I would go with a very brief reply.

Dear xxxx,
Thanks for taking the time to respond to my enquiry. I look forward to hearing from you soon
Regards.......

If they have lots of applicants any thing that makes you stand out in a positive way or look like you have some initiative might make the difference between shortlist and reject pile.

Don't undervalue pester power. I gave a girl an interview because she was pestering me and DH hired her