Dear Dr. Pusztai,
Thank you for your letter about Dr. Henry's paper and your comments about the papers from Nadeau and Dr. D'Adamo. I am sure that you noticed in D'Adamo's rebuttal to Nadeau that he used your table as validation of the blood type specificity part of his theory:
Biological Effects of Plant Lectins on the Gastrointestinal Tract:Metabolic Consequences and Applications:
Specifically, this table from that study: Table I: Factors influencing membrane glycosylation in the gut
That part of his rebuttal reads :
|TABLE 1: Factors influencing membrane glycosylation in the gut|
Dr. D'Adamo uses this particular table a lot as evidence of his theories. Whenever he uses it, the implication is that you are talking also about humans, and therefore feel human blood types (in particular ABO) have a great influence with regard to lectin specificity.
Yes, I know that D'Adamo refers to this Table and everything in it is true. However, it is a general Table in which not everything is valid in all species.
Most of our work has been done in rats as you know in which, obviously, no human blood groups are expressed.
As I said a number of times before very few lectins recognise and react with human ABO blood group sugar structures specifically. If anyone takes the trouble to go through all the entries in our book it ought to be plain to them that most lectins are not strictly blood group specific. They may react with the blood group epitopes, but not specifically.
For example, the main human B blood group determinant is galactose and obviously all galactose-specific lectins will react with it. However, as 95% of all galactose-specific lectins will also react with N-acetylgalactosamine that is the determining sugar in blood group A, these lectins cannot be human blood group specific. I hope this is clear. As far as I am concerned there is some truth in what D'Adamo says but the whole situation is far more complex than he or others can imagine.
I guess I did not express myself very well. I was not asking about the blood type specificity of lectins again. You have been very clear in explaining this in all your letters.
I do understand exactly what you are saying about the small number of lectins that are blood type specific. When Cheryl went through the lectins in your book to create her food lectin web page, she found this to be true. There were very few food lectins that were ABO blood type specific. It was a real eye opener for us. However, when we first wrote you, we were not certain this was true of all lectins (food and non-food). You verified that indeed, this was the case for all lectins.
I also realize that for a lectin to be specific for type A, it should be specific for GalNAc, since this is the part of the ABO antigen that makes it uniquely type A. For a lectin to be specific for type B, it should be specific for galactose, the determining sugar of the type B antigen. I did not realize that 95% of all galactose-specific lectins will also react with GalNAc. Thank you for that information... very interesting! Perhaps Cheryl already knows this. Wow, this really narrows down the group of lectins that are ABO specific to just a few.
However, I am not sure of how a lectin can be specific for type O. I don't think of type O as having any determining sugar, since the H antigen forms the "base" of the other antigens. So, I am not sure if a lectin can be specific for type O or not. If a lectin can be specific for type O, I would like to know how.
Anyway, both Cheryl and I definitely understand that there are not many ABO blood type specific lectins. I'm sorry if you thought I was asking that yet again.
What I was wondering was how you felt about how D'Adamo uses (or misuses) your research. However, I realize now that this was rather presumptuous of me to ask. And to be perfectly honest, I am more interested in your views on lectins and how you think they affect the human digestion, the human body. Perhaps in the future (I realize you are very busy now), you can explain a little more of this to Cheryl and me.
Dear Lynne and Cheryl,
The book has safely arrived. I am afraid, we have not had much time to look into it but as I said before we shall take it with us to ---- on Sunday.
You asked me about blood group O specificity. Strictly speaking you are correct; it is always the H antigen specificity we speak of. The blood groups A and B specificities are transferred on to the H antigen structures by fucosylating them. I think you ought to read a reasonably up-to-date review of blood group genetics. Unfortunately, I have nothing new to recommend. My time was with E. A. Kabat (1956) or R.R. Race and Ruth Sanger (1962; Blood groups in man). I am sure you will find other more recent ones.
Most fucose-specific lectins such as the Ulex europeaus (see them in the Lectin Handbook) can be used as blood group O/H reagents. In fact, when I was at the Lister in London, this was the preferred reagent.
I am not very disturbed by D'Adamo or anybody else misusing my work. I am now quite used to this, particularly after our GM potato work.
I think that a lot of scientists, unfortunately, are some of the most careless people on earth. Some do this out of carelessness but some do this deliberately. I leave it to you to think which category Dr D'Adamo belongs to.