A few other observations from the paper:

• Reference 21 is cited as describing the identification of the 12 amino acid Mtf-pep. Looks like another paper should be published soon. "Eyford BA, Abraham T, Munro L, et al. A peptide vector delivers siRNA across the blood-brain barrier resulting in attenuation of ischemic stroke. In revision. Nature Biomed Eng."

• "MTfpep sequence differs between rodent species and human by two amino acids, with histidine and alanine at positions 4 and 5 are replaced by tyrosine and serine, respectively, in the rodent species. The two amino acids variation between rodent and human species have no effect on the ability of MTfpep to cross the brain capillary endothelium, nor the ability to transport a payload into the brain and the subsequent efficacy (data not shown)."

• "It is of significance to note that the reversal of hyperalgesia was two to four days in length, one day more than if IL-1RA is directly injected intrathecally where the effect lasted one day." This refers to reference 23 below, another MedImmune publication that used anti-Tfr approach.

• "In addition, we have shown here that our peptide of 12 amino-acid originating from MTf is delivering an analgesic compound (IL-1RA) in the CNS which shows better plasma and brain PK properties than a construct targeting the Tf receptor by an antibody." This refers to reference 23 below, another MedImmune publication that used anti-Tfr approach.

• Ref. 23: Webster CI, Hatcher J, Burrell M, et al. Enhanced delivery of IL-1 receptor antagonist to the central nervous system as a novel anti-transferrin receptor-Il-1RA fusion reverses neuropathic mechanical hypersensitivity. Pain 2017; 158: 660–668. https://www.ncbi.nlm.nih.gov/pubmed/28009628