Effect of Iron on the Bactericidal Proteins from Rabbit Polymorphonuclear Leucocytes

Gladstone, G. P.; Walton, E. F.

doi:10.1038/227849a0

Cited by 37 publications

(20 citation statements)

References 11 publications

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“…Cytotoxicity of murine lymphocytes decreased in the presence of Zn :+ ions [6]. The excess of iron ions suppresses activity of human lymphocytes in vitro [5,11 ], inhibits cell functions in talassemia patients [4], and interferes with leukocyte bactericidal activity [9] and cell-mediated immunity [10]. Iron is also associated with sensitivity to bacterial infections [7].…”

Section: Resultsmentioning

confidence: 99%

Regulation ofin vitro human lymphocyte blast transformation associated with γ-globulin fraction containing a carbohydrate component

Чекнев

1999

Bull Exp Biol Med

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Carbohydrate-enriched components were isolated from human serum y-globulin by chelation of associated transition metals. Similar to the initial y-globulin preparation, these components stimulate in vitro blast transformation of human lymphocytes from healthy donors and inhibit subsequent phytomitogen-induced lymphocyte blast transformation. Key words: y-globulin; carbohydrate component, lymphocyte blast transformationThe ability of y-globulin to maintain a definite level of human lymphocyte blast transformation (LBT) in vitro [3] is known to depend on the expression of Fc Yreceptors in cell membrane [8,12]. The effect of LBT stimulation was shown to correlate with the presence of protein aggregates in the y-globulin preparation [3].The effector functions of y-globulin also depend on the presence of carbohydrate-containing fraction bound to polypeptide chains via non-covalent bonds [1]. Carbohydrate component (CC) is associated with y-globulin molecule via metal ions of alternating valency [1]. These cations interact with specific sites of y-globulin molecule [ 13,14] and stimulate aggregation by forming bridges between protein molecules at a certain metal/IgG ratio. A positive correlation between IgG affinity to transition metal and the effect of protein on spontaneous LBT was found [2].y-Globulin aggregation is accompanied by significant changes in its conformation stability and enhances the release or exposure of components not bound covalently to polypeptide chains. MATERIALS AND METHODSMononuclear cells (MNC) were isolated from peripheral venous blood of 4 healthy men aged 20-46. The cells were separated in Ficoll-Verografin (d = 1.077 g/cm 3) one-step density gradient and MNC were harvested from the interface layer. After repeated washout with medium 199 MNC were resuspended in complete nutrient medium (CNM) consisting of RPMI-1640 (Flow) supplemented with 12% fetal calf serum (Hamaleya Institute of Epidemiology and Microbiology), 2 mM glutamine and 40 ~tg/ml gentamicin (Pharmachim) to a concentration of 2• cells/ml. To initiate spontaneous LBT, 0.1 ml MNC suspension was applied to round-bottom 96-well plates, 0.1 ml CNM and 10 ~tCi/ ml 3H-thymidine were added to each well and the plates were incubated for 18 h at 37~ in humidified atmosphere containing 5% CO 2. LBT was induced by 2 ~tg/ml phytohemagglutinin M (PHA, Serva) or 1 ~tg/ml con-0007 -4888/99/0006-0610522.00 9

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Section: Resultsmentioning

confidence: 99%

Regulation ofin vitro human lymphocyte blast transformation associated with γ-globulin fraction containing a carbohydrate component

Чекнев

1999

Bull Exp Biol Med

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“…Excessive iron may enhance infection by reversing iron limitation and stimulating the growth of bacteria. Alternatively, others have suggested that iron overload may interfere with host defense mechanisms such as cell-mediated immunity (85) and the bacteriocidal activity of leukocytes (64). Thus, it may be difficult to separate the contribution of iron overload in stimulating bacterial growth from its contribution in interfering with host defense mechanisms.…”

Section: Role Of Iron In Host-bacterium Interactions Iron Limitationsmentioning

confidence: 97%

Role of iron in regulation of virulence genes

1993

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The abilities of bacterial pathogens to adapt to the environment within the host are essential to their virulence. Microorganisms have adapted to the iron limitation present in mammalian hosts by evolving diverse mechanisms for the assimilation of iron sufficient for growth. In addition, many bacterial pathogens have used the low concentration of iron present in the host as an important signal to enhance the expression of a wide variety of bacterial toxins and other virulence determinants. The molecular basis of coordinate regulation by iron has been most thoroughly studied in Escherichia coli. In this organism, coordinate regulation of gene expression by iron depends on the regulatory gene, fur. Regulation of gene expression by iron in a number of pathogenic organisms is coordinated by proteins homologous to the Fur protein of E. coli. Additional regulatory proteins may be superimposed on the Fur repressor to provide the fine-tuning necessary for the precise regulation of individual virulence genes in response to iron and other environmental signals. Studies of the mechanisms of regulation of iron acquisition systems and virulence determinants by iron should lead to a better understanding of the adaptive response of bacteria to the low-iron environment of the host and its importance in virulence.

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“…The systemic virulence of E. coli (Bullen et al, 1968) and Staph. aureus (Gladstone and Walton, 1970) is also increased by iron, but we found little or no enhancement of the local lesions. However, only three strains of E. coli were tested.…”

Section: Discussionmentioning

confidence: 59%