Superinfection exclusion (kw:KW-1260)

Superinfection exclusion is a phenomenon in which a preexisting viral infection prevents a secondary infection with the same or a closely related virus. This phenotype is often poorly understood, and may reflect programmed virus superinfection or a kind of antiviral state of the infected cell.

Some bacterial viruses encode proteins to achieve superinfection exclusion. These viral proteins can interfere with DNA release into the host cytoplasm or modify the entry receptor. They can also act as inhibitors of viral peptidoglycan degradation enzymes thereby preventing entry of incoming phages .

Many viruses can make superinfection exclusion, few examples are described below:

Family	Genus	Virus	Superinfection exclusion protein	strategy	references
Baculoviridae	Alphabaculovirus	AcMNPV	undocumented	undocumented
Closteroviridae	Closterovirus	Citrus tristeza virus	p33	undocumented
Flaviridae	Hepacivirus	Hepatitis C	Undocumented	post entry
Siphoviridae	Lambdalikevirus	Enterobacteria phage HK97	gp15	Undocumented
Siphoviridae	T5likevirus	Enterobacteria phage T5	Lipoprotein Llp	Blocks T5 entry receptor FhuA
Myoviridae	T4likevirus	Enterobacteria phage T4	Immunity protein Imm Protein spackle Sp	Blocks DNA translocation into host cytoplasm Inhibits the lysozyme activity
Siphoviridae	unclassified	Bacteriophage TP-J34	Lipoprotein LTP	Blocks DNA ejection into host cytoplasm
Siphoviridae	unclassified	Lactococcus phage Tuc2009	ORF2	Blocks DNA ejection into host cytoplasm
Podoviridae	P22likevirus	Enterobacteria phage P22	SieA	Blocks DNA translocation into host cytoplasm
Myoviridae	Punalikevirus	Enterobacteria phage P1	Sim	Probably blocks DNA translocation into host cytoplasm