T cell-dependent mediator in the immune response. III. The role of non-specific factor (NSF) in the in vitro immune response.
Evidence is presented which suggests that T cell-dependent nonspecific factor (NSF) cannot be the sole mediator of 'co-operation' for all types of thymus-dependent antibody response. NSF can replace the requirement for T cells in responses to hapten conjugated to particulate carriers, but cannot do so in responses to hapten conjugates of soluble thymus-dependent carriers.