TREM1 and infection: On the other hand, studies on lung infection models (e.g., Pseudomonas aeruginosa-induced pneumonia) indicated that administration of LP17 peptide reduced the bacterial load at an early stage of infection while increasing it at later stages; these effects, however, were attributed to indirect antimicrobial effects of TREM-1 related to early enhancement of neutrophil influx and consequent increase in phagocytic activity [43].