Isolation and characterization of cell wall and cytoplasmic antigens and peripheral blood leukocyte responses in rabbits immunized with Candida albicans

Summary The aim of this study is to carry out enzymatic digestion of cell wall polysaccharides using β-(1–3)-glucanase to prepare antigen extracts of cell wall and cytoplasma of Candida albicans. These antigens were used to measure in vitro lymphocyte transformation and in vivo skin test responses in rabbits following inoculation with living C. albicans. The results of this study show that both cell-wall and cytoplasmic antigens of C. albicans in both the yeast and mycelial phases induce high levels of transformation in the infected host. The in vivo skin test, which gave indurated reactions typical of delayed type hypersensitivity, confirmed the in vitro findings. In addition, the in vitro cellular responses were not influenced in any major way by the presence of immune serum. Whole blood and purified leukocyte microculture techniques were established to test cellular reactivity in vitro. Although no report was found in the literature previously on the use of the whole blood leukocyte (WBL) assay system for the measurement of cellular mediated immune (CMI) responses to Candida antigens, the correlation between the WBL and peripheral blood leukocyte assay system indicates that its use is a valid way to measure CMI in vitro. The nature of the cells involved in the in vitro response of immunized rabbits was further characterized. Leukocyte cultures depleted of T-cells, B-cells or monocytes showed that T-cells and monocytes were essential for the production of the transformation response in vitro.