Immunosuppression caused by antigen feeding. I. Evidence for the activation of a feedback suppressor pathway in the spleens of antigen-fed mice
✍ Scribed by Thomas Thornton Macdonald
- Publisher
- John Wiley and Sons
- Year
- 1982
- Tongue
- English
- Weight
- 733 KB
- Volume
- 12
- Category
- Article
- ISSN
- 0014-2980
No coin nor oath required. For personal study only.
✦ Synopsis
Abstract
Sheep red blood cells (SRBC) administered by the oral route to normal mice elicited no detectable splenic anti‐SRBC plaque‐forming cell (PFC) response until 8 weeks of antigen feeding. At this time a splenic IgA anti‐SRBC PFC response was detected. On the other hand, spleen cells taken from mice given oral SRBC for 1‐5 weeks showed striking changes in their in vitro anti‐SRBC responsiveness as compared to spleen cells from normal mice. This was evidenced by enhanced early (days 3‐4) in vitro responses, followed by suppressed late (day 5‐6) in vitro responses. Both early enhancement and late suppression were T cell‐mediated. Early enhancement appeared to be mediated by helper T cells of the Lyt‐1^+^2.3^−^ phenotype. Late suppression was also mediated by Lyt‐1^+^2.3^−^ cells, but Lyt‐2‐bearing cells had to be present in culture for suppression to occur. Lyt‐2‐bearing cells could be replaced with normal T cells. Furthermore, elimination of cells bearing I‐J‐encoded determinants from the T cell population isolated from the spleens of antigen‐fed mice also partially relieved suppression. Thus, antigen feeding appears to activate a feedback suppressor pathway in which Lyt‐1^+^2.3^−^, I‐J subregion determinant‐bearing T cells can suppress immune responses by causing normal T cells to become suppressor effectors. No evidence was found to show that antigen feeding induced Lyt‐1^−^2.3^+^ suppressor cells in the spleen, nor were any serum suppressor factors detected.