The systemic distribution of soluble antigen injected into the footpad of the laboratory rat

Abstract

Injection into the hind footpad of the rat combines intradermal and subcutaneous routes. Material injected into the dermis of the sole is rapidly distributed by the lymphatics to several lymph node groups and enters the bloodstream principally with the thoracic duct lymph. The diffuse character of the lymphatic drainage of this site is emphasized. Material in the subcutaneous tissues gradually enters the systemic circulation and is filtered through various organs. Antigen injected into the footpad can elicit both effective delayed hypersensitivity and humoral host responses.