Question

So few HIV virions released in the blood are actually infectious because

	a.	very few cells in the immune system express the receptor HIV requires for binding.
	b.	the immune system inhibits these virions from causing infections.
	c.	reverse transcriptase has a high error rate.
	d.	HIV is not a very infectious virus.

Answer 1

c.reverse transcriptase has a high error rate

• Unlike any other DNA polymerases reverse transcriptase don't have any proof reading ability.
• Hence there is more chance of errors - thus only a few virions that enter our blood can cause infection.
• HIV virions work by binding with the  CD4+ receptors.
• CD4+ receptors are found in Monocytes, Macrophages, Dendritic cells and T cells.
• So a is not the answer.
• HIV is not a very infectious virus because it can't cause death directly, it works by decreasing the immune power by attacking helper T cells . So, d is also not the answer.
• a,b and d are correct but these are not the reasons for the question.