Carrie L. Frey

Identification of Unique Truncated KC/GROβ Chemokines with Potent Hematopoietic and Anti-Infective Activities

SK&F 107647, a previously described synthetic immunomodulatory peptide, indirectly stimulates bone marrow progenitor cells and phagocytic cells, and enhances host defense effector mechanisms in bacterial and fungal infection models in vivo. In vitro, SK&F 107647 induces the production of a soluble mediator that augments colony forming cell (CFU-GM) formation in the presence of CSFs. In this paper we purified and sequenced the stromal cell-derived hematopoietic synergistic factors (HSF) secreted from both murine and human cell lines stimulated with SK&F 107647. Murine HSF is an N-terminal 4-aa truncated form of the CXC chemokine, KC, while human HSF was identified as an N-terminal 4-aa truncated form of the CXC chemokine, GROβ. In comparison to their full-length forms, truncated KC and truncated GROβ were 10 million times more potent as synergistic growth stimulants for CFU-GM. Enhanced potency of these novel truncated chemokines relative to their full-length forms was also demonstrated in respiratory burst assays, CD11b Ag expression, and intracellular killing of the opportunistic pathogen, Candida albicans. Administration of truncated KC significantly enhanced survival of mice lethally infected with C. albicans. The results reported herein delineate the biological mechanism of action of SK&F 107647, which functions via the induction of unique specific truncated forms of the chemokines KC and GROβ. To our knowledge, this represents the first example where any form of KC or GROβ were purified from marrow stromal cells. Additionally, this is the first demonstration of in vivo efficacy of a CXC chemokine in an animal infectious fungal disease model.

Identification of a17β-estradiol binding protein inCandida albicans andCandida (Torulopsis) glabrata

Abstract The presence of a corticosterone binding system in Candida albicans has been confirmed, and a specific binding system for17β-estradiol has been identified in C. albicans and C. glabrata . The dissociation constants (approximately 6 × 10 −8 M and approximately 2 × 10 −8 M , respectively) are in the range of those encountered in mammalian systems. Competition for binding sites was exhibited only by estrogenic steroids. Unlike the situation in mammalian systems, neither diethylstilbestrol nor tamoxifen was competitive. More detailed studies with C. albicans indicated that viable, intact fungal cells also incorporated17β-estradiol in a specific manner.