In this video, we're going to introduce the two terms MAMPs and DAMPs. First, we need to recall from some of our previous lesson videos that immune cells use pattern recognition receptors, or PRRs, to detect different types of signs that will indicate either microbial invasion or host cell damage. The term MAMPs is an abbreviation for Microbe Associated Molecular Patterns. Microbe Associated Molecular Patterns, or MAMPs, represent signs of microbes. Signs of pathogens are referred to as PAMPs, and so, PAMPs are pathogen associated molecular patterns. The terms MAMPs and PAMPs can be used interchangeably to refer to a broad group of different types of molecules that are associated directly with microbes or pathogens. Some examples of MAMPs or PAMPs include lipopolysaccharide or LPS, a component found in the outer surface membranes of gram-negative bacteria; peptidoglycan, a molecule specific to bacterial cell walls; viral nucleic acids; fungal cell walls; and flagellin, a protein component important for bacterial flagella. These are all direct signs of microbes or pathogens, and so these are all examples of what could be considered MAMPs or PAMPs.

DAMPs, on the other hand, are damage associated molecular patterns. These are not direct signs of microbes but are more like indirect signs of microbes and pathogens; however, they are direct signs that indicate host cell damage. These are molecules that actually originate from the host but indicate host cell damage. For example, it could be a phospholipid, a component of a host cell membrane, or something of that nature. Something that belongs to the host that indicates that the host cells have been damaged.

If we take a look at our image down below, which is not provided here, you'll notice that we are discussing a macrophage, an immune system cell that has many different types of PRRs, many different types of pattern recognition receptors. These different types of PRRs can detect either MAMPs or DAMPs in different regions. Some PRRs are found on the surface, and these are capable of detecting microbe or pathogen associated molecular patterns, or MAMPs, on the outside of the cells. Notice that we are showing you these PRRs that are positioned on the cytoplasmic membrane that are detecting signs of microbes outside the cell, including lipopolysaccharide, peptidoglycan, and flagellin. Other types of PRRs are going to be embedded in the membranes of endosomes or phagosomes, and they can detect MAMPs like viral DNA or RNA or bacterial DNA that have been ingested by the cell. We also have cytoplasmic PRRs that can detect either MAMPs or DAMPs, where DAMPs are damage associated molecular patterns. Those are going to detect damage to cellular components.

This concludes our brief introduction to the terms MAMPs and DAMPs: molecular associated and microbe associated molecular patterns, and damage associated molecular patterns. We'll be able to apply some of these concepts as we move forward in our course. I'll see you all in our next video.