B cells require activation to efficiently present Ag to T cells. In agreement with this earlier observation we show that live, mitomycin C-treated B cells, but not B cells fixed in paraformaldehyde, stimulated the growth of allogeneic T cells in the primary MLR. However, if B cells were cultured with anti-Ig antibodies and IFN-γ before fixation they acquired excellent T cell stimulatory activity. Neither reagent alone conferred this novel co-stimulatory function on the B cell surface. The activity induced by both stimuli was not attributed to an increase expression of class II-MHC molecules or Il-1. IL-2 or IL-4, in combination with anti-Ig, also induced B cell stimulatory activity, but were less effective than IFN-γ. TNF failed to stimulate B cells, but synergized with IFN-γ in the induction of this activity. These studies therefore demonstrate an important role for lymphokines in modulating B cell Ag-presenting activity as well as the acquisition by B cells of a novel co-stimulatory surface activity.
|Number of pages||6|
|Journal||Journal of Immunology|
|State||Published - Dec 1 1988|