Phages are reported to contain protein sequences that play an important role in human immunology various uncharacterized proteins are present in phages which can prove to be highly immunogenic. The outer capsid protein (Hoc) of the T4 phage head contains an immunoglobulin superfamily domain which includes antibodies, major histocompatibility antigens, T-cell receptors and cell adhesion molecules. The functions of these phage proteins are unknown (they are not relevant for phage interactions with bacteria); thus, their possible role in potential phage interactions with the human immune system cannot be excluded (Górskia and Dabrowska, 2005).