KM110r is a double-mutant Herpes Simplex Virus Type I (HSV-I), meaning that the genome of the wild-type strain of HSV-I manifests new characteristics due to two changes in its genetic material. These changes resulted in the creation of KM110.

Two genes of the HSV-I genome (which has been completely decoded) called VP16 and ICP0 were the two mutations leading to KM110.

The VP16 gene was truncated from the genome and replaced with a 12 bp (stop codon) linker comprised of Amino Acid #422 (V422).

The ICP0 gene was almost entirely truncated from the genome and replaced with a stop codon linker comprised of amino acid 212 (n212).

In order to create the virus, Human Embryonic Lung Fibroblasts (HEL) were infected with HSV-1 wild type. Plasmids containing the VP16 and ICP0 mutations were subsequently added. This resulted in a double mutant combining the n212 ICP0 mutation with the V422 VP16 mutation, which was then named KM110.

In order for this virus to be used in immunofluorescent microscopy, it required fluorescent labelling. KM110 was then recombined with a red fluorescent protein (RFP) in order for it to be visible under immunofluorescent conditions. This made the virus KM110red, or KM110r.