Intrinsic immunity refers to a set of cellular-based anti-viral defense mechanisms, notably genetically encoded proteins which specifically target eukaryotic retroviruses.
The development of the innate and adaptive immune system reflects the evolutionary importance of fighting infection.
Intrinsic immunity comprises cellular proteins which are always active and have evolved to block infection by specific viruses or viral taxa.
[2] The recognition of intrinsic immunity as a potent anti-viral defense mechanism is a recent discovery and is not yet discussed in most immunology courses or texts.
This is particularly important in retroviral infections since viral integration into the host genome occurs quickly after entry and reverse transcription and is largely irreversible.