Purpose <p>General anesthesia combined with surgery is thought to suppress the immune system. However, few studies have examined the effects of anesthetics alone on humoral immunity. In this study, we aimed to investigate the effects of the intravenous anesthetic propofol on antibody production after immunization and the underlying mechanisms in mice.</p> Methods <p>Mice were immunized with 4-hydroxy-3-nitrophenylacetyl (NP) hapten–conjugated keyhole limpet hemocyanin (NP–KLH), a T cell–dependent antigen, or NP hapten–conjugated Ficoll (NP–Ficoll), a T cell–independent antigen, followed by treatment with propofol, or PBS or intralipid as controls, for five consecutive days. The mice were re-immunized, and antibody production and immune cell subsets were evaluated. The effects of propofol on T cell proliferation and survival were also examined.</p> Results <p>NP-specific IgM and IgG1 titers were reduced in propofol-treated NP–KLH–immunized mice compared to those treated with PBS or intralipid, and this reduction was more pronounced in the secondary response than in the primary response. By contrast, propofol treatment did not affect NP-specific antibody titers in NP–Ficoll–immunized mice. In vitro, propofol inhibited IL-2–mediated proliferation and IL-7–dependent survival of CD4⁺ T cells.</p> Conclusions <p>Propofol suppresses T cell–dependent antibody production in mice and directly affects T cell proliferation and survival in vitro. These data suggest that anesthetics administered close to the time of vaccination may affect vaccine-specific antibody production.</p>