PRIMARY HUMAN IMMUNE-RESPONSE TO NEISSERIA-MENINGITIDIS SEROGROUP-C IN INTERLEUKIN-12-TREATED SEVERE COMBINED IMMUNODEFICIENT MICE ENGRAFTED WITH HUMAN PERIPHERAL-BLOOD LYMPHOCYTES

Lack of primary immune response in severe combined immunodeficient (SC ID) mice engrafted with human peripheral blood lymphocytes (hu-PBL) ha s limited the applicability of this model. Use of human cytokines, in particular interleukin (IL)-12, was studied in the hu-PBL-SCID model. SCID mice were treated with IL-12 and reconstituted with hu-PBL in T r eplacement factor. The hu-PBL-SCID mice were immunized with serogroup C meningococcal polysaccharide (MCPS). The MCPS-specific antibody resp onse was determined by ELISA. Thirteen of the 15 immunized, IL-12-trea ted hu-PBL-SCID mice demonstrated a primary human antibody response to MCPS ranging from 0.25 to 3.3 mu g/mL, while no MCPS-specific antibod y response was detectable in the 18 controls. Expression of cross-reac tive idiotypic markers found on human anti-MCPS antibodies in the immu nized hu-PBL-SCID mice was similar to that observed in immunized volun teers.