Study shows transfer of immunity over two generations in pigeons

[Eboard10]

http://phys.org/news/2015-11-immunity-pigeons.html

A team of researchers with Sorbonne Universités and Prédictive CEREEP-Ecotron Ile-De-France has found that grandmothers of pigeon chicks are somehow able to transfer immunity to a third generation, though the means is not apparent. In their paper published in the journal Biology Letters, the team describes how they injected three generations of pigeons with a protein to monitor their level of immunity response and what they found by doing so.

Suspecting that older generations were passing along immunity capabilities to more than just their own chicks, the researchers conducted a several year study of urban pigeons. They started by injecting 60 females with a protein called haemocyanin—it helps to transport oxygen in some invertebrates but does not do anything beneficial to pigeons. They also injected 60 additional female pigeons with a saline solution to serve as a control group. The team then injected the same protein into all of the offspring of the test pigeons, and then two years later, into all of the third generation of offspring as well. The purpose of the injections was to cause the birds to produce antibodies as a part of an immune response[/b]—after the birds were injected, blood tests were taken to see how strong of a response was triggered. They discovered that the immune response of the third generation was stronger for those chicks whose grandmothers had received haemocyanin than for those whose grandmothers had received the saline. This of course suggested that in reacting to the protein initially, the grandmother pigeons had developed an immune response that they had somehow passed down through their offspring, to their grand-chicks.

Logic would suggest that the grandmother birds had somehow sent antibodies to their offspring to be wary of the haemocyanin protein—if so, there would be evidence of more antibodies in the eggs of their offspring. But, testing the eggs failed to find more antibodies, which left the researchers stumped as to how the grandmothers were passing on their immunological message. They suggest the immune system must be trained in some other way (via hormones, possibly, or nutrients), which means more studies need to be done to find the ultimate answer.

The study showed that the immune system seems to remember the need to counter the injected protein from grandparents to third generation chicks, however, it wasn't able to determine how this information is passed through each generation. The paper suggests that the solution should be looked into hormones or nutrients. I wonder though if the knowledge about immune responses might rather be caused by epigenetic changes in grandparents or it may be even carried through the information/morphogenetic field. Link to paper:

http://rsbl.royalsocietypublishing.org/content/11/11/20150780

Transfer of humoural immunity over two generations in urban pigeons

Abstract
Maternal antibodies (MatAb) are known to provide passive protection early in life for young vertebrates but their effects on the development of offspring immune response across generations are still unknown. Here, we investigated the effects of antigen exposure (keyhole limpet haemocyanin, KLH) experienced by urban pigeon (Columba livia) females on the amount of antigen-specific antibodies (Abs) transferred into the egg yolk of their daughters and on the humoural immune response towards this same antigen in their grandchildren. We found that chicks from KLH-injected maternal grandmothers had a higher humoural response than chicks from sham-injected grandmothers. However, we did not detect a significant effect of female KLH exposure on the ability of their daughters to transmit anti-KLH Abs into their eggs. These results suggest that antigen exposure at one generation may shape the immune profile of offspring over two next generations, although the underlying mechanisms remain to be investigated.

 

[A Jay]

I agree that it seems more likely to have something to do with changes in the information field than anything hormonal, but then maybe I'm not understanding it correctly. In any case, it certainly is interesting!

 

[Eboard10]

I agree that it seems more likely to have something to do with changes in the information field than anything hormonal, but then maybe I'm not understanding it correctly. In any case, it certainly is interesting!

Agree, these inherited traits seem to go much deeper than just hormonal changes. The article actually relates to a previous study where mice were subject to odour fear conditioning and it resulted in the following generations acquiring the same fear response to that specific odour. The reason for the inheritance of the condition was attributed to behavioural and epigenetic changes but the exact mechanism behind these changes is still unknown.

The standard assumption is that epigenetic marks are erased in the so-called primordial gene cells after each generation, leaving the offsprings with a new set that allows all genes to be read afresh. Since studies have shown that epigenetic inheritance does occur, they attributed the failure to erasing some of the marks to a flaw in the process where "rare" methylation marks manage to be passed to the offspring.

http://www.sott.net/article/257060-Scientists-discover-how-epigenetic-information-could-be-inherited

The new Cambridge study initially discovered how the DNA methylation marks are erased in PGCs, a question that has been under intense investigation over the past 10 years. The methylation marks are converted to hydroxymethylation which is then progressively diluted out as the cells divide. This process turns out to be remarkably efficient and seems to reset the genes for each new generation. Understanding the mechanism of epigenetic resetting could be exploited to deal with adult diseases linked with an accumulation of aberrant epigenetic marks, such as cancers, or in 'rejuvenating' aged cells.

However, the researchers, who were funded by the Wellcome Trust, also found that some rare methylation can 'escape' the reprogramming process and can thus be passed on to offspring - revealing how epigenetic inheritance could occur. This is important because aberrant methylation could accumulate at genes during a lifetime in response to environmental factors, such as chemical exposure or nutrition, and can cause abnormal use of genes, leading to disease. If these marks are then inherited by offspring, their genes could also be affected. [...]

"It seems that while the precursors to sperm and eggs are very effective in erasing most methylation marks, they are fallible and at a low frequency may allow some epigenetic information to be transmitted to subsequent generations. The inheritance of differential epigenetic information could potentially contribute to altered traits or disease susceptibility in offspring and future descendants."

Basically they cannot explain the reason for the epigenetic inheritance and relegate the phenomenon to the system being fallible and allowing certain epigenetic marks to be transmitted through the sperm and egg to the offspring. In light of the more recent studies, the chances of the information field playing a role in the transmission of the DNA methylation marks is more likely IMO.

 

[arpaxad]

The paper suggests that the solution should be looked into hormones or nutrients. I wonder though if the knowledge about immune responses might rather be caused by epigenetic changes in grandparents or it may be even carried through the information/morphogenetic field.

Eboard10

You seem to be quite knowledgeable on the subject, and I would like to ask you what is a good source for some studies of the information/morphogenetic field if such exists. I don't think that the chemical mechanisms (such as suggested here) should be looked upon, but I wonder about the morphogenetic changes and what not. It seems quite extraordinary that something as specific as an antibody would be transferred in the M-field. Really, if such a power exists in the field, what use is for the antibodies at all? Besides, I'm not an expert on bird immunology, and it appears that the egg would be a good medium for transferring immunological information, although I think that the scientists would check that first, but who knows how far this particular field has advanced.

 

[arpaxad]

I don't think that the chemical mechanisms (such as suggested here) should be looked upon...

Damn Freudian slips, I really meant to say that they should not be looked down upon.

 

[Eboard10]

Eboard10

You seem to be quite knowledgeable on the subject, and I would like to ask you what is a good source for some studies of the information/morphogenetic field if such exists. I don't think that the chemical mechanisms (such as suggested here) should be looked upon, but I wonder about the morphogenetic changes and what not. It seems quite extraordinary that something as specific as an antibody would be transferred in the M-field. Really, if such a power exists in the field, what use is for the antibodies at all? Besides, I'm not an expert on bird immunology, and it appears that the egg would be a good medium for transferring immunological information, although I think that the scientists would check that first, but who knows how far this particular field has advanced.

Hi aparxad, I wouldn't say I'm knowledgable in information theory (hence why I only mentioned it as a possible reason for the inheritance), but I try to post articles when I find links between studies that are relevant to the topics discussed here. In the post, I didn't mean to discount the possibility of hormones or nutrition playing a role in the transmission of methylation but I was suggesting that these factors, including epigenetic changes, are likely not the causative agent of this phenomenon, rather the means through which the information is carried. I mentioned the morphogenetic field as a possible source which "informs" the DNA marks to be inherited rather than just being a product of chance due to the fallibility of the system as proposed in the article. There are still too many unknowns to understand exactly how this works so we'll have to wait for more studies to come out. Learning is fun :)

Here are some topics I would recommend:

Information (Theory)
The Science Delusion - Rupert Sheldrake
Survival Genes: Scientists find DNA mutations that helped Russians during war

SOTT BlogTalkRadio - Information Theory, or why your brain is not your mind