The AbiK defense system was discovered in 1997 in *Lactococcus lactis* :ref{doi=10.1128/aem.63.4.1274-1283.1997}. AbiK is a single gene system with a size of around 650 amino acid.
AbiK is one of the so-called "Abi" systems for "Abortive infection" discovered in the 90's in research related to the dairy industry :ref{doi=10.1016/j.mib.2005.06.006}.
AbiK is one of the so-called "Abi" systems for "Abortive infection" discovered in the 90's in research related to the dairy industry :ref{doi=10.1016/j.mib.2005.06.006}. AbiT is classified as abortive infection in :ref{doi=10.1016/j.mib.2023.102312}.
Since it was discovered a similarity in amino acids was found with [AbiA](/defense-systems/abia).
However, with the discovery of dozens of new systems, it was categorize as one of the UG/Abi defense systems :ref{doi=10.1093/nar/gkac467} along with [DRT](/defense-systems/drt) different subsystems, [AbiA](/defense-systems/abia) and [AbiP2](/defense-systems/abip2).