title: Separate application of adjuvant and antigen: the effect of a water-in-oil emulsion on the splenic plaque-forming cell response to sheep red blood cells in mice.
abstract: The effect of a non-immunogenic adjuvant on the murine splenic plaque-forming cell (PFC) response against sheep red blood cells (SRBC) was studied. The adjuvant, a stable water-in-oil (W/O) emulsion, was injected intraperitoneally at the same time as or prior to the intravenous (i.v.) injection of SRBC. Enhancement of the SRBC-specific IgM-, but not IgG- and IgA-responses was observed. The stimulatory effect depended on the dose of both adjuvant and antigen and on the interval between their application. The minimal dose of adjuvant needed to induce maximal stimulation increased with the interval between the injections. Administration of an optimal adjuvant dose one week before antigen application still resulted in a clear stimulation of the response to the antigen. In adjuvant-treated animals, the primary PFC response did not exceed the maximum level reached after i.v. injection of a high dose of SRBC. Adjuvant therapy also resulted in polyclonal B cell-activation, since the number of spontaneous Ig-secreting cells in the spleen was increased. The kinetics and isotype distribution of the SRBC-specific and polyclonal responses, however, were different. Therefore, the observed stimulatory effect on the SRBC-specific PFC-response cannot be explained by the polyclonal activation of the immune system. From this study it appears that injection of a W/O emulsion provokes an active stimulation of the immune system, which demonstrates that the adjuvant effect of W/O emulsions is not only passively obtained by prolonged antigen presentation by depot formation.
mesh_terms: D000276:Adjuvants, Immunologic; D000818:Animals; D000941:Antigens / Q000276:immunology*; D004655:Emulsions; D004912:Erythrocytes / Q000276:immunology*; D006462:Hemolytic Plaque Technique; D007070:Immunoglobulin A / Q000276:immunology; D007074:Immunoglobulin G / Q000276:immunology; D007075:Immunoglobulin M / Q000276:immunology; D008214:Lymphocytes / Q000276:immunology*; D051379:Mice; D008809:Mice, Inbred C3H; D008810:Mice, Inbred C57BL; D008899:Mineral Oil; D012756:Sheep; D013154:Spleen / Q000276:immunology*; D014867:Water
chemical_list: D000276:Adjuvants, Immunologic; D000941:Antigens; D004655:Emulsions; D007070:Immunoglobulin A; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D014867:Water; D008899:Mineral Oil