This strain is a Tlr4 knockout (Tlr4 KO) mouse model utilizing gene editing technology to knock out the Tlr4 gene homologous to the human TLR4 gene in mice. Homozygous Tlr4 KO mice are viable and fertile and exhibit a variety of phenotypes associated with immune responses, including hyporesponsiveness to bacterial lipopolysaccharide (LPS) and elevated levels of respiratory syncytial virus.