In vivo neurotoxin administration alters immune responses in chickens (Gallus domesticus)

1. 6-Hydroxydopamine (6-OHDA) administered in ovo enhanced in primary immune response to sheep red blood cells (SRBC) in chicks 2. Splenic norepinephrine levels increased during the peak anti-SRBC response. 3. Cell-mediated immunity as measured by delayed-type hypersensitivity to phytohemagglutinin-P (PHA-P) was not affected by treatment with 6-OHDA.