Immune Response Damage to the Host - Online Tutor, Practice Problems & Exam Prep

The immune response, while essential for pathogen elimination, can inadvertently damage host tissues. This occurs through mechanisms like inflammation, where neutrophils and macrophages release harmful substances, potentially leading to conditions such as pneumonia due to fluid buildup in the lungs. Additionally, adaptive immunity can cause damage through antibody-antigen complexes that accumulate in organs like the kidneys, resulting in kidney failure or autoimmune diseases. Understanding these unintended consequences is crucial for comprehending immunopathology and the balance between protection and harm in immune responses.

Intro to Immune Response Damage

In this video, we're going to begin our lesson on how the immune response can sometimes cause unintentional damage to the host. An immediate and overwhelming immune response, which is intended to protect us and eliminate pathogens, can sometimes have unintended or accidental damaging effects on host tissues. The immune response in our body can actually be compared to a sprinkler system in a building. We'll be able to make that comparison below in our image in order to better understand the accidental or unintended damaging effects of immunity.

What you'll notice is on the left-hand side of our image over here, Doctor Klutch is sitting at his office doing some important work on his computer when he suddenly notices his favorite textbooks have caught on fire. The fire here represents the damage from the pathogen or injury. Notice Doctor Klutch is saying, "Oh, no, a fire." This fire is creating a signal, and the pathogens would also create signals that can be detected by our immune system, which is being represented as the sprinkler system here. Upon detecting the signals of the pathogen, and the fire, the sprinkler system or our immune system can take action.

What you'll notice here is that although the sprinkler system is designed to eliminate the fire and the pathogen, it may also cause unintended damage. Here, the sprinkler system is causing unintended damage to Doctor Klutch's electrical equipment, and all of his hard work on his computer and his light bulb is now going to be damaged. You can see the unintended damage is all over here. Of course, the pathogen has been eliminated, which is great. Again, this is all due to the effects of the immune response.

Our immune response can be like this in some scenarios. Although it is intended to eliminate pathogens, in some circumstances, an overwhelming or an inappropriate immune response can lead to unintended damaging effects. We'll get to talk more about this idea of how the immune response can sometimes lead to unintended or accidental damage as we move forward in our course. But for now, this here concludes our introduction to this, and I'll see you all in our next video.

Inflammatory Response Can damage the Host

In this video, we're going to talk a little bit about how the inflammatory response can sometimes cause damage to the host. An inflammatory response can sometimes cause unintended accidental damage to the host in multiple ways. Recall from our previous lesson videos where we covered inflammation in more detail that during inflammation, neutrophils and other phagocytic cells like macrophages can be recruited to the site of infection. When a phagocytic cell such as the macrophage performs phagocytosis and brings in microbes, it starts to destroy and break down these microbes, and then it releases those microbes, a lot of times when it releases the end product, there could be several different types of chemicals, bacterial enzymes, toxins, perhaps exotoxins that can be released, and perhaps endotoxins as well. These released substances could potentially cause damage to the surrounding tissues. In this image, we're showing you bacterial enzymes or bacterial toxins, again, being released. These released substances can cause damage. This damage here is associated with the inflammatory response because these macrophages are recruited to the site of infection during the inflammatory response.

Inflammation specifically in the lungs can cause the capillaries of the lungs to leak fluids, and those fluids can collect and build up over time and can interfere with oxygen-carbon dioxide gas exchange. Basically, it's interfering with the function of the lungs and affecting your ability to breathe. In this image, down below, notice that we're showing a person's lungs here. These lungs are indeed infected and may undergo inflammation. Inflammation in the lungs can lead to a liquid build-up in the lungs as you see here. This liquid build-up in the lungs, due to inflammation, can inhibit oxygen-carbon dioxide gas exchange. This inhibited gas exchange can interfere with your ability to breathe and inhibit the function of your lungs, which could be, of course, very dangerous. This could be something that occurs as a result of bacterial pneumonia. This here concludes our brief lesson on how the inflammatory response can cause damage to the host unintentionally, again through performing its normal function but then releasing chemicals, bacterial enzymes, or toxins that can cause damage to the surrounding tissues. We'll be able to learn more about this and get some practice applying these concepts as we move forward. So I'll see you all in our next video.

Why might pathogenic 'remains' released from a phagocytic cell be dangerous to the surrounding cells?

• A. Many pathogens produce toxins which may damage neighbor cells when released.
• B. Many pathogens have destructive enzymes which may damage neighbor cells when released.
• C. If the pathogenic DNA is still intact upon release from the phagocyte it can infect surrounding cells.
• D. Antibodies will bind to the phagocytic cell and trigger apoptosis.
• E. A and B.
• F. A and D.
• G. A, B and C.

Adaptive Immunity Can Damage the Host

In this video, we're going to briefly discuss how adaptive immunity can also sometimes cause unintentional damage to the host. In addition to innate immune responses such as inflammation, adaptive immune responses can sometimes also lead to accidental damage to the host. For example, antibody-antigen complexes, which are complexes consisting of an antibody binding to its specific antigen, can form during an immune response. Sometimes, these antibody-antigen complexes may not be detected or eliminated by phagocytes and can build up or collect in specific types of organs, such as the kidneys or specific types of joints. When these antibody-antigen complexes accumulate in specific organs, they can lead to unintentional damage. They can damage capillaries in the kidneys called glomeruli, resulting in kidney failure, where the kidney no longer functions the way it should.

In addition to antibody-antigen complexes leading to unintentional damage, certain types of infections also result in the production of antibodies that bind to surface proteins of self cells. This is when antibodies bind to our own self cells, causing autoimmune diseases where our adaptive immune system starts to target our own healthy self cells.

Below, we're showing you an example of how adaptive immunity can also cause unintentional damage to the host. Notice over here, we're showing you our kidneys. This is a cartoon image of our kidneys. Notice that the cartoon image of our kidney is saying, "Stay away from me; you are hurting me," addressing the antibody-antigen complex. This is the antibody-antigen complex. Notice that the antibody is this Y-shaped protein here, and the antigens are these little blue molecules at the tip. These can sometimes build up and cause damage. Over here on the right-hand side, we're showing you the kidney, highlighting these antigen-antibody complexes building up in the kidney tissues. The buildup of these complexes can sometimes settle in the kidneys and again cause kidney damage, leading to kidney failure. This is just a brief lesson talking about how, in some cases, the adaptive immune system can cause unintentional accidental damage to the host. We'll be able to get some practice applying these concepts and learn more as we move forward. So, I'll see you all in our next video.

Overall our immune system protects us from foreign invaders and pathogens. Which of the following are ways in which our immune system inadvertently damages our body?

• A. Severe allergic reactions to allergens that results in anaphylactic shock.
• B. Phagocytic immune cells engulfing pathogens and releasing the dangerous pathogenic 'remains' into the body.
• C. Antibody-antigen complexes settling in the kidneys and the joints resulting in damaging inflammation.
• D. Damaging fevers, inflammation, and shock caused by excessive cytokine production in response to antigens.
• E. All of the above.

Here’s what students ask on this topic:

How can the immune response cause damage to host tissues?

The immune response, while essential for eliminating pathogens, can inadvertently damage host tissues. This occurs through mechanisms like inflammation, where neutrophils and macrophages release harmful substances such as bacterial enzymes, toxins, and other chemicals. These substances can damage surrounding tissues. For example, in the lungs, inflammation can cause capillaries to leak fluids, leading to fluid buildup that interferes with oxygen and carbon dioxide exchange, potentially causing conditions like pneumonia. Additionally, adaptive immunity can cause damage through antibody-antigen complexes that accumulate in organs like the kidneys, resulting in kidney failure or autoimmune diseases. Understanding these unintended consequences is crucial for comprehending immunopathology and the balance between protection and harm in immune responses.

What are the unintended effects of inflammation on the host?

Inflammation, a key component of the immune response, can have unintended effects on the host. During inflammation, immune cells like neutrophils and macrophages are recruited to the infection site. These cells release various substances, including bacterial enzymes and toxins, which can damage surrounding tissues. For instance, in the lungs, inflammation can cause capillaries to leak fluids, leading to fluid buildup that interferes with gas exchange, potentially resulting in pneumonia. This fluid buildup can inhibit oxygen and carbon dioxide exchange, affecting lung function and breathing. These unintended effects highlight the delicate balance the immune system must maintain to protect the host without causing harm.

How do antibody-antigen complexes cause damage to the host?

Antibody-antigen complexes, formed during an immune response, can sometimes cause damage to the host. These complexes consist of antibodies binding to specific antigens. If not properly eliminated by phagocytes, they can accumulate in organs like the kidneys or joints. In the kidneys, these complexes can damage capillaries called glomeruli, leading to kidney failure. Additionally, certain infections can produce antibodies that bind to self cells, causing autoimmune diseases where the immune system targets healthy cells. This accumulation and misdirected immune response can result in significant tissue damage and impaired organ function.

What role do neutrophils and macrophages play in immune response damage?

Neutrophils and macrophages are crucial in the immune response but can also contribute to host tissue damage. During inflammation, these phagocytic cells are recruited to the infection site to engulf and destroy pathogens. However, in the process, they release various substances, including bacterial enzymes, toxins, and other chemicals. These released substances can damage surrounding tissues. For example, in the lungs, inflammation can cause capillaries to leak fluids, leading to fluid buildup that interferes with gas exchange, potentially causing pneumonia. Thus, while neutrophils and macrophages are essential for pathogen elimination, their actions can inadvertently harm host tissues.

How does inflammation in the lungs affect breathing?

Inflammation in the lungs can significantly affect breathing by causing capillaries to leak fluids. This fluid buildup in the lungs interferes with the exchange of oxygen and carbon dioxide, a process essential for respiration. The accumulation of fluid can inhibit the lungs' ability to function properly, leading to difficulty in breathing. This condition can be particularly dangerous and is often seen in cases of bacterial pneumonia. The impaired gas exchange due to fluid buildup highlights the potential unintended consequences of the inflammatory response in the lungs.