A murine model for study of anticryptococcal activity mediated by cytotoxic immune cells: Role in immunization and human vaccine strategies

Abstract

NK and T cells play a pivotal role in host defense to Cryptococcus neoformans (C. neoformans) fungus which affects especially hosts with impaired cell mediated immunity. The vaccine against cryptococcosus is not developed yet, thus we established an animal BALB/c mice model to analyze anticryprococcal activity of immune cells. We detected that non-stimulated spleen mononuclear cells (MNC) from non-immunized mice have the capacity to exhibit anticriptococcal activity on the incapsulated C. neoformans strain (ATCC 34873) and this activity can be enhanced by non-adherent cells (NAC). In order to obtained antigen-specific anticryprococcal activity, MNC and NAC were stimulated in vitro with corpuscular (Ag1) or soluble (Ag2) C. neoformans antigen prepared from the acapsular strain Cap67 (ATCC 52817). In vitro stimulation of immune cells with both C. neoformans antigens enhanced the anticryptococcal activity of MNC and NAC. NAC fraction expressed the highest anticryptococcal activity, also in the presence and in the absence of accessory cells (AC). The highest anticryptococcal activity of effector cells was detected after immunization of mice with the same C. neoformans antigens and after additional stimulation of immune cells in vitro with the some antigens. These data demonstrated that growth inhibition of C. neoformans mediated by mice effector cells can be enhanced with corpuscular, as well as soluble antigens. Thus designin an animal model which is simple and reproducible and can be used for further studies and development of immunization strategies against human cryptococcosis