Biomedical subjects

J M McKibbin

Publications and source records attributed to J M McKibbin.

7 recordsLinked to original sources

PubMed1985

Monoclonal antibodies defining blood group A variants with difucosyl type 1 chain (ALeb) and difucosyl type 2 chain (ALey).

Three hybridomas secreting monoclonal antibodies, HH1, HH2, and HH3, defining different difucosyl A structures (ALeb or ALey), have been established. Antibody HH1 (IgG2a) reacts specifically with the difucosyl A structure irrespective of a type 1 or type 2 chain, while antibody HH2 (IgG3) reacts exclusively with the difucosyl type 2 chain A (ALey) and does not react with the difucosyl type 1 chain or monofucosyl type 2 chain. Antibody HH3 (IgG2a) reacts exclusively with the difucosyl type 1 chain A (ALeb) and does not react with the monofucosyl type 1 chain A or mono- and difucosyl type 2 chain A. These hybridoma antibodies were obtained by immunization of mice with purified glycolipid antigens and were selected by their reactivity with the specific glycolipid structures. These antibodies, together with previously established monoclonal antibody AH-21, specific for monofucosyl type 1 chain A, and monoclonal antibody TH-1, specific for type 3 chain A, are extremely useful to define blood group A variants present in cells and tissues.

ABO Blood-Group System↗

PubMed1978

Fucolipids.

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ABO Blood-Group System↗

PubMed1977

Characterization of dog small intestinal fucolipids with human blood group A activity. Differences in dog and human A-active fucolipids.

Glycolipids containing fucose (fucolipids) which carried human blood group A activity were isolated from a number of dog small intestines and analyzed. On the basis of sugar analysis, methylation, periodate oxidation, enzyme degradation, mass spectrometry, and immunologic studies, a structure is proposed for these substances. The ceramides of the dog fucolipids containing only hydroxylated fatty acids with 85% saturated and 15% monoenoic acids ranging from 16 to 25 carbon atoms. Sphingosine and phytosphingosine comprised 48% each of the long chain bases. An A-active fraction isolated from human small intestine was shown to have two components, one of which was immunologically distinct and the other identical with the dog intestinal fucolipids. The human fraction differed from the dog fucolipids in migration on thin-layer chromatography and contained two types of amino sugar substitution. It is proposed that the human fraction was composed of two fucolipids with incomplete structures.

ABO Blood-Group System↗

PubMed1977

Blood group A antigen in human erythrocytic membranes and membrane fractions.

Erythrocytic membranes from blood group A individuals were assayed for A antigen using a quantitative hemagglutination inhibition technique. The membranes were then extracted for lipid and glycoprotein. Although some A antigen was usually found in the glycoprotein fraction, most of the activity was in the lipid fraction. The sum of A antigen activity in the lipid, glycoprotein, and membrane residue fractions only occasionally was equal to the A activity in the erythrocytic ghosts. However, when certain lipid preparations with little or no A antigen (enhancement factors) were added to the glycolipid fractions, the amount of A antigen demonstrated was usually greatly increased. Under these conditions, the sum of the fractions often was much greater than the A antigen demonstrated in erythrocytic membranes. This suggests that the organization or arrangement of A antigenic determinants in the red cell membrane may not always permit a stoichiometric reaction with anti-A molecules.

ABO Blood-Group System↗

PubMed1975

Characterization of a human intestinal fucolipid with blood group Lea activity.

A fucolipid that carried human blood group Lea activity was isolated from human small intestine. It contianed fucose, galactose, N-acetyl glucosamine, glucose, and ceramide in a molar ratio of 1:2:1:1:1. After periodate oxidation only 1 molecule of galactose and the N-acetylglucosamine remained. Permethylation of the lipid gave derivatives of a terminal fucose and galactose residue together with 2,4,6-tri-O-methylgalactose and 2,3,6-tri-O-methylglucose. After removal of fucose the lipid could be converted to a ceramide trihexoside with beta-galactosidase, and this, in turn, to ceramide lactoside by the action of beta-N-acetylhexosaminidase. Both enzymes converted the defucosylated derivative to a ceramide monohexoside. The methylated and the methylated and reduced derivatives of the intact lipid gave ions in mass spectrometry for a terminal hexose and deoxyhexose, a terminal trisaccharide of hexose, deoxyhexose and N-acetylhexosamine, and terminal tetra-and pentasaccharides. Ceramide fragments characteristic of hydroxy fatty acids with 16, 22, 23, and 24 carbons were found together with those of phytospingosine as the major long chain base. On the basis of these results and the immunologic activity of the fucolipid, the following structure is proposed: betaGal (1 leads to 3)betaGlcNAc (1 leads to 3)betaGal (1 leads to 4)Glc-ceramide alphaFuc (1 leads to 4).

Acetylglucosamine↗

PubMed1975

Characterization of dog small intestinal fucolipids with human blood group H activity.

Fucolipids with human blood group H activity were isolated from several dog small intestines. On the basis of mass spectrometry, periodate oxidation, enzyme degradation, methylation, and immunologic studies the following structure is proposed: Fucalpha(1 yields2)Galbeta(1 yields 4)Glc-NAcbeta(1 yields 3)Galbeta(1 yields 4)Glc-ceramide. The ceramide was shown by mass spectrometry to contain hydroxyhexadecanoic acid and phytosphingosine as major consitutuents.

ABO Blood-Group System↗

PubMed1975

Characterization by mass spectrometry of blood group A active glycolipids from human and dog small intestins.

Glycolipids with blood group A activity isolated from human and dog small intestine have been characterized by mass spectrometry of intact lipid in methylated and in methylated and reduced (LiAiH4) form. Without degradative studies the glycolipids were conclusively shown to be hexaglycosyleramides with phytosphingosine as the major long-chain base and hydroxypalmitic acid as the major fatty acid. The exact sugar ratio was hexose-hexosamine-deoxyhexose 3:2:1 and the sequence established as hexosamine-[deoxyhexose-]hexose-hexosamine-hexose-hexose-ceramide. Evidence is presented that mass spectrometry can differential between type ) and type 2 saccharide chains.

ABO Blood-Group System↗