Mechanisms of the adjuvant effect of nystatin on in vitro antibody response of mouse spleen cells: indication of nystatin as a B-cell mitogen and as a stimulant for polyclonal antibody synthesis in B cells

Identification of novel pharmacological activities of an antifungal agent, nystatin, to promote dendritic cell maturation

As an unbiased functional screen to identify agents activating dendritic cells (DCs), we recently developed a DC-based biosensor system, in which a stable murine DC line XS106 was engineered to express the yellow fluorescent protein (YFP) gene under the control of the IL-1beta promoter. Here we report that nystatin (NYT), an antifungal drug of the family of polyene macrolide antibiotics, elevated YFP expression by the resulting XS106-pIL1-YFP DC biosensor clone in a dose-dependent fashion. With respect to the underlying mechanisms, NYT activated the NFkappaB p65 and c-Rel subunits in the parental XS106 DC line. Moreover, NYT dose-dependently increased the surface expression of major histocompatibility complex (MHC) class II (MHC II), CD40, CD54, CD80, and CD86 by murine bone marrow-derived DCs and triggered their robust production of IL-1beta, IL-6, IL-12, tumor necrosis factor alpha, and macrophage inflammatory protein-1alpha. Our results document previously unrecognized pharmacological activities of the most commonly used antifungal drug to promote DC maturation.

Immunological activities of multiprenylacetyl derivatives of muramyldipeptides

The immunological properties of six kinds of multiprenylacetic acids and six kinds of multiprenylacetyl muramyldipeptide (MDP) derivatives were examined by using experimental models in mice and guinea-pigs. All the multiprenylacetyl MDP derivatives, particularly TMD-232, showed potent adjuvant activity on the circulating antibody formation against bacterial alpha-amylase in mice, and induction of delayed-type hypersensitivity to monoazobenzenearsonate N-acetyl-L-tyrosine in guinea-pigs. All multiprenylacetic acid preparations tested in this study, however, showed no adjuvant activity in these immune systems. Both TMD-17 and TMD-232 entrapped into multilamellar vesicles showed potent host stimulation activity against Sendai virus infection in mice.

How do the polyene macrolide antibiotics affect the cellular membrane properties?

In the 1970's great strides were made in understanding the mechanism of action of amphotericin B and nystatin: the formation of transmembrane pores was clearly demonstrated in planar lipid monolayers, in multilamellar phospholipid vesicles and in Acholeplasma laidlawii cells and the importance of the presence and of the nature of the membrane sterol was analyzed. For polyene antibiotics with shorter chains, a mechanism of membrane disruption was proposed. However, recently obtained data on unilamellar vesicles have complicated the situation. It has been shown that: membranes in the gel state (which is not common in cells), even if they do not contain sterols may be made permeable by polyene antibiotics, several mechanisms may operate, simultaneously or sequentially, depending on the antibiotic/lipid ratio, the time elapsed after mixing and the mode of addition of the antibiotic, there is a rapid exchange of the antibiotic molecules between the vesicles. Although pore formation is apparently involved in the toxicity of amphotericin B and nystatin, it is not the sole factor which contributes to cell death, since K+ leakage induced by these antibiotics is separate from their lethal action. The peroxidation of membrane lipids, which has been demonstrated for erythrocytes and Candida albicans cells in the presence of amphotericin B, may play a determining role in toxicity concurrently with colloid osmotic effect. On the other hand, it has been shown that the action of polyene antibiotics on cells is not always detrimental: at sub-lethal concentrations these drugs stimulate either the activity of some membrane enzymes or cellular metabolism. In particular, some cells of the immune system are stimulated. Furthermore, polyene antibiotics may act synergistically with other drugs, such as antitumor or antifungal compounds. This may occur either by an increased incorporation of the drug, under the influence of a polyene antibiotic-induced change of membrane potential, for example, or by a direct interaction of both drugs. That fungal membranes contain ergosterol while mammalian cell membranes contain cholesterol, has generally been considered the basis for the selective toxicity of amphotericin B and nystatin for fungi. Actually, in vitro studies have not always borne out this assumption, thereby casting doubt on the use of polyene antibiotics as antifungal agents in mammalian cell culture media.(ABSTRACT TRUNCATED AT 400 WORDS)

Effect of 2-mercaptoethanol and mycostatin on guinea pig lymphocyte transformation: interpretation of results depends on the method of calculation

The stimulating effects of 2-mercaptoethanol (2-ME) reported in murine cell cultures were confirmed for guinea pig lymphocyte transformation (LT). 2-ME was mitogenic for peripheral blood lymphocytes (PBL) and lymph node lymphocytes (LNL) and enhanced PPD-induced LT. The effect on LNL was dependent on the magnitude of the response of non-2-ME treated cultures. The 2-ME effect on PPD-stimulated LNL was reversed when stimulation index (SI) replaced the delta cpm estimate. Mycostatin (MYC) inhibited the blastogenic response of PBL control cultures, whereas its effect on LNL control cultures varied. The interpretation of the effect of MYC on PPD-stimulated cultures was dependent on the use of the delta cpm or SI estimates. The interpretation of LT experiments is therefore highly dependent on whether delta cpm or SI is used for expression of results. Analysis of effects on control and stimulated cultures should precede the addition of 2-ME or MYC to cultures for LT.

A comparison of saponin with other adjuvants for the potentiation of protective immunity by a killed Plasmodium yoelii vaccine in the mouse

The protective immunity conferred by subcutaneous injection of outbred CD-1 mice with a killed Plasmodium yoelii (YM strain) vaccine was strongly potentiated by saponin. By adjusting the dose of antigen, the number of immunizations and the number of living parasites in the challenge infection, conditions were defined where antigen alone was non-protective but 100% protection was obtained by the addition of saponin. Inbred BALB/c, CBA/CA and C57 B1 mice were much less responsive than the CD-1 mice. The following adjuvants were compared with saponin: mineral oil emulsions (Freund's incomplete and complete adjuvants); A1(OH)3(Alhydrogel); bacteria and synthetic bacterial derivatives (Bordetella pertussis, Corynebacterium parvum and muramyl dipeptide); surface active materials (digitonin, vitamin A, Arquad 18, dimethyldioctadecyl ammonium bromide, and the polyene antibiotics, Nystatin and Amphotericin B). None of these adjuvants were as effective as saponin, although FCA, A1(OH)3 and C. parvum augmented immunity considerably. The possible reasons for the efficacy of saponin as an adjuvant for protozoal vaccines are discussed. The P. yoelli/mouse system provides a sensitive and rapid screening assay for comparison of potential adjuvants suitable for use with a malaria vaccine.

Role of T cells in the mitogen-induced proliferation and polyclonal antibody response of murine B cells

The effect of thymus-derived lymphocytes (T cells) on the responsiveness of bone marrow-derived lymphocytes (B cells) to bacterial lipopolysaccharide (LPS) was determined in in vitro experiments. Radiation resistant splenic T cells obtained from euthymic nu/+ mice increased the number of proliferating cells in the cultures of splenic B cells from athymic nu/nu mice even in the nonstimulated state. The radiation resistant T cells augmented significantly the responsiveness of B cells to LPS, as determined by an increase in proliferating cells and polyclonally induced anti-sheep erythrocyte (SRBC) IgM hemolysin plaque-forming cells (PFC). Addition of the T cells to B cell cultures not only augmented the responsiveness of B cells to suboptimal doses of LPS but also enabled B cells to respond to supraoptimal doses of LPS. As is well documented, the radiation resistant T cells were unable to induce the generation of anti-SRBC PFC in B cell cultures, unless the cultures were simultaneously stimulated with SRBC. Colcemid, a specific inhibitor of cell mitosis, blocked almost completely the exponential generation of anti-SRBC PFC in B cell cultures responding to SRBC with the aid of radiation resistant T cells. In contrast, colcemid did not affect the exponential generation of anti-SRBC PFC of a polyclonal nature in B cell cultures responding to LPS, either in the presence or absence of radiation resistant T cells.

Congenitally athymic nude (nu/nu) mice have Thy-1-bearing immunocompetent helper T cells in their peritoneal cavity

Heavily irradiated peritoneal cells (PC) from congenitally athymic nude (nu/nu) mice markedly restored the impaired in vitro antibody response of nu/nu spleen cells to sheep erythrocyte antigens (T-dependent antigen), whereas irradiated spleen or lymph node cells from nu/nu mice had no effect on the response. This activity of the irradiated PC of nu/nu mice was completely abolished by treatment with anti-Thy-1.2 antiserum plus normal guinea pig serum (C') and is, therefore, attributable to a function of matured T cells.

Macrophage cytostasis and T and B cell blastogenic transformation in mice treated with nystatin

Treatment of normal BALB/c mice with nystatin, an amphoteric polyene, activated macrophages to become tumoricidal for MBL-2 lymphoblastic leukemia target cells while augmenting the in vitro blastogenic response of splenic lymphocytes to B and T cell mitogens. These responses were both shown to be highly dose dependent and occurred 6 days following the intraperitoneal injection of nystatin into normal mice. Macrophages from untreated mice did not show similar activity. The significance of these observations and the potential use of nystatin as a pharmacologic agent is discussed.