Other interesting candidates were HtrA, serine protease (Rv1223; previously reported to be a major virulence factor of Streptococcus pneumoniae in an in vivo pneumonia model (56, –, 58)), and KasB (Rv2246; causes subclinical latent tuberculosis in immunocompetent mice (59, –, 61)). Here, HTRA1 is linked to susceptibility to pneumonia measurement.