Polymorphisms in lymphotoxin alpha and CD14 genes influence TNFα production induced by Gram-positive and Gram-negative bacteria

Abstract

Improved understanding of how host genetic variation affects resistance to microbial pathogens could lead to better treatment and/or prevention of infectious diseases. The lymphotoxin alpha (LTA)+250 and CD14À159 polymorphisms are associated with differences in susceptibility or outcome to several infections. We stimulated peripheral blood mononuclear cells (PBMC) from 22 healthy individuals with purified lipopolysaccharide (LPS), heat-killed Escherichia coli or Streptococcus pneumoniae. TNFaintracellular protein levels were measured by flow cytometry and mRNA was quantitated by RT-PCR. TNFa mRNA levels were higher in LTA+250GG subjects after 4 h incubation with LPS compared with LTA+250AA (T test, P ¼ 0.001). In contrast, after 8 h incubation with S. pneumoniae, there was slightly more TNFa mRNA in cells from LTA+250AA subjects. After 4 h incubation with LPS or E. coli, CD14À159TT subjects had higher TNFa mRNA levels than CD14À159CC (P ¼ 0.05, 0.033, respectively). Neither polymorphism affected the proportion of cells expressing intracellular TNFa protein. This suggests that the polymorphisms affected transcription and that other regulatory mechanisms affect production of TNFa protein. The effect of these two polymorphisms on TNFa mRNA production is stimulus dependent, with opposite effects observed for Gram-positive and Gram-negative stimuli.

Predisposition to abacavir hypersensitivity conferred byHLA-B*5701and a haplotypicHsp70-Homvariant

“…One of these cases (case 16) carried the HLA-B*5701 allele and the Hsp70 region of the 57.1 AH but lacked the region from snRNP to MEGT1, expressing non-57.1 AH alleles at one SNP and two microsatellite loci in this region. The translated sequences of Hsp70.1 and Hsp70.2 were similar in abacavir-hypersensitive individuals (cases [15][16][17] and controls with recombinant 57.1 AHs (cases [19][20][21][22] and were therefore excluded as candidate susceptibility loci.…”

“…The centromeric boundary of the susceptibility region 3Ј of Hsp70.2 was demarcated by the presence of three non-57.1 AH alleles, one in each of the recombinant abacavir-hypersensitive individuals (cases [15][16][17]. In addition, the telomeric end of the hypersensitivity region is flanked by snRNP, as an abacavir-hypersensitive individual (case 16) carried non-57.1 AH alleles between snRNP and MEGT1 (identified by non-57.1 AH alleles at two microsatellites and one SNP loci).…”

“…Intracellular expression of TNF was assessed in cultured peripheral blood mononuclear cells (PBMCs) grown in the presence and absence of abacavir sulfate at 4 g͞ml (Ziagen 300-mg commercial grade tablet dissolved in PBS, pH 7.4) by means of three-color flow cytometry (15). The PBMCs were stained with CD45-ECD, CD14-FITC, or IgG1-FITC (isotype control) antibodies (all obtained from Immunotech, Marseille, France) and analyzed on a Coulter EPICS XL-MCL flow cytometer by using the LISTMODE FCS2 data analysis program (Coulter) (15).…”

The Interleukin-6 G(−174)C Promoter Polymorphism Does Not Determine Plasma Interleukin-6 Concentrations in Experimental Endotoxemia in Humans

“…These findings are in accordance with a study on patients with sepsis (2 ), which also reported no association between IL-6 genotype and systemic IL-6 concentrations in vivo (compare the findings in Table 1). Possibly other polymorphisms (35-37 ) may be overruling the putative effect of the IL-6 G(Ϫ174)C promoter polymorphism on the release of IL-6 into the circulation, such as the recently described polymorphisms in the Toll-like receptor 4 (38,39 ) or in the CD14 gene (40 ).…”

Influence of Cd14 Gene Polymorhism on Clinic Al Course and Outcome of Nosocomial Pneumonia

“…В ранее проведенных исследованиях in vivo и in vitro высказана гипотеза о влиянии полимор-физма гена СD14 на продукцию фактора некроза опухоли-альфа (TNFα), зависящую от характера микрофлоры; в частности, экспозиция данного цитокина должна быть различной в зависимости от преобладания грамположительной или грам-отрицательной микрофлоры [26].…”