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Query: UMLS:C0023418 (leukemia)
 93,477 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Rat basophilic leukemia cells (RBL-2H3) have receptors for immunoglobulin E (IgE) and immunoglobulin G (IgG). These receptors for IgE mediate the endocytosis of chemically or immunochemically cross-linked IgE but not monomeric IgE. However, unoccupied receptors were endocytosed with cross-linked IgE. To further assess the degree and specificity of the observed coendocytosis, we exposed cells carrying monomeric rat IgE and monomeric mouse IgE anti-DNP to a DNP-protein conjugate. We found that up to 30% of the surface-bound monomeric rat IgE redistributed at 0 to 4 degrees C and was then internalized at 37 degrees C with the immunochemically cross-linked mouse IgE. To assess the specificity of the coendocytosis, we exposed cells carrying monomeric rat IgE to immunochemically cross-linked mouse IgG. We found that the binding, patching, and endocytosis of cross-linked mouse IgG had no effect on the monomerically bound rat IgE. The rate of coendocytosis was the same as the rate of endocytosis (t 1/2 3 to 5 min). The extent of coendocytosis depended on the extent of endocytosis but was relatively insensitive to changes in the ratio between mouse and rat IgE over a broad range. These results indicate that some of the receptors for IgE are associated in a specific fashion.
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PMID:The fate of IgE bound to rat basophilic leukemia cells. IV. Functional association between the receptors for IgE. 315 72

The studies reported here demonstrate that immunocompetent lymphoid cells from allogeneic donor guinea pigs stimulate the synthesis of anti-DNP and anti-OVA antibodies by recipients previously primed with DNP-OVA. This allogeneic effect occurs spontaneously in the absence of any further anti-genic challenge. Furthermore, the transfer of allogeneic cells prepares DNP-OVA-primed recipients for a striking secondary anti-DNP response to DNP-BGG; this occurs in equal degree whether or not the cells are derived from BGG-primed donors. We suggest that the allogeneic cells function by virtue of a specific immunologic attack of grafted cells on host cells. This conclusion is made on the basis of the following evidence: (a) The failure of observing the phenomenon with L(2)C leukemia cells and irradiated strain 2 lymph node and spleen cells which, although capable of initiating a host-versus-graft response, are incapable of mediating graft-versus-host reactions; and (b) the inability of (strain 2 x strain 13) F(1) hybrids to mediate the allogeneic effect in strain 13 recipients. The analysis of this phenomenon may offer a key to the delineation of mechanisms involved in the activation of precursors of antibody-forming cells.
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PMID:Carrier function in anti-hapten antibody responses. 3. Stimulation of antibody synthesis and facilitation of hapten-specific secondary antibody responses by graft-versus-host reactions. 410 11

It has been previously shown that alloantisera prepared by reciprocal immunization of strain 2 and strain 13 guinea pigs specifically block the activation of T lymphocytes from immune guinea pigs by antigens, the response to which is controlled by Ir genes. In this report we have examined the effect of absorption of the 13 anti-2 serum with different populations of lymphoid cells. It is unlikely that the inhibitory activity of the anti-2 serum on the proliferation of (2 x 13)F(1) lymphocytes to a DNP derivative of a copolymer of L-glutamic and L-lysine (DNP-GL) is due to the presence of antibodies specific for the unique antigenic determinants (idiotypes) of clonally distributed T-lymphocyte receptors. Thus, cells obtained from a normal animal and a DNP-GL immune animal were equivalent in their absorptive capacity. Populations of T lymphocytes were ineffective in absorbing either the cytotoxic or inhibitory activity of the anti-2 serum, while L(2)C leukemia cells, a malignant B-cell population, were most efficient in absorbing both activities. Thus, the antigen(s) against which the cytotoxic and inhibitory activities are directed are present to a greater extent on B lymphocytes than on T lymphocytes. However, these results do not allow us to definitively determine whether the inhibitory activity of the alloantisera is due to antibodies specific for Ir gene products or antibodies specific for linked antigens in the MHC. We also examined the effect of a number of anti-immunoglobulin reagents which had specificity for the heavy and/or light chains of guinea pig immunoglobulin on the in vitro lymphocyte proliferative response to antigen. Under conditions in which we were able to completely and specifically suppress the response of (2 x 13)F(1) lymphocytes to DNP-GL with anti-2 serum, the anti-immunoglobulin reagents were devoid of inhibitory effect on the response of these same F(1) cells to DNP-GL, a copolymer of L-glutamic and L-tyrosine (GT), or purified protein derivative of tuberculin (PPD). These results strongly suggest that conventional serum-type immunoglobulin is not important in antigen recognition by the T cells involved in the DNA synthetic response.
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PMID:Alloantiserum-induced inhibition of immune response gene product function. I. Cellular distribution of target antigens. 459 Nov 74

Monoclonal DNP-specific IgG (lambda 2 epsilon 2), IgM (kappa 2 mu2) and IgG [kappa 2 (gamma 1)2] were isolated fom the culture supernatant of hybridomas by affinity chromatography with 2,4-dinitrophenol bovine serum albumin (DNP-BSA) sepharose and characterized by biochemical and biological methods. The molecular weights were 84,200 for the epsilon chain, 55,400 for the gamma chain and 77,500 for the mu chain as determined by sodium dodecylsulphate polyacrylamide del electrophoresis (SDS-PAGE). The association constants for [3H]-DNP-lysine determined by equilibrium dialysis were 0 . 87 X 10(7) l/mol for IgE and 1 . 91 X 10(8) 1/mol for IgG1. The isoelectric focusing of the purified monoclonal antibodies revealed for IgG1 seven bands at a pH range of 6 . 3 - 7 . 2 and for IgE sixteen bands at a pH range of 4 . 5 to 6 . 8. the binding of 125I-anti-IgE to rat basophilic leukaemia (RBL) and rat mast cells which had been preincubated with various amounts of monoclonal IgE was studied. At saturation conditions of IgE, about 2 . 14 X 10(5) molecules of anti-IgE were bound per rat mast cell. Rat mast cells coated with monoclonal anti-DNP IgE were triggered for the release of histamine in the presence of either the antigen or guinea-pig anti-mouse IgE. A mutual inhibition of the passive cutaneous anaphylaxis (PCA) reaction in the rat by either mixing mouse reaginic serum directed against ovalbumin or rat reaginic serum directed against Nippostrongylus brasiliensis with monoclonal mouse anti-DNP IgE was demonstrated.
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PMID:Generation of monoclonal murine anti-DNP-IgE, IgM and IgG1 antibodies: biochemical and biological characterization. 618 Sep 75

The cross-reactivity of the human IgE receptor with mouse and rat IgE was studied. Using leukocytes from a patient with chronic myelogenous leukemia, in which the mononuclear fraction contained up to 75% basophils, both rat and mouse IgE were found to inhibit the binding of 125I-human IgE to the human basophilic leukemia (HBL cells). About 15-fold more rodent IgE was required for 50% inhibition of binding than unlabeled human IgE (hIgE). Dose-response studies using increasing amounts of rodent vs human 125I-IgE indicated that the HBL cells had about 8000 receptors per cell for hIgE and 5500 receptors per cell for rodent IgE. When the HBL cells were surface labeled with 125I and subsequently solubilized with non-ionic detergent, the labeled hIgE receptor could be isolated by either affinity chromatography on IgE-Sepharose (either human or rodent) or by immunoprecipitation with hIgE and anti-IgE. By SDS-PAGE on 10% gels, the receptor had a m.w. of 58,000 daltons. The solubilized receptors exhibited some rebinding to hIgE-Sepharose, and this rebinding could be inhibited by either human or rodent IgE but not by human IgG. Both the HBL cells and normal human basophils could be passively sensitized with murine IgE anti-DNP for antigen-induced histamine release. The minimum concentration of the mouse IgE antibody for sensitizing normal basophils was 20 to 200 ng/ml. Pretreatment of basophils with human IgE, but not human IgG, abrogated the capacity of the murine IgE antibody to sensitize the cells for histamine release, which indicated that the human and rodent IgE were interacting with the same receptor.
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PMID:The interaction of human and rodent IgE with the human basophil IgE receptor. 618 55

We studied the effect of polyethylene glycol (PEG) on the solubility of the receptor for immunoglobulin E (IgE) in non-ionic detergent extracts of rat basophilic leukemia (RBL) cells. We found that the precipitation patterns of free and IgE-bound receptor were identical but differed from that of unbound IgE. Thus, 85 to 95% of the free receptor and the IgE-receptor complexes precipitated at 13% PEG in the presence of 0.5% Nonidet P-40, whereas 95% of the unbound IgE remained soluble. A similar degree of differentiation between the precipitation of receptor-bound and unbound IgE was found when we used extracts and PEG solutions prepared with several non-ionic and/or neutral detergents. The intact IgE-receptor complex with the full complement of subunits (alpha, beta, gamma) precipitated more efficiently than the IgE-alpha-chain-complex. The presence of phospholipids, which were previously shown to be important for preservation of the association between the receptor subunits, enhanced the efficiency of precipitation of the IgE-receptor complex. The presence of PEG also had an effect on the solubility of cellular phospholipids and some of the detergents, although the effect of PEG on either could not be directly related to its effect on the solubility of the IgE-receptor complex. The radioiodinated receptor for IgE, much like other radioiodinated RBL cell membrane proteins, was soluble (greater than or equal to 95%) at approximately 7% PEG but could be specifically and efficiently precipitated from crude cell extracts, in the presence of 7% PEG upon the addition of anti-receptor immunoglobulins alone. Using mouse anti-dinitrophenyl IgE antibody, we found that unlike unbound antigen (DNP-BGG) or the IgE-receptor complex, the detergent-solubilized DNP-BGG-IgE-receptor complex was insoluble at 7% PEG. Consequently, PEG can be employed in assays to quantitate the soluble receptor, and to immunoprecipitate it specifically and directly. Moreover, the use of PEG can facilitate the distinction between unbound antigen and antigen-IgE-receptor complex as well as between the latter and IgE-receptor complex.
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PMID:The behavior of the solubilized receptor for immunoglobulin E in polyethylene glycol-detergent solutions: characterization and potential applications. 620 83

We have previously shown that, unlike monomeric IgE, chemically derived dimers, trimers, and heavier oligomers of IgE were internalized efficiently. This finding suggested that endocytosis, like mediator release, is triggered by cross-linking of the cell surface receptors for IgE. In the present study, we analyzed the temporal and functional relationships between the two events. We used rat basophilic leukemia cells (RBL-HR+-2H3) and rat peritoneal mast cells, which were allowed to bind monomeric 125I mouse IgE hybridoma anti-dinitrophenyl (HI-DNP-E-26-82), and the polyvalent antigen 131I-dinitrophenylated human serum albumin (DNP15-HSA). We found that at 37 degrees C, 50% of the cell surface-bound immune complexes were internalized rapidly (t1/2 3 to 5 min) by RBL-HR+-2H3 cells with only minimal reduction (1/3) in the extent of internalization when very few of the receptors (approximately 5%) were saturated with IgE. Normal mast cells internalized cell surface-bound immune complexes at a similar rate (t1/2 4 to 5 min). Unlike serotonin release, internalization was independent of extracellular calcium and continued to increase as the ratio of DNP15-HSA to IgE increased 10- to 100-fold over the ratio required for optimal histamine release. In the RBL cells, internalization preceded serotonin release, reaching a peak at about 10 min, while the release (t1/2 13 to 19 min) continued for up to 60 min. Presumably, some of the cross-linked IgE internalized less effectively and continued to trigger serotonin release. The reverse relationship between the rates of internalization and release (t1/2 less than 1 min) was found in normal rat mast cells. We conclude that although cross-linking of two or more receptors triggered both endocytosis and exocytosis, the two events are not necessarily sequential.
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PMID:The fate of IgE bound to rat basophilic leukemia cells. III. Relationship between antigen-induced endocytosis and serotonin release. 620 83

BALB/c mice treated with total lymphoid irradiation (TLI) develop non-antigen-specific suppressor cells of the adoptive secondary antibody response and of the mixed leukocyte reaction. Suppressors of the adoptive anti-DNP response were eliminated by incubation of spleen cells with anti-Thy-1.2 or anti-thymus-leukemia (TL) antiserum and complement before cell transfer. Thymectomy before TLI prevented the appearance of the latter suppressor cells. On the other hand, suppressors of the MLR were eliminated by incubation of spleen cells with anti-Thy-1.2 but not anti-TL antiserum and complement. Thymectomy before TLI did not prevent their subsequent development. Thus, two subpopulations of suppressor T cells that differ in the expression of the TL surface antigen, dependence on the presence of the thymus, and in regulatory functions develop after TLI. The TL+, thymus-dependent cell suppresses the adoptive antibody response, and the TL-, thymus-independent cell suppresses the MLR.
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PMID:Immunoregulatory changes induced by total lymphoid irradiation. II. Development of thymus-leukemia antigen-positive and -negative suppressor T cells that differ in their regulatory function. 645 53

A model, employing murine L1210 leukemia to which the artificial determinant TNP was bound in vitro and an anti-DNP antibody-ricin A-chain conjugate, was used to explore the in vivo therapeutic potential of combined immunotoxin-chemotherapy treatment. Under conditions in which immunotoxin and chemotherapy as single therapies had only marginal therapeutic activity, their combined use was markedly effective.
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PMID:Chemotherapy-increased antineoplastic effects of antibody-toxin conjugates. 671 20

High frequency of hybridoma lines secreting large amounts of reaginic anti-DNP antibodies were generated by the fusion of splenic lymphocytes enriched by adoptive transfer of immune cells and the NSI plasmacytoma cell line. The murine IgE molecule binds DNP with high affinity and was specifically purified by immunoabsorption. The 190,000 dalton molecule is composed of a lambda-light chain and an epsilon-heavy chain of an apparent m.w. of about 90,000. Absorption studies with anti-class-specific antisera suggest that some of the hybrid clones secrete also a mixed molecule consisting of lambda- and kappa-light chains in addition to the epsilon-heavy chain. The monoclonal reaginic antibody binds to mast cells or rat basophilic leukemia cells and, upon binding of DNP-protein, triggers an anaphylactic reaction.
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PMID:Generation of hybridomas secreting murine reaginic antibodies of anti-DNP specificity. 718


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