Table 1.

RSV proteins in live attenuated or subunit vaccines.

Protein	Size aa	Functions related to vaccine design	Role in a live virus vaccine	Role in a subunit vaccine
NS1	139 aa	Inhibits type 1 interferon production to block host response to control infection	Attenuation when deleted or codon de-optimized	None
NS2	124 aa	Inhibits type 1 interferon production to block host response to control infection	Attenuation when deleted or codon de-optimized	None
Nucleoprotein (N)	391 aa	Nucleocapsid formation and T cell epitopes	Attenuation or temperature sensitivity when mutated	Induce T cell immunity
Phosphoprotein (P)	241 aa	Nucleocapsid formation, replication	Attenuation when codon pair de-optimized	Platform for RSV VLPs
Matrix protein (M)	256 aa	Envelop, virion assembly	Attenuation and temperature sensitivity when the gene start signal mutated	Induce T cell immunity and platform for RSV VLPs
Small hydrophobic (SH)	64 aa	Ion channel	Attenuation when deleted or codon pair de-optimized	Induce ADCC antibodies to decrease virus replication
G protein	292-319 aa	Attachment and immune modulation	Attenuation when deleted and improved safety and immunogenicity when mutated	Induce antibodies to inhibit virus replication by blocking binding to the cell surface receptors CX3CR1 and glycosaminoglycans and/or ADCC and to block virus-induced inflammation
F protein	574 aa	Attachment, entry, fusion	Attenuation when mutated or codon pair de-optimized and improved protective immunity and virus stability when mutated	Induce antibodies to inhibit virus replication by blocking fusion and possibly by ADCC
M2-1 protein	194 aa	Anti-termination factor during transcription	Attenuation when mutated	Induce T cell immunity, platform for RSV VLPs
M2-2 protein	90 aa	Switch from transcription to replication	Attenuation and enhanced immunity when deleted	None
L protein	2,165 aa	Viral polymerase	Attenuation when mutated or codon pair de-optimized	None

Adapted with permission from Anderson (29).