Cell co-operation in antibody formation on hapten-carrier complexes: Some regulatory aspects

Abstract Previous experiments suggest that, in the secondary antibody (IgG) response to hapten-carrier complexes in an adoptive transfer system, a synergism exists between B cells recognizing hapten (B hapten ), T cells recognizing carrier (T carrier ) and T cells recognizing new antigenic determinants (NAD) and/or hapten (T NAD/hapten ). In the present study some of the regulatory mechanisms in this cell co-operating system were evaluated using the numbers of indirect anti-DNP plaque forming cells produced as the measuring parameter. Independent dilutions of cells from donors primed with either bovine serum albumin (BSA) or a complex of 2,4-dinitrophenyl (DNP) and isologous mouse immunoglobulin (MIg) indicated that the T carrier cells were the limiting helper cell populations in the anti-DNP response. The IgG response of recipients of BSA cells and DNP 27 -MIg cells was completely abrogated when the recipients were injected with BSA and DNP 28 -BSA. This suppression was both carrier specific and T cell dependent, suggesting the possible generation of T suppressor cells. A non-related carrier only caused suppression if donor cells of mice primed with that carrier (free or haptenated) were also transferred. This response was augmented if cells of donors immunized with DNP-unrelated carrier complex were added to the normal co-operative system and the recipients immunized with DNP-BSA complexes with an intermediate hapten/carrier ratio. This suggests that on transfer, there was an enhancement of the response and stimulation of additional NAD/DNP cells. The present experiments suggest that manipulation of both different helper and suppressor cell populations and cells reactive to a non-related carrier can result in either suppression or enhancement of anti-hapten response.