1) Hide Within Host Cells - Online Tutor, Practice Problems & Exam Prep

Some pathogens evade the immune system by hiding within host cells, which protects them from antibodies and phagocytic cells like macrophages. This mechanism allows pathogens to cause disease while remaining undetected. Understanding this strategy is crucial for grasping concepts related to adaptive immunity and pathogenesis. By recognizing how pathogens utilize host cells for protection, students can better appreciate the complexities of immune responses and the challenges in treating infections.

Hide Within Host Cells

In this video, we're going to discuss how some pathogens can hide within host cells to evade the immune system. And so, once again, certain pathogens can evade the host defense mechanisms by hiding inside of host cells. And so hiding inside of host cells can protect the pathogen from antibodies and other phagocytic cells.

If we take a look at our image down below, we can get a better understanding of how these microbes can hide inside of host cells. Notice in this cartoon image on the left-hand side that we have a bacterial cell over here that's saying, "Ah, a macrophage." And notice that the macrophage over here, which is a phagocytic cell, says, "A microbe." This macrophage would want to phagocytose this microbe and destroy it. However, some of these pathogens are capable of hiding inside of a host cell.

So notice here we have a host cell. And notice that this pathogen has made its way inside a host cell, and the macrophage is no longer able to phagocytose. Notice it's saying, "Where did that microbe go?" And notice that the microbe is now saying, "I should be safe in here." Some pathogens have evolved this mechanism of hiding inside of host cells in order to evade the immune system, and this is how they are able to cause disease by hiding in this type of way.

This concludes our brief lesson on how some pathogens can hide within host cells to evade the immune system, and we'll be able to get some practice applying these concepts as we move forward. So I'll see you all in our next video.

Certain pathogens, like Staphylococcus aureus, hide within host cells to avoid being phagocytosed by immune cells. What other advantageous reasons would a pathogen have for hiding within host cells?

• A. Avoid being bound by antibodies.
• B. Avoid being bound by opsonization proteins like C3b.
• C. Avoid triggering the complement system.
• D. The pathogen can lie dormant until an opportune time to cause disease.
• E. All of the above.

Intracellular pathogenesis refers to:

• A. The metabolic processes that occur inside of pathogenic bacteria.
• B. Pathogens establishing an infection within host cells.
• C. The intracellular defense mechanisms host cells have to prevent infection.
• D. None of the above.

Here’s what students ask on this topic:

How do pathogens hide within host cells to evade the immune system?

Pathogens hide within host cells to evade the immune system by entering and residing inside the cells, making them inaccessible to antibodies and phagocytic cells like macrophages. This intracellular lifestyle allows pathogens to avoid detection and destruction by the immune system. For example, some bacteria can manipulate the host cell's machinery to create a niche where they can survive and replicate. This strategy helps pathogens persist in the host, leading to chronic infections and complicating treatment efforts.

What are some examples of pathogens that hide within host cells?

Several pathogens are known to hide within host cells to evade the immune system. Examples include Mycobacterium tuberculosis, which causes tuberculosis and resides within macrophages; Listeria monocytogenes, which can escape the phagosome and replicate in the cytoplasm; and viruses like HIV, which integrates its genetic material into the host cell's DNA. These pathogens use various mechanisms to enter, survive, and replicate within host cells, making them challenging to eliminate.

Why is it difficult for the immune system to detect pathogens hiding within host cells?

The immune system finds it difficult to detect pathogens hiding within host cells because these pathogens are shielded from immune surveillance. Antibodies and phagocytic cells, which are crucial for identifying and eliminating pathogens, cannot access intracellular pathogens. Additionally, some pathogens can manipulate host cell processes to avoid triggering immune responses. This intracellular hiding allows pathogens to persist and replicate without being targeted by the immune system, leading to prolonged infections.

How does hiding within host cells contribute to the pathogenesis of diseases?

Hiding within host cells contributes to the pathogenesis of diseases by allowing pathogens to evade the immune system, survive, and replicate in a protected environment. This evasion leads to persistent infections, chronic inflammation, and tissue damage. For instance, Mycobacterium tuberculosis can survive within macrophages, leading to the formation of granulomas and chronic tuberculosis. By avoiding immune detection, these pathogens can cause prolonged disease, complicate treatment, and increase the risk of transmission to new hosts.

What are the challenges in treating infections caused by pathogens that hide within host cells?

Treating infections caused by pathogens that hide within host cells presents several challenges. First, these pathogens are protected from the immune system, making it difficult for the body to clear the infection naturally. Second, many antibiotics and antiviral drugs are less effective against intracellular pathogens because they cannot penetrate host cells or are inactivated within the cellular environment. Additionally, the ability of these pathogens to persist and replicate within host cells can lead to chronic infections and resistance to treatment, requiring prolonged and complex therapeutic strategies.