The spatial relationship between the musculature and the 5-HT and FMRFamide immunoreactivities in cercaria,metacercaria and adult <Emphasis Type="Italic">Opisthorchis felineus</Emphasis> (Digenea)

The organisation of the neuromuscular system in cercariae, metacercariae and adult Opisthorchis felineus was studied. The patterns of nerves immunoreactive (IR) to antibodies towards serotonin (5-HT) and FMRFamide are described in relation to the musculature, stained with TRITC-conjugated phalloidin. The general organisation of the musculature in the body wall, suckers, pharynx, intestine and sphincter of the excretory pore remains the same from the larval stages to the adult worms. However, the diameter of the individual muscle fibres increases distinctly in the adult worms. The general pattern of 5-HT IR fibres in cercariae, metacercariae and adult O. felineus remains the same. Despite the large increase in body size, the number of 5-HT IR neurones remains almost the same in the cercariae and metacercariae and only a modest increase in number of neurones was observed in the adult worms. Thus the proportion of 5-HT IR neurones/body mass is greatest in the actively moving cercariae. Anti-FMRFamide stains the nervous system strongly.     

D2-but not D1-dopamine receptors are involved in the inhibitory control of alpha-melanocyte-stimulating hormone release from the rat hypothalamus

Summary Release of alpha-melanocyte-stimulating hormone (-MSH) from slices of rat hypothalamus superfused with artificial cerebro-spinal fluid (ACSF) was quantified by radioimmunoassay. Addition of 10^-6 M quinpirole, a D2-dopamine receptor agonist, to the superfusion medium caused a significant (P < 0.001) reduction in the amount of -MSH released upon depolarisation with 50 mM potassium from 319 ±37% to 110 ±16% of basal release in normal ACSF (mean ±S.E.M.). Basal peptide release in the presence of quinpirole was unaffected. Sulpiride, a D2-dopamine receptor antagonist, at a concentration of 10^-6 M, induced a significant (P < 0.05) increase of both basal and potassium-stimulated -MSH release to 203 ±21% and 447 ±88% of basal release in normal ACSF respectively. The latter increases were abolished when sulpiride and quinpirole were added in combination. SK&F 38393-A and SCH 23390, a D1-dopamine agonist and antagonist respectively, had no significant effect on either basal or potassiumstimulated -MSH release. It is proposed that endogenous dopamine exerts an inhibitory control on -MSH release from the rat hypothalamus via D2-dopamine receptors and that in isolated hypothalamic slices there is a tonic inhibition of peptide release due to the activity of this system.     

Immunohistochemical studies on S-100 cells in the anterior pituitary gland of Sprague Dawley rats and spontaneous dwarf rats

The S-100 cells in the pituitary glands of adult male Sprague Dawley rats (SDs) and spontaneous dwarf rats (SDRs) were immunohistochemically examined using anti-S-100 and anti-S-100 monoclonal antibodies. The immunoreactive cells against S-100 protein were divided into three subtypes on the basis of their immunore-activity against subunits of S-100 protein: S-100 dominant type (the -type cell), S-100 dominant type (the \-type cell) and immunoreactive against both S-100 and S-100 (the -type cell). In the SD, -type cells represented 26% of the total S-100 immunoreactive cells (S-100 cells) and were localized in the peripheral area of the ventral region of the pituitary gland. This type of cell was observed forming clusters, with more abundant cytoplasm than the -type cell. The proportion of -type cells was 53%. They were diffusely distributed throughout the gland, and their processes were thicker than those of the -type cell. In the SDR, the proportion of -type cells was 55%, and they were observed throughout the gland. In contrast, -type cells totalled 12% and were localized in small areas of the central and peripheral region of the gland. The proportion of -type cells was 21% in the SD and 33% in the SDR and they were observed forming small clusters in both animal groups. The proportion of -type cells compared with the total of S-100-immunoreactive cells was significantly higher (P < 0.05) in the SDR than in the SD, while the proportion of -type cells was markedly lower (P < 0.05).     

Solitary mastocytoma of the eyelid

Summary Solitary mastocytoma (mast cell naevus) of the skin represents a relatively rare dermal tumour. Its occurrence on the lower eyelid is exceptional. We report the case of a 4 month old male infant who exhibited a firm, yellowish nodule (1 cm in maximum diameter) on the lower lid of the right eye from birth. Histologically, the tumour consisted of strongly metachromatic tissue mast cells (TMC) infiltrating the whole dermis, the adjacent subcutaneous tissue and the lid muscle. Since comparable skin lesions in other sites were not observed, a diagnosis of solitary mastocytoma was made. Immunocytological investigations revealed strong reactivity of the TMC to antisera against vimentin, common leucocyte antigen (CLA),1-antitrypsin (1-AT) and 1-antichymotrypsin (1-ACT). A minor proportion of the TMC reacted to antisera against lysozyme and KiB3. Surprisingly, the TMC also reacted to antisera against certain regulatory peptides (RP), namely adrenocorticotropic hormone (ACTH), peptide histidine isoleucine (PHI), leu-enkephalin and met-enkephalin. However, absorption controls revealed that the immunostaining for ACTH and the two enkephalins was non-specific. The immunocytological phenotype of TMC suggests a close relationship to the myeloid-monocytic lineage, but a possible relationship between TMC and the diffuse neuroendocrine system needs further investigation.     

Regional location of α1-antichymotrypsin and α1-antitrypsin genes on human chromosome 14

The human protease inhibitor genes ₁ antitrypsin (₁-PI) and ₁-antichymotrypsin (₁-ACT) are acute-phase proteins which are induced in response to inflammation. These inhibitors function to limit the activity of serine proteases in vivo. ₁-PI acts as an inhibitor of neutrophil elastase to protect the elastin fibers of the lung. Genetic deficiencies of ₁-PI result in development of chronic pulmonary emphysema. The physiologic role of ₁-ACT has not been clearly defined, but it also appears to function in the maintenance of protease-protease inhibitor equilibrium in the lung. Nucleic acid and protein sequence homologies detected between ₁-PI and ₁ t-ACT suggested an evolutionary relationship. Gene mapping experiments were performed to determine if these protease inhibitor genes reside at the same chromosomal locus in man. In situ hybridization data demonstrate that both ₁-PI and ₁-ACT map to the same region, q31–q32.3, on chromosome 14.     

Structure of the liver as a possible factor in the regulation of α-fetoprotein synthesis

During regeneration of the mouse liver after poisoning with CCl₄ and paracetamol, hepatocytes containing -fetoprotein (FP) lose their membrane antigen that served as marker for biliary capilaries. Both during regeneration and in early postnatal development, cessation of FP synthesis by the cells coincides with the appearance of an antigen marking the biliary capillaries on their surface. It is suggested that cessation of FP synthesis is the result of establishment of a system of contacts characteristic of the definitive hepatic column.Laboratory of Immunochemistry and Diagnosis of Tumors, Oncologic Scientific Center, Academy of Medical Sciences of the USSR, Moscow. (Presented by Academician of the Academy of Medical Sciences of the USSR L. M. Shabad.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 87, No. 6, pp. 576–579, June, 1979.     

Immunocytochemical localization of amino acid neurotransmitter candidates in the ventral horn of the cat spinal cord: a light microscopic study

The distribution of immunoreactivities to six amino acids, possibly related to synaptic function, was investigated in the motor nucleus of the cat L7 spinal cord (laminae VII and IX) using a postembedding peroxidase-antiperoxidase technique. Consecutive 0.5 m transverse sections of plastic-embedded tissue were incubated with antisera raised against protein-glutaraldehyde conjugates of -aminobutyric acid (GABA), glycine, aspartate, glutamate, homocysteate, and taurine. This method allowed localization of the different immunoreactivities in individual cell profiles. The results showed that all these amino acids, except homocysteate, could be clearly detected in either neuronal or glial elements in the ventral horn. In cell bodies of neurons in lamina VII, immunoreactivity was observed for aspartate, glutamate, GABA, and glycine. Adjacent section analysis revealed that combinations of immunoreactivity for glycine/glutamate/aspartate, GABA/glycine/glutamate/aspartate and glutamate/aspartate, respectively, may occur in one and the same cell. In the motor nuclei (lamina IX), immunoreactivity to amino acids was observed in two types of neuron. Large cells, probably representing -motoneurons, were harboring immunoreactivity to both glutamate and aspartate, while a few small neurons in this area displayed a colocalization of glycine, glutamate, and aspartate. Dendrites and axons in the motor nuclei cocontained glycine/glutamate/aspartate, GABA/glycine/glutamate/aspartate, and glutamate/aspartate immunoreactivities. In both laminae VII and IX, taurine-like immunoreactivity was absent in neuronal cell bodies, but highly concentrated in perivascular cells and small cells with a morphology resembling that of glial cells. A punctate immunolabeling, in all probability representing labeling of nerve terminals, could be demonstrated in the ventral horn for GABA, glycine, and glutamate, but not with certainty for aspartate or taurine. A quantitative estimate of the covering of cell bodies of -motoneuron size by immunoreactive puncta revealed that glycine immunoreactive terminal-like structures were most abundant (covering 26–42% of the somatic membrane), while glutamate immunoreactive terminals were seen least frequently (5–9% covering). GABA-immunoreactive terminals covered from 10 to 24% of the soma surface. A colocalization of GABA and glycine immunoreactivities in putative nerve terminals could be shown both in the neuropil and in close relation to cell bodies of motoneurons. These results suggest that among the studied amino acids probably only three, namely GABA, glycine, and glutamate, can be considered to be neurotransmitter candidates in the ventral horn of the cat spinal cord.     

alpha1-acid glycoprotein possesses in vitro pro- and antiinflammatory activities

We studied the effects of ₁-acid glycoprotein on tumor necrosis factor- (TNF-) and interleukin-10 (IL-10) production and lymphocyte response to phytohemagglutinin in cultured peripheral blood mononuclear leukocytes from 6 healthy donors. We observed 2 opposite responses to ₁-acid glycoprotein: first, stimulation of TNF- and IL-10 production and inhibition of lymphocyte proliferation, and second, suppression of cytokine production and stimulation of lymphocyte proliferation. In cell cultures isolated from 4 of 6 donors, the TNF-/IL-10 ratio remained unchanged after addition of native ₁-acid glycoprotein, but some fractions isolated by chromatography on concanavalin A-Sepharose changed this parameter. These changes were most pronounced after treatment with fraction C enriched with molecules with incomplete (biantennary) carbohydrate chains. The mechanisms of ₁-acid glycoprotein-induced effects on peripheral blood mononuclear leukocytes are discussed.     

α2-Macroglobulin production by cultured human fibroblasts

Alpha₂-macroglobulin (₂M), a high-molecular-weight plasma protease inhibitor has been shown, by both immunological and functional methods, to be produced by cultured adult lung fibroblasts. Cultured skin fibroblasts synthesized approximately one tenth as much ₂M as lung fibroblasts. This quantitative difference in ₂M production was also demonstrated in fibroblasts of isogenic origin. There was no difference in the amount of ₂M produced between adult and fetal fibroblasts of the same tissue type (i.e., of lung or of skin origin). ₂M was produced in culture during log-phase growth as well as at confluence. Two other plasma protease inhibitors, C1-esterase inhibitor and a substance immunologically cross-reacting with human inter--trypsin inhibitor, were also made by the cultured fibroblasts. Plasma protease inhibitors not detectable in culture supernatants were ₁-antitrypsin, ₁-antichymotrypsin, and antithrombin III.     

Bioactive 5-Reduced 16α,17α-Cyclohexanoprogesterone Derivatives Weakly Interact with Proteins of the Soluble Uterine Fraction

We studied competitive activities of 16,17-cyclohexano-5- and 5-dihydroprogesterone in replacing ₃H-progesterone and ₃H-16,17-cyclohexano-6-methylprogesterone from protein complexes. Direct binding of ₃H-5-reduced derivatives with proteins of soluble fractions from rat and rabbit uteri was also assayed. Cd values for 5-reduced derivatives were in the micro- or submicromolar range. The data suggest that biological effects of these analogues are not mediated via soluble uterine receptors.     

Gastric histamine methyltransferase: Different methylation rates for enantiomers of side-chain methylated histamine analogues using a highly purified enzyme preparation

The inhibitor/activator and substrate properties of enantiomers of two methylated histamines (MH) were investigated using a histamine methyltransferase preparation which was purified 1207-fold from pig fundic mucosa by ultracentrifugation, ion-exchange chromatography on DEAE-cellulose and preparative electrofocusing.In 1–100 M concentrations,S--MH andR--MH were acceptor substrates as good as histamine itself. When substrate concentrations were increased to 1 mM these substances were methylated to an even greater extent than histamine, since they did not exert substrate inhibition on HMT. Introduction of a further methyl-group into the N-position reduced acceptor substrate properties drastically. A difference in methylation was then seen sinceR-,N -DMH was a better substrate thanS-,N -DMH,Whereas -MH's could not activate HMT the ,N -DMH's did. The poorer the substrate affinity of the investigated substances was, the better they were able to activate HMT.This work was supported by grants from the Deutsche Forschungsgemeinschaft (Schu 228/6-1 and Lo 199/7).     

Development of high-throughput radioligand binding assays for interleukin-1α (IL-1α) and tumor necrosis factor (TNF-α) in isolated membrane preparations

Cytokine binding has been studied in a variety of intact cells, and in isolated receptor preparations. Each approach is associated with limitations with regard to screening large numbers of samples on a repetitive basis. In order to provide a more reproducible system of screening for compounds which modify IL-1 and TNF-, binding, we have developed isolated membrane preparations for studying agents which can alter the association of these ligands with their receptors. These results demonstrate IL-1 binding to BALB/c 3T3 cell membranes and TNF- binding to HeLa S3 cell membranes, and indicate that this is a viable approach to high-throughput screening.     

Erythrocytes carrying mutations in spectrin and protein 4.1 show differing sensitivities to invasion byPlasmodium falciparum

The role of the erythrocyte skeleton in the invasion process ofPlasmodium falciparum was evaluated using genetically variant erythrocytes containing well-defined molecular defects in spectrin (Sp) or protein 4.1 from eight unrelated families. Invasion into red cells from subjects of three black families with hereditary pyropoikilocytosis (HPP) due to inheritance of I/74 mutant spectrin was significantly reduced in cells both from the patients and from the relatives of these who carried asymptomatic hereditary elliptocytosis (HE). Like-wise, reduced invasion was also seen in red cells from two families with HE in which the I/65 variant spectrin was present. Resistance to invasion was not absolute in any sample and varied between 38% and 71% of that seen in normal cells. The decreased invasion correlated with the percentage of spectrin dimers present within the membrane of variant cells. In contrast, invasion into elliptocytes from three families that had a partial deficiency in protein 4.1 (HE/4.1⁺) but a normal percentage of spectrin dimers was either unchanged or increased. The precise mechanism and molecular basis behind the reduced invasion into HPP and HE red cells bearing SpI domain variants remains to be elucidated but might relate to alterations in merozoite/red cell-receptor interactions and/or merozoite endocytosis. The occurrence of elliptocytosis with spectrin defects (in particular, SpI/65 and SpI/46 variants in West Africa) suggests that these mutations of the Sp gene could be related to some protection against malaria.     

Two types of glomus cell in the rat carotid body as revealed by alpha-bungarotoxin binding

Summary Horseradish peroxidase (HRP)-conjugated -bungarotoxin (Bgt) was used to localize Bgt-acetylcholine receptor sites in the rat carotid body. Two types of glomus cell were differentiated on the basis of the staining of their plasma membranes by the conjugate: type A, devoid of staining or only partly stained; and type B, exhibiting staining over the entire cell surface. The parts of type A glomus and supporting cells stained were always in direct apposition to type B glomus cells. It is concluded that type B glomus cells are possibly the only cell types exhibiting specific binding sites of Bgt. Other morphological characteristics and quantitative studies indicated that the type A and type B glomus cells presented in this study were equivalent to those described in the rat carotid body by other investigators (McDonald & Mitchell, 1975). Bgt-HRP staining facilitated the observation of the distribution pattern of glomus cells in the parenchyma: type A glomus cells were arranged in groups and often showed polarity toward neural elements and sinusoidal capillaries; and clusters of type B glomus cells were frequently situated in a demilune-like fashion over groups of type A glomus cells. Because of differences in morphology, synaptology, Bgt-binding affinity, and polarity toward the blood vessels, we propose that type A and type B glomus cells in the rat carotid body represent functionally distinct cell types.     

Serotonin and neuropeptide immunoreactivities in the intramolluscan stages of three marine trematode parasites

Using an indirect immunofluorescence technique interfaced with confocal scanning laser microscopy, whole-mount preparations of three general of marine trematode larvae,Cryptocotyle lingua, Cercaria emasculans andHimasthla leptosoma, were screened for 5-hydroxytryptamine (5-HT) and selected neuropeptide immunoreactivities (IRs). IRs for pancreatic polypeptide (PP), peptide YY (PYY) and FMRFamide were found in the central nervous systems of the three species of cercariae, immunostaining the paired ganglia and central commissure and the longitudinal nerve cords, with slight differences in both distribution and intensity of IRs being observed for the different antisera used. PP, PYY and FMRFamide IRs were evident in both central and peripheral components of the nervous system in the rediae ofC. lingua. 5-HT IR was confined to the peripheral nervous systems of the cercariae ofC. emasculans and the rediae ofC. lingua, appearing in the form of a network of immunoreactive fibres and associated large cell bodies. A moderate substance P IR was observed in the nervous system of the cercariae ofC. lingua. The patterns of immunostaining described were compared with those obtained using antiserum directed to the C-terminal decapeptide amide of neuropeptide F (NPF), a native parasitic peptide from the cestodeMoniezia expansa. Results demonstrated that serotoninergic and peptidergic components were present in the nervous systems of all of the trematode larvae studied and that some, if not all, of the IR for PP, PYY and FMRFamide was due to the presence of a trematode NPF homologue.     

The action of steroid hormones on peripheral myelin proteins: A possible new tool for the rebuilding of myelin?

The present paper summarizes recent results we have obtained while studying the effect of sex steroids on the gene expression of two peripheral myelin proteins, the glycoprotein Po (Po) and the peripheral myelin protein 22 (PMP22). In particular, we have analyzed the effect of progesterone (P), testosterone (T) and their 5- and 3-5-reduced derivatives [respectively, dihydrotestosterone (DHT) and 5-androstan-3, 17-diol (3-diol) for T, and dihydroprogesterone (DHP) and tetrahydroprogesterone (THP) for P]. The data obtained, utilizing different in vivo and in vitro experimental models, have indicated that: a) DHP is able to enhance the low messenger levels of Po present in the sciatic nerve of aged male rats; b) P, DHP and THP treatments stimulate the gene expression of Po in the sciatic nerve of adult male rats or in cultures of rat Schwann cells, while only THP is effective on PMP22; c) P and DHP are also able to increase the low messenger levels of Po present in transected sciatic nerve; d) the removal of circulating androgens by castration is able to decrease the mRNA levels of Po in the sciatic nerve, a phenomenon which is counteracted by the consequent treatment with DHT; e) the stimulatory effect of DHT on the gene expression of Po is also evident in cultures of rat Schwann cells, but in this case the effect seems to be due to the interaction of this steroid with the progesterone receptor; f) in cultures of Schwann cells PMP22 mRNA levels are stimulated only by 3-diol treatment. Taken together, these observations showing the positive effects of sex steroid hormones on the gene expressions of Po and PMP22, suggest that a treatment with these molecules or their synthetic agonists may be useful in cases in which the rebuilding of myelin is necessary.     

α 2-Adrenoceptors activate dihydropyridine-sensitive calcium channels via Gi-proteins and protein kinase C in rat portal vein myocytes

The presence of functional ₂-adrenoceptors was investigated in isolated smooth muscle cells from rat portal vein using the nystatin-perforated patch-clamp technique. The free cytoplasmic calcium concentration ([Ca²⁺]_i) was estimated using emission from the dye Fura-2. Activation of ₂-adrenoceptors by clonidine (an ₂-adrenoceptor agonist) or noradrenaline (a non-selective -adrenoceptor agonist), both in the presence of 0.1 M prazosin to block ₁-adrenoceptors, caused a slow and sustained increase in [Ca²⁺]_i which was inhibited by 0.1 M rauwolscine (an ₂-adrenoceptor antagonist). A similar Ca²⁺ response was obtained with oxymetazoline (a selective _2A-adrenoceptor agonist) suggesting that the increase in [Ca²⁺]_i resulted from activation of the _2A-adrenoceptor subtype. The increase in [Ca²⁺]_i did not occur in calcium-free solution or in the presence of oxodipine (a voltage-dependent calcium channel blocker), indicating that it depended on a calcium influx. The _2A-adrenoceptor-activated calcium influx was unchanged after complete release of the stored calcium induced by applications of ryanodine and caffeine. In addition, no accumulation of inositol trisphosphate was detected in the presence of 0.1 M prazosin. Taken together, these results indicate that _2A-adrenoceptor activation does not stimulate phosphoinositide turnover and subsequent calcium release from intracellular stores. Wholecell patch-clamp experiments showed that _2A-adrenoceptor activation promoted calcium influx through voltage-dependent L-type channels. Concomitant with calcium influx, _2A-adrenoceptor activation induced a 10- to 15-mV depolarization. Similar effects on both calcium channel current and [Ca²⁺]_i were obtained with mastoparan, an activator of Gi-proteins. Activation of calcium influx by both _2A-adrenoceptors and mastoparan was reduced by treatment with pertussis toxin and GF 109203X (a protein kinase C inhibitor). These data suggest that activation of protein kinase C through a transduction pathway involving Gi-proteins phosphorylates voltage-activated L-type calcium channels and thus, increases their opening probability.     

Epidermal growth factor,transforming growth factor-α, and epidermal growth factor receptor content in normal and carcinomatous gastric and colonic tissue

Summary Epidermal growth factor (EGF) and transforming growth factor- (TGF-) are polypeptides which bind to the EGF receptor (EGFr) and may play a role in cell growth and carcinogenesis. Our study investigated the content of EGF, TGF-, and EGFr in tumors of the stomach and the colon in comparison with the sourrounding mucosa. EGF was detected in half of the stomach specimens with concentrations between 1 and 9 ng/g weight irrespective of histology. In the colon no EGF was found in the tumor or normal mucosa. In the stomach normal mucosa contained higher TGF- concentrations (mean 22.4 ng/g) than the tumors (mean 11.8 ng/g), but the difference was not statistically significant because of a wide variation in mucosal values. By contrast, the colon mucosa displayed significantly higher TGF- concentrations than the tumor tissues (33 ng/g versus 12 ng/g; P < 0.01). EGFr content in the gastric mucosa was lower compared to gastric carcinoma (48 fmol/g versus 75 fmol/g) yet not significantly different. In contrast, colorectal tumor specimens disclosed significantly higher concentrations than the mucosal tissues (mean of 155 fmol/g versus 80 fmol/g; P < 0.01). In conclusion, TGF- should not be considered a tumorigenic but a physiological growth factor in the stomach and colon. An elevated EGFr content in colorectal tumors in comparison with the normal mucosa could lead to a growth advantage by an autostimulating mechanism.Abbreviations EGF epidermal growth factor - EGFr epidermal growth factor receptor - TGF- transforming growth factor - ROC receiver operating characteristic Dedicated to Prof. Dr. G. Paumgartner on the occasion of his 60th birthday     

Effects of thalassaemic serum on the in vitro development of the malarial parasitePlasmodium falciparum

Sera from thalassaemic individuals were experimentally tested for their suppressive effects on the in vitro development of asexual stages ofPlasmodium falciparum. Cultures in sera collected from six patients who had classical haemoglobin H disease (-thal₁--thal₂) and six patients who had haemoglobin H disease with haemoglobin (Hb) Constant Spring (-thal₁-CS) showed a significantly higher degree of inhibition of parasite multiplication than cultures of thalassaemic erythrocytes in sera from healthy individuals. Similarly, sera from 12 patients with -thalassaemia/haemoglobin E (-thal-HbE) diminished parasite development in vitro. Schizonts ofP. falciparum cultured in erythrocytes from non-thalassaemic individuals containing normal Hb (₂₂) were also inhibited when thalassaemic serum was used in place of normal serum. The degree of inhibition was proportional to the concentration (vol/vol) of the thalassaemic serum.     

αv Integrins mediate adhesion and migration of breast carcinoma cell lines

Integrins with the _v subunit are involved in cell adhesion and cellular signaling. Some _v integrins have been associated with tumor progression and dissemination. The objective of this study was to assess the contribution of _v integrins to the adhesive and migratory behavior of cells derived from breast carcinoma (BCA). The expression and function of _v integrins was characterized in three BCA cell lines which exhibit different metastatic potentials. These include MCF-7 cells which metastasize inefficiently, MDA-MB-231 cells, which have a moderate metastatic potential, and MDA-MB-435 cells, which metastasize extensively. Each cell type displays a different repertoire of _v integrins on the cell surface. The complement of _v integrins on each cell type influences their ability to adhere and migrate. The most striking difference among these cell lines was the expression of the _{v3 3} integrin. The highly metastatic MDA-MB-435 cells express substantial levels of this receptor, whereas MDA-MB-231 and MCF-7 cells do not. The MDA-MB-435 cells showed a greater ability to adhere and to migrate and this functional difference can largely be attributed to the expression of _v3 integrin. This characterization is a first step toward determining the role of _v integrins in animal models of BCA metastasis, and lends support to the hypothesis that the _v3 integrin can be a contributing factor in metastatic disease. © Rapid Science 1998