Induction of immunity and tolerance in vitro by hapten protein conjugates. II. Carrier independence of the response to dinitrophenylated polymerized flagellin

The response to dinitrophenylated polymeric flagellin (DNP POL) in vitro, unlike that to DNP monomeric flagellin (DNP MON) or erythrocyte antigens does not require the presence of T cells. It was thus proposed that antigens with repeating determinants, like DNP POL, may immunize B cells without the cooperation of the usual helper cells. Since carrier specificity in secondary anti‐hapten responses is based upon the cooperation of carrier‐reactive T cells and hapten‐reactive cells, the requirement for carrier‐reactive cells in the response to “thymus‐independent” DNP POL and “thymus‐dependent” DNP MON was investigated. Using flagellin‐primed spleen, the anti‐DNP response to DNP MON was enhanced, but not that caused by DNP POL. Furthermore, there was no carrier specificity in the anti‐DNP responses with DNP POL, which elicited similar responses in spleen cells primed with various DNP proteins, whereas DNP MON only immunized spleen cells which were primed with that carrier. Carrier‐hapten cooperation has also been demonstrated by the suppressive effect of unconjugated carrier on the anti‐hapten response to carrier hapten conjugates. Neither the induction of tolerance to flagellin, the carrier, nor the presence of free flagellin in vitro suppressed the anti‐DNP response to DNP POL. In contrast, both these manoeuvres suppressed the anti‐flagellin response to DNP POL, and both the anti‐DNP and anti‐flagellin responses elicited by DNP MON. Thus, by several criteria, there was no cooperation between carrier‐reactive and hapten‐sensitive cells in the genesis of the response to DNP POL.