Question

scientists often use viral vectors (modified viruses) in gene therapy to deliver therapeutic genetic material to target cells, but these vectors can trigger immune responses that neutralize the treatment. to overcome this limitation, researchers modify the protein shells that enclose a viruss genetic material, called viral capsids, or combine specific components from different variations of the virus within the same species. this engineering approach allows the therapeutic genes to enter cells while reducing the impact of pre - existing immunity, though immune responses may still affect the possibility of subsequent treatments. which choice best states the main idea of the text? choose 1 answer: a gene therapy researchers have discovered that combining components from different viral species allows them to avoid triggering immune responses to viral vectors. b studies of viral modification techniques have revealed that immune responses pose a substantial challenge to successful gene therapy delivery. c researchers are developing modified viral delivery systems that may reduce but not eliminate immune system interference with gene therapy treatments.

Explanation:

The text first mentions the use of viral vectors in gene - therapy and the problem of immune responses. Then it describes how researchers modify viral components to reduce immune response interference, while also noting that immune responses may still affect subsequent treatments. Option C best captures this overall idea. Option A is incorrect as it says "different viral species" instead of "different variations within the same species" as in the text. Option B only focuses on the problem of immune responses and not the solution.

Answer:

C. Researchers are developing modified viral delivery systems that may reduce but not eliminate immune system interference with gene - therapy treatments.