Non-secretors

The stroma-independent mutants belong to two different classes secretors and non secretors. The supernatants of the 89 mutants were tested for their ability to support stroma-independent growth of Myl-D7. Myl-D7 cells were plated at two concentrations (2.0x10 cells/mL and SxIO cells/mL) in triplicate in 24-well plates containing CM from confluent mutant cultures. 

For most of the supernatants tested the number of wild type Myl-D7 indicator cells decreased rapidly to less than 10% within the first 10 days. These mutants were classified as non secretors. Only 26 of the total 89 mutants secreted an activity stimulating the survivaFproliferation of Myl-D7 for at least two weeks. Furthermore, only ten of these secretor mutants (e.g. 6i-4, 6i-22) stimulated the growth of Myl-D7 for longer than 6 weeks (data not shown Heberlein et al, 2006). 

Concanavalin A was found by Clarke and Denborough (35) to precipitate with blood group glycoproteins from human gastric juice from two group O non-secretors and 2 group O and 3 group A secretors it... 

W16. Witebsky, E., and Klendshoj, N. C., The isolation of an O specific substance from gastric juice of secretors and carbohydrate-like substances from gastric juice of non-secretors. ]. Exptl. Med. 73, 655-667 (1941). 

In non-secretors, the a 1,2 fucosyltransferase is not found in epithelial tissues (Chester and Watkins, 1969), so the function of the 5egene must be to regulate the tissue specificity of the enzyme s expression (i.e. the tissue-specific activity of the H-gene). 

The enzyme of human milk is present in all women of blood-group A, irrespective of secretor status. In non-secretors, however, the //-dependent al,2-fucosyltransferase is absent and so the al,3-A-acetylegalactosaminyl-transferase can never function synthetically because of the lack of its substrate. This is a good demonstration of the necessary sequential action of gjycosyltransferases in oligosaccharide assembly. 

Six oligosaccharides which are di- and tri-L-fucosyl-derivatives of lacto-7V-octaose (36—38) and lacto-7V-neo-octaose (39—41) have been isolated and characterized from the human milk of a non-secretor Lewis (a+b ) individual. ... 

---