Heterogeneity of the Cellular Immune Response

Antigen-mediated stimulation of thymidine incorporation was demonstrated in lymph node cells from guinea pigs immunized with 100 microg human serum albumin in either Freund's incomplete or Freund's complete adjuvant. Animals receiving HSA in IFA exhibited both cutaneous basophil (Jones-Mote) hypersensitivity and lymphocyte stimulation at 1, but not at 6 wk after immunization. Significant stimulation required >/= 10 microg HSA/ml of culture. Sensitization with HSA in CFA produced delayed hypersensitivity and permitted lymphocyte stimulation at both 1 and 6 wk. Stimulation was observed with as little as 0.1 microg HSA/ml at the later interval. Administration of 5 mg HSA intravenously at the time of sensitization with 100 microg HSA in IFA reduced but did not eliminate both CBH and lymphocyte stimulation at 1 wk. Antigen-specific inhibition of macrophage migration could be demonstrated with exudates from animals immunized with HSA in CFA, but not with HSA in IFA at 3 wk after sensitization. HSA was cleared from depots of CFA and IFA at similar rates, but significantly more antigen appeared in the plasma and subsequently in the draining lymph nodes following administration in IFA. Conversely, accumulated antigen disappeared more rapidly following CFA immunization.