Potential of histamine release factor for the utilization as a universal vaccine antigen against poultry red mites, tropical fowl mites, and northern fowl mites.

Poultry red mites (PRMs, Dermanyssus gallinae), tropical fowl mites (TFMs, Ornithonyssus bursa), and northern fowl mites (NFMs, Ornithonyssus sylviarum) are hematophagous mites that are distributed worldwide which pose a serious challenge to the poultry industry and negatively impact poultry production and welfare. Vaccines represent a promising approach for controlling avian mites, and the identification of antigens with broad efficacy against multiple avian mite species is advantageous for vaccine control. This study aimed to identify histamine release factor (HRF), which was previously reported as a candidate vaccine antigen against PRMs, from TFMs and NFMs and to analyze its cross-reactivity and acaricidal effects on different avian mite species. The deduced amino acid sequences of the HRFs identified in the TFMs and NFMs were highly homologous to those of the PRMs. We generated recombinant HRF (rHRF) of TFMs, NFMs, and PRMs, and immune plasma against each rHRF was produced by immunization with each antigen. The immune plasma contained antibodies specific to each antigen and showed cross-reactivity with rHRFs from different avian mites. Moreover, PRM nymphs (protonymphs) artificially fed each immune plasma showed higher mortality rates than those fed the control plasma. These results suggest that HRFs can be used as candidate antigens for a universal vaccine with broad efficacy across avian mites.