Women have a more powerful immune system than men

When it comes to immunity, men may not have been dealt an equal hand. The latest study by Dr. Maya Saleh, of the Research Institute of the McGill University Health Centre and McGill University, shows that women have a more powerful immune system than men. In fact, the production of estrogen by females could have a beneficial effect on the innate inflammatory response against bacterial pathogens. These surprising results were published today in the Proceedings of the National Academy of Sciences.

More specifically, estrogen naturally produced in women seems to block the production of an enzyme called Caspase-12, which itself blocks the inflammatory process. The presence of estrogen would therefore have a beneficial effect on innate immunity, which represents the body's first line of defence against pathogenic organisms. "These results demonstrate that women have a more powerful inflammatory response than men," said Dr. Saleh.

This study was conducted on mice that lack the Caspase-12 gene, meaning that the mice were extremely resistant to infection. The human Caspase-12 gene was implanted in a group of male and female mice, yet only the males became more prone to infection. "We were very surprised by these results, and we determined that the estrogen produced by the female mice blocked the expression of the human Caspase-12 gene," explained Dr. Saleh. "We were also able to locate where the estrogen receptor binds on the gene in order to block its expression, which indicates that the hormone exerts direct action in this case."

Since these experiments were conducted using a human gene, the researchers consider these results to be applicable to humans. This feature of the female innate immune system might have evolved to better protect women's reproductive role.

The positive effect of natural estrogen on our resistence to infection is also exhibited with synthetic hormones such as 17-beta-estradiol. This finding might therefore open the door to new therapeutic applications that reinforce the immune system, but a question remains: will men be amenable to the idea of being treated with an exclusively female hormone?

Source: McGill University Health Centre (news : web)

   

• Birger - May 12, 2009
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  Makes sense in an evolutionary context. If a woman succumbs to a lethal disease when pregnant, or before a child is weaned off milk, the child will die too. Men are more "expendable" from the gene's point of view.
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• Scire - May 12, 2009
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  Could this go toward explaining the difference in life expectancy between males and females?
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• PPihkala - May 12, 2009
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  Could this go toward explaining the difference in life expectancy between males and females?

  
  Very probably. The big question will be how much does it affect it? Much or only weakly?
  
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• smiffy - May 12, 2009
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  You might suppose that the statistics for infections and auto-immune diseases (like rheumatoid arthritis) would reflect this alleged difference. It's news to me if they do.
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• L_Joyce - May 12, 2009
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  This study looked at the effect of expressing and blocking (technically allowing to be blocked naturally via estrogen) a single human gene transferred into mice, and then assumes that that lone effect would translate to humans. Does that not ignore the fact that the Caspase-12 gene works in humans as just one tiny genetic component of a complex immune system? If this gene and estrogen work in this way, then would not males have evolved to compensate?
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• Velanarris - May 12, 2009
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  You might suppose that the statistics for infections and auto-immune diseases (like rheumatoid arthritis) would reflect this alleged difference. It's news to me if they do.

  Actually they do. Most autoimmune diseases show a preponderance to women. The only recorded exceptions are Crohn's which is about equal and AS which is more prevalent in men.
  
  

  If this gene and estrogen work in this way, then would not males have evolved to compensate?

  Not really considering estrogen in higher amounts promotes ED in males, reduces male sexual appetite, and enhances social anxiety in males making them less able to procreate and pass the genes on.
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• PeterVermont - May 13, 2009
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  Estrogen increases the effectiveness of vitamin D and vitamin D has essential powerful roles in innate immunity.
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• austux - May 16, 2009
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  This helps to explain how GF can survive so well, despite the various trauma thrown at her.
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