The induction of hapten-specific immunologic tolerance and immunity in B lymphocytes. I. The effect of delayed immunization on the adoptive response to TNP-LPS.

An improved adoptive transfer procedure has been developed for the thymus-independent conjugate TNP-LPS. This technique involving delayed immunization results in increased sensivity and makes possible studies of various cell types, the response of which is normally very low or which are difficult to manipulate experimentally in situ. The standard adoptive immune response of adult spleen cells to TNP-LPS was low in comparison to the primary AFC response of intact mice. Adult bone marrow cells gave a 30-fold lower and neonatal spleen cells an 8-fold lower adoptive response than an equivalent number of adult spleen cells. If the administration of antigen was delayed past the normal time of immunization (1 hr after cell transfer), the resulting AFC response of adult spleen, adult bone marrow, and neonatal cells was enhanced. The peak response occurred with a delay interval of 4 days, and the magnitude decreased with greater delay. Part of the reason for the decline was an acceleration in the attainment of a peak response in mice given antigen past the 4-day optimum. The enhancement of the adult splenic response was not restricted to the antigen TNP-LPS, and was a transferrable phenomenon which did not require antigen to persist past the 4-day optimum delay period. The ineffectiveness of host pre-irradiation indicated that host recovery alone was not involved. Although the results are more compatible with B cell proliferation causing the enhancement, a combination of effects may be involved.