Question

1. List the two mechanisms that pathogens use to attack host membranes.

2. Is a particular pathogen equally infective in all portals of entry into the human body?

3. How do pathogens damage host cells? Give examples of each

Answer 1

Question No:1)

Answer:

• Basically, the two most common mechanisms that pathogens use to attack host membranes are :

A. The bacterial pathogen attacks the human host. The bacterial pathogen has various mechanism to induce the attack such as:

• Capsules: They cause Frustrated phagocytosis.
• LPS (Lipopolysaccharides) /Cell wall components: They induce septic shock in the host membranes.
• Toxins: These cause the bacterial cells to induce invasion and cause host cell damage.
• Adhesins: These substances in the pathogen bind to the host cell membrane.

B. The adhered bacterial pathogen attacks the human host membrane via phagocytosis (macrophage or neutrophils). The pathogens also secrete proteases and glycanases that digest the host extracellular matrix. The pathogen then attacks the host membranes and resides in the phagolysosomal vacuole or host cell cytosol.

Question No: 2)

Answer: No, a particular pathogen is not equally effective in all portals of entry into the human body. The portal of entry is important for pathogens to cause infection. For example, an airborne pathogen would in ineffective if it is not attacking in the respiratory system and instead gets in the digestive system. Thus, the effectiveness is not the same in all portal of entry.  

Question No: 3)

Answer:

• Mainly, the pathogens damage the host cells in two ways:

Direct damage: Pathogens are able to cause direct damage to the host cells during the pathogen's replication process or during its production of toxins. The bacterial pathogen does intracellular replication within the host cells and replicates exponentially until the cell lysis and the intracellular bacteria gets released. This causes damage to the host cell.

• For example, Shiga toxin causes damage to the intestinal epithelial tissue and Tetanus is also a common example which causes neurons to become paralyzed by Direct damage.

Indirect damage: In this method, the pathogen causes damage to the host cells indirectly by triggering an immune response in the host which causes damage to the host cell. The immune system of the host recognizes a pathogen in the host and tries to attack it and it kills the host cells along with the pathogens.

• For example, Streptococcus in the lungs causes immune damage in the epithelial cells of the host and gains to access to the bloodstream of the host to spread further damage to the host cells.