Enhancement of delayed-type hypersensitivity to sheep red blood cells in mice by granulocyte colony-stimulating factor administration at the elicitation phase.

We previously demonstrated that selective depletion of polymorphonuclear neutrophils by a mAb inhibits both the priming and effector phases of delayed-type hypersensitivity (DTH) to SRBC. To better understand the role of polymorphonuclear neutrophils in DTH, we examined the effect of granulocyte CSF (G-CSF) on DTH to SRBC in mice. G-CSF administered at the elicitation phase enhanced a DTH response that was weak in control G-CSF-untreated mice. This treatment also augmented mononuclear leukocyte recruitment in DTH in these mice. However, G-CSF administration failed to augment priming of DTH to SRBC under any conditions examined.