Which inhibitors prevent the enzyme from integrating viral DNA into the nucleus?

The integration of viral DNA into the host cell's nucleus is a critical step in the replication cycle of viruses like HIV. Integrase inhibitors are specifically designed to target and inhibit the integrase enzyme, which is responsible for this integration process. By blocking this enzyme, integrase inhibitors prevent the viral DNA from being incorporated into the host’s genome, effectively stopping the virus from replicating and spreading within the body.

In contrast, other classes of inhibitors have different mechanisms of action. Protease inhibitors work by inhibiting the protease enzyme involved in the maturation of viral proteins. Nonnucleoside reverse transcriptase inhibitors target the reverse transcriptase enzyme, which is responsible for converting viral RNA into DNA but does not affect the integration of that DNA into the nucleus. Entry inhibitors function by preventing the virus from entering the host cell altogether, thus, they do not directly interfere with the integration process either. Therefore, the unique role of integrase inhibitors in blocking the activity of integrase makes them the correct answer to this question.