RABBIT IGG DISTRIBUTION IN SKIN, SPINAL-CORD AND DRG FOLLOWING SYSTEMIC INJECTION IN RAT

In order to determine the distribution of antibodies such as anti-NGF following systemic injection in neonates, immunocytochemical technique s were used to examine the localization of rabbit IgG in rat skin, DRG , and spinal cord after treatments with normal rabbit serum or purifie d rabbit IgG. Daily subcutaneous injections beginning on postnatal day 2 or on day 15 were given for three days. On the fourth day the anima ls were sacrificed and tissues were processed for rabbit IgG-IR. In th e dorsal and ventral spinal cord, staining intensities suggest a subst antial increase in the blood-brain barrier during the first two weeks after birth. Staining intensity in the epidermis of the glabrous skin from the hindpaw was substantially lower than in the adjacent dermis. In addition, IgG infrequently accumulated intracellularly in intensely stained patches in the epidermis. IgG was also able to reach relative ly high intracellular concentrations in a small number of sensory neur ons. The IgG staining pattern in the skin was similar when anti-NGF it self was administered to the animals. The results are discussed in the context of the effects of anti-NGF on the development of nociceptive afferents. (C) 1997 Elsevier Science B.V.