Mouse monoclonal IgE antibodies specific for ragweed pollen antigens

In order to obtain monoclonal IgE antibody specific for the major allergens in ragweed pollen extracts, hybridomas were constructed from spleens of mice immunized with ragweed antigen E (AgE). Two hybridomas were selected for thorough study, both secreting antibodies of the IgE class. Large quantities of IgE antibodies were isolated by affinity purification using Sepharose 4B conjugated with ragweed pollen proteins (Fraction A). Both MAbs were found to bind to a high molecular weight and heterogeneous population of proteins, but not to monomeric AgE as demonstrated by protein blot analysis. It is suspected that both MAbs react with low affinity with AgE determinants and binding could be demonstrated only with aggregated forms of AgE. Although the specific antigens with which they react are unknown, these monoclonal IgE antibodies should be useful reagents, complementing the previously obtained monoclonal anti-dinitrophenyl IgE antibody, for studying various aspects of the mouse and human IgE antibody systems.

Induction of T lymphocyte responses to a small molecular weight antigen. I. Failure to induce tolerance in azobenzenearsonate (ABA)-specific T cells in guinea pigs with an ABA conjugate of A copolymer of D-glutamic acid and D-lysine (D-GL)

2,4-Dinitrophenyl (DNP) coupled to the copolymer D-glutamic acid and D-lysine (D-GL) induces B cell tolerance but not T cell tolerance. This implies either a lack of DNP determinant recognition by T cells or a substantial difference in tolerance mechanisms for the two cell types. In the present study D-GL was conjugated with the well-defined determinant azobenzenearsonate (ABA) coupled to single amino acids shown here and previously by others to trigger effectively T lymphocytes. The experiments presented here demonstrate that these ABA conjugates of D-GL, although capable of diminishing anti-ABA antibody production, completely fail to render ABA-specific T lymphocytes tolerant thus drawing us to conclude that there are significant operational differences in the mechanisms of tolerance induction in T and B lymphocytes, respectively.

Non-allergenic haemolysins in grass pollens and housedust mites

25 batches of pollen (six common grasses, maize, short ragweed) and two batches of housedust mite (Dermatophagoides pteronyssinus) all contained haemolysins. The haemolysins of two grass pollens and of the housedust mites were of small MW (100-200 Da) and apparently non-allergenic. Both caused inflammation when injected into human skin, at doses that could be experienced naturally. The "allergic" airways diseases may not be entirely immunologically mediated.

Monoclonal antibodies against vasoactive intestinal polypeptide: studies of structure and related antigens

Hybridomas secreting monoclonal anti-vasoactive intestinal polypeptide (VIP) antibodies were constructed from spleen cells sensitized to VIP in vitro. The secreted antibodies were characterized by binding to VIP in indirect radioimmunoassays and enzyme-linked immunosorbent assays. Two monoclonal antibodies, characterized for their binding activities with synthetic fragments of VIP, were found to bind different sites on the VIP molecule. These monoclonal antibodies may recognize tertiary structures of the VIP. A search was conducted for antigens recognized by the monoclonal antibodies in brain: brain proteins separated on polyacrylamide gels were electroblotted onto nitrocellulose filters and were reacted first with the mouse antibody and then with goat anti-mouse immunoglobulin coupled to horseradish peroxidase as a means of detection. The monoclonal antibodies were found to react with a protein of molecular weight 60,000, which was also recognized by polyclonal antibodies, although the latter reacted with a number of additional proteins. The relationship of the protein of molecular weight 60,000 to VIP is discussed.

Macrophage-activating factor produced by a T cell hybridoma: physiochemical and biosynthetic resemblance to gamma-interferon

Biochemical and biosynthetic evidence has been obtained which indicates that the macrophage activating factor (MAF) produced by the murine T cell hybridoma clone 24/G1, which primes macrophages for nonspecific tumoricidal activity, is a form of gamma-interferon (IFN gamma). MAF and antiviral activities were generated by the clone in proportional amounts under a variety of culture conditions. Production of both activities showed identical dependence on cell density even when production precipitously ceased at cell concentrations greater than 1.2 X 10(6) cells/ml. MAF and antiviral activities displayed identical sensitivities to pH and temperature and were indistinguishable on the basis of binding to insolubilized polynucleotides. Dye-ligand chromatography of a stimulated hybridoma supernatant on a column of Matrex Gel Red A resulted in the 1500-fold purification and 100% recovery of the MAF activity. A qualitatively identical elution profile was also obtained for the antiviral activity; however, only 32% of the original activity was recovered. When subjected to gel filtration on a high performance liquid chromatography system (HPLC), the MAF and antiviral activities present in the Matrex Red pool displayed identical elution profiles and exhibited an apparent m.w. of 50,000. This technique resulted in another 10-fold purification and 50% recovery of the two activities. On HPLC chromatofocusing the MAF activity in the Matrex Red pool could be resolved into seven chromatographically distinct species yet could not be resolved from the antiviral activity on either a qualitative or quantitative basis. These results thus provide quantitative molecular evidence to support the concept that IFN gamma can act as a MAF.

Macrophage-activating factor produced by a T cell hybridoma: physiochemical and biosynthetic resemblance to gamma-interferon

Biochemical and biosynthetic evidence has been obtained which indicates that the macrophage activating factor (MAF) produced by the murine T cell hybridoma clone 24/G1, which primes macrophages for nonspecific tumoricidal activity, is a form of gamma-interferon (IFN gamma). MAF and antiviral activities were generated by the clone in proportional amounts under a variety of culture conditions. Production of both activities showed identical dependence on cell density even when production precipitously ceased at cell concentrations greater than 1.2 X 10(6) cells/ml. MAF and antiviral activities displayed identical sensitivities to pH and temperature and were indistinguishable on the basis of binding to insolubilized polynucleotides. Dye-ligand chromatography of a stimulated hybridoma supernatant on a column of Matrex Gel Red A resulted in the 1500-fold purification and 100% recovery of the MAF activity. A qualitatively identical elution profile was also obtained for the antiviral activity; however, only 32% of the original activity was recovered. When subjected to gel filtration on a high performance liquid chromatography system (HPLC), the MAF and antiviral activities present in the Matrex Red pool displayed identical elution profiles and exhibited an apparent m.w. of 50,000. This technique resulted in another 10-fold purification and 50% recovery of the two activities. On HPLC chromatofocusing the MAF activity in the Matrex Red pool could be resolved into seven chromatographically distinct species yet could not be resolved from the antiviral activity on either a qualitative or quantitative basis. These results thus provide quantitative molecular evidence to support the concept that IFN gamma can act as a MAF.

Specificity of anti-nucleoside antibodies in systemic lupus erythematosus

The titer of IgG antinucleoside antibodies in the sera of 162 individuals was determined by an enzyme-linked immunosorbent assay. The nucleosides used in the assay were adenosine, cytidine, guanosine, and thymine-riboside conjugated to human serum albumin. The specificity of IgG antinucleoside antibodies was indicated by appropriate reduction in antibody binding after solid-phase adsorptions of antibody with specific immobilized nucleoside conjugates. Disease-associated increases in serum IgG antibodies to cytidine and guanosine but not to adenosine or thymine-riboside occurred in patients with systemic lupus erythematosus (SLE). The epitope density of nucleosides in the conjugates and differences in the sensitivity of each nucleoside assay were not responsible for disease-associated IgG antinucleoside antibody responses. These findings support a possible pathogenic role for cytidine and guanosine as antigens or crossreactive antigenic determinants in some patients with SLE.

IgE-mediated chemotaxis of rat basophilic leukemia cells towards specific antigen

We evaluated chemotactic properties of four sublines of rat basophilic leukemia cells using blindwell Boyden chamber assays. After sensitization with a mouse monoclonal IgE directed against dinitrophenyl (DNP), cells from sublines 2H3-C and 926a underwent chemotaxis toward DNP-bovine serum albumin (BSA) and sublines RBL-1 and 4A did not. Chemotactic responses required specific IgE and were determined by the IgE antigen specificity used for sensitization. The threshold for chemotaxis was on the order of 10(-10) M DNP-BSA. Release of incorporated [3H]-serotonin did not always parallel chemotactic responses, which suggests that chemotaxis and secretion may be two unlinked processes that occur during basophil activation. Our results predict a possible in vivo mechanism whereby specific chemotactic responses of basophils and other FcR epsilon-bearing cells are mediated via specific IgE bound to membrane FcR epsilon.

Macrophage activation: priming activity from a T-cell hybridoma is attributable to interferon-gamma

Antiviral and macrophage-priming activities in the supernatant medium of a subclone of a concanavalin A-stimulated mouse T-cell hybridoma were investigated. The two activities were associated with a molecular weight of approximately 50,000 and could not be separated by various approaches. Both activities were eliminated by a highly specific neutralizing antibody against mouse interferon-gamma, but not by antibody against interferon-alpha and -beta. The ratio of priming to antiviral activity in the hybridoma culture supernate was indistinguishable from the ratio obtained with mouse interferon-gamma prepared by recombinant DNA technology. It was concluded from these data that the priming activity in hybridoma culture supernates was attributable to interferon-gamma and that this mediator is one form of the lymphokine macrophage-activating factor. Interferon-gamma was greater than 800 times more efficient at priming mouse macrophages for tumor cell killing than was a mixture of interferon-alpha and -beta. This finding contributes to growing awareness that type II interferon may have greater immunoregulatory potential than type I interferons.

A rapid screening assay for detection of IgE-binding factors in humans

During the last few years studies in rats and mice have demonstrated IgE-binding factors, some of which have IgE-selective regulatory activities. This prompted us to develop a rapid, sensitive screening assay for measuring IgE-binding factors in humans. The principle of the assay is to measure the degree of inhibition of binding between anti-human IgE antibodies and human IgE. Thus, 200 pg IgE plus testing samples were added to each well precoated with anti-human IgE antiserum. After an overnight incubation, the wells were washed and radiolabeled anti-IgE antibodies were added to the wells. Under the optimum conditions, the assay can detect 10(-11)M anti-human IgE antibodies. With this assay, we have been able to detect IgE-binding factors in the supernatants of 2 human B cell lines which bear Fc receptors for IgE (FcR epsilon) on their surface membranes (e.g., WIL-2 and RPMI 8866), but not in the supernatants of DAUDI cells (a human cell line without FcR epsilon). Furthermore, the IgE-binding factors of WIL-2 cells were specifically adsorbed to, and eluted from, IgE-coupled Sepharose, but not BSA-Sepharose. These findings prove that the inhibition factors are indeed human IgE-binding factors, and that the assay described herein is a specific and sensitive screening assay for detecting human IgE-binding factors.

IgE class-restricted tolerance induced by neonatal administration of soluble or cell-bound IgE

Induction of IgE class-restricted tolerance was studied in high IgE-responder (BALB/c X SJL)F1 mice, of which the parental BALB/c and SJL mice are high and low IgE-responder mice, respectively. 2,4-Dinitrophenyl (DNP)-specific monoclonal IgE was administered to (BALB/c X SJL)F1 mice neonatally in two forms: soluble IgE at 250 micrograms per injection, or 10-100 ng of IgE coupled to 25-50 X 10(6) syngeneic splenocytes by binding to the chemically reactive hapten trinitrobenzene sulfonate (TNBS) or directly conjugated via a heterobifunctional reagent, N-succinimidyl 3-(2-pyridyldithio) propionate (SPDP). Polyclonal induction of IgE class-restricted tolerance was observed in (BALB/c X SJL)F1 mice, neonatally treated with soluble IgE or IgE-conjugated syngeneic splenocytes. Thus these mice failed to mount IgE antibody responses to either keyhole limpet hemocyanin or ovalbumin challenge, assessed by the passive cutaneous anaphylaxis reaction. The IgG antibody responses to these same antigens, however, were not affected by this treatment. The IgE class-restricted tolerance induced by both forms of IgE persisted up to at least 6 mo with repeated antigenic challenges. IgE coupled to syngeneic cells by TNBS or the SPDP method induced prolonged tolerance up to 9 mo. The induction of polyclonal IgE class-restricted tolerance was achieved only by monoclonal IgE, whereas DNP-specific monoclonal IgG1 plus IgG2b coupled to syngeneic splenocytes by the SPDP method failed to modulate either IgE or IgG antibody responses. In contrast, (BALB/c X A/J)F1 mice, of which both parental strains are high IgE responders, developed IgE class-restricted tolerance upon repeated neonatal injection of soluble IgE, but not IgE-conjugated syngeneic splenocytes, indicating that gene products of the low IgE-responder mice contributed to the effective presentation and/or recognition of epsilon heavy chain of the IgE molecules. Taken collectively, these results demonstrated that non-antigen-specific, isotype-restricted tolerance can be induced in the IgE antibody system. The differential induction of IgE class-restricted tolerance by different forms of tolerogen in the strains studied perhaps distinguishes two underlying cellular mechanisms for IgE class-restricted tolerance.

Cloning and nucleotide sequence of mouse immunoglobulin epsilon chain cDNA

cDNA corresponding to mouse IgE heavy (epsilon) chain mRNA was cloned from mouse IgE-secreting hybridoma cells. A clone containing the epsilon cDNA insert was identified by hybridization to epsilon mRNA and subsequent translation in vitro to unprocessed epsilon chain reactive with anti-mouse IgE antibodies. This clone was used to select 20 other epsilon cDNA clones by colony hybridization. The clone containing the longest insert was selected and the epsilon cDNA insert was subjected to sequence analysis. The determined sequence is 1,279 nucleotides long and contains the coding regions for part of the constant region (C epsilon) I and all of the C epsilon 2, C epsilon 3, and C epsilon 4 domains and also the entire 3' untranslated region of epsilon mRNA. When the amino acid sequence determined from the nucleotide sequence is compared to that of human epsilon chain, significant homologies between corresponding domains of the two epsilon chains are found, including conservations in cysteine and tryptophan residues and carbohydrate attachment sites.

Secretion of leukotriene C and other arachidonic acid metabolites by macrophages challenged with immunoglobulin E immune complexes

Resident mouse peritoneal macrophages release the slow-reacting substance leukotriene C (LTC) on exposure to particulate IgE immune complexes. Because these cells lose their responsiveness to an IgE stimulus after 4 h in culture, maximum release of 20:4 metabolites is observed before this time. However, a similar diminution in 20:4 metabolism was not observed with a zymosan stimulus. Freshly explanted cells are deficient in intracellular glutathione (GSH) (12.4 +/- 0.4 pmol/micrograms cell protein), but GSH increases to a steady state value of 30-35 pmol/micrograms of cell protein between 3 and 9 h of culture. Because GSH is required for the synthesis of LTC and prostaglandin (PG)E2, cultures challenged immediately after explanation have a diminished capacity to synthesize these 20:4 metabolites and release prostacyclin as the major product. By 4-5 h in culture, macrophages form significant amounts of LTC and PGE2. Under optimum conditions of maximum responsiveness to an IgE stimulus and GSH content (after 4 h of culture), macrophages challenged with latex beads coated with IgE immune complexes synthesize 1.0 +/- 0.3 pmol of LTC/microgram cell protein (60 +/- 18 pmol/10(6) cells) in addition to prostacyclin (8.2 +/- 0.8 pmol/micrograms cell protein) and PGE2 (4.7 +/- 1.5 pmol/micrograms cell protein). These amounts are quantitatively similar to the arachidonic acid metabolites produced by macrophages challenged with IgG immune complex-coated latex beads or zymosan. These data demonstrate that macrophages produce large quantities of LTC and other 20:4 metabolites in response to particle-bound IgE and antigen, provided that the appropriate in vitro conditions are met. The macrophage might, therefore, be a major source of slow-reacting substance and other 20:4 metabolites generated during IgE-mediated reactions in vivo.

IgE immune complexes stimulate arachidonic acid release by mouse peritoneal macrophages

Resident mouse peritoneal macrophages were labeled with [3H]arachidonic acid and challenged with Sephadex beads coated with immune complexes of IgE and antigen. Arachidonic acid release by the cells was assessed by the quantity or radiolabel recovered from the culture medium. Freshly isolated macrophages responded to IgE immune complexes with a release of [3H]arachidonic acid that was linear for 1-2 hr. The magnitude of the response was dependent on both the number of immune complex-coated beads and on the degree of opsonization of the beads. Under conditions of maximal stimulation, macrophages challenged with IgE immune complex-coated Sephadex released 23 +/- 4.5% of their incorporated radiolabel. This is compared to values of 34.2 +/- 0.5% and 38.1 +/- 3.3% for cultures that received IgG immune complex-coated Sephadex or zymosan, respectively. Macrophages did not release arachidonic acid upon exposure to soluble IgE and antigen given sequentially or simultaneously, and soluble IgE did not inhibit the cells' response to IgE immune complexes. Incubation of macrophages for longer than 3 hr prior to challenge resulted in a selective loss in the cells' ability to respond to IgE immune complexes. After 16 hr of culture, macrophages released only 3.9 +/- 0.3% of their incorporated 3H on exposure to IgE immune complexes; however radiolabel release in response to zymosan (42.0 +/- 0.8%) was identical to that of freshly isolated cells. These data indicate that macrophages are capable of releasing arachidonic acid in response to preformed particulate immune complexes of IgE and antigen. Because Sephadex beads are too large to be interiorized by the cells, this response results from the interaction of the immune complexes with the macrophage plasma membrane.

Identification of a T cell hybridoma that produces large quantities of macrophage-activating factor

A murine T cell hybridoma, constructed by fusion of alloantigen-activated T cells with the BW5147 T cell lymphoma, which produces a lymphokine capable of inducing tumoricidal activity in macrophages, has been identified. Lymphokine release could be detected only after mitogen stimulation of the T cell hybridoma culture. Upon cloning of the parental hybridoma, 24 out of 27 clones produced tumoricidal-inducing activity. Seven clones produced more cytocidal-inducing activity than did conventional supernatants, generated by concanavalin A stimulation of normal murine spleen cell cultures, which contained macrophage-activating factor (MAF). The supernatant of hybridoma clone 24/G1 was 25 times more active than conventional MAF preparations. Using supernatants from a variety of clones, the levels of macrophage-activating activity and interleukin 2 were found to vary independently of one another. The lymphokine produced by hybridoma clone 24/G1 appeared to be identical to conventional MAF by a variety of criteria including: (a) a requirement for a second signal for induction of tumoricidal activity in macrophages, (b) inactivation after incubation for 1 h at 65 degrees C, and (c) loss of activity after treatment at pH 4.0 but not at pH 5.0. Like conventional MAF, the hybridoma MAF eluted as a single peak after molecular sieve chromatography on Sephadex G100 and exhibited an apparent molecular weight of 55,000. Although somewhat heterogeneous, the majority of hybridoma 24/G1 MAF displayed an isoelectric point of 5.4 as determined using the chromatofocusing technique. These results thus illustrate the usefulness of T cell hybridomas in distinguishing between various lymphokine activities and indicate that the T cell hybridoma clone 24/G1 will be of particular usefulness in achieving the biochemical purification of substantial quantities of murine MAF.

Genetics of cell interactions in aged mice: age-related decline in capacity of parental cells or environment to induce allogeneic effects on F1 lymphocytes

In order to ascertain whether the process of aging would affect various aspects of genetic control of cell-cell interactions in mice, studies were initiated to examine the capacities of lymphoid cells and host lymphoid tissues of parental mice of varying ages to induce allogeneic effects of primed lymphocytes of young F1 donor origin. These studies demonstrate that with increasing age, both parental cells and parental environment gradually lose the capacity to influence antibody responses via the allogeneic effect. This age-related decline in induction of allogeneic effects could be attributed to 1) dysfunction or loss of allogeneic effect-inducing cells from lymphoid populations of aged mice, and 2) a change in the homing pattern of transferred immunocompetent cells to lymphoid tissues in the aged environment.

Genetics of cell interactions in aged mice: age-related decline in capacity of parental cells or environment to induce allogeneic effects on F1 lymphocytes

In order to ascertain whether the process of aging would affect various aspects of genetic control of cell-cell interactions in mice, studies were initiated to examine the capacities of lymphoid cells and host lymphoid tissues of parental mice of varying ages to induce allogeneic effects of primed lymphocytes of young F1 donor origin. These studies demonstrate that with increasing age, both parental cells and parental environment gradually lose the capacity to influence antibody responses via the allogeneic effect. This age-related decline in induction of allogeneic effects could be attributed to 1) dysfunction or loss of allogeneic effect-inducing cells from lymphoid populations of aged mice, and 2) a change in the homing pattern of transferred immunocompetent cells to lymphoid tissues in the aged environment.

Constitutive and mitogen-induced production of T cell growth factor by stable T cell hybridoma lines

Stable T cell growth factor- (TCGF; IL 2) producing cloned T cell hybridoma lines were constructed by fusing murine alloantigen-activated T cells with the 8-azaguanine-resistant lymphoma line, BW5147. Many, but not all, clones of one of these hybridomas, i.e., hybridoma 24, secreted TCGF constitutively, but production was markedly enhanced by stimulation with T cell mitogens. Large numbers of TCGF-secreting hybridoma cells in a stable functional state could be obtained from histocompatible mice inoculated with cloned T cell hybridomas. Moreover, such in vivo-derived hybridoma cells could be stimulated sequentially with mitogen at least twice to secrete their biologically-active product, resulting in larger TCGF yields from the same cells. The secreted product of these T cell hybridoma lines resembled TCGF isolated from other cellular sources in that it: a) supported the growth of a TCGF-dependent T cell line; b) provided help for the induction of alloantigen-reactive cytotoxic T lymphocytes from thymocyte precursors; c) facilitated concanavalin A-induced mitogenic responses of low thymocyte numbers; d) had an apparent m.w. of 30,000 to 40,000 by gel filtration chromatography; and e) was eluted from DEAE-Sephacel ion-exchange chromatography columns by salt concentrations of 30 to 150 mM NaCl. The ability of these T cell hybridomas to grow in vivo and retain their functional characteristics in a stable form should prove useful in terms of providing large numbers of TCGF-secreting cells and studying in vivo aspects of the production of TCGF as well as other immunoregulatory mediators.

Constitutive and mitogen-induced production of T cell growth factor by stable T cell hybridoma lines

Stable T cell growth factor- (TCGF; IL 2) producing cloned T cell hybridoma lines were constructed by fusing murine alloantigen-activated T cells with the 8-azaguanine-resistant lymphoma line, BW5147. Many, but not all, clones of one of these hybridomas, i.e., hybridoma 24, secreted TCGF constitutively, but production was markedly enhanced by stimulation with T cell mitogens. Large numbers of TCGF-secreting hybridoma cells in a stable functional state could be obtained from histocompatible mice inoculated with cloned T cell hybridomas. Moreover, such in vivo-derived hybridoma cells could be stimulated sequentially with mitogen at least twice to secrete their biologically-active product, resulting in larger TCGF yields from the same cells. The secreted product of these T cell hybridoma lines resembled TCGF isolated from other cellular sources in that it: a) supported the growth of a TCGF-dependent T cell line; b) provided help for the induction of alloantigen-reactive cytotoxic T lymphocytes from thymocyte precursors; c) facilitated concanavalin A-induced mitogenic responses of low thymocyte numbers; d) had an apparent m.w. of 30,000 to 40,000 by gel filtration chromatography; and e) was eluted from DEAE-Sephacel ion-exchange chromatography columns by salt concentrations of 30 to 150 mM NaCl. The ability of these T cell hybridomas to grow in vivo and retain their functional characteristics in a stable form should prove useful in terms of providing large numbers of TCGF-secreting cells and studying in vivo aspects of the production of TCGF as well as other immunoregulatory mediators.

Immunoglobulin E-rheumatoid factor in the serum of patients with rheumatoid arthritis, asthma, and other diseases

A solid-phase radioimmunoassay was developed to detect immunoglobulin (Ig)E antibodies that bound to human IgG. IgE-rheumatoid factor activity was found in the serum of 18 of 20 patients with seropositive rheumatoid arthritis, 1 of 4 patients with seronegative rheumatoid arthritis, 3 of 32 patients with seronegative rheumatoid arthritis, 3 of 32 patients with asthma, and in 1 patient with hypocomplementemic vasculitis and iodide sensitivity. Immunopathologic implications of IgE-rheumatoid factor are discussed.