Membranes des globules lipidiques du laithumain. Preparation, etude morphologique et composition chimique

Martel, M.B.; Dubois, Philippe; Got, R.

doi:10.1016/0005-2736(73)90130-2

Cited by 39 publications

(16 citation statements)

References 25 publications

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“…Also in other systems, tumor cell membranes have been found to continue to carry differentiation antigens, such as TL antigens (alloantigens characteristic of mouse thymus cells) found in murine leukemias (29) and NS-1 (nervous system antigen-i) detected on mouse glioma cells (2). The presence of multiple proteinaceous components on the surface of the human breast epithelial cell is evident from the present results, and those of others (25). At least three of the four major components of the HMFG are antigenic (Fig.…”

Section: Resultssupporting

confidence: 71%

“…Penetration of the anti-HMEC into intact cells cannot be ensured. For this same reason, if small quantities of intracellular material were present in the defatted HMFG (25,26) that was used as a source of immunogen and they gave rise to subpopulations of antibodies in anti-HMEC against intracellular antigens, the latter antigens would not be detected.…”

Section: Resultsmentioning

confidence: 99%

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Surface differentiation antigens of human mammary epithelial cells carried on the human milk fat globule.

Ceriani¹,

Thompson²,

Peterson³

et al. 1977

Proc. Natl. Acad. Sci. U.S.A.

212

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Rabbit antibodies against components of the human milk fat globule bind specifically to normal human breast epithelial cells and cell lines derived from breast carcinomas, as well as to the outer surface of the human milk fat globule. Variation in indirect immunofluorescence staining in both intensity per cell and percentage of cells stained is observed for the different breast cell lines. Cells derived from other epithelial and other ectodermal tissues, fetal fibroblasts, cells of the blood buffy coat, and even fibroblasts of the breast itself do not bind the antibodies. This suggests that these antibodies are detecting cell-type-specific antigens. These normal breast epithelial cell antigens are on the cell surface and their exptession is stable in long-term cultured cell lines, even after much chromosomal variation in a given line. By affinity chromatography, three distinct antigenic components can be isolated from the milk fat globule, one of which contains carbohydrate. These differentiation antigens of the human breast epithelial cell are not only useful as specific cel-ype markers, but also can provide a tool to study the role of the cell surface in normal and neoplastic mammary development. The production of antibodies directed solely against outer cell surface components is hindered by-the difficulties inherent in purifying such cell membranes. Plasma membrane constituents amount to about 2-3% of the total cell protein (5); thus, separation from other cellular components present in much greater amounts is difficult. Moreover, when a source of normal human tissue, other than blood, is needed for purification of normal cell surface antigens, one is faced with an unresolved problem. Because the milk fat globules are secreted into milk by the breast epithelial cell-by envelopment of fat droplets by the plasma membrane (6)-they represent an accessible source of enriched plasma membrane. Additional information that enzyme markers of the plasma membrane are found in the milk fat globule membrane (7) and the fact that churned milk fat globules appear as an almost pure membrane fraction when examined by electron microscopy (8) make this material the immunogen of choice.Here we describe the production of an anti-human mammary epithelial cell antiserum (anti-HMEC) raised against the defatted human milk fat globule (HMFG), which specifically identifies mammary epithelial cells from both the normal breast and from human breast carcinoma cell lines. Also, we describe characteristics of the antigenic components present on the HMFG, and procedures for their separation. MATERIALS AND METHODSFor the preparation of defatted HMFG, the washed cream fraction of human milk (8) was extracted twice with two volumes of chloroform and twice with 1 volume of ether, and then lyophilized. Electrophoresis was performed in 5% polyacrylamide gels (12 cm long and 0.6 cm in diameter) in the presence of 0.1% sodium dodecyl sulfate, 7 M urea, and 0.1 M sodium phosphate buffer, pH 7.2, with samples dissolved in 1% sodium dodecyl su...

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Section: Resultssupporting

confidence: 71%

Section: Resultsmentioning

confidence: 99%

Surface differentiation antigens of human mammary epithelial cells carried on the human milk fat globule.

Ceriani¹,

Thompson²,

Peterson³

et al. 1977

Proc. Natl. Acad. Sci. U.S.A.

212

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“…Typically, preparations of isolated bovine MLGM form homogeneous sheets of membrane, which are unable to form vesicles because of the large amount of coat protein, which can be removed by digestion with proteinase [see refs (5, 30, 31) for examples from goat, cow and human]. In contrast, mouse MLGM was strikingly heterogeneous, comprising a mixture of membrane-bounded vesicles and sheets, which generally maintain a similar morphology after digestion with papain (Figure 8A–E).…”

Section: Resultsmentioning

confidence: 99%

A Test of Current Models for the Mechanism of Milk‐Lipid Droplet Secretion

Jeong

Lisinski

Kadegowda

et al. 2013

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Milk lipid is secreted by a unique process, during which triacylglycerol droplets bud from mammary cells coated with an outer bilayer of apical membrane. In all current schemes, the integral protein butyrophilin 1A1 (BTN) is postulated to serve as a transmembrane scaffold, which interacts, either with itself, or with the peripheral proteins, xanthine oxidoreductase (XOR) and possibly perilipin-2 (PLIN2), to form an immobile bridging complex between the droplet and apical surface. In one such scheme, BTN on the surface of cytoplasmic lipid droplets interacts directly with BTN in the apical membrane without binding to either XOR or PLIN2. We tested these models using both biochemical and morphological approaches. BTN was concentrated in the apical membrane in all species examined and contained mature N-linked glycans. We found no evidence for the association of unprocessed BTN with intracellular lipid droplets. BTN-enhanced-green-fluorescent-protein was highly mobile in areas of mouse milk-lipid droplets that had not undergone post-secretion changes, and endogenous mouse BTN comprised only 0.5–0.7%, (w/w) of the total protein, i.e., over fifty-fold less than in the milk-lipid droplets of cow and other species. These data are incompatible with models of milk-lipid secretion in which BTN is the major component of an immobile global adhesive complex and suggest that interactions between BTN and other proteins at the time of secretion are more transient than previously predicted. The high mobility of BTN in lipid droplets, mark it as a potential mobile signaling molecule in milk.

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“…The membrane fraction was obtained from a pool of 10 liters of cow milkby churning and centrifugation [7] . Electron microscopic controls revealed a rather pure membrane preparation devoid of casein granules.…”

Section: Methodsmentioning

confidence: 99%

Glycosaminoglycans of the fat globule membrane of cow milk

Lis

Monis

1978

J Supramol Struct

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Membranes of fat globules of cow milk contained 163 pg/lOO mg (dry weight) of glycosaminoglycans (expressed as uronic acid); 62.5% of the uronic acids corresponded to hyaluronic acid, the remaining consisted of sulfated glycosaminoglycans (chondroitin-4-(-6) sulfates, and dermatan and heparan sulfates) with different degrees of sulfation. The present report deals with the isolation and characterization of these glycoconjugates from the fat globule membrane of cow milk. METHODSThe membrane fraction was obtained from a pool of 10 liters of cow milkby churning and centrifugation [7] . Electron microscopic controls revealed a rather pure membrane preparation devoid of casein granules.volumes of chloroform-methanol (2: 1, by volume), digested for 6 h with papain [8] , treated with trichloroacetic acid (10% final concentration), neutralized with NaOH, and run through a Sephadex G-50 column (2.5 X 30 cm). The excluded material was dried, digested with ribonuclease [9] , and rechromatographed on Sephadex G-50. This crude preparation was fractionated on a DEAE-Sephadex A-25 column (0.25

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Membranes des globules lipidiques du laithumain. Preparation, etude morphologique et composition chimique

Cited by 39 publications

References 25 publications

Surface differentiation antigens of human mammary epithelial cells carried on the human milk fat globule.

Surface differentiation antigens of human mammary epithelial cells carried on the human milk fat globule.

A Test of Current Models for the Mechanism of Milk‐Lipid Droplet Secretion

Glycosaminoglycans of the fat globule membrane of cow milk

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