bluuebunny/crossref_metadata_2025_split huggingface dataset:
The interaction of monoclonal antibodies with MHC class I antigens on mouse spleen cells. I. Analysis of the mechanism of binding.
Authors: Dower S K , Ozato K , Segal D M 
Published: December 2022

Abstract
We studied the mechanism of binding of radiolabeled, monoclonal anti-H-2 antibodies to mouse spleen cells to determine the number of H-2 antigen molecules per cell. Equilibrium and kinetic data were analyzed in detail according to theoretical models developed for different modes of antibody binding. The results of binding experiments from three monoclonal IgG antibodies (36-7-5, anti-Kk; 27-11-13, anti-DbDd; and 11-4-1, anti-Kk) and their F(ab')2 and F(ab') fragments show that for the IgG and F(ab')2 from all three antibodies, the monovalently and bivalently bound states of the antibody co-exist in rapid equilibrium with one another on the cell surface, with the bivalent state predominating. We show that the relative proportions of the monovalently and bivalently bound species can be estimated from dissociation kinetics experiments, and that once the mode of antibody binding has been established, the density of H-2 determinants on the cell surface can be estimated from equilibrium-binding data. We conclude that the average numbers of H-2K and H-2D molecules on B10.A spleen cells are 5 X 10(4) and 1.1 X 10(5) molecules/cell, respectively.
A novel differentiation antigen on proliferating murine thymocytes identified by a rat monoclonal antibody.
Authors: Takei F 
Published: December 2022

Abstract
A surface antigen on the mouse lymphoma cell line EL-4 has been identified by a rat monoclonal antibody. The antigen, YE1/7.1, is strongly expressed on at least two other T lymphoma cell lines, BW5147 and MBL-2, but not on several Thy-1-lymphoid cell lines. This antigen is not significantly expressed on normal adult thymocytes, spleen cells, bone marrow cells, or mitogen-activated T and B cells as tested by radioimmunoassay or fluorescence analysis using flow cytometry. Whether a small number (up to 5%) of very weakly positive cells in Con A-stimulated spleen cell populations represent a unique subpopulation is unknown. This antigen is, however, demonstrable on a subpopulation of fetal thymocytes as well as on mitogen-activated adult thymocytes. When adult thymocytes are separated by agglutination with peanut agglutinin (PNA) into PNA+ and PNA-, and stimulated with Con A in the presence of Con A culture supernatant, YE1/7.1 antigen is expressed on the majority of stimulated PNA+ cells but only weakly on a small proportion of PNA- cells. It therefore seems likely that the YE1/7.1 is a differentiation antigen expressed on a population of proliferating immature thymocytes. Immunoprecipitation of the antigen from the surface of iodinated EL-4 cells shows it to have an apparent m.w. of 60,000 under reducing and nonreducing conditions.
Activation of the first component of complement, C1, by a monoclonal antibody recognizing the C chain of C1q.
Authors: Heinz H P , Burger R , Golan M D , Loos M 
Published: December 2022

Abstract
The effect of a purified monoclonal anti-C1q anti-body (Ab 242 G3) on the function of C1q, a subcomponent of the first component of complement C1, was studied. No inhibition of purified activated C1 was observed, whereas binding of the Ab to fluid phase C1q, to C1q bound to immune complexes (EAC1q), or to serum C1 in fluid phase resulted in a dose-dependent inhibition of the hemolytic activity of C1. In contrast, when the effect of the Ab on serum C1 bound to immune complexes (EAC1) was measured, no inhibition, but a dose-dependent enhancement, of the hemolytic activity was obtained. The dose-response curve of the Ab-treated cell-bound serum C1 was indistinguishable from that of activated C1. Isolated Fab fragments of this Ab did not cause an increase in C1 activity. After separation of the A, B, and C chains of C1q by SDS-PAGE, Ab 242 G3 reacted in immunoblotting selectively with the C chain. These data indicate that cross-linking of C1q via the C chain of C1q might lead to an internal activation of C1.
Oxygen metabolism in cloned macrophage cell lines: glucose dependence of superoxide production, metabolic and spectral analysis.
Authors: Kiyotaki C , Peisach J , Bloom B R 
Published: December 2022

Abstract
The requirements of a cloned macrophage-like cell line, J774.16, for oxygen metabolism, and the nature of the defect in oxidative metabolism in a variant clone derived from it, J774.C3C, were studied. Upon stimulation with phorbol myristate acetate (PMA), the parental clone produced approximately 1 nmol O2-/min/10(6) cells, whereas the variant clone produced no detectable O2- under the same conditions. Sustained O2- production by J774.16 was totally dependent on extracellular glucose; in glucose-free medium, the cells initiated O2- production but could not sustain it. When cells were stimulated with PMA, glucose-C-1 oxidation of J774.16 cells increased 20-fold while that of J774.C3C remained at resting levels. O2- production in J774.16 cells was inhibited by some agents known to block mitochondrial electron transport before coenzyme Q, such as rotenone and tetrathiafulvalene, whereas antimycin A enhanced O2- production. A dissociation between O2- production and glucose-C-1 oxidation was observed when J774.16 was treated with certain metabolic inhibitors. Quinacrine, 2,4-dinitrophenol, chlorpromazine, and trifluoperazine inhibited O2- production completely under conditions in which glucose-C-1 oxidation was reduced only by 30%. Rotenone inhibited O2- production with no effect on glucose-C-1 oxidation whereas antimycin A augmented O2- production 50% but inhibited glucose oxidation by 20%. Glucose transport studies, with 2-deoxy-D-glucose, showed that the Km for glucose transport of both clones was about 1 mM, indicating that cells could effectively transport glucose even at low concentrations. The Vmax for glucose transport in both J774.16 and variant J774.C3C cells doubled after PMA stimulation, indicating that the variant was effectively stimulated by PMA, even though O2- was not produced. Similarly, PMA induced protein phosphorylation in both clones. No differences between clones J774.16 and J774.C3C in hexokinase, glucose-6-phosphate dehydrogenase, 6-phosphogluconate dehydrogenase, glutathione reductase, or glutathione peroxidase activities could be found. When dithionite-reduced and -oxidized difference spectra of plasma membranes of these clones were compared, comparable levels of b-type cytochrome were found in both clones. However, CO difference spectra indicated that CO was bound to a b-type cytochrome (presumed to be b-245) in clone J774.16 but not in J774.C3C.(ABSTRACT TRUNCATED AT 400 WORDS)
VL-VH expression by monoclonal antibodies recognizing avian lysozyme.
Authors: Smith-Gill S J , Mainhart C R , Lavoie T B , Rudikoff S , Potter M 
Published: December 2022

Abstract
Seven BALB/c hybridoma antibodies directed against the protein antigen, hen egg-white lysozyme c (HEL), were characterized on the basis of their ability to bind lysozymes from 10 species of birds, and their ability to bind HEL competitively. The hybridomas were separable into three complementation groups based upon competitive interactions. The fine specificities of all antibodies were distinct, but two, HyHEL-8 and HyHEL-10, had very similar and overlapping reactivity patterns. To test the hypothesis that VL-VH pairing correlates with binding specificity, the N-terminal amino acid sequences were determined to identify the VL and VH isotopes (subgroups) of the anti-HEL antibodies. HyHEL-8 and -10 shared the VK23 light chain isotype and nearly identical heavy chains in Kabat subgroup I, whereas the heavy and light chain isotypes of all other antibodies differed from HyHEL-8 and -10 and from each other. The heavy and light chain isotypes expressed by HyHEL-8 and -10 are also expressed by XRPC-25, a DNP-binding myeloma protein that does not bind lysozyme. These results are discussed with respect to the contributions of various genetic sources of structural diversity to antibody functional diversity.
Allogeneic bone marrow transplantation in mice after total lymphoid irradiation: influence of breeding conditions and strain of recipient mice.
Authors: Waer M , Ang K K , Van der Schueren E , Vandeputte M 
Published: December 2022

Abstract
Different groups of C57BL/ka or BALB/c mice received a dose of 34 Gy or 42 Gy of fractionated total lymphoid irradiation (TLI) before bone marrow transplantation with 30 X 10(6) BALB/c or C57BL nucleated bone marrow cells, respectively. BALB/c mice that were not bred in specific pathogen-free conditions before TLI showed a high morbidity and mortality rate after 34 Gy of TLI and allogeneic bone marrow transplantation as compared with BALB/c or C57BL that were bred in pathogen-free conditions before irradiation. Many of the conventionally bred BALB/c mice had clinical and histologic signs of graft-vs-host disease after TLI and allogeneic bone marrow infusion. Although leucocytosis and lymphocytosis and the immunologic competence as measured with in vitro tests were equally depressed after 34 Gy TLI in BALB/c and C57BL mice, chimerism was nevertheless significantly easier to obtain in BALB/c mice. The incidence of chimerism after TLI could be enhanced in C57BL mice by increasing the total radiation dose from 34 to 42 Gy. This augmentation of chimerism was paralleled by the induction of more suppressor cells after 42 Gy of TLI in C57BL mice.
The long-lived medullary thymocyte re-visited: precise quantitation of a very small subset.
Authors: Scollay R 
Published: December 2022

Abstract
The cortical and medullary regions of the thymus are well defined, both histologically and in terms of the phenotype and immunocompetence of the cells found in them. The relationship between the two populations is controversial however, and we still do not know which one contains the immediate precursors of peripheral T cells. Data derived from thymus grafts have suggested that medullary cells remain in the thymus for very long periods (perhaps a year or more) and this has been used as argument against the medulla being the source of significant numbers of emigrating cells. In those experiments, however, the T6 chromosomal marker was used to distinguish graft from host cells, so only cells that were dividing or could be induced to divide were detected, leaving the possibility of a considerable bias in the sample. We have repeated these experiments, but have used donor/host combinations differing at the Thy-1 locus, so that greater than 99% of graft cells could be analyzed. We have shown that medullary cells with a life span of more than a few weeks make up considerably less than 1% of the total thymocyte population, although these long-lived cells appear to be a real and potentially interesting population. Thus a long intrathymic life span is not typical of medullary cells in general and cannot be used as an argument against the medulla as a possible source of emigrant T cells.
The role of T cell subsets in the generation of secondary cytolytic responses in vitro against class I and class II major histocompatibility complex antigens.
Authors: Vidović D , Klein J , Nagy Z A 
Published: December 2022

Abstract
Strain combinations generating cytotoxic T lymphocytes (CTL) specific for a single class I (K or D) or class II (A or E) MHC molecule were set up. The responder cells were separated into Ly subsets (Ly-1+2-, Ly-1-2+, and Ly-1+2+) on day 5 of culture by using lytic or non-lytic selection techniques and monoclonal Ly-specific antibodies. The separated subsets were restimulated on day 8 and tested for secondary CTL activity on day 12. Class II-specific secondary CTL could be generated from all three subsets, whereas class I-specific CTL developed only in the Ly-1+2+ and Ly-1-2+ subsets. The Ly-1+2+ cells underwent a phenotypic shift to Ly-1-2+ by day 12, whereas CTL generated from the Ly-1+2- and Ly-1-2+ subsets retained their phenotype up to the secondary effector stage. The cells separated according to their Ly phenotypes on day 5 were the progeny of unprimed progenitors expressing the same Ly phenotypes. Unprimed Ly-1+2+ cells gave rise to CTL in the absence of the other subsets, while unprimed Ly-1+2- and Ly-1-2+ cells required the help of Ly-1+2+ cells (or soluble factors) during priming to become non-lytic CTL precursors by day 5, and cytolytic cells after restimulation. The Ly-1+2- subset could generate class II-specific secondary CTL only in the absence of the other two subsets. Apparently, alloantigen-primed Ly-1+2+ and Ly-1-2+ cells suppressed the development of cytolytic activity in the Ly-1+2- subset. The combined data provide a comprehensive pathway of CTL differentiation from T cell subsets.
Epidermal Langerhans cells can function as stimulatory cells but not as accessory cells in CTL induction.
Authors: Tsuchida T , Iijima M , Fujiwara H , Pehamberger H , Shearer G M , Katz S I 
Published: December 2022

Abstract
In this study, we determined whether Langerhans cells (LC) can function as both stimulatory and accessory cells (ACC) in alloreactive and syngeneic modified CTL induction in vitro. LC exhibited potent Ia+ stimulatory function, comparable to spleen cells, in both allo-CTL induction and in TNP-modified CTL induction assays. In contrast to spleen cells, however, when LC were syngeneic to the responders in an Ia+-adherent cell-depleted CTL culture, they could not restore the CTL responses. This was due, in part, to the suppression of CTL induction, presumably via secretion of prostaglandin E by epidermal cells (EC), because addition of indomethacin reversed the suppression. Even in the presence of indomethacin, however, LC were unable to exhibit ACC function. Finally, we tested the possibility that both Ia+ and Ia- cells were required to fulfill ACC functions. However, when spleen cells treated with anti-Ia antibody and complement and EC and indomethacin were added to an Ia+-adherent cell-depleted CTL culture, there was no significant restoration of the CTL response. Thus, LC can clearly act as Ia+ stimulatory cells in CTL induction but cannot serve as ACC in CTL induction, whereas Ia+ spleen cells may subserve both functions. These data suggest a functional heterogeneity of Ia+ antigen-presenting cells in spleen and in epidermis.
Immunoglobulin production by human peripheral lymphocytes induced by anti-C3 receptor antibodies.
Authors: Daha M R , Bloem A C , Ballieux R E 
Published: December 2022

Abstract
The exact function of receptors for C3b (CR1), which are present on B lymphocytes, is not clear. The present studies were performed to determine the influence of heterologous anti-CR1 on the production of IgM, IgG, and IgA by human peripheral B lymphocytes in vitro. Anti-CR1, raised in rabbits by immunization with purified erythrocyte CR1, was rendered immunospecific and was converted to F(ab')2 and Fab' by enzyme digestion. Pre-immune F(ab')2 and Fab' served as controls. Normal human blood T lymphocytes and T cell-depleted mononuclear cells were cultured for 6 days in RPMI medium and 10% heated fetal calf serum with a low dose (7 micrograms/ml) of pokeweed mitogen (PWM) alone or with PWM and F(ab')2-anti-CR1. In control experiments the effects of F(ab')2-anti-CR1 without PWM and of pre-immune F(ab')2, Fab'-anti-CR1 and pre-immune Fab' in combination with PWM were also tested. When PWM and F(ab')2-anti-CR1 were present simultaneously, 4.3 X 10(3), 2.5 X 10(3), and 1.8 X 10(3) ng/ml of IgM, IgG, and IgA were synthesized, respectively, in cultures containing 4.5 X 10(5) mononuclear blood cells. All other combinations resulted in synthesis of less than 250 ng/ml of each class of Ig. The presence of purified CR1 in the cultures containing PWM and F(ab')2-anti-CR1 caused a dose-dependent decrease of Ig synthesis. By culturing B cells isolated by E-C3b rosetting with T cells and monocytes, the anti-CR1 responding population was demonstrated to be mainly in the CR1-rich B cell fraction. Fab'-anti-CR1 at high doses was also able to stimulate Ig production in the presence of low concentrations of PWM. These data suggest that triggering of CR1 on B cells results in modulation of antibody production and that triggering of CR1 with more than one antibody is required for an optimal response.
Induction of lymphocyte blast transformation by purified fibronectin in vitro.
Authors: Lause D B , Beezhold D H , Doran J E 
Published: December 2022

Abstract
Purified rat plasma fibronectin (Fn) induces a dose-dependent, nonspecific proliferation of lymphoid cells isolated from spleen and lymph nodes, but has no effect on thymocytes. Proliferation of cells occurred after 4 to 5 days of incubation and was generally 5- to 10-fold greater than control cells cultured without Fn or in the presence of the same concentrations of rat serum albumin. The responding cell appears to be the T cell and requires the presence of adherent accessory cells (macrophages). Although purified T and B cells failed to demonstrate a significant increase in blastogenesis in the presence of Fn, reconstitution of T, but not B, cells with irradiated peritoneal exudate macrophages restored the stimulatory effect of Fn. Furthermore, comparison of the effect of various concentrations of macrophages on the restored T cell response shows that proliferative activity in the presence of Fn is dependent on a critical number of macrophages. Adding higher numbers of macrophages beyond the optimal concentration results in a sharp decline in lymphocyte responsiveness to Fn, although the proliferation of control cells continues to increase at these macrophage concentrations. Macrophages pulsed with Fn for 1 hr failed to evoke an increase in T cell responsiveness after 3 or 5 days of incubation. In addition, incubation of Fn-pulsed T cells with macrophages that had been precultured with or without Fn also failed to result in T cell activation. The effect of Fn on T lymphocyte transformation appears to be mediated indirectly through its interaction with the macrophage, because 125I-Fn, which shows significant binding to peritoneal exudate macrophages, fails to interact with purified T cells. Radiolabeled Fn also demonstrated little or no binding activity for unseparated lymph node cells.
Natural and recombinant Escherichia coli-derived interferon-gamma differ in their reactivity with monoclonal antibody.
Authors: Le J , Rubin B Y , Kelker H C , Feit C , Nagler C , Vilcek J 
Published: December 2022

Abstract
Monoclonal antibody GIF-1 was found to neutralize human natural immune interferon (IFN-gamma), but not Escherichia coli-derived recombinant IFN-gamma. In addition, GIF-1 antibody failed to immunoprecipitate 125I-labeled recombinant IFN-gamma, whereas it precipitated natural IFN-gamma in a concentration-dependent manner. The lack of recognition of recombinant IFN-gamma by antibody GIF-1 may not be due to the absence of the oligosaccharide moiety in the molecules of recombinant IFN-gamma alone, because removal of carbohydrate from natural IFN-gamma by treatment with a mixture of glycosidases did not alter the selective binding of antibody, i.e., deglycosylated and untreated natural IFN-gamma were equally neutralized and immunoprecipitated by GIF-1 antibody. In addition, a minor monomeric component of natural IFN-gamma with the m.w. of 15,500, which apparently lacks carbohydrate, was also recognized by antibody GIF-1. These results suggest that the discriminative recognition of natural and recombinant IFN-gamma by monoclonal antibody GIF-1 may be due to a conformational difference at or near the active regions of natural and recombinant human IFN-gamma molecules.
Induction of interleukin 1 messenger RNA and translation in oocytes.
Authors: Windle J J , Shin H S , Morrow J F 
Published: December 2022

Abstract
Macrophages and P388D1 murine cultured cells produce interleukin 1 (lymphocyte-activating factor) when stimulated with lipopolysaccharide or other agents. Poly A+ RNA extracted from either type of stimulated cells and injected into Xenopus oocytes causes synthesis of material with the biologic and biochemical properties of interleukin 1. It potentiates lectin-mediated thymocyte proliferation, and it has the molecular dimensions of interleukin 1, as determined by gel exclusion chromatography. RNA from either cell type causes the synthesis of interleukin 1 with an isoelectric point of 4.8 to 5.0. RNA prepared from unstimulated macrophages or P388D1 cells does not cause interleukin 1 production by oocytes. We conclude that the amount of interleukin 1 mRNA increases greatly after stimulation of either cell type, and oocytes carry out any modifications of the polypeptide necessary for activity. The kinetics of interleukin 1 mRNA accumulation and of interleukin 1 production by macrophages and P388D1 cells are compared.
Neoantigens appear in human IgG upon antigen binding: detection by antibodies that react specifically with antigen-bound IgG.
Authors: Brown E J , Bekisz J 
Published: December 2022

Abstract
We raised rabbit antibodies that specifically recognize antigen-bound but not monomeric human IgG. These rabbit IgG antibodies (RAb) were induced in rabbits that were made tolerant to monomeric human IgG. They bound to immune complexes (IC) made with human IgG and various antigens including tetanus toxoid, sheep erythrocytes (E), rabbit E, or human Rh(D) + E, and were very poorly inhibitable with monomeric IgG compared to conventional rabbit anti-human IgG. RAb did not recognize complement components bound to the IgG containing IC. Cleavage of the Fc domain from human IgG markedly decreased binding of RAb to IC. Surprisingly, RAb did not bind to heat-aggregated human IgG (agg-IgG) better than to monomeric IgG. We conclude that human IgG expresses an Fc neoantigen when it binds its own antigen, and that this determinant is not expressed by agg-IgG. The implications of these findings for the biologic functions of antigen-complexed IgG are discussed.
Ia antigens and associated invariant chain are induced simultaneously in lines of T-dependent mast cells by recombinant interferon-gamma.
Authors: Koch N , Wong G H , Schrader J W 
Published: December 2022

Abstract
Metabolic labeling and immunoprecipitation with monoclonal antibodies, showed that lines of T-dependent mast cells (P cells) that were cultured in the absence of interferon-gamma (IFN-gamma) did not synthesize detectable amounts of Ia antigens or the invariant chain (Ii). After exposure for 24 hr to IFN-gamma produced from the cloned Mu IFN-gamma gene, P cells synthesized large amounts of Ia alpha- and beta-chains and of the invariant chain. The I-A and I-E antigens of these T-dependent mast cells were indistinguishable from those of B cells in terms of the binding of a panel of monoclonal antibodies and in terms of their structure and that of associated molecules as analyzed in two-dimensional gels. The effect of IFN-gamma on Ii synthesis in P cells was not due merely to inhibition of proliferation, as is the case with certain B cell lines, because treatment of P cells with mitomycin C did not induce the invariant chain. Variant lines of P cells that did not respond to IFN-gamma with the synthesis of Ia antigens, but only the enhanced expression of H-2K, H-2D, and H-2L antigens, also failed to synthesize Ii chain. Experiments using three tumor lines related to B lymphocytes, however, indicated that in these cells IFN-gamma could enhance the synthesis of Ii in the absence of Ia antigens. Whereas Ii chain may be essential for Ia expression, Ii chain may have further functions and in some lines can be regulated independently by IFN-gamma in the absence of Ia antigen expression.