Blood groups A-type

Paulsen and co-workers [191] synthesised the trisaccharide (263) representing the afucosyl end group of the blood-group A (type 1) determinant from the disaccharide (264). This was acetylated and deacetonated and the product converted into the acetate (265) via the 3, 4 -orthoacetate. Condensation of (265) with the azido-chloride (237) in the presence of silver perchlorate gave the a-linked trisaccharide (266) which was deprotected to give (263). 

The intermediate trisaccharide (270) on deprotection gave the blood-group H (type 1) trisaccharide (278), and (271) was also condensed with tetra-O-benzyl-galactopyranosyl bromide in the presence of silver carbonate — silver perchlorate or mercury (II) cyanide to give a tetrasaccharide derivative which was converted into the blood-group B (type 1) tetrasaccharide (279). The blood-group A (type 2) tetrasaccharide (280) was prepared from the a-anomer of the bromide (275) by Paulsen and co-workers [156] via an intermediate trisaccharide used for the preparation of the blood-group B (type 2) tetrasaccharide (see Sect. 6.1). 

Khorlin and co-workers [194, 195] prepared the blood-group A (type 1) tetrasaccharide (267) from the chloroacetate (272). This was condensed with 2-O-benzyl-3,4-di-O-p-nitrobenzoyl-a-L-fucopyranosyl bromide to give the 2-O-a-L-fucosyl derivative and after removal of the chloroacetyl group with thiourea the product was... 

While it is impossible to make any precise statement regarding the structure of this blood group A polysaccharide until our present investigations are more advanced, it does seem possible that the structure of the alkali-stable carbohydrate residue is of a ramified type, bearing some general relationship to that deduced for ovomucoid, which, however, is much less resistant to hydrolysis than is this blood group A polysaccharide. 

In continuation of this work, Sinay and co-workers [221] prepared the terminal tetrasaccharide of the blood-group B (type 2) glycolipid which has A-acetyllactos-... 

Paulsen and co-workers [156] have also prepared the blood group B (type 2) tetrasaccharide (324) from the lactosamine derivative (318). They attached the 2 -0-l-fucosyl residue using the fucosyl bromide (322) in the presence of mercury(II) bromide and molecular sieves and obtained (319) in 80% yield. Removal of the benzoyl group and glycosidation with 2,3,4,6-tetra-O-benzyl-oc-gaIactopyranosyl bromide in the presence of mercury(II) bromide and molecular sieves at 20 °C or with silver triflate — silver carbonate at —25 °C gave the 3 -0-a-D-galactosyl derivative (323) in 80% yield. In this paper Paulsen discusses in detail the conditions (reactivity of alcohol,... 

Nashed and Anderson [155] prepared an isomer of the blood-group B (type 2) tetrasaccharide with lactosamine substituted at the 4 -position with an a-D-galactosyl residue and at the 2 -position with an a-L-fucosyl residue. For this purpose, the lactosamine derivative (331), prepared via (330), was a-glycosylated with tetrabenzyl-galactosyl bromide in the presence of silver carbonate and silver triflate and the benzoyl group removed from the product so that the 2 -position could be fucosylated with the bromide (302) in the presence of bromide ion. If the fucose residue was added first to the lactosamine derivative (332), then the product (333) [which was converted into the trisaccharide of the blood group H (type 2)] would not react with the tetrabenzyl-galactosyl bromide. 

The blood-group H (type 2) trisaccharide L-fuc-a-(l —>2)-gal-P-(l —>4)-7VAcglc was also prepared by Matta and co-workers [230] by glycosidation of the lactosamine derivative (340) with the fucosyl bromide (322) in the presence of bromide ion and subsequent deprotection. 

Blood is a multi-component system with formed elements of red and white blood cells as well as platelets, and a liquid fraction (plasma), each containing a vast array of biochemical constituents. The forensic serologist has chosen three classes of the blood constituents for their genetic information and use in individualization endeavors. These constituent classes are 1) the blood grouping and typing antigens, 2) the polymorphic enzymes and 3) the polymorphic proteins. 

Sometimes both members of a pair of alleles express their phenotypes. In such cases, the alleles are codominant. An example is found in blood groups a person with both A and B genes has both A and B antigens and has blood type AB. Dominance is often incomplete, the heterozygote being somewhere between the two homozygotes in its phenotype. 

Lima-bean lectin precipitated blood-group A and B secretor saliva, but not O it did not precipitate the saliva of any nonsecretors.2,3,103 Kriipe77 substantiated Boyd s results, using secretor saliva as an inhibitor of lima-bean lectin-erythrocyte agglutination. Types A,B, A,A2, AiO, and A20 saliva all inhibited the lima-bean lectin, whereas type OO saliva and type OO ovarian-cyst material were noninhibitory. 

---