react with IgG2a of the b allotype. These results demonstrate the importance of subclass specificity in the production of RF in vivo. With the exception of the IgG2b-specific clones, all these monoclonal RF reacted preferentially with heat-aggregated or antigen-bound IgG. Among the hybridomas generated by the fusion of in vitro polyclonally activated spleen cells of 4-wk-old mice, the frequency of clones with RF activity was at least 40 times higher than that of clones specific for mouse IgM, human IgG, ovalbumin, and hen lysozyme.
Escape of mouse mastocytoma P815 after nearly complete rejection is due to antigen-loss variants rather than immunosuppression.
Authors: Uyttenhove C , Maryanski J , Boon T
Published: June 2004

Even though mastocytoma P815 often undergoes a nearly complete rejection in syngeneic mice, the tumor cells almost always escape to form progressive tumors. We found that this was not due to the establishment of an immunosuppressed state because genetically marked P815 cells, that were injected in mice where tumor escape was occurring, were readily rejected. An analysis of escaping tumor cell populations with anti-P815 cytolytic T lymphocyte (CTL) clones showed the presence of stable resistant variants. Using antigen-loss variants found in escaping populations or selected in vitro with CTL clones, we were able to define four different tumor-associated antigenic specificities, each recognized by a specific CTL clone. One of these specificities was absent from all escaping tumor cells and another had been lost by some of them.
On the function of Ly-5 in the regulation of antigen-driven B cell differentiation. Comparison and contrast with Lyb-2.
Authors: Yakura H , Shen F W , Bourcet E , Boyse E A
Published: June 2004

Generation of anti-sheep erythrocyte plaque-forming cells (PFC) is greatly reduced in the presence of monoclonal Ly-5 alloantibody. Although Ly-5 is expressed in one of its molecular forms on T cells and macrophages (M phi ) involved in this response, the only demonstrated action of Ly-5 antibody was on B cells. Evidence from elimination of Lyt-2+ cells, and from the responses of serial proportions of Ly-5.1 and Ly-5.2 cells and of Ly-5 heterozygous cells, signifies that PFC reduction cannot be ascribed to any known mechanism of suppression or to a direct suppressive action of Ly-5 antibody on B cells. A critical distinction of Ly-5 from Lyb-2 is that Ly-5 antibody reduces PFC generation to trinitrophenylated Ficoll, a thymus-independent type 2 antigen requiring T cells and M phi for maximal PFC generation in vitro. A second distinction is that PFC reduction by Ly-5 antibody is strictly tied to the time of operation of M phi factor, whereas PFC reduction by Lyb-2 antibody relates to the time of B cell triggering by antigen. Accordingly, M phi factor competitively and quantitatively inhibits the action of Ly-5 antibody in reducing PFC generation. It is likely that the Ly-5 system is concerned in the reception or handling of M phi message by B cells.
Two independent receptors allow selective target lysis by T cell clones.
Authors: Binz H , Fenner M , Frei D , Wigzell H
Published: June 2004

Dimethylbenzanthracene-induced P1 sarcoma cells induce P1-specific antibodies in syngeneic DA rats. Antiidiotypic antibodies of specificity DA anti-(DA anti-P1) were induced against the tumor-specific antibodies and used to restimulate P1-primed DA T cells in vitro. Using antiidiotypic antibodies and T cell growth factor, P1-specific cytotoxic DA T cell clones were established by limiting dilution and kept in vitro. Two of these clones acquired during culture periods in addition to the P1 specificity lytic activity towards natural killer (NK) targets YAC-1 or K562. Cold target inhibition experiments showed that the very same cytotoxic T cells kill P1 and NK targets. Antiidiotypic antibodies of specificity DA anti-(DA anti-P1) inhibited cytotoxicity against P1 but not against YAC-1 or K562. We conclude that two independent receptors are located on these double-reactive T cell clones, one that is idiotypic and antigen-specific, and another displaying the binding profile of NK cells.
Studies of insulin resistance in adipocytes induced by macrophage mediator.
Authors: Pekala P , Kawakami M , Vine W , Lane M D , Cerami A
Published: June 2004

An apparent insulin resistance is noted in 3T3-L1 adipocytes after the addition of an endotoxin-induced mediator from macrophages. Examination at the level of the insulin receptor has revealed that the mediator does not effect either the functional ability of the cells to bind insulin or the ability of insulin to stimulate the uptake of glucose. The resistance appears to reflect a post-receptor interference with the insulin-induced biosynthesis of the anabolic enzymes, acetyl Co-A carboxylase and fatty acid synthetase, which are required for the conversion of glucose into storage lipid. These studies offer a new in vitro model for investigating the molecular basis of insulin resistance.
Receptor-mediated entry of beta-glucuronidase into the parasitophorous vacuoles of macrophages infected with Leishmania mexicana amazonensis.
Authors: Shepherd V L , Stahl P D , Bernd P , Rabinovitch M
Published: June 2004

125I-labeled rat preputial gland beta-glucuronidase was shown by light and electron microscopic radioautography to accumulate within the parasitophorous vacuoles of in vitro derived bone marrow macrophages infected with Leishmania mexicana amazonensis. beta-glucuronidase uptake was mediated by the mannose receptor, since the penetration of the ligand was inhibited by mannan. Uptake was detected as soon as 4 h after incubation of infected cells with the ligand, and increased at 24 and 48 h. The label persisted in the vacuoles for at least 24 h after a 24-h pulse with the ligand, a finding compatible with the relatively long half-life of labeled beta-glucuronidase in normal macrophages. Parasitophorous vacuoles were also labeled in macrophages exposed to the ligand only before infection, indicating that secondary lysosomes containing the ligand fused with the parasitophorous vacuoles. Another mannosylated ligand, mannose-BSA, which, in contrast to beta-glucuronidase, is rapidly degraded in macrophage lysosomes, did not detectably accumulate in the vacuoles. The results support and extend information previously obtained with electron opaque tracers that emphasizes the phagolysosomal nature of Leishmania parasitophorous vacuoles. In addition, the results suggest that appropriate mannosylated molecules may be used as carriers for targeting of leishmanicidal drugs to the parasitophorous vacuoles of infected macrophages.
Surface antigens of Leishmania donovani promastigotes.
Authors: Lepay D A , Nogueira N , Cohn Z
Published: June 2004

Surface antigen profiles of Leishmania donovani promastigote isolates have been studied. Surface patterns of Brazilian and African isolates display remarkable similarities and are extremely simple, consisting of three major peptides of 65,000, 25,000, and 23,000 mol wt. Surface iodination and biosynthetic labeling coupled to immunoprecipitation techniques revealed that a single major determinant of 65,000 mol wt is recognized in all strains by sera from kala-azar patients from both Brazil and Africa. This major determinant is not brought down by sera from normal individuals and shows no significant cross-reactivity with sera from Chagas' disease, leprosy, or syphilis patients. Binding to concanavalin A suggests a glycoprotein nature for this antigen. Sera from patients with cutaneous leishmaniasis (L. braziliensis) also recognized the same 65,000-mol wt determinant, although to a lesser extent. The possibility that this major surface antigen is shared, with minor differences, not only by L. donovani strains but between Leishmania species in general is suggested.
Mononuclear phagocyte system of the mouse defined by immunohistochemical localization of antigen F4/80. Identification of resident macrophages in renal medullary and cortical interstitium and the juxtaglomerular complex
Authors: Hume DA , Gordon S
Published: June 2004

Macrophages have been identified in mouse kidney by immunohistochemical localization of the macrophage-specific antigen F4/80. They constitute the majority of the renal medullary interstitial cell population and are also found in contact with cortical distal and proximal tubules and Bowman's capsule. They are a physical component of the juxtaglomerular complex.
B cell dependence on and response to accessory signals in murine lupus strains.
Authors: Prud'homme G J , Balderas R S , Dixon F J , Theofilopoulos A N
Published: June 2004

B cell hyperactivity, a feature common to all lupus-prone murine strains, may be caused by hyperresponsiveness to, overproduction of, or bypassing of certain signals required for B cell activation, proliferation, and differentiation. In this study, we have compared the responses of B cells from three lupus-prone strains of mice (BXSB males, MRL and NZB/W females) and normal strains in a number of assays for which two or more signals are required to obtain a response. In medium to low density cultures of B cells from BXSB and NZB/W but not MRL/l lupus mice, the cells' proliferation induced by bacterial lipopolysaccharide (LPS) or anti-mu antibody was much higher than that of B cells from normal controls. At low B cell density, polyclonal activation by these substances and subsequent Ig secretion were dependent on accessory signals present in supernatants of concanavalin A-treated normal lymphocytes (CAS) or on the MRL/l proliferating T cell-derived B cell differentiation factor (L-BCDF) in both lupus-prone and immunologically normal mice. However, the responses of B cells from BXSB and NZB/W, but not MRL/l, mice to these accessory signals were higher than those of normal mice. Ig synthesis by fresh B cells of BXSB and NZB/W mice cultured in the absence of mitogens but in the presence of CAS or L-BCDF was higher than by similar cells from other strains, suggesting an increased frequency of B cells activated in vivo in these two autoimmune strains of mice. The patterns of IgG subclass secretion in response to LPS (without added CAS or L-BCDF) were abnormal in all lupus strains, with a predominance of IgG2b and/or IgG2a and low levels of IgG3, contrary to normal B cells for which IgG3 synthesis predominated. However, IgG1 synthesis in vitro by autoimmune and normal B cells alike was highly dependent on T cell-derived soluble mediators. Antigen-specific responses to SRBC in vitro of B cells from all lupus strains, like those of B cells from normal strains, required a minimum of three signals (antigen, LPS, T cell-derived antigen nonspecific helper factors). Yet, once triggered, B cells of BXSB and NZB/W mice gave higher responses than those of the other strains. We conclude that B cells of lupus mice have signal requirements similar to those of normal mice. Nevertheless, B cells of BXSB and NZB/W, but not MRL/l, lupus mice hyperrespond or process some accessory signals abnormally.