Production of immunity and unresponsiveness in the mouse by feeding contact sensitizing agents and the role of suppressor cells in the peyer's patches, mesenteric lymph nodes and other lymphoid tissues.

Mice were fed the contact sensitizing agents “oxazolone” or picryl chloride by tube. A single feed gave rise to contact sensitivity. However, the contact sensitivity and antibody production which occurred in mice painted with oxazolone were almost abolished when the mice were fed oxazolone 14 days before the skin painting. Feeding also reduced the DNA synthesis response in the regional lymph nodes. Two types of suppressor cells were found in mice after feeding. After a single feed of picryl chloride the Peyer's patches and mesenteric lymph nodes contained suppressor cells which suppressed the passive transfer of contact sensitivity. After three feeds of either agent spleen cells also caused inhibition. These suppressor cells were presumptive B cells as shown by their ability to form rosettes with red cells coated with antibody and complement and their resistance to anti-θ serum and complement. However, separated T cells from the same spleen transferred contact sensitivity. In addition to these B suppressor cells the spleens and peripheral lymph node cells of mice fed with contact sensitizing agent and then painted on the skin contained T cells which limited DNA synthesis in lymph nodes. This was shown by injecting their cells into normal recipients which were then painted with contact sensitizing agent and measuring DNA synthesis 4 days later in the regional lymph nodes. It was concluded that suppressor B and T cells were an important part of the mechanism of unresponsiveness caused by feeding contact sensitizing agents.