Submitted to: ARS Immunology Workshop
Publication Type: Abstract only
Publication Acceptance Date: 12/3/2003
Publication Date: 12/3/2003
Citation: FERRO, P.J., SWAGGERTY, C.L., KAISER, P., PEVZNER, I.Y., KOGUT, M.H. HETEROPHILS ISOLATED FROM CHICKENS RESISTANT TO EXTRAINTESTINAL SALMONELLA ENTERITIDIS INFECTION EXPRESS HIGHER LEVELS OF PRO-INFLAMMATORY CYTOKINE MRNA FOLLOWING INFECTION THAN HETEROPHILS FROM SUSCEPTIBLE CHICKENS. ARS IMMUNOLOGY WORKSHOP. 2003. ABSTRACT P. 21. Interpretive Summary:
Technical Abstract: Previous studies in our laboratory have shown differences in in vitro heterophil function between two pure lines of broiler chicks and their F1 reciprocal crosses. The objectives of the current study were to 1) determine if the previously reported in vitro differences in heterophil function between the lines translated to an increase in in vivo resistance to extraintestinal infection with Salmonella enteritidis (SE) and 2) to quantitate pro-inflammatory cytokine mRNA expression levels in heterophils isolated from SE-infected chicks from different lines. Day-old chicks from four different lines (pure lines=A and B; line C = male B x female A; line D = male A x female B) were challenged orally with SE. Twenty-four hours post-challenge, livers and spleens were aseptically removed from each chick and incubated overnight in tetrathionate enrichment broth. Enrichment cultures were plated and subsequently analyzed for the presence of non-lactose fermenting Salmonella colonies. The two lines reported to have more functionally efficient heterophils (A and D) were less susceptible to extraintestinal SE infections whereas the two lines reported to have functionally less efficient heterophils (B and C) were more susceptible to SE organ invasion. Four hours post-challenge peripheral blood heterophils were isolated from SE-infected and control chicks, total RNA extracted, and then analyzed for pro-inflammatory cytokine (IL-1beta, IL-6, IL-8) expression using real-time quantitative RT-PCR. Pro-inflammatory cytokine mRNA expression was significantly up-regulated in heterophils isolated from chicks that were more resistant to SE organ invasion (A and D) when compared to expression in heterophils isolated from the more susceptible lines (B and C). To our knowledge, this is the first report to quantitate IL-1beta, IL-6, and IL-8 mRNA expression levels in heterophils isolated from day-old chicks orally challenged with SE. These results show a relationship between in vitro heterophil function and resistance to organ invasion by SE. These data also indicate that pro-inflammatory cytokine mRNA expression by heterophils contributes, at least in part, to resistance/susceptibility of day-old chicks to extraintestinal infection by SE.