Submitted to: American Journal of Veterinary Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/25/1998
Publication Date: N/A
Interpretive Summary: During the first week of life after hatching, the immune system of the baby chick is not very good at fighting bacterial infections such as Salmonella. The objective of this experiment was to determine whether the cells of the chick¿s natural immune system are just non-functional at this time or whether they are able to function if stimulated. We found that the cells of the natural immune system can be stimulated to function normally. The results of this experiment are important to the poultry industry in the United States because it shows that we can stimulate the baby chick¿s natural immune system to increase its resistance to bacterial infections such as salmonellae.
Technical Abstract: Heterophils, the avian equivalents to the mammalian neutrophil, are highly phagocytic, polymorphonucleated white blood cells which respond to various inflammatory stimuli produced locally at the site of invading microorganisms. In mammals, these stimuli have been found to activate the function of neutrophils. To date, no studies have been performed to define the activation process which primes and augments the function of avian heterophils. Therefore, the purpose of the present research was to evaluate the steps of activation of poultry heterophils stimulated with various conventional inflammatory agonists which will help define the mechanisms that direct and maintain the avian inflammatory response. Peripheral blood heterophils, isolated from day-old chickens and turkeys, were stimulated with either a calcium ionophore (ionomycin), phorbol myristate acetate (PMA), opsonized zymosan (OZ), or formyl-methionyl- leucyl-phenylalanine (fMLP). The function of these treated heterophils was compared with that of the control cells in shape change, adherence, phagocytosis, and chemiluminesence assays. Neither turkey nor chicken heterophils were responsive to fMLP stimulation. Chicken heterophils responded to ionomycin and PMA with significant increases (P<0.001) in adherence, shape change, phagocytosis, and oxidative burst. Similarly, turkey heterophils reacted to ionomycin stimulation with significant increases (P<0.001) in adherence, phagocytosis, shape change, and oxidative burst. However, turkey heterphils did not respond to PMA stimulation. OZ stimulated significant increases in the oxidative burst of both chicken and turkey heterophils although chicken heterophils responded with a significantly greater response than the turkey heterophils.