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C Heusser

Publications and source records attributed to C Heusser.

At least 19 recordsLinked to original sources
PubMed1992

Origin and fate of IgE-bearing lymphocytes. II. Gut-associated lymphoid tissue as sites of first appearance of IgE-bearing B lymphocytes and hapten-specific IgE antibody-forming cells in mice immunized with benzylpenicilloyl-keyhole limpet hemocyanin by various routes: relation to asialo GM1 ganglioside+ cells and IgE/CD23 immune complexes.

The organs in which B cells bearing membrane-bound IgE (sIgE+) and benzylpenicilloyl (BPO)-specific IgE antibody-forming cells (AFC) first appeared were determined in BALB/c mice given BPO-keyhole limpet hemocyanin (10 micrograms) in aluminum hydroxide by various routes (i.p, gavage, s.c., i.v., or i.m.). In mice immunized by the i.p. route, the numbers and location of sIgE+ B cells and asialo GM1 ganglioside (AsGm1+) cells, the location of IgE/CD23 immune complexes, and the numbers of BPO-specific IgE AFC in lymphoid organs were determined. With all routes of immunization, no sIgE+ B cells or BPO-specific IgE AFC were ever detected in any organ before day 8. On day 8, with the s.c., i.v., or i.m. routes, sIgE+ B cells and IgE AFC appeared exclusively in Peyer's patches (PP); with the i.p. or gavage routes, sIgE+ B cells simultaneously appeared in both PP and mesenteric lymph nodes, whereas IgE AFC appeared only in PP. In mice immunized by the i.p. route, IgE/CD23 immune complexes and strikingly increased numbers of AsGm1+ cells transiently appeared only in PP after the appearance and preceding the "disappearance" of the sIgE+ B cells and IgE AFC. The data suggest that specific IgE responses originate in gut-associated lymphoid tissue and appear later in spleen. The data also associate the appearance of IgE/CD23 immune complexes and AsGm1+ cells with the "disappearance" of sIgE+ B cells and IgE AFC from PP.

Animals↗
PubMed1992

Immunophotodiagnosis of colon carcinomas in patients injected with fluoresceinated chimeric antibodies against carcinoembryonic antigen.

Based on previous experiments in nude mice, showing that fluoresceinated monoclonal antibodies against carcinoembryonic antigen localized specifically in human carcinoma xenografts and could be detected by laser-induced fluorescence, we performed a feasibility study to determine whether this immunophotodiagnosis method could be applied in the clinic. Six patients, with known primary colorectal carcinoma, received an i.v. injection of 4.5 or 9 mg of mouse-human chimeric anti-carcinoembryonic antigen monoclonal antibody coupled with 0.10-0.28 mg of fluorescein (molar ratio 1/10 to 1/14). The monoclonal antibody was also labeled with 0.2-0.4 mCi of 125I (1 Ci = 37 GBq). Photodetection of the tumor was done ex vivo on surgically resected tissues for the six patients and in vivo by fluorescence rectosigmoidoscopy for the sixth patient. Upon laser irradiation, clearly detectable heterogeneous green fluorescence from the dye-antibody conjugate was visually observed on all six tumors; almost no such fluorescence was detectable on normal mucosa. The yellowish tissue autofluorescence, which was emitted from both tumor and normal mucosa, could be subtracted by real-time image processing. Radioactivity measurements confirmed the specificity of tumor localization by the conjugate; tissue concentrations of up to 0.059% injected dose per g of tumor and 10 times less (0.006%) per g of normal mucosa were found. The overall results demonstrate the feasibility of tumor immunophotodiagnosis at the clinical level.

Antibody Affinity↗
PubMed1992

Different behaviour of mouse-human chimeric antibody F(ab')2 fragments of IgG1, IgG2 and IgG4 sub-class in vivo.

Mouse-human chimeric monoclonal antibodies (MAbs) of 3 different human IgG sub-classes directed against carcinoembryonic antigen (CEA) have been produced in SP-0 cells transfected with genomic chimeric DNA. F(ab')2 fragments were obtained by pepsin digestion of the purified chimeric MAbs of human IgG1, IgG2 and IgG4 sub-class and of parental mouse MAb IgG1. The 4 F(ab')2 fragments exhibit similar molecular weight by SDS-PAGE. They were labelled with 125I or 131I and high binding (80 to 87%) to purified unsolubilized CEA was observed. In vivo, double labelling experiments indicate that the longest biological half-life and the highest tumour-localization capacity is obtained with F(ab')2 from chimeric MAb of human IgG2 sub-class, whereas F(ab')2 from chimeric MAb IgG4 give very low values for these 2 parameters. F(ab')2 from chimeric MAb IgG1 and from parental mouse MAb yield intermediate results in vivo. Our findings should help to select the appropriate human IgG sub-class to produce chimeric or reshaped MAb F(ab')2 to be used for tumour detection by immunoscintigraphy and for radioimmunotherapy.

Animals↗
PubMed1992

Interleukin-3-treated non-B, non-T cells switch activated B cells to IgG1/IgE synthesis.

The switch of activated B cells to IgE synthesis is an interleukin (IL)-3-dependent process. It is currently thought that specific T cells activated by antigen presented in the context of class II major histocompatibility complex are the major source of IL-4. Recently it has been demonstrated that a splenic non-T non-B cell population (termed NBNT) has the capacity to produce IL-4 following IgE and IgG receptor cross-linkage. In this study we demonstrate that IL-4 producing NBNT cells can induce the switch of lipopolysaccharide-activated B cells to the synthesis of IgG1 and IgE antibodies. Furthermore, it was found that not only IgE receptor cross-linkage but IL-3 was able to stimulate NBNT cells to produce IL-4 and induce the switch of B cells to IgE synthesis. NBNT cells derived from the spleen and bone marrow of SCID mice were able to produce IL-4 on exposure to IL-3. This suggested that the ability of IL-3 to stimulate IL-4 production was not dependent on prior exposure of the NBNT cells to antibody complexes in vivo. Taken together these findings represent the first observation that enough IL-4 is produced by NBNT cells to actually influence a B cell IgG/Ig response. The findings also clearly demonstrate that B cells do not need high concentrations of IL-4 to be directed to switch to IgG1 and IgE synthesis.

Animals↗
PubMed1992

Modulation of human IgE synthesis by transforming growth factor-beta.

Exogenous transforming growth factor-beta 2 (TGF-beta 2) markedly inhibits the interleukin 4 (IL4)-stimulated synthesis of human IgE in three models where the B cell co-stimulation signals are contact dependent. This concerns T cell-dependent IgE production by (i) unfractionated peripheral blood mononuclear cells (PMBC) cultured with IL4 and (ii) highly purified B cells cocultured with irradiated EL4 thymoma cells in the presence of IL4 and phorbol myristate acetate, as well as monocyte-dependent IgE production by rigorously T cell-depleted PBMC cultured with IL4 and hydrocortisone. The suppression is not isotype specific. TGF-beta exerts its effect by inhibiting the proliferation of B cells and perhaps also the differentiation of proliferating B cells. However, at a later stage of differentiation, IgE B cells are refractory to the inhibitory effect of TGF-beta, as shown by the slight but significant increase of the spontaneous secretion of IgE by PBMC of atopic patients. This enhancement is due to the suppression of endogenous interferon-gamma production. Most interestingly the synthesis of IgE by highly purified B cells costimulated with IL4 and Epstein-Barr virus is unaffected by TGF-beta. It is concluded that TGF-beta mainly acts by inhibiting IL4-supported B cell proliferation; however, its effects depend upon the B cell costimulation signals that are required together with IL4 for the induction of IgE synthesis.

Antibody-Producing Cells↗
PubMed1992

Effect of cyclosporin A and zidovudine on immune abnormalities observed in the murine acquired immunodeficiency syndrome.

Two therapeutic modalities, zidovudine (targeting retroviral replication) and cyclosporin A (targeting immunopathologic consequences of retroviral expression) were evaluated in a murine model of AIDS. In previous studies, cyclosporin A treatment (40 or 60 mg/kg/day) before and after infection with LP-BM5 murine leukemia viruses protected against the development of immunodeficiency disease. The present study extends these findings. First, a low dose of cyclosporin A (20 mg/kg/day) was ineffective, and treatment initiated 5 days after infection did not protect against virus-induced lymphoproliferation and hypergammaglobulinemia. Second, zidovudine added to drinking water (0.1 mg initiated 5 days after infection and continued for 8 weeks) was more effective than 0.2 mg/mL given day 5-12 after infection. This treatment reduced lymph node size, disease severity as determined histologically, retrovirus-induced gp70 expression, and IgE (but not IgM and IgG) levels. Third, combined treatment had an additive, protective effect on lymphocyte proliferative capacity. This successful dual therapeutic strategy in a mouse model has potential applicability for similar approaches in treating human immunodeficiency virus infection.

Animals↗
PubMed1991

A sensitive and efficient induction system for murine IgE. Single cell analysis at the clonal level.

A culture system is described which permits the analysis of IgE expression by single murine cells within clones of B cells. The system is based on the use of a CB5.1 stroma cell line as a feeder which optimally supports the IL-4-induced switch to IgE of LPS-stimulated B cells in culture. In this system 100 U/ml IL-4 induces the switch to IgE, in 3-5% of B cells and the switch frequency to IgG1 was as high as 2%. Five ng IgE or 12 ng IgG1 were produced per clone containing on average 13-15 PFC. The detection of single IgE secreting B cells was possible due to two newly developed, highly specific rat anti-mouse IgE antibodies used in a sandwich-ELISA. The frequency of IgE-secreting B cells was enhanced 2.5 times when the fibroblastoid CB5.1 cells rather than thymocytes were used as feeder cells. CB5.1 cells supported the differentiation of B cells to IgM-PFC almost as well as rat thymocytes (which have, to date, been used as the standard feeder layer) whereas the amount of secreted IgG1 was about 3 times lower than in thymocyte cultures. Optimal switching to IgE occurred at concentrations of IL-4 which were 10-fold lower than that required for IgG1 expression, a situation quite opposite to that observed in the rat thymocyte-supported culture system. In confirmation of established data the switch of B cells to IgE or IgG1 occurred randomly. The advantages of CB5.1 cells as feeder cells are (1) the use of a homogeneous and defined cell line, (2) their limited release of defined lymphokines (IL-6 and GM-CSF), and (3) the low degradation and consumption of cytokine factors. The combination of the CB5.1 cell line with a highly specific IgE ELISA assay made it possible to analyse the appearance of IgE producing cells within a developing B cell clone.

Animals↗
PubMed1991

Normal serum immunoglobulins participate in the selection of peripheral B-cell repertoires.

In B-cell development, expression of immunoglobulin heavy-chain variable-region (VH) gene repertoires is determined by genetic mechanisms that favor rearrangement of the most D-proximal genes, resulting in overutilization of the VH7183 gene family early in ontogeny and in differentiating B cells of the adult bone marrow. Maturation of the immune system is accompanied by a decreased expression of VH7183 genes in the peripheral immunocompetent B-cell pool of adult animals. By comparing VH gene family expression in the bone marrow (emergent) and peripheral (available and actual) B-cell repertoires of germ-free and conventionally raised BALB/c mice, we found that peripheral selection of VH gene family utilization does not occur in germ-free animals. Reconstitution of germ-free mice with normal serum immunoglobulins purified from syngeneic donors reestablishes selection of VH7183-expressing B cells. Our results indicate that preimmune B-cell repertoires are selected in normal animals by environmental antigens and serum immunoglobulins.

Animals↗
PubMed1991

Kinetics of interleukin-4 induction and interferon-gamma inhibition of IgE secretion by Epstein-Barr virus-infected human peripheral blood B cells.

Interleukin-4 (IL-4) acts directly on purified human peripheral blood B cells cultured in the presence of Epstein-Barr virus (EBV) to induce IgE secretion and to enhance the secretion of IgG and IgM. Interferon-gamma (IFN-gamma) inhibits IgE secretion in this system, without affecting the secretion of the other Ig isotypes. To identify the time period during which EBV-infected B cells can be induced by IL-4 to secrete IgE, we have studied the effects of delayed addition of IL-4, or the termination of IL-4 stimulation by wash out or by neutralization with anti-IL-4 antibodies, on the induction of an IgE response. To induce a maximal IgE response, IL-4 had to be added to cultures of B cells plus EBV no later than 2 days after the initiation of culture, and had to remain present through the tenth day of culture. These two time points correspond to the initiation of detectable DNA synthesis (Days 3 to 4) and the earliest detectable Ig secretion (Days 10 to 12) by EBV-stimulated B cells. No IgE response was induced if the period during which EBV-stimulated B cells were cultured with IL-4 was less than 4 days, or if IL-4 were added later than the tenth day of culture, regardless of how long the culture was continued beyond that time. In contrast, IL-4 considerably enhanced IgG and IgM secretion and B cell CD23 expression, even if it was added after the tenth day of culture. IFN-gamma strongly inhibited the IgE response of B cells cultured with IL-4 plus EBV if added within 6 days of the initiation of culture, but had little effect on the generation of IgM or IgG responses made by these cells, regardless of the time of addition. Neither IL-4 nor IFN-gamma affected ongoing IgE secretion by an established, IgE-secreting, EBV-transformed cell line. These observations suggest that: (i) IL-4 first becomes able to induce EBV-activated B cells to secrete IgE as these cells begin to synthesize DNA, must stimulate B cells for at least 4 days to induce IgE secretion, and loses its ability to induce IgE secretion as these cells differentiate into Ig-secreting cells; (ii) the ability of IFN-gamma to suppress an IgE response is limited to this same time period; and (iii) IL-4 enhancement of CD23 expression and IgM and IgG secretion are independent of IL-4 induction of an IgE response.

Antigens, Differentiation, B-Lymphocyte↗
PubMed1991

Normal serum immunoglobulins influence the numbers of bone marrow pre-B and B cells.

The homeostatic mechanisms controlling B lymphocyte output from bone marrow are not well understood. The present experiments evaluated putative influences of circulating immunoglobulins (Ig) on bone marrow (BM) pre-B and B cell populations. Injections into normal mice of Ig isolated from normal mouse serum, resulted in a dose-dependent and reversible reduction in numbers of BM B lineage cells, in particular of small B220+ surface IgM- cells. Maximal effects were observed upon injection of isologous polyclonal Ig and were independent of mature T cells. These results suggest a feedback modulation of peripheral Ig on cellular activities in BM B lineage compartments, mediated by mechanisms that seem to involve the variable regions of the Ig molecule.

Animals↗
PubMed1991

Antigen dose-dependent regulation of B epsilon-memory cell expression.

The data presented in this study document that the phospholipase A2 (PLA2)-specific IgE antibody response in high responder CBA/J mice is solely dependent on the antigen dose used for immunization. Repeated injections of minute doses (MD) of antigen (0.1 microgram/mouse) induce a persisting high level of PLA2-specific IgE antibody titer, whereas large doses (LD) (10 micrograms/mouse) induce a persisting low level of IgE. The IgG antibody titers are the same under both conditions. The low level IgE immune status induced by repeated LD is irreversible and cannot be boosted by MD. In contrast a single LD primes for a secondary IgE response which can be recalled by MD. A high level of PLA2-specific IgE antibodies induced by MD can be downregulated by a single intervening LD of antigen. A low level IgE immune status can be transferred with spleen cells of mice immunized with LD into naive syngeneic recipients, which then fail to mount a high level IgE response upon injection of MD of antigen. The experiments reveal two countercurrent processes, induction of B epsilon-memory cells after a single LD and additional activation of a persisting IgE-specific cellular suppression mechanism after repeated LD of antigen. These properties make the system suitable for the analysis of cellular interactions and of potential desensitization protocols.

Animals↗
PubMed1991

Glucocorticoids increase the synthesis of immunoglobulin E by interleukin 4-stimulated human lymphocytes.

This study indicates that hydrocortisone (HC) markedly increases the synthesis of immunoglobulin E (IgE) by interleukin 4 (IL-4)-stimulated human lymphocytes. The effect is glucocorticoid specific and is obtained with low concentrations of HC (0.1-10 microM). In both the early and the late phase of the IL-4-induced response HC exerts its effects which are respectively IL-4 dependent and IL-4 independent. The IgE potentiation cannot be explained by the inhibition of interferon-gamma (IFN-gamma) production since it is observed in the absence of endogenous secretion of IFN-gamma. HC inhibits the production of IgE-binding factors (soluble CD23) and the expression of the low-affinity receptor for IgE, also known as the (Fc epsilon RII) CD23 antigen; however, the residual expression of Fc epsilon RII by IL-4- and HC-treated peripheral blood mononuclear cells (PBMCs) is important since the IgE response of these cells is markedly inhibited by anti-CD23 monoclonal antibody. HC acts mainly by amplifying the cellular interactions between monocytes and lymphocytes; indeed, HC has no effect on monocyte-depleted PBMCs, and moreover, monocytes cannot be replaced by soluble factors. Most importantly, T cells are not required for the induction of IgE synthesis by costimulation with IL-4 and HC. However, the IgE response of rigorously T cell-depleted PBMCs may be further increased by the addition of T cells. Further analysis of the permissive effect of HC on the synthesis of IgE by T cell-depleted PBMCs suggests that HC acts in synergy with IL-4 to trigger the activation and the differentiation of B cells into IgE-producing cells.

Antigens, CD↗
PubMed1991

The influence of interferon-gamma and interleukin-4 on IgE production in B lymphocytes of patients with atopic dermatitis. A possible criterion for selection of patients for interferon therapy.

The regulation of IgE production in B lymphocytes of patients with atopic dermatitis by interleukin-4 (IL-4) and interferon-gamma (IFN-gamma) was studied. IL-4 stimulated IgE production in vitro in B-cells of healthy donors and of children with atopic dermatitis, but had only a marginal effect on the high basal level of IgE production by lymphocytes from adult patients with atopic dermatitis. The addition of IFN-gamma prevented in all cases the stimulation of IgE synthesis induced by IL-4. The production of IgG and IgM was differently influenced. These results indicate that the in vitro production of IgE by mononuclear cells from adult patients is more resistant to the regulatory effects of IL-4 and IFN-gamma than is that in B cells of children with atopic dermatitis. We propose that a previous in vitro test of the responsiveness of IgE-producing B cells to IFN-gamma may be used to select patients with atopic dermatitis for treatment with IFN-gamma.

Adolescent↗
PubMed1990

An in vitro murine model of a penicillin specific IgE anamnestic response.

A new murine model system was developed to study hapten specific IgE anamnestic antibody forming cell (AFC) responses induced in vitro. BALB/c mice injected intraperitoneally with BPO-KLH (10 micrograms) in aluminum hydroxide gel (alum) on day 0 and 21 were killed on day 42. Spleen cells (4 X 10(7] were cultured for 0-8 days in the presence of BPO-KLH (0.25-2500 ng/ml), after which the numbers of BPO specific IgE AFC were enumerated in an ELISPOT assay at 37 degrees C using BPO-BSA coated plates. Peak BPO specific IgE anamnestic AFC responses (approximately 40 AFC/10(7) cultured cells) occurred when cells were cultured with 100 ng/ml BPO-KLH for 5 days; peak BPO specific IgG1 and IgA responses (approximately 3000 and approximately 280 AFC/10(7) cultured cells) were detected one day earlier with the same antigen concentration. No ELISPOTs of any isotype were detected if: cells were cultured in the absence of specific antigen; cells from alum treated or unsensitized mice were used; assay wells were coated with BSA alone; isotype specific antibodies were omitted; or assays were performed in the presence of cycloheximide or at 4 degrees C. Cellular interactions in IgE anamnestic AFC responses were studied using the newly developed model system. We found that these responses were partially T cell independent, and that spleens from sensitized and unsensitized adult mice, as well as neonatal mice, contained cells which suppressed these responses.

Animals↗
PubMed1990

Localization of gamma/delta T cells to the intestinal epithelium is independent of normal microbial colonization.

Using monoclonal antibodies identifying all gamma/delta and alpha/beta T cell receptors in cytofluorometric analysis, we have compared the composition of intestinal intraepithelial lymphocytes (i-IEL) in euthymic and athymic germ-free (GF) and conventional (SPF) mice. The results show a marked influence of microbial colonization in the numbers of single-positive (CD4+ or CD8+) alpha/beta i-IEL, but little effect in the pool size or characteristics of gamma/delta i-IEL. In young athymic mice, virtually no alpha/beta i-IEL are detected, while considerable numbers of gamma/delta i-IEL remain, though reduced in GF animals.

Animals↗
PubMed1989

Generation of a recombinant mouse-human chimaeric monoclonal antibody directed against human carcinoembryonic antigen.

A procedure was devised for the identification and specific cloning of functionally rearranged variable region immunoglobulin (Ig) gene segments from genomic DNA of a murine hybridoma cell line which produces a high-affinity monoclonal antibody (MAb) directed against human carcinoembryonic antigen (CEA). The cloned, functionally-rearranged murine Ig H-chain and L-chain variable region gene segments were incorporated into plasmid vectors capable of directing the expression of a chimaeric mouse-human antibody molecule with human (gamma 4, kappa) constant region sequences. Expression plasmids were transfected into a mouse myeloma cell line by electroporation and transfectomas secreting functional chimaeric antibody selected. Chimaeric antibody generated by transfectomas was analysed and shown to compete effectively with its murine counterpart for binding to the CEA epitope, and to have an equivalent antigen-binding affinity. This anti-CEA recombinant antibody should find application in in vivo diagnosis by immunoscintigraphy of human colonic carcinoma, and possibly also in therapy of the disease, overcoming some of the difficulties associated with the repeated use of non-human immunoglobulins in human patients.

Animals↗
PubMed1989

Pure human inactive renin. Evidence that native inactive renin is prorenin.

To clarify contradicting observations on the identity of inactive renin and prorenin, inactive renin was completely purified from native human chorion laeve and the culture medium of human chorion cells. A 720,000-fold purification with 14% recovery was achieved from chorion laeve in 6 steps, including immunoaffinity chromatography on a monoclonal antibody to human renin coupled to Protein A-Sepharose CL-4B. A 3,100-fold purification with 40% recovery was achieved from chorion culture medium in 4 steps, including immunoaffinity chromatography. Inactive renin purified from the two different sources migrated as a single protein band with the same molecular weight of 47,000 on sodium dodecyl sulfate-polyacrylamide gel electrophoresis and consisted of multiple components that could be resolved by isoelectric focusing. Both had the same pI values which shifted downward upon activation by trypsin; however, relative peak heights were different between the two preparations. The purified inactive renin from chorion laeve was completely inactive and did not bind to pepstatin-aminohexyl-Sepharose; however, that from chorion culture medium was partially active and completely bound to the pepstatin gel, indicating that each molecule is partially activated. Trypsin-activated inactive renins from both sources were identical with human renal renin in terms of pH optimum and Km. Specific activities of trypsin-activated inactive renin from chorion laeve and chorion culture medium were 529 Goldblatt units/mg of protein and 449 Goldblatt units/mg of protein, respectively. Amino acid sequence analysis of both of the purified inactive renin preparations demonstrated a leucine residue at the amino terminus. The sequence of 11 additional amino acids was identical in both and agreed with that predicted from the base sequence of the renin gene. These findings indicate that preprorenin is converted to prorenin following removal of a 23-amino acid signal peptide and that the native inactive renin, whose amino acid sequence commences with Leu-Pro-Thr..., is prorenin.

Amino Acid Sequence↗