Table 2.

Examples of pathogen-associated molecules with experimental evidence of cross-protection.

Component	Source	Cross-protection	References
LPS (endotoxin)	Most Gram-negative bacteria, such as E. coli	Staphylococcus aureus	(29)
Peptidoglycan component muramyl dipeptide	Bacteria	Toxoplasma	(30)
Flagellin	Gram-negative bacteria	Gram-positive bacterium Streptococcus pneumoniae	(31)
		Rotavirus	(32)
FimH	E. coli	Influenza virus	(33)
β-glucan	Fungi	Staphylococcus aureus Streptococcus pneumoniae.	(34)
Chitin	Fungi	Staphylococcus aureus or Escherichia coli	(35)
CpG oligodeoxynucleotide	Bacteria, synthetic	E. coli	(36)
		Influenza virus	(37)
			(38)