AbstractFractions of dextran (DE) B512, DE B1355 and levan (LE) have been shown to induce a specific blockade of antibody‐forming cells (AFC) when injected into previously immunized mice. Whereas specific blockade with DE B512 (450 000 daltons) was easily induced by as little as 10 μg, blockade to LE and DE B1355 was more resistant and required 1 and 10 mg, respectively.AFC blockade and tolerance are dissociable phenomena, as the former effect could be achieved with nontolerogenic low mol. wt. DE B512 (10 000 daltons). Conversely, perennial rye grass fructosan (7600 daltons), which is tolerogenic for LE, did not induce blockade. Furthermore, blockade of anti‐DE response specific for α(1→3)‐linked glucosyl determinants was achieved in BALB/c mice, whereas attempts to induce stable tolerance have been uns
展开▼
