R. Oriol

Genetics of ABO, H, Lewis, X and related antigens

Abstract. The present knowledge on chemical, enzymatic, serologic and genetic aspects of ABH antigens is reviewed in an effort to produce a simple and coherent genetic model for the biosynthesis of these antigens and chemically related structures. The genetic control of type 1 (Lea, Leb, Lec and Led), type 2 (X, Y, I, and H), type 3 and type 4 ABH and related antigens in different animal and human tissues is analyzed, taking into account the properties of the glycosyltransferases which are involved in their synthesis and considering possible competition for common acceptor and donor substrates. The phylogeny of ABH determinants shows that they appeared as tissular antigens much earlier than as red cell antigens. The ontogeny of ABH antigens suggests that they behave as differentiation antigens, and an effort is made to correlate their tissular distribution in the adult with the embryological origin of each tissue.

Genetic control of the fucosylation of ABH precursor chains. Evidence for new epistatic interactions in different cells and tissues

The general structure of the ABH antigens is analysed taking into account six possible precursor chains and two α‐2‐fucosyltransferases. The classical genetic model with one structural gene and two regulatory genes for the synthesis of the H antigen and the events which prompted the proposal of the new model with two structural genes for the synthesis of H determinants are discussed.

Heterogeneity of the ABH antigenic determinants expressed in human pyloric and duodenal mucosae

We defined the chemical structure and the genetic control of the various A or B determinants expressed by pyloric and duodenal epithelial cells by indirect immunofluorescent staining using monoclonal anti-A or anti-B reagents that recognize only certain variants of A or B antigenic determinants.Some mucous cells in pyloric and Brünners glands express AY or BY antigens whereas other mucous cells in the same glands express only the Y antigen. Absorptive and goblet cells of the duodenal villi and Lieberkühn glands express mono- and difucosylated A or B structures, mainly of type 1. The pyloric surface epithelium expresses mono- and difucosylated, type 1 and type 2, A or B structures. In addition, A or B antigens, with a so far undefined structure are found in the pyloric surface mucosae of non-secretor individuals.

Use of a Simple Method for the Epstein-Barr Virus Transformation of Lymphocytes from Members of Large Families of Réunion Island

A simple method for the preparation of lymphoblastoid cell lines from small amounts (100 microliter) of frozen whole blood is described. A success score greater than 90% was obtained for EBV transformations using blood samples which had been collected several months before the infection. Due to the simplicity of the technique, up to 80 samples could be processed per day. This technique was used to prepared 242 permanent cell lines from 13 large families from Réunion Island showing blood group H deficiency. These cell lines are now available for genetic studies.

Heterogeneity of Anti‐A and Anti‐B Monoclonal Reagents

Abstract. Eight anti‐A and seven anti‐B monoclonal reagents were tested in parallel, with normal and weak ABH red cell phenotypes. A whole range of different reactivity patterns was found, but by making a comparison with the results obtained using polyclonal standard reagents, two major categories of reagents were distinguished: (a) stronger and more specific reagents, and (b) reagents similar to, or weaker than, the standard polyclonal controls. The analysis of the specificity of the reagents by tissue fluorescence staining and reactivity with synthetic oligosaccharides and purified glycolipids confirmed the existence of broad and restricted specificities. Two kinds of anti‐A1 reagents are described. One related to type 3/4 structures, which stains the Golgi apparatus, and another with broad anti‐A specificity which cross‐reacts with ‘A‐like’ structures. The inhibition of anti‐A reagents with salivas and synthetic oligosaccharide antigens gave parallel results for the secretor salivas and the difucosylated A antigens.

Red cell H-deficient, salivary ABH secretor phenotype of Reunion island. Genetic control of the expression of H antigen in the skin

Based on the genetic model proposing thatH andSe are two structural genes, we predicted that the red cell H-deficient, salivary ABH secretor phenotype should be found on Reunion island, where a large series of H-deficient non-secretor families have been previously described. Two such Reunion individuals are now reported. POU [Ah, Le(a−b+), secretor of A, H, Lea and Leb in saliva] and SOU [Oh, Le(a−b+), secretor of H, Lea and Leb in saliva]. Both are devoid of H α-2-fucosyltransferase activity in serum. In addition, the preparation of total non-acid glycosphingolipids from plasma and red cells of POU revealed the type 1ALeb heptaglycosylceramide and small amounts of the monofucosylated type 1 A hexaglycosylceramide. Both glycolipids possess an H structure probably synthesised by the product of theSe gene. No other blood group A glycolipids, with types 2, 3 or 4 chains, normally present in the presence of the product of theH gene, were found on red cells or plasma of POU.TheH,Se andLe genetic control of the expression of ABH and related antigens in different tissue structures of the skin is described in 54 H-normal individuals of known ABO, secretor and Lewis phenotypes; in one red cell H-deficient salivary secretor (SOU); and in one H-deficient non-secretor (FRA). Sweat glands express ABH under the control of theSe gene. Sweat ducts express ABH under the control of bothH andSe genes and Lewis antigens under the control ofLe and bothH andSe genes. Epidermis, vascular endothelium and red cells express ABH under the control of theH gene. The products ofH andSe genes are usually expressed in different cells. However, the results illustrate that in some structures, like the epithelial cells of sweat ducts, both the products ofH andSe genes can contribute to the synthesis of the same Leb structure.

Competition between ABO and Le gene specified enzymes

Abstract. Radioimmunoassays were prepared using two anti‐A and one anti‐B reagents. The specificity of the procedures was assessed with 13 artificial antigens. The amounts of A and B natural antigens in saliva of ABH secretors of known Lewis phenotype were measured with these assays. The results confirmed that the average amount of A antigen is lower in Lewis‐positive (Leb) than in Lewis‐negative (Led) donors and in A2 than in A1 donors. However, the differences among the four combined A and Lewis phenotypes were only supported by significantly lower amounts of A antigenic determinants in A2Leb as compared to the other three phenotypes (A1 Leb, A1Led and A2Led) that had similar amounts of A antigenic determinants. No Lewis‐related difference could be detected in the amounts of B antigens between BLeb and BLed donors. The results are discussed in terms of competition between A, B and Lewis‐gene‐specified enzymes for their common acceptors. The difference in the efficiency of the A2 enzyme as compared to that of the A1 enzyme is proposed as a possible explanation for the A1‐A2 phenotypic difference.

Chromosome 11q localization of one of the three expected genes for the human α-3-fucosyltransferases, by somatic hybridization

Seventy-one human x mouse hybrid cell lines were used to map the locus of a human alpha-3-fucosyltransferase to 11q. The enzyme transfers fucose onto H type 2 more efficiently than onto sialyl-N-acetyllactosamine, suggesting that it is the myeloid type of alpha-3-fucosyltransferase (Mollicone et al., 1990), which makes the 3-fucosyllactosamine epitope on polymorphonuclear cells and monocytes. This epitope is also known as CD15 (Tetteroo et al., 1987).

α-2-L-Fucosyltransferase Activity in Sera of Individuals with H-Deficient Red Cells and Normal H Antigen in Secretions

Abstract. α‐2‐L‐Fucosyltransferase activity was found in the sera of 4 H‐deficient secretor individuals (Hz). This activity represented about 5–10% of the activity present in the serum of normal H phenotypes.

Purification of Anti‐Lec Antibodies with Specificity for βDGal(1→3)βDGlcNAcO‐ Using a Synthetic Immunoadsorbent

Artificial antigens: Antibodies were raised in rabbits with βDGal(13) βDGlcNAc‐BSA and purified by absorption elution on a column of the synthetic oligosaccharide covalently bound to a silicate instead of BSA. The purified antibodies agglutinated specifically erythrocytes from Le (a‐b‐) nonsecretor donors (Lec).