Analysis of mouse dendritic cell migration in vivo upon subcutaneous and intravenous injection

Dendritic cells (DC) have an increasingly important role in vaccination the rapy; therefore, this study sought to determine the migratory capacity and immunogenic function of murine bone-marrow (BM)-derived DC following subcut aneous (s.c.) and intravenous (i.v.) injection in vivo. DC were enriched fr om BM cultures using metrizamide. Following centrifugation, the low-buoyant density cells, referred to throughout as DC, were CD11c(high), Ia(b) (high ), B7-1(high) and B7-2(high) and potently activated alloreactive T cells in mixed lymphocyte reactions (MLR). In contrast, the high-density cells expr essed low levels of the above markers, comprised mostly of granulocytes bas ed on GR1 expression, and were poor stimulators in MLR. Following s.c. inje ction of fluorescently labelled cells into syngeneic recipient mice, DC but not granulocytes migrated to the T-dependent areas of draining lymph nodes (LN). DC numbers in LN were quantified by flowcytometric analysis, on 1, 2 , 3, 5 and 7 days following DC transfer. Peak numbers of around 90 DC per d raining LN were found at 2 days. There was very little migration of DC to n on-draining LN, thymus or spleen at any of the time-points studied. In cont rast, following i.v. injection, DC accumulated mainly in the spleen, liver and lungs of recipient mice but were largely absent from peripheral LN and thymus. The ability of DC to induce T-cell-mediated immune responses was ex amined using trinitrobenzenesulphate (TNBS)-derivatized DC (TNBS-DC) to sen sitize for contact hypersensitivity responses (CHS) in naive syngeneic reci pients. Following s.c. injection, as few as 10(5) TNBS-DC, but not TNBS-gra nulocytes, sensitized for CHS responses. However, the same number of TNBS-D C failed to induce CHS following i.v. injection. In summary, this study pro vides new and quantitative data on the organ specific migration of murine P M-derived DC following s.c. and i.v. injection. The demonstration that the route of DC administration determines the potency of CHS induction, strongl y suggests that the route of immunization should be considered in the desig n of vaccine protocols using DC.