DNA is not antigenic?

[netfunda]

Why is DNA not antigenic, while other macromolecules such as polysaccharides, proteins, etc. are antigenic?

[Bluenoise]

Well different DNA's from a molecular perspective are very simular. The possibility of having antigens produced that would recognise a unique DNA isn't very realistic, and if you recognised a small sequence it wouldn't be specific enough to be very useful. DNA just doesn't have the unique structural elements and functional groups need.

[Yggdrasil]

DNA is not antigenic because antibodies recognize antigens via specific structural features, and DNA fragments from different organisms are very structurally similar. For example, the sugar-phosphate backbone, on the outside of the DNA molecule, is identical in all DNA molecules. Only the base pairs differ between DNA molecules. Since the base pairs are sequestered within the interior of the DNA double helix, specialized structures are needed to access them.

 

Proteins and oligosaccharides, on the other hand, have many structural features which an antibody can use to distinguish between native and foreign proteins/oligosaccharides.

[zyncod]

Well, actually DNA is antigenic in one sense. When the process of tolerance (killing autoreactive T and B cells) breaks down, like in lupus, the body can mount an immune response to DNA. But, like the other people said, the two- and three-dimensional structure of DNA is too similar to cause an antigenic response under normal circumstances.

[newty]

Although it is not quite antigenic, but there are plenty of bacterial strains that recognize methylated DNA and digest these DNA. Not an immunological response, just thought to be an host defense mechanism. Many of the restriction enzymes used in molecular biology work are sensitive to certain kinds of methylation.

 

DNA itself is recognized and chewed up when cells spill out their guts (cell lysis), and there are signals that recognize this. As far as being antigenic in eukaryotes, I do not know.

 

Newty

[Bluenoise]

Although it is not quite antigenic' date=' but there are plenty of bacterial strains that recognize methylated DNA and digest these DNA. Not an immunological response, just thought to be an host defense mechanism. Many of the restriction enzymes used in molecular biology work are sensitive to certain kinds of methylation.

 

DNA itself is recognized and chewed up when cells spill out their guts (cell lysis), and there are signals that recognize this. As far as being antigenic in eukaryotes, I do not know.

 

Newty[/quote']

 

Being a bit picky, but they recognize the non-methylated DNA. methylation usually prevents recognition.

[newty]

I stand corrected.

 

Newty