Question

Impaired phagocytosis can lead to several disorders. This activity asks you to think specifically about the process through which phagocytes kill and digest microbes and to identify steps of the process that might be compromised and interfere with this killing activity. Select each of the items that would be likely to interfere with the killing of microbes once phagocytes have ingested them. Assume that chemotaxis, attachment, and ingestion occurred normally. ineffective opsonization defective microtubule function an increase in the number of leukocytes defective oxidative burst lack of chemotactic receptors on phagocytes myeloperoxidase deficiency

a) Inhibition of lysosomal enzymes.
b) Inability to form pseudopods.
c) Defective respiratory burst.
d) Adequate opsonization.
e) Normal phagosome-lysosome fusion.

Answer 1

Factors that interfere with the killing of microbes by phagocytes post-ingestion include defective microtubule function, defective oxidative burst, and myeloperoxidase deficiency. These impairments can prevent the efficient destruction of the ingested pathogens by disrupting essential processes like the formation of phagolysosomes and the respiratory burst.

Step-by-step explanation:

Once phagocytes, such as macrophages and neutrophils, have ingested microbes, several factors are critical for the successful killing of these invaders. The correct options that would likely interfere with the killing activity of phagocytes after ingestion of microbes, assuming normal earlier steps, are:

• Defective microtubule function
• Defective oxidative burst
• Myeloperoxidase deficiency

Ineffective opsonization would affect the attachment phase, not the killing phase, so it is not included in the selections. Also, the lack of chemotactic receptors on phagocytes and an increase in the number of leukocytes do not directly interfere with the killing of microbes once ingested by phagocytes.

Specific factors that disrupt the killing of pathogens include a defective respiratory burst, known as the oxidative burst, which produces reactive oxygen species to kill pathogens. Additionally, deficiencies in enzymes such as myeloperoxidase, which is part of the oxidative weaponry of phagocytes, can reduce the killing efficiency.