Isolation and partial characterisation of a new antiproliferative substance from human leucocytes inhibiting growth of Candida albicans.
OBJECTIVE
To purify and partially characterise a fraction from human leucocytes containing a substance cytotoxic to Candida albicans.


METHODS
Leucocytes were isolated from the buffy coats of healthy blood donors. The cytotoxic factor (CF) was isolated from the soluble fraction of the cells. A cell lysate was passed through a filter with a cut off value of 3 kDa, and the filtrate was processed by anionic exchange chromatography and gel filtration. The purified CF was analysed for its chemical and biological properties. The cytotoxicity of CF was tested on C albicans grown on agar plates.


RESULTS
Mass spectrometry showed a molecular mass of 2.148 kDa. CF was found in polymorphonuclear neutrophilic cells only. No amino acids were detected, and a low ultraviolet absorbance at 260 nm and resistance to nuclease indicate the absence of nucleic acids. An anthrone test was positive for carbohydrate. The substance was soluble in water. CF showed a dose related cytotoxicity in the range of 0.1-1 mg/ml. The cytotoxic effect was abrogated by zinc ions. Preliminary testing indicated that CF also had cytotoxic effects against some bacteria.


CONCLUSIONS
This report describes a factor from isolated human leucocytes that is cytotoxic to C albicans. The substance contains a carbohydrate moiety, whereas no amino acids were detected. The cytotoxicity can be abrogated by zinc ions in vitro. This substance is probably part of the repertoire by which leucocytes prevent infections.
Naess-Andresen
C F
CF
Department of Immunology and Transfusion Medicine, Ullevaal University Hospital, 0407 Oslo, Norway. andresen@ikb-nhl.no
Ekeberg
D
D
Fagerhol
M K
MK
Sandvik
K
K
Staahl
L
L
D000838:Anions; D000935:Antifungal Agents / Q000097:blood / Q000302:isolation & purification*; D002176:Candida albicans / Q000187:drug effects*; D002241:Carbohydrates / Q000032:analysis; D002850:Chromatography, Gel; D002852:Chromatography, Ion Exchange; D003601:Cytotoxicity Tests, Immunologic; D004305:Dose-Response Relationship, Drug; D006801:Humans; D007963:Leukocytes, Mononuclear / Q000737:chemistry*; D008970:Molecular Weight; D015032:Zinc / Q000494:pharmacology
D000838:Anions; D000935:Antifungal Agents; D002241:Carbohydrates; D015032:Zinc