Movement patterns for a critically endangered species, the leatherback turtle (Dermochelys coriacea), linked to foraging success and population status.

Foraging success for pelagic vertebrates may be revealed by horizontal and vertical movement patterns. We show markedly different patterns for leatherback turtles in the North Atlantic versus Eastern Pacific, which feed on gelatinous zooplankton that are only occasionally found in high densities. In the Atlantic, travel speed was characterized by two modes, indicative of high foraging success at low speeds (<15 km d(-1)) and transit at high speeds (20-45 km d(-1)). Only a single mode was evident in the Pacific, which occurred at speeds of 21 km d(-1) indicative of transit. The mean dive depth was more variable in relation to latitude but closer to the mean annual depth of the thermocline and nutricline for North Atlantic than Eastern Pacific turtles. The most parsimonious explanation for these findings is that Eastern Pacific turtles rarely achieve high foraging success. This is the first support for foraging behaviour differences between populations of this critically endangered species and suggests that longer periods searching for prey may be hindering population recovery in the Pacific while aiding population maintenance in the Atlantic.

CD25-expressing B-lymphocytes in rheumatic diseases.

B cells play an important role in the development of autoimmune diseases due to their production of autoantibodies, antigen-presenting capacity and production of pro-inflammatory cytokines. The purpose of the present study was to analyse B cells from rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE) patients, with respect to their expression of the IL-2 receptor (IL-2R) subunit CD25. Using flow cytometry, we found that CD25(+) B cells from RA patients expressed significantly higher frequencies of CD122 and CD132 than CD25(+) B cells from control subjects, indicating a fully functional IL-2R. These CD25(+) B cells also expressed higher frequencies of the co-stimulatory molecule CD80, whereas IgM and IgA expression was decreased compared with CD25(+) B cells from healthy controls. In addition B cells from SLE patients co-expressed CD25 together with CD80, CD122, and CD132, but to a lower degree IgD and IgM, when compared with healthy controls. Taken together, our results indicate that CD25(+) B cells from RA and SLE patients are in a highly activated state, display a more mature phenotype and suggest that this B cell subset may be involved in the pathogenesis of RA and SLE.

Evaluation of peracid formation as the basis for resistance to infection in plants transformed with haloperoxidase.

Nonheme haloperoxidase (HPO-P) isolated from Pseudomonas pyrrocinia catalyzed the peroxidation of alkyl acids to peracids. Among acids tested as substrates, acetic acid was most readily peroxidized. The reaction product peracetate possessed potent antifungal activity: 50% death (LD(50)) of Aspergillus flavus occurred at 25 microM peracetate. Viability of A. flavus was inhibited by up to 80% by leaf extracts of tobacco plants transformed with the HPO-P gene from P. pyrrocinia compared to viability of fungi exposed to extracts from controls. To elucidate if peracid formation by HPO-P was the basis for antifungal activity in transgenic leaf tissues, lethalities of hydrogen peroxide-acetate-HPO-P combinations against A. flavus were examined in vitro. LD(50) of A. flavus exposed to the combinations occurred at 30 mM acetate when concentrations of hydrogen peroxide and HPO-P were held constant. This value was identical to the LD(50) produced by 30 mM acetate in the absence of hydrogen peroxide-HPO-P and therefore did not account for enhanced antifungal activity in transgenic plants. For clarification, kinetics of the enzymic reaction were examined. According to the concentration of acetate needed for enzyme saturation (K(m) = 250 mM), acetate was lethal prior to its oxidation to peracetate. Results indicate that peracid generation by HPO-P was not the basis for enhanced antifungal activity in transgenic plants expressing the HPO-P gene.

Epidermal growth factor receptor signaling and the invasive phenotype of ovarian carcinoma cells.

BACKGROUND: Most (70%-100%) ovarian carcinomas express high levels of the epidermal growth factor receptor (EGFR). To examine the relationship between EGFR and the invasive phenotype, we assessed integrin expression, adhesion, matrix metalloproteinase (MMP) activity, and migration in ovarian cancer cells in which EGFR expression was modified. METHODS: NIH:OVCAR-8 human ovarian carcinoma cells were transfected with an expression vector containing the human EGFR complementary DNA in an antisense orientation (EGFR-antisense cells) or the vector alone (vector control cells). We compared vector control and EGFR-antisense cells for cell morphology and adhesion by light microscopy, expression of alpha(6)- and alpha(3)-integrin subunits by flow cytometry, MMP and tissue inhibitor of MMP (TIMP) activity by zymography, and migration by a wound migration assay. In some experiments, EGFR kinase activity in parental cells was inhibited by treatment with PD153035. All statistical tests were two-sided. RESULTS: EGFR-antisense cells were morphologically distinct from vector control cells and had a selective decrease in adhesion to laminin-1 that was not observed with vector control cells (P = .008) or on other extracellular matrix substrates. Compared with vector control cells, cell surface alpha(6)-integrin expression decreased by approximately 80% (difference = 78.7%; 95% confidence interval [CI] = 77.8% to 79.6), MMP-9 activity decreased by approximately 50%, and TIMP activity increased by approximately 50% in EGFR-antisense cells. Vector control cells were highly motile (5.51 arbitrary distance unit; 95% CI = 4.98 to 6.04), whereas the EGFR-antisense cells were not (0.99 arbitrary distance units; 95% CI = 0.38 to 1.60). The morphology and integrin profile of NIH:OVCAR-8 parental cells treated with PD153035 were similar to those of the EGFR-antisense cells. CONCLUSIONS: Reduced EGFR expression in ovarian carcinoma cells decreased their adhesion to laminin-1, expression of the alpha(6)-integrin subunit (a well-characterized laminin-1 receptor), and MMP-9 activity. These data support the hypothesis that EGFR overexpression in ovarian cancer cells results in multiple phenotypic changes that enhance the invasive phenotype.

Combustion of gasolines in premixed laminar flames European certified and California phase 2 reformulated gasoline.

Two gasoline qualities, European unleaded certified gasoline (EUCG) and California phase 2 reformulated gasoline (P2 RFG), were analysed. EUCG contained about twice the amount of alkyl benzenes compared to P2 RFG and a large amount of cyclohexane. As a balance, P2 RFG contained higher amounts of isooctane and MTBE. The gasolines were burned in a premixed laminar flame burner at 1 atm and at about stoichiometric fuel/air ratio. The species profiles were measured using on-line GC/MS. About 40 compounds were be detected in the gasoline flames. The EUCG resulted in formation of more reactive and toxic compounds. The combustion profiles of the fuel components showed a similar slope, which suggests that the fuel components burn quite independently of each other. Ethene and propene were the dominating species produced from the two gasolines. Commonly, substantial amounts of higher alkenes were found. Combustion of P2 RFG produced higher amounts of isobutene, propene, propyne, propadiene and methanol compared to combustion of EUCG. The high amount of isobutene is reasonably a result of high concentration of isooctane and MTBE in the fuel. The high amount of methanol formed is probably due to the MTBE present in the gasoline. EUCG produced significantly higher amounts of 1,3-butadiene, which quite likely is formed from the cyclohexane in the fuel. The benzene profiles from both gasolines shows an almost constant level up to 800 microm from the burner surface; this is probably due to formation of benzene from alkyl benzenes.

Broad-spectrum antimicrobial activity in vitro of the synthetic peptide D4E1.

Broad-spectrum antimicrobial activity of a synthetic peptide, D4E1, is documented in this paper. D4E1 inhibited the growth of several fungal phytopathogens belonging to four classes-Ascomycetes, Basidiomycetes, Deuteromycetes, and Oomycetes, and two bacterial pathogens, Pseudomonas syringae pv. tabaci and Xanthomonas campestris pv. malvacearum race 18. The minimum inhibitory concentration (MIC) of D4E1 required to completely inhibit the growth of all fungi studied ranged from 4.67 to 25 microM. Fungal pathogens highly sensitive to D4E1 include Thielaviopsis basicola, Verticillium dahliae, Fusarium moniliforme, Phytophthora cinnamomi, and Phytophthora parasitica. Comparatively, the least sensitive fungal pathogens were Alternaria alternata, Colletotrichum destructivum, and Rhizoctonia solani. The two bacterial pathogens, P. syringae pv. tabaci and X. campestris pv. malvacearum race 18, were most sensitive to D4E1 with MIC values of 2.25 and 1.25 microM, respectively. Microscopic analysis of D4E1 effects on fungal morphology of Aspergillus flavus and R. solani revealed abnormal hyphal growth and discontinuous cytoplasm. After 8 h of exposure to 25 microM D4E1, A. flavus spore germination was reduced by 75%. The suitability of peptide D4E1 to enhance disease resistance in transgenic crop plants is discussed.

Anti-sense suppression of epidermal growth factor receptor expression alters cellular proliferation, cell-adhesion and tumorigenicity in ovarian cancer cells.

Over-expression of epidermal growth factor receptor (EGFR) in ovarian cancer has been well documented. Human NIH:OVCAR-8 ovarian carcinoma cells were transfected with an expression vector containing the anti-sense orientation of truncated human EGFR cDNA. EGFR anti-sense over-expression resulted in decreased EGFR protein and mRNA expression, cell proliferation and tumor formation in nude mice. In accordance with the reduced levels of EGFR in EGFR anti-sense-expressing cells, tyrosine phosphorylation of EGFR was decreased compared to untransfected parental cells treated with EGF. In EGFR anti-sense-transfected cells, expression of erbB-3, but not erbB-2, was increased. In addition, basal and heregulin-beta 1-stimulated tyrosine phosphorylation of erbB-3 was higher in EGFR anti-sense vector-transfected cells. A morphological alteration in EGFR anti-sense gene-expressing cells was correlated with a decrease in the expression of E-cadherin, alpha-catenin and, to a lesser extent, beta-catenin. Changes in the expression of these proteins were associated with a reduction in complex formation among E-cadherin, beta-catenin and alpha-catenin and between beta-catenin and EGFR in EGFR anti-sense-expressing cells compared to sense-transfected control cells. These results demonstrate that EGFR expression in ovarian carcinoma cells regulates expression of cell adhesion proteins that may enhance cell growth and invasiveness.

Antifungal and peroxidative activities of nonheme chloroperoxidase in relation to transgenic plant protection.

Nonheme chloroperoxidase (CPO-P) of Pseudomonas pyrrocinia catalyzes the oxidation of alkyl acids to peracids by hydrogen peroxide. Alkyl peracids possess potent antifungal activity as found with peracetate: 50% killing (LD(50)) of Aspergillus flavus occurred at 25 microM compared to 3.0 mM for the hydrogen peroxide substrate. To evaluate whether CPO-P could protect plants from fungal infection, tobacco was transformed with a gene for CPO-P from P. pyrrocinia and assayed for antifungal activity. Leaf extracts from transformed plants inhibited growth of A. flavus by up to 100%, and levels of inhibition were quantitatively correlated to the amounts of CPO-P activity expressed in leaves. To clarify if the peroxidative activity of CPO-P could be the basis for the increased resistance, the antifungal activity of the purified enzyme was investigated. The LD(50) of hydrogen peroxide combined with CPO-P occurred at 2.0 mM against A. flavus. Because this value was too small to account for the enhanced antifungal activity of transgenic plants, the kinetics of the enzyme reaction was examined and it was found that the concentration of hydrogen peroxide needed for enzyme saturation (K(m) = 5.9 mM) was already lethal. Thus, the peroxidative activity of CPO-P is not the basis for antifungal activity or enhanced resistance in transgenic plants expressing the gene.

EGF-related antisense oligonucleotides inhibit the proliferation of human ovarian carcinoma cells.

BACKGROUND: The epidermal growth factor (EGF)-like peptides CRIPTO (CR), amphiregulin (AR) and transforming growth factor alpha (TGFalpha) are expressed in human ovarian carcinomas. MATERIALS AND METHODS: The expression of AR, CR and TGFalpha in ovarian carcinoma cell lines was assessed by immunocytochemistry and reverse transcriptase polymerase chain reaction (RT-PCR). The antiproliferative effects of antisense phosphorothioate oligodeoxynucleotides (AS S-Oligos) directed against either AR, CR or TGFalpha was evaluated by using a clonogenic assay. RESULTS: A majority of the ovarian carcinoma cell lines was found to express TGFalpha, AR and CR mRNAs and proteins. AS S-Oligos directed against either AR, CR or TGFalpha were able to inhibit the anchorage-independent growth of NIH:OVCAR3 and NIH:OVCAR8 cells in a dose dependent manner. A 30%-50% growth inhibition was observed at a 2 microM concentration of the AS S-Oligos. Treatment of these cells with combinations of EGF-related AS S-Oligos resulted in a more significant growth inhibition when compared to treatment with a single AS S-oligo. A 60%-75% growth inhibition was observed using combinations of AR, CR and TGFalpha AS S-oligos at a total concentration of 2 microM. An additive growth-inhibitory effect occurred when ovarian carcinoma cells were exposed to the AS S-Oligos after treatment with either paclitaxel or cis-platinum. CONCLUSIONS: These data suggest that EGF-related peptides function as autocrine growth factors in ovarian carcinoma cells, and that they might represent targets for experimental therapy of ovarian carcinoma.

Inhibition of fungal growth in planta and in vitro by transgenic tobacco expressing a bacterial nonheme chloroperoxidase gene.

Transgenic tobacco plants producing chloroperoxidase (CPO-P), encoded by a novel gene from Pseudomonas pyrrocinia, were obtained by Agrobacterium-mediated transformation. Successful transformation was shown by PCR, Southern, northern and western blot analyses, and assays of CPO-P enzyme activity. Extracts from plants transformed with the CPO-P gene significantly reduced Aspergillus flavus colonies by up to 100% compared with extracts from control plants transformed with pBI121. Compared with controls, the transformed plants showed increased disease resistance in planta against a fungal pathogen, Colletotrichum destructivum, the causal agent of tobacco anthracnose.

ErbB receptor expression and growth response to heregulin beta 1 in five ovarian carcinoma lines.

SKOV-3, NIH:OVCAR-3, NIH:OVCAR-8, Ovca 429 and Ovca 433 ovarian carcinoma cell lines were examined to correlate biological behavior (growth in monolayer and soft agar) with erbB family receptor expression levels and response to recombinant Heregulin beta1 (Hrg). While all lines expressed variable amounts of each receptor, erbB-3 and to a lesser extent erbB-2 were constitutively tyrosine phosphorylated in all lines. Hrg beta1 treatment enhanced only erbB-3 tyrosine phosphorylation; however, the addition of Hrg in low serum did not stimulate ovarian cell growth, unlike all three breast cancer cell lines examined. In addition, all five of the ovarian carcinoma cell lines expressed Hrg mRNA by RT-PCR, unlike two of the three breast cancer cell lines. These results suggest the apparent importance of erbB-3 and endogenous Hrg in ovarian carcinoma cell growth in vitro.

Relationship Between Phyllosphere Population Sizes of Xanthomonas translucens pv. translucens and Bacterial Leaf Streak Severity on Wheat Seedlings.

ABSTRACT The relationship between leaf-associated population sizes of Xanthomonas translucens pv. translucens on asymptomatic leaves and subsequent bacterial leaf streak (BLS) severity was investigated. In three experiments, X. translucens pv. translucens was spray-inoculated onto 10-day-old wheat seedlings over a range of inoculum densities (10(4), 10(5), 10(6), 10(7), and 10(8) CFU/ml). Lesions developed most rapidly on plants inoculated with higher densities of X. translucens pv. translucens. Leaf-associated pathogen population sizes recovered 48 h after inoculation were highly predictive of BLS severity 7 days after inoculation (R(2) = 0.970, P < 0.0001). The relationship between pathogen population size on leaves and subsequent BLS severity was best described by the logistic model. Leaf-associated X. translucens pv. translucens population size and BLS severity from a particular pathogen inoculum density often varied among experiments; however, the disease severity level caused by a particular leaf-associated X. translucens pv. translucens population size was not significantly different among experiments. Biological and disease control implications of the X. translucens pv. translucens population size-BLS severity relationship are discussed.

Inducible antisense inhibition of erbB-2 expression reduces anchorage independent growth of ovarian carcinoma cells.

We have investigated the effect of c-erbB-2 expression on the growth of ovarian carcinoma cell lines using antisense methodology. A 1.5 kb fragment of c-erbB-2 cDNA was cloned in an antisense and sense orientation into an IPTG inducible vector. These vectors were stably transfected into two ovarian carcinoma cell lines, one of which (NIH:OVCAR-8) grew well in soft agar. Inhibition of expression of endogenous c-erbB-2 protein was detected by immunoprecipitation and Western blot in both of the induced transfectants with the antisense construct. Although growth in monolayer culture was unaffected, NIH:OVCAR-8 cells transfected with the antisense construct and induced with IPTG lost their ability to form colonies in soft agar. Consequently, endogenous expression of c-erbB-2 modulates anchorage-independent growth of NIH:OVCAR-8.

Effects of 3,3',4,4',5-pentachlorobiphenyl (PCB 126) and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) injected into the yolks of chicken (Gallus domesticus) eggs prior to incubation.

The yolks of White Leghorn chicken (Gallus domesticus) eggs were injected prior to incubation with either 3,3',4,4',5-pentachlorobiphenyl (PCB 126) at doses ranging from 0.1 to 12.8 microg/kg egg or 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) at doses ranging from 0.04 to 0.64 microg/kg egg. Chicks were subjected to necropsy within 24 h of hatching. The brain, bursa, heart, liver, and spleen were removed and weighed. Assessment of the rate of hatching indicated an LD50+/-S.E. of 2.3+/-0.19 microg/kg egg (7. 1+/-0.58 nmol/kg egg) for PCB 126 and 0.15 +/- 0.012 microg/kg egg (0.47 +/- 0.037 nmol/kg egg) for TCDD. No significant differences in the incidence of developmental abnormalities (structural defects and edema) were observed in TCDD-exposed embryos, while PCB 126 caused significantly more developmental abnormalities at 3.2, 6.4, and 12.8 microg/kg egg than the vehicle control. PCB 126 caused lower hatchling weights and greater relative brain, heart, and liver weights when compared to the vehicle control group at a dose of 3.2 microg/kg egg which is greater than the LD50. TCDD at 0.08 microg/kg egg caused relative bursa weights to be less than those of the vehicle control. A toxic equivalency factor (TEF) of 0.07 was determined for PCB 126 in relation to TCDD based on overt lethality.

mRNA phenotyping of the major ligands and receptors of the EGF supergene family in human ovarian epithelial cells.

mRNA amplification phenotyping (MAPPing) was used to determine the level of mRNA expression of the major EGF-related ligands (EGF, TGF-alpha, and Amphiregulin) and receptors (EGF-receptor and erbB-2) of the EGF supergene family in three ovarian carcinoma lines (OVCA 429 and 433, and NIH:OVCAR-8) under serum-supplemented and reduced serum (minimal medium with 2% fetuin) growth conditions. mRNA levels of TGF-alpha, EGF-R, and erbB-2 were particularly high, and increased approximately 2-3 orders of magnitude when grown in serum, consistent with an autocrine involvement of these genes in ovarian epithelial growth in vitro. Moreover, even when grown without serum, OVCA 429 and NIH:OVCAR-8 expressed elevated levels of mRNA for erbB-2.

Frequent immunohistochemical detection of EGF supergene family members in ovarian carcinogenesis.

Primary and metastatic ovarian cystadenocarcinomas, carcinomas of low malignant potential (borderline tumors), benign ovarian cystadenomas, and normal ovaries were compared for immunoperoxidase detection of the ligands epidermal growth factor (EGF), transforming growth factor-alpha (TGF-alpha), amphiregulin (AR), cripto, and the receptors, epidermal growth factor receptor (EGF-R), and c-erbB-2. This matrix analysis of these EGF family members indicated no specific pattern of ligand or receptor expression with a specific ovarian histologic category except in the case of AR and TGF-alpha. AR was detected almost exclusively in borderline tumors, suggesting that these tumors may not arise as a pathological continuum between benign cystadenomas and invasive cystadenocarcinomas. Second, the presence of TGF-alpha immunoreactivity in the absence of coexpression of cripto or EGF appeared to be associated only with adenocarcinomas of high grade and stage.

An albumin-like protein is the major secretory protein of ovarian epithelial cells in vivo and in vitro.

Contemporary experimental techniques were used to evaluate the protein secretion of ovarian epithelium. The protein composition of 14 ovarian cyst fluids (OCF) from either cystadenomas or cystadenocarcinomas, and conditioned media (CM) from seven ovarian carcinoma lines in culture, were analyzed by SDS-PAGE under reducing conditions, and Western immunoblots. The major protein common to all the above samples was a 65 kDa protein that, by densitometry, constituted between 43% and 77% of OCF protein and 19% and 38% of CM protein. By Western blot analysis, this band was immunologically related to human albumin. Moreover, immunoreactivity to albumin was demonstrated in ovarian epithelium in vivo. Ovarian epithelium synthesizes and releases an albumin-like protein that constitutes the major secretory protein. This may suggest an osmotic mechanism for cyst enlargement in ovarian cystadenomas.

Regulatory concerns in the development of topical recombinant ophthalmic and cutaneous wound healing biologics.

The use of recombinant DNA technology has enabled the development of an increasing number of endogenous growth regulatory peptides for potential use as therapeutic biologics. Numerous such recombinant peptides are now licensed, and many are in various stages of pharmaceutical development. Although currently there are a number of "Points to Consider" and related guidance documents available concerning various issues of biotechnology-derived products, the purpose of this article is to focus on the use of these biologics in topical ophthalmic and chronic cutaneous wound healing. Regulatory expectations with respect to product quality, safety, and efficacy that may be particularly germane to these products will be discussed. Providing regulatory guidance on these issues may not only facilitate the introduction of safe and effective new biologic therapies into clinical trials at the investigational level but also provide appropriate information to aid in their eventual approval for licensure and widespread clinical use.

Characterization of high and low molecular weight forms of amphiregulin that differ in glycosylation and peptide core length. Evidence that the NH2-terminal region is not critical for bioactivity.

Human amphiregulin (AR) is a polypeptide growth regulator which acts by binding to and activating the epidermal growth factor (EGF) receptor tyrosine kinase. AR consists of an EGF-like domain and an NH2-terminal extension which contains potential glycosylation sites and nuclear localization signals. Two high molecular weight species which had molecular masses of approximately 16.5 kDa (HMW-AR1 and HMW-AR2) and a approximately 9.5-kDa low molecular weight form (LMW-AR) were isolated from the conditioned medium of phorbol 12-myristate 13-acetate-treated MCF-7 human breast carcinoma cells by sequential heparin affinity, immunoaffinity, and reverse phase-high performance liquid chromatography. HMW-AR1 and HMW-AR2 were found to possess complex or hybrid type N-linked oligosaccharide structures that contained sialic acid. Additionally, HMW-AR1 and HMW-AR2 contained the disaccharide, Gal beta(1-->3)GalNAc, linked to Ser/Thr residues. No carbohydrate moieties were detected in LMW-AR. Mapping of the peptide cores of these molecules using antipeptide antibodies revealed that HMW-AR1 and HMW-AR2 were intact molecules, whereas LMW-AR contained the EGF-like domain, but possessed a truncated NH2-terminal extension. LMW-AR, HMW-AR1, and HMW-AR2 were all found to be potent stimulators of DNA synthesis in MCF-10A human mammary epithelial cells. These results suggest that the NH2-terminal region of the AR molecule is not critical to the ability of AR to activate the EGF receptor tyrosine kinase.

Amphiregulin induces tyrosine phosphorylation of the epidermal growth factor receptor and p185erbB2. Evidence that amphiregulin acts exclusively through the epidermal growth factor receptor at the surface of human epithelial cells.

The COOH-terminal half of the amphiregulin (AR) molecule has sequence homology to epidermal growth factor (EGF). The ability of AR to elicit in vivo phosphorylation of the EGF receptor (EGFR) and p185erbB2 was studied in four human epithelial cell lines which expressed either or both of the receptor tyrosine kinases. AR induced the phosphorylation of the EGFR and p185erbB2, and phosphoamino acid analysis revealed enhanced phosphorylation of tyrosine residues in both receptor proteins. A monoclonal antibody (mAb) which binds to the extracellular domain of the EGFR blocked the phosphorylation of the EGFR and p185erbB2 as well as AR-induced mitogenesis indicating that the EGFR mediated these responses. In MDA-MB-453 cells which lack EGFRs, AR did not induce phosphorylation of p185erbB2, did not affect proliferation, and had no detectable effect on the phosphorylation of cellular proteins isolated using an anti-phosphotyrosine mAb. Qualitatively, in vivo phosphorylations induced by AR and EGF were found to be indistinguishable as demonstrated by analysis of cellular 32P-labeled proteins isolated with the anti-phosphotyrosine mAb. Moreover, in the presence of the anti-EGFR mAb, AR had no effect on the proliferation of cells. These results provide strong evidence that the EGFR is the sole cell surface mediator of the action of AR in human epithelial cells.