@misc{indiciae323b51afafad,
  title = {PPD tuberculin--a B-cell mitogen.},
  author = {B M Sultzer and B S Nilsson},
  year = {1972},
  doi = {10.1038/newbio240198a0},
  url = {https://pubmed.ncbi.nlm.nih.gov/4539345/},
  note = {Source identifier: 4539345}
}