Nonspecific signals for B-cell localization and activation.

Virgin, inactive mammary gland autografted to the anterior chamber of the rabbit eye remains free of lymphoid cells. Activation of the ectopic gland by systemic injection of chorionic gonadotropin results in maturation of the gland and milk production, accompanied by the immirgration of lymphocytes and their activati-n to Ig formation, predominantly of the IgA class. In the presence of antigen-induced intraocular inflammation, the activated gland is able to influence the Ig class of B cells in the neighboring ocular tissues. These data suggest that even nonlymphoid tissues may elaborate lymphocyte-homing and polyclonal B-cell activating factors which function independently of specific antigen.