Activity of rabbit leukocyte peptides against Candida albicans

Abstract

Six related cysteine-rich, low-molecular-weight peptides were purified from rabbit peritoneal granulocytes and tested in vitro for fungicidal activity against Candida albicans. Two peptides (NP-1 and NP-2) were highly effective, one (NP-3a) was moderately active, and three (NP-3b > NP-4 >> NP-5) had substantially less potency. There was a general, but imperfect, correlation between the candidacidal potency of each peptide and its net cationic charge. Candidacidal activity by NP-1 was concentration and time dependent and occurred rapidly under optimal low-ionic-strength conditions. It was inhibited by increasing either the ionic strength or Ca2+ concentration of the incubation mixtures, but was relatively unaffected by Mg2+. Candidacidal activity was independent of H+ concentrations between pH 5 and 8, but decreased below pH 5. Candidacidal activity was temperature sensitive and was virtually abolished when NP-1 was incubated with C. albicans at 0°C. Cysteine-rich antimicrobial peptides such as NP-1 and NP-2 may equip leukocytes to deal with infections caused by C. albicans and other fungi that are susceptible to their microbicidal effects.

Antimicrobial activity of chicken and turkey heterophil peptides CHP1, CHP2, THP1, and THP3

“…It is also possible that the higher ionic concentration of the cell medium vs. the buffers used in other assays may have influenced microbicidal activity. Defensins can be less active against bacteria and fungi under high-ionic-strength conditions (Selsted et al, 1984(Selsted et al, , 1985.…”

Expression of β‐defensin 1 and 2 mRNA by human monocytes, macrophages and dendritic cells

“…Defensins display antimicrobial activity against a variety of microorganisms, such as bacteria, fungi and enveloped viruses. [3][4][5] Six a-defensins and three b-defensins have been described in humans. Among the a-defensins, human neutrophil peptide (HNP)-1 to -4 are stored in the azurophilic granules of neutrophils 6 whereas human defensins (HD)-5 and -6 are expressed by specialized epithelial cells of the intestines, i.e.…”

H1 Histones Contribute to Candidacidal Activities of Human Epidermal Extract

“…Even though, we did not discuss these fractions in this report; their study is also in progress. Supporting the hypothesis that more cationic proteins may have stronger candidacidal activity (27), the last fractions (the most cationic ones), #35-#38, of the Mono S cation exchange column chromatography showed the highest activity. The most active candidacidal proteins of the human epidermis were purified from those fractions by reversed phase HPLC.…”

“…Many cationic proteins, which may be extracted under acidic conditions, have been reported to possess microbicidal activities (6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(25)(26)(27)(28)(29). Human epidermal proteins extracted by citric acid have also shown candidacidal activity.…”