H1 Histones Contribute to Candidacidal Activities of Human Epidermal Extract

In the study of the purification of candidacidal cationic proteins from human epidermis by using high performance liquid chromatography, it was found that these proteins were composed of several groups. Among them, the most active group was purified. The amino acid compositions of this protein group were almost the same as those of human splenic H1 histones. The results of immunoblotting suggested that the proteins were human epidermal H1 histones. The killing speed of the epidermal H1 histone was very rapid, 8 micrograms of the protein killed 90% of Candida tropicalis (1 x 10(5) CFU) within 10 minutes. The cidal activity increased in lower pH conditions and decreased at higher ionic strengths. Because nuclei of the epidermis disintegrate in the granular layer, it is suggested that, in this layer, nuclear histones may be released from the nuclei. My immunohistochemical results suggest that H1 histones may contribute to form a barrier which inhibits candida from invading deeper than the granular cell layer in cases of skin candidial infection.