Kinetic Study of Humoral and Cellular Immune Responses to Cryptococcus Neoformans Measured by Elisa and Immunocyte Migration Inhibition

The isolation of purified metabolic (polysaccharidic) and somatic (glycoproteinic) antigens (Ag) of Cryptococcus neo-formans (Cn), paves the way to a more precise study of the immune response to this fungus (Reyes, Dandeu, Drouhet, Abstracts, IX Inter. Congress ISHAM, Atlanta, May 1985, pp. 3–4). It is thought that resistance to Cn is related to the development of cell-mediated immunity (CMI), the role of antibody being only indirect. The inhibition of migration (MI) of immunocytes in the presence of specific Ag, has been considered an in vitro correlate of delayed type hypersensitivity, and more recently as a parameter of CMI. The capsular polysaccharide of Cn produced inhibition of the migration of leukocytes (E. Drouhet and G. Segretain, 1951, Ann. Inst. Pasteur, 78A:891). The development of a rapid and sensitive photoelectric method of reading cell migrations (Gauthier-Rahman et al., J. Immunol. Methods, 1982, 53:77) has enabled us to use this otherwise laborious technique to explore CMI in response to Cn in presence of a wide range (10 logs) of in vitro concentrations of purified polysaccharidic cryptococcal Ag.