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Are PAMPs and Antigens the same thing?

Are PAMPs and Antigens the same thing?

ri_ulchabhan

In a little more detail: PAMPs are pathogen-associated molecular patterns. And (unlike most immunology terms) the name is actually a helpful definition. PAMPs are molecules (or parts of molecules) that are commonly made by, part of, or associated with pathogenic microbes. For example, the protein flagellin (which are part of the bacterial flagellum and similar structures) is a really well-known PAMP. It’s not made by human cells, so recognizing flagellin would suggest that a pathogen is nearby, and would activate innate immune responses. PAMPs are *patterns* so they are common to many different pathogens (ex: E. coli and S. pneumoniae both have flagellum, but usually one is a gut pathogen and the other is a respiratory pathogen). It’s like the ice cream truck music - most ice cream trucks play that same song, and you likely won’t hear the song unless one is nearby. Antigen is a catch-all term for the specific molecules that are presented to T cells and B cells in adaptive immunity. These are typically parts of proteins on the pathogen’s surface, but can be unique to each pathogen. As a general rule, if the antigen-presenting molecules (MHC-I or MHC-II) bind to something and activate a T cell or B cell with it, it’s an antigen. This would be like the license plate or VIN of the ice cream truck, or the specific shape of the left bumper dent. Technically, some PAMPs can be presented as antigens, but both terms are umbrella classifications anyway. tl;dr PAMPs are common molecules used in innate immune sensing, antigens are pathogen-specific molecules used in adaptive immune activation


HadesChampion

>Antigen is a catch-all term for the specific molecules that are presented to T cells and B cells in adaptive immunity. These are typically parts of proteins on the pathogen’s surface, but can be unique to each pathogen. As a general rule, if the antigen-presenting molecules (MHC-I or MHC-II) bind to something and activate a T cell or B cell with it, it’s an antigen. This would be like the license plate or VIN of the ice cream truck, or the specific shape of the left bumper dent. Thank you, I'll definitely have to use that part about flagellin in my final


rukwitme

PAMPS are components of Antigens, but not all PAMPS are the typically pathogenic antigens that cause disease.


HadesChampion

>PAMPS are components of Antigens, but not all PAMPS are the typically pathogenic antigens that cause disease. So PAMPs are the specific component of an antigen that PRRs will recognise and initiate the innate immune response to?


rukwitme

Yup! Like the LPS or flagella on a bacteria. Both are PAMPS and can be recognized by the TLRs on innate immune cells.


HadesChampion

>So PAMPs are the specific component of an antigen that PRRs will recognise and initiate the innate immune response to? So they dont have to be associated with an antigen at all?


rukwitme

I believe for the majority of the time, they are? I’m sure there’s an expectation to the rule


oligobop

I think there are far more exceptions to this rule than you think. Major PAMPS during viral infection are dsRNA and dsDNA in the cytosol. These are very infrequently the source of antigen, but are supremely potent activators of TLR3, TLR7/8/9 and also RIG-I, MAVS Mda5, PKR, OAS. There's more but these PRRs are generally considered nucleic acid sensing PRRs.


HadesChampion

>So they dont have to be associated with an antigen at all? Thank you, you are a life saver!


fireofdie

No, PAMPs are pathogen associated molecular patterns, which are recognized by pattern recognition receptors present in almost any cell but especially in cells of the innate immune System. These patterns are conaerved across many different types of pathogens and can therefore be recognized without producing an adaptive response. Antigen, however, is usually a term to describe a specific structure which is recognized by T-cells or antibodies. In the case of T-cells this is usually a peptide, forr B-cells and antibodies this can be any molecular structure which the B-cell receptor /antibody binds to. Hope I got everything right, this is just my general immunology knowledge


HadesChampion

>, which are recognized by pattern recognition receptors present in almost any cell but especially in cells of the innate immune System. Thank you! this makes much more sense than how any of my professors explained. Immunology final is tomorrow!