Abstract
Six acapsular strains ofCryptococcus neoformans obtained by chemical mutagenesis failed to produce a capsulein vivo and were avirulent in mice following high dose intramuscular, intraperitoneal or intravenous inoculation. Peritoneal granulomas were observed in all animals inoculated with the acapsular mutants. These granulomas were characterized by a large central mass consisting of intact, degenerating and necrotic yeast cells. This was surrounded by concentric layers of a broad band of histiocytes, a narrow band of fibroblasts, and around the periphery, a mass of lymphocytes and plasma cells. These isolates did not revert to an encapsulated or virulent state after more than a year of subculturing or 18 passages through mice.
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Bulmer, G. S. & Sans, M. D., 1968. Cryptococcus neoformans. III. Inhibition of phagocytosis. J. Bacteriol. 95: 5–8.
Bulmer, G. S., Sans, M. D. & Gunn, C. M., 1967. Cryptococcus neoformans. I. Nonencapsulated mutants. J. Bacteriol. 94: 1475–1479.
Emmons, C. W., Binford, C. H., Utz, J. P. & Kwon-Chung, K. J., 1977. Medical Mycology, 3rd ed., p. 223–224. Lea and Febiger, Philadelphia.
Farhi, F., Bulmer, G. S. & Tacker, J. R., 1970. Cryptococcus neoformans. IV. The not-so-encapsulated yeast. Infect. Immun. 1: 526–531.
Farmer, S. G. & Komorowski, R. A., 1973. Histologic response to capsule-deficient Cryptococcus neoformans. Arch. Pathol. 96: 383–387.
Fromtling, R. A., Blackstock, R. & Bulmer, G. S., 1980. Immunization and passive transfer of immunity in murine cryptococcosis, p. 122–125. In: E. S. Kuttin and G. L. Baum (ed.) Human and Animal Mycology. Proceedings of the VII Congress of ISHAM, International Congress Series No. 480, Excerpta Medica, Amsterdam.
Fromtling, R. A., Blackstock, R., Hall, N. K. & Bulmer, G. S., 1979. Immunization of mice with an avirulent pseudohyphal form of Cryptococcus neoformans. Mycopathologia 68: 179–181.
Fromtling, R. A., Blackstock, R., Hall, N. K. & Bulmer, G. S., 1979. Kinetics of lymphocyte transformation in mice immunized with viable avirulent forms of Cryptococcus neoformans. Infect. Immun. 24: 449–453.
Gutierrez, F., Fu, Y. S. & Lurie, H. I., 1975. Cryptococcosis histologically resembling histoplasmosis. A light and electron microscopical study. Arch. Pathol. 99: 347–352.
Ishaq, C. M., Bulmer, G. S. & Felton, F. G., 1968. An evaluation of various environmental factors affecting the propagation of Cryptococcus neoformans. Mycopathol. Mycol. Appl. 35: 81–90.
Jacobson, E. S. & Ayers, D. J., 1979. Auxotrophic mutants of Cryptococcus neoformans. J. Bacteriol. 139: 318–319.
Kozel, T. R. & Cazin, Jr., J., 1971. Nonencapsulated variant of Cryptococcus neoformans. I. Virulence studies and characterization of soluble polysaccharide. Infect. Immun. 3: 287–294.
Littman, M. L. & Tsubura, E., 1959. Effect of degree of encapsulation upon virulence of Cryptococcus neoformans. Proc. Soc. Exp. Biol. Med. 101: 773–777.
Lurie, H. I. & Shadomy, H. J., 1971. Morphological variations of a hypha-producing strain of Cryptococcus neoformans (Coward strain) in tissues of mice. Sabouraudia 9: 10–14.
Neilson, J. B., Fromtling, R. A. & Bulmer, G. S., 1977. Cryptococcus neoformans: size range of infectious particles from aerosolized soil. Infect. Immun. 17: 634–638.
Shadomy, H. J. & Lurie, H. I., 1971. Histopathological observations in experimental cryptococcosis caused by a hypha-producing strain of Cryptococcus neoformans (Coward strain) in mice. Sabouraudia 9: 6–9.
Staib, F., 1962. Cryptococcus neoformans im Muskelgewebe. Zentralbl. Bakteriol. I. Orig. 185: 135–144.
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Fromtling, R.A., Shadomy, H.J. & Jacobson, E.S. Decreased virulence in stable, acapsular mutants ofCryptococcus neoformans . Mycopathologia 79, 23–29 (1982). https://doi.org/10.1007/BF00636177
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DOI: https://doi.org/10.1007/BF00636177