Prion Disease Research, Neurodegenerative Illness Treatment reports how researchers were in the process of exploring the use of D-Cycloserine for treatment of neurological illness. That was in September, 2010.
It appears that D-Cycloserine has more recently proven to help reduce autistic features to do with socialization, in mice. That can be found here.
Previously the drug was utilized for treatment of TB.
From the September 2010 article - Prion Disease Research... (link provided above):
Is it that the pathologic prions are actually a later result, from an initial infectious process involving filterable forms of M avium, M bovis, and M tuberculosis bacteria? These are represented as having pleomorphic properties; a plasticity to assume many forms, some viral-like and different from their classical parent. If it is true, that the trickier bacteria morph in an as yet to be entirely understood infectious process that in turn result in amyloid plaque and latent pathologic prion - then one researcher proposes antitubercular drugs might help in cases of neurodegenerative illnesses.