Potential use of G-CSF for protection against Streptococcus suis infection in swine

Authors: Brockmeier, Susan; Loving, Crystal; EBERLE, KIRSTEN - Orise Fellow; HAU, SAMANTHA - Orise Fellow; MOU, KATHY - Orise Fellow; Kehrli Jr, Marcus

Submitted to: Veterinary Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/10/2019
Publication Date: 3/11/2019
Citation: Brockmeier, S., Loving, C.L., Eberle, K.C., Hau, S.J., Mou, K.T., Kehrli Jr., M.E. 2019. Administration of granulocyte-colony stimulating factor (G-CSF) to pigs results in a longer mean survival time after exposure to Streptococcus suis. Veterinary Microbiology. 231:116-119. https://doi.org/10.1016/j.vetmic.2019.03.010.
DOI: https://doi.org/10.1016/j.vetmic.2019.03.010

Interpretive Summary: The use of immunomodulators is a promising alternative to the use of antibiotics to prevent and combat infectious disease. Previously we demonstrated a replication-defective adenovirus vector that expresses G-CSF elicited a sustained increase in circulating neutrophils, a type of white blood cell that is beneficial in preventing bacterial diseases. In new studies, pigs given the vectored G-CSF had an improved outcome when infected with Streptococcus suis, the leading cause of meningitis in weaned pigs. Thus, the use of G-CSF in pigs to induce an increase in circulating neutrophil numbers may be a useful alternative to antibiotics for prevention of Streptococcal and other bacterial diseases, especially during times of stress and pathogen exposure such as post-weaning.

Technical Abstract: The use of immunomodulators is a promising alternative to the use of antibiotics for therapeutic, prophylactic, and metaphylactic use to prevent and combat infectious disease. Previously we demonstrated a replication-defective adenovirus vector that expresses porcine granulocyte colony-stimulating factor (G-CSF) elicited a sustained neutrophilia, lasting nearly 3 weeks, which may be beneficial to prevent bacterial diseases during times of peak incidence. In a pilot study using the vectored G-CSF with a Caesarian-derived, colostrum-deprived (CDCD) pig model of Streptococcus suis disease, only 1 of 4 pigs given G-CSF developed disease, while 3 of 4 non-treated pigs developed Streptococcal disease. In a subsequent study using a larger number of pigs, although there was no difference in overall survival, there was a longer mean survival time in G-CSF treated pigs. S. suis infection is more severe in CDCD pigs than conventionally raised pigs, consequently results in the field may be superior to the ones reported in this study. Thus, the use of G-CSF in pigs to induce a sustained increase in circulating neutrophil numbers may be a useful alternative to antibiotics for prevention of Streptococcal disease, especially during times of stress and pathogen exposure such as post-weaning.