Histomonas meleagridis excretory-secretory protein ES19 (ES19)

Histomonas meleagridis excretory-secretory protein ES19 (also identified as 40S ribosomal protein S19 or eS19) is a protein found in the exoproteome (secretome) of the protozoan parasite Histomonas meleagridis. While its canonical role is in protein synthesis within the ribosome, proteomic studies have identified it as a significant component of the parasite's secreted products, where it is believed to act as a moonlighting protein involved in host-parasite interactions. It is notably immunogenic, being recognized by the sera of infected turkeys and chickens, the primary hosts affected by histomoniasis (Blackhead disease). Due to its consistent presence in the secretome of both virulent and attenuated strains, ES19 is considered a potential target for the development of vaccines and diagnostic tools. Histomoniasis is a re-emerging poultry disease that causes severe cecal inflammation and crater-like liver necrosis, often leading to 80-100% mortality in turkey flocks. Since traditional chemotherapeutics like nitroimidazoles and arsenicals have been banned in many regions, research into the immunogenicity of secreted proteins like ES19 is crucial for creating new prophylactic measures. Currently, no specific drugs are approved to interact with this target, but it remains a focal point for immunological intervention and disease monitoring.

Other names

40S ribosomal protein S19eS19RPS19Histomonas meleagridis 19 kDa excretory-secretory protein

None (currently investigated as a vaccine candidate or diagnostic target)