Monoclonal antibodies to mammalian heat shock proteins impair mouse embryo development in vitro

Two-cell mouse embryos (B6D2F1) were cultured in the presence or absence of 100 microg/ml monoclonal antibodies specific for the mammalian 60 kDa (HSP60), 70 kDa (HSP70) and 90 kDa (HSP90) heat shock proteins. Embryo development was evaluated after 3, 5 and 7 days in culture by determining the number of blastocysts, hatched blastocysts and outgrown trophoblasts at the successive time points. At day 3, only 29% (22/75) of the embryos cultured with anti-HSP60 antibody developed to the blastocyst stage (P < 0.0001) as compared to 67% (31/46) of the embryos cultured with anti-HSP70, 72% (43/60) cultured with anti-HSP90, and 79% (49/62) in medium plus mouse IgG1. By day 5, hatched embryos were present in 28% (13/ 46) of the cultures containing anti-HSP70 (P < 0.0001), as opposed to 57% (34/60) containing anti-HSP90 and 73% (45/62) containing IgG1. At day 7, outgrown trophoblasts were observed in 9% (4/46) of cultures containing anti-HSP70 (P < 0.0001), 45% (27/60) containing anti-HSP90 (P < 0.01) and 66% (41/62) cultured in medium plus IgG1. Antibodies to different heat shock proteins exerted a detrimental effect on mouse embryo development at unique development stages. Immune sensitization to heat shock proteins may be a cause of reproductive failure.     

Monoclonal antibodies against human collagenase and stromelysin

Mouse monoclonal antibodies against recombinant human fibroblast procollagenase and prostromelysin have been generated and characterized. The epitope-containing domains for the antibodies have been assigned based on their immunoreactivities against recombinant proenzymes, mature enzymes, truncated collagenases, proteolytic fragments of stromelysin, and chimeric molecules constructed from different domains of the two enzymes. These antibodies can be divided into four groups: (1) antibodies that recognize the truncated 19-kDa NH2-terminal collagenase, (2) antibodies that recognize the C-terminal domain of collagenase and stromelysin, (3) antibodies that recognize a 31-kDa NH2-terminal collagenase fragment, and (4) antibodies that recognize the 19-kDa NH2-fragment of stromelysin. The prostromelysin-specific antibody 11N13 is of particular interest; it neutralizes stromelysin activity in a stromelysin peptide substrate assay, with an IC50 value of 75 nM. MAb 11N13 may be useful for in vivo and in vitro studies to validate the roles of stromelysin in tumor cell invasion, metastasis, and connective tissue disorders.     

Monoclonal antibodies against human endothelin-converting enzyme-1

Endothelin-converting enzyme-1 (ECE-1) is a membrane-bound metalloprotease which specifically converts the inactive precursor big-endothelin-1 (big ET-1) to the vasoactive endothelin-1 (ET-1). Six different mouse hybridoma cell lines have been generated secreting monoclonal antibodies specific to human ECE-1. These antibodies have been proven useful in a fast and efficient one-step purification of membrane-bound ECE-1 as well as of artificial soluble ECE-1 by immunoaffinity chromatography. The antibodies are suitable for a quantification of ECE-1 in solution by a sandwich-ELISA and for the immunohistochemical detection of ECE-1 in the cell membrane.     

Blockade of epidermal growth factor receptor function by bivalent and monovalent fragments of 225 anti-epidermal growth factor receptor monoclonal antibodies

We have previously described anti-epidermal growth factor (EGF) receptor monoclonal antibodies (MAbs) which can block binding of transforming growth factor alpha (TGF-alpha) and EGF to receptors and inhibit activation of receptor tyrosine kinase. Studies with these MAbs involving cell cultures and nude mouse xenografts demonstrated their capacity to inhibit the growth of a variety of tumor cell lines, which express EGF receptors and TGF-alpha and appear to depend upon receptor activation for cell proliferation. To explore the mechanism(s) by which anti-EGF receptor 225 MAb inhibits cell proliferation, we have compared the activity of native 225 MAb with the response to bivalent 225 F(ab')2 and monovalent 225 Fab' fragments. Both native 225 MAb and its fragments could inhibit the binding of 125I-EGF to EGF receptors. Scatchard analysis revealed that the Kd of 225 F(ab')2 is comparable to that of 225 MAb (1 nM), whereas the Kd of 225 Fab' is 5 nM. Both bivalent 225 MAb and 225 F(ab')2 and monovalent 225 Fab' were able to completely inhibit TGF-alpha-induced EGF receptor tyrosine kinase activation, as assayed by autophosphorylation of tyrosine residues of EGF receptors on MCF10A nonmalignant human mammary cells, MDA468 human breast adenocarcinoma cells, and A431 human vulvar squamous carcinoma cells. The bivalent forms of MAb could inhibit proliferation stimulated by endogenous (autocrine) TGF-alpha in cultures of these three cell lines. They also blocked growth stimulation by added exogenous TGF-alpha in cultures of MCF10A cells and the growth-inhibitory effect of exogenous TGF-alpha upon MDA468 and A431 cell cultures. Monovalent 225 Fab' had weaker inhibitory effects upon the proliferation of these cell lines. To determine whether the in vivo antiproliferative activity of anti-EGF receptor MAb can occur without the participation of the Fc portion of MAb, the capacities of 225 F(ab')2 and native 225 MAb to inhibit growth of s.c. A431 cell xenografts were compared. Equimolar amounts of either 225 MAb or 225 F(ab')2 were administered at intervals equivalent to the half-lives of the molecules, to attempt to maintain comparable plasma levels. Both 225 MAb and 225 F(ab')2 inhibited A431 cell xenograft growth in a dose-dependent manner, with a more sustained response in the case of the intact antibody.(ABSTRACT TRUNCATED AT 400 WORDS)     

Monoclonal antibodies against Schistosoma mekongi surface tegumental antigens

Monoclonal antibodies were produced from naturally infected BALB/c mice. Thirteen hybridomas which were found to produce monoclonal antibodies against surface tegumental antigens of Schistosoma mekongi by ELISA assay were used in this study. The antigen specificities of hybridomas reactive with surface tegumental antigens were characterized and localized by immunoblotting analysis and Avidin-Biotin method. Of the 13 hybridomas, only three produced monoclonal antibodies to the single epitopes in the surface tegumental antigens. These epitopes (125 kDa, 97 kDa and 38 kDa) have been found to be the major antigenic components of the surface tegument of S. mekongi. The 38 kDa antigen was found to associate with the surface tegumental layers, the muscular layers lying just beneath the tegument, as well as in the gut surface. The 97 and 125 kDa antigens were detectable only in the surface tegumental area. The biochemical identity of these proteins or glycoproteins is unknown. However, these antigens have also been described in S. japonicum and S. mansoni.     

Interaction between adrenaline and epidermal growth factor in the control of liver glycogenolysis in mouse

Epidermal growth factor (EGF) stimulates glycogenolysis in mouse liver, but the effect requires concentrations that are only achieved in plasma upon adrenergic stimulation of EGF release from submandibular salivary glands. Thus, we studied the interaction between adrenaline and EGF in liver glycogen metabolism, both in whole animals and in isolated hepatocytes. Adrenaline administered to anesthetized mice stimulated both the endocrine secretion of EGF from submandibular salivary glands and the degradation of glycogen in the liver. In sialoadenalectomized mice, adrenaline administration did not increase plasma EGF concentration. In these animals, the glycogenolytic response to adrenaline was enhanced. The sensitivity of hepatocytes to adrenaline was similar in cells from sialoadenalectomized and sham-operated mice. EGF, added to isolated hepatocytes, reduced the glycogenolytic effect of adrenaline (the maximal effect but not the ED50). Adrenaline stimulated glycogen degradation through both an alpha1-adrenergic mediated Ca2+ increase and a beta-adrenergic-mediated cAMP increase. EGF did not interfere with the rise of cytosolic Ca2+ but decreased the cAMP signal. EGF did not decrease the glycogenolytic effect of phenylephrine or VP (which increased cytosolic Ca2+ but not cAMP), but EGF decreased both the glycogenolytic effect and the cAMP signal generated by glucagon or forskolin. EGF did not interfere with the glycogenolytic effect of CPT-cAMP or bt2-cAMP. The effect of EGF on cAMP was blocked by 3-isobutyl-1-methylxanthine. These results demonstrate that the effect of EGF on the glycogenolytic action of adrenaline involves interference with the generation of the cAMP signal. We suggest that EGF induces such an effect through the activation of a phosphodiesterase.     

Immunocytochemical localization of transforming growth factor alpha, epidermal growth factor and epidermal growth factor receptor in the cat endometrium and placenta

Hoxb-5 is one of the few homeobox genes strongly expressed in the developing mouse lung. To explore the hypothesis that Hoxb-5 acts to regulate epithelial cell fate and branching morphogenesis in the developing lung, we studied the temporal, spatial, and cell-specific expression of Hoxb-5 from gestational day (d) 13.5 to postnatal day (P) 2. Immunocytochemistry demonstrated regional localization of Hoxb-5 protein to developing conducting airways and surrounding mesenchyme. The cellular expression pattern changed from diffusely positive nuclei of mesenchymal cells on d13.5 to become more localized to nuclei of subepithelial fibroblasts and some adjacent columnar and cuboidal epithelial cells on d14.5. After d14.5, Hoxb-5 protein expression continued to decrease in mesenchymal cells distal from developing airways, but persisted in fibroblasts underlying conducting airways. Hoxb-5 protein expression persisted in nuclei of columnar and cuboidal epithelial cells on d16.5 and d17.5, with expression in low cuboidal epithelial cells as well from d17.5 to P2. Western blot analysis showed temporal and quantitative changes in Hoxb-5 protein expression with peak expression on d14.5-15.5. We conclude that Hoxb-5 protein is developmentally regulated in a temporal, spatial, and cell-specific manner throughout the pseudoglandular, canalicular, and terminal saccular periods of lung development in the mouse. This localization and expression pattern suggests that Hoxb-5 may influence branching morphogenesis, cell-cell communication, cell fate, and differentiation of conducting airway epithelia.     

Effect of recombinant human epidermal growth factor on the expansion of human skin in vitro

We investigated the effect of the different concentrations of recombinant human epidermal growth factor (rhEGF) on the expansion of human skin in vitro. Pieces of skin about 2 mm2 in area were placed in 24-cell wells and rhEGF in different concentrations was added. The wells were incubated at 37 degrees C in 5% CO2 for 4 d. The expanded area of each piece of skin was measured. The results indicated that rhEGF possessed a regulating effect on the expansion of skin pieces, and the expanded area was parabolically related with the concentrations of rhEGF. When the rhEGF concentration reached 5 micrograms/L, the maximal area expansion (7.08 +/- 2.40 mm2) was found, which was as twice as the area in control group (3.63 +/- 1.98 mm2). It was suggested that rhEGF had a potential therapeutic effect in wound healing.     

Monoclonal antibodies against potato virus A -- immunoblot analysis

Monoclonal antibodies (MoAbs) against potato virus A (PVA) were examined in their reactivity with PVA and its denatured capsid protein (PVA-CP) bound to the nitrocellulose membrane. Five MoAbs reacted with native PVA, three of them also with PVA-CP. One MoAb gave no reaction in dot-blot test. In polyacrylamide electrophoresis in the presence of sodium dodecyl sulphate (SDS-PAGE) PVA-CP migrated as two major bands. In immunoblot analysis, two MoAbs reacted only with the slower band, one only with the faster one. We presume that those bands do not correspond to the intact CP but they do to truncated N- and C-terminal CP molecules, respectively, and that the corresponding epitopes reacting with MoAbs are localized near to both termini of CP molecules. After mild trypsinolysis of PVA particles no MoAb reacted with resulting "core" CP.     

Intestinal adaptation is enhanced by epidermal growth factor independent of increased ileal epidermal growth factor receptor expression

BACKGROUND/PURPOSE: Intestinal adaptation after massive small bowel resection (SBR) is augmented by epidermal growth factor (EGF) via an unknown mechanism. We recently have observed that EGF increases the expression of EGF receptor mRNA and protein content in the remnant ileum after SBR. The purpose of this study was to determine whether the magnitude of EGF-induced receptor expression correlates with intestinal adaptation. METHODS: A 50% proximal SBR or sham operation (bowel transection with reanastomosis) was performed on male ICR mice. Animals from each group were then selected randomly to receive either human recombinant EGF (150 microg/kg/d) or saline by twice daily intraperitoneal injections. The remnant ileum was harvested at 1 week, and parameters of adaptation measured as changes in protein content. Ileal EGF receptor mRNA was quantitated using a ribonuclease protection assay. Changes in the expression ileal EGF receptor protein were determined by Western blot after immunoprecipitation. Comparisons of mean values between groups was performed using analysis of variance (ANOVA) and a P value of less than .05 was considered significant. Values are presented as mean +/- SEM. RESULTS: EGF was mitogenic to the ileum after sham operation as monitored by increases in ileal protein content (2.21 +/- 0.002 mg/cm Sham v 2.97 +/- 0.25 mg/cm Sham +/- EGF; P < .05). After SBR, adaptation resulted in increased ileal protein content (4.45 +/- 0.27 mg/cm), which was substantially boosted by EGF (5.98 +/- 0.39 mg/cm; P < .05). No differences were detected in ileal EGF receptor mRNA or protein expression between Sham or SBR groups that did not receive EGF. However, EGF significantly enhanced the expression of ileal EGF receptor mRNA to an equal extent after both sham and SBR (approximately threefold). The magnitude of this increase in EGF receptor protein (four- to sixfold) was similar in both EGF groups as shown by Western blotting. CONCLUSIONS: Changes in ileal EGF receptor expression are not mandatory for adaptation to occur. EGF upregulates the expression of mRNA and protein for its own intestinal receptor in vivo. Because EGF-induced receptor expression was comparable after both SBR and Sham operation, the beneficial effect of EGF during adaptation is likely caused by other factors in addition to increased receptor expression.     

Evidence for the requirement of autocrine growth factors for development of mouse preimplantation embryos in vitro

The mitotic stimuli in the early mammalian embryo have not been unequivocally identified. One hypothesis is that the embryo releases autocrine growth factors (GFs) that have a role in such growth. To determine whether such putative GFs were limited by dilution, and hence secreted, development was observed at various embryo concentrations in culture. Embryos were collected at the zygote or 2-cell stage. Zygotes were produced by fertilization in situ (ISF) or in vitro (IVF). Two-cell-stage embryos had a high rate of development to the blastocyst stage across an embryo concentration range of 1/microl-0.001/microl. By contrast, zygotes produced by either ISF or IVF were adversely affected by reducing the embryo concentration over this range (p < 0.001), with approximately 80% of ISF zygotes developing to blastocysts at the highest concentration but only 26% at the lowest. For IVF zygotes the corresponding results were 64% and 6%. For all three embryo types, the number of cells in each blastocyst was significantly lower with reduced embryo concentration. The major determinant of zygote development was the concentration of embryos in culture rather than the absolute volume of culture medium or the actual number of embryos present. A concentration of 1 embryo/microl (in the form of 10 embryos/10microl) gave the best development rates and highest cell numbers per blastocyst. Varying the albumin concentration influenced development rates; a 10-fold reduction in BSA concentration (to 0.3 mg/ml) resulted in significantly more IVF zygotes developing to the blastocyst stage. Platelet-activating factor (PAF) is released by embryos, and albumin can act as a competitive inhibitor of PAF's action on cells. ISF embryos released more PAF (p < 0.05) into media than did similarly treated IVF embryos. There was no difference in the amount of PAF remaining associated with the resulting 2-cell embryos. The amount of PAF released by both these groups was markedly less (p < 0.001) than the amount released by 2-cell embryos collected fresh from the reproductive tract and cultured for 24 h. PAF supplementation of media caused a significant increase in the rate of blastocyst development of IVF zygotes at embryo concentrations of 0.1/microl (1 ng/ml) and 0.01/microl (100 ng/ml). Insulin-like growth factor (IGF)-I (30 ng/ml) and IGF-II (1 ng/ml) also stimulated development of IVF zygotes when cultured at an embryo concentration of 1/10 microl. Epidermal growth factor was without effect over the range 0.2-2000 ng/ml. Supplementation of media with both PAF and IGF-II gave no additional benefit over that caused by IGF-II alone, but this treatment was marginally better (p < 0.05) than PAF treatment alone. The results show that factors necessary for normal embryo development are diluted to suboptimal levels during culture at low embryo concentration. The ability of PAF, IGF-I, and IGF-II to partially compensate for the adverse effects of low embryo concentration during culture is consistent with their having roles as autocrine embryotrophic factors. The use of IVF and low embryo concentrations in culture may provide a functional multiple ablation model that will help to define the range of GFs required for normal embryo development.     

Expression of epidermal growth factors and epidermal growth factor receptor in normal cycling human ovaries

Immunolocalization of transforming growth factor-alpha (TGF alpha), epidermal growth factor (EGF), cripto-1, amphiregulin and epidermal growth factor receptor (EGFR) was studied in 51 premenopausal human ovaries at various phases of the menstrual cycle. Localization of mRNA for TGF alpha and EGF was also studied by in-situ hybridization. Immunoreactive TGF alpha was observed predominantly in theca cells in 12 of 33 antral follicles in the follicular phase (6/14 dominant follicles, and 6/19 non-dominant) but not in any of the 18 follicles in the luteal phase or in primordial and pre-antral follicles. TGF alpha immunoreactivity was present predominantly in the luteinized granulosa cells in 13 of 15 corpora lutea in the luteal phase, which are considered to be active in steroidogenesis, but not in any of the regressed corpora lutea. Accumulation of TGF alpha mRNA hybridization signal was observed only in the theca cells in the follicles and luteinized theca cells in the ovaries that were immunohistochemically positive for TGF alpha. EGFR immunoreactivity was detected in 24 of 33 antral follicles in the follicular phase and in two of 18 follicles in the luteal phase but not in any of the corpora lutea. Immunoreactive EGF, cripto-1 and amphiregulin or EGF mRNA was not detected in any follicles, corpora lutea, or the stroma cells examined. These results indicate that, of the epidermal growth factors examined in this study, TGF alpha is locally synthesized in normal cycling human ovaries and TGF alpha may be synthesized in theca cells and act on the granulosa cells in a paracrine fashion through the EGFR in ovarian follicles.     

Monoclonal antibodies directed against lipopolysaccharide of Legionella pneumophila serogroup 1

The monoclonal antibodies (MAbs) against lipopolysaccharide of virulent strain of Legionella pneumophila serogroup 1 were produced. Three most productive hybrid clones (5F4, 5F10 and 2C9) were selected from fusions of mouse myeloma cells with spleen cells from BALB/c mice, immunized with bacterial outer membrane antigens. All generated clones were IgG-secreting. The MAbs had narrow strain specificity and showed no cross-reactions with other unrelated bacterial species. These antibodies were tested in sandwich ELISA. The results suggest that the MAbs could be used for diagnostic purposes.     

Monoclonal antibodies against vascular endothelial antigens expressed in normal human brain

A panel of monoclonal antibodies reactive with human-brain vessels was raised by immunizing BALB/c mice with homogenate of whole human brain, obtained from temporal lobectomies. Hybridoma supernates were screened by immunohistochemical methods on frozen sections of human brain, liver and spleen and 16 clones were isolated. The pattern of immunoreactivity varied with respect to the type of brain blood vessels predominantly labelled and to tissue specificity. Some antibodies cross-reacted with cow or squirrel monkey forebrain microvessels with an intensity equal to that shown by human brain. The immunoreactivity patterns reflected antigenic heterogeneity among different subsets of vascular endothelial cells in human brain.     

Neutralizing antibodies to IFN-gamma-inducing factor prevent experimental autoimmune encephalomyelitis

Specific oligonucleotide primers were used to identify and isolate IFN-gamma-inducing factor (IGIF) from the brain of rats with developing experimental autoimmune encephalomyelitis (EAE), a T cell-mediated autoimmune disease of the central nervous system that serves as a model for multiple sclerosis. IGIF was highly transcribed in the brain at the onset and during the course of active EAE. PCR products encoding rat IGIF were used to generate the recombinant protein that was used to induce anti-IGIF neutralizing Abs. These Abs significantly reduced the production of IFN-gamma by primed T cells proliferating in response to their target myelin basic protein epitope and by Con A-activated T cells from naive donors. When administered to rats during the development of either active or transferred EAE, these Abs significantly blocked the development of disease. Splenic T cells from protected rats were cultured with the encephalitogenic myelin basic protein epitope and evaluated for production of IL-4 and IFN-gamma. These cells, which proliferated, exhibited a profound increase in IL-4 production that was accompanied by a significant decrease in IFN-gamma and TNF-alpha production. Thus, we suggest that perturbation of the Th1/Th2 balance toward Th2 cells is the mechanism underlying EAE blockade by anti-IGIF immunotherapy.