Figure 1.
Schematic representation of the TLR-1, -2 and -6 genes, proteins and selected sequence variants.
(A) Schematic representation of human chromosome 4 showing location of TLR-1, -2 and -6 genes. (B) Schematic representation of the five selected variants in TLR proteins. TLR1 G1805T is in the TM domain; TLR2 T597, T1350 and TLR6 C745T are in extracellular domains between the LRRs. TLR2 G2258A is in the intracellular TIR domain. LRR: Leucine-rich repeats; LRR TYP: LRR Typical Subfamily; LRR CT: C-terminal LRR Domain; TIR: Toll-Interleukin-1 Receptor Domain; TM: Trans-membrane Region; LCR: Low Complexity Region. Different domains are detected by SMART.
Figure 2.
Flow chart showing the study selection procedure.
Ovid: Ovid MEDLINE; ISI WoK: ISI Web of Knowledge; CNKI: China National Knowledge Infrastructure.
Table 1.
Characteristics of the 16 studies included in the meta-analysis.
Table 2.
Genotype and allele distribution of TLR -1, -2, and -6 polymorphisms in TB and controls.
Figure 3.
Forrest plot of the association between TLR1 C1805T and TB risk in allele comparison (T vs. C).
Subgroup analysis was performed by ethnicity. OR: odds ratio; CI: confidence interval; df: degrees of freedom.
Table 3.
Summary of different comparative meta-analysis results.
Figure 4.
Forrest plot of the association between TLR2 G2258A and TB risk in allele comparison (A vs.
G). Subgroup analysis was performed by ethnicity. OR: odds ratio; CI: confidence interval; df: degrees of freedom.
Figure 5.
Forrest plot of the association between TLR6 745T and TB risk in allele comparison (T vs. C).
OR: odds ratio; CI: confidence interval; df: degrees of freedom.
Figure 6.
Signaling pathway of TLR-1, -2 and -6.
TLR2 ligands induce conformational changes of TLRs that allow interactions of TLR2 and TLR-1, -6. This heterodimer could recruit adaptor proteins MyD88 and TIRAP. MyD88 can activate NF-κB and AP-1 through IRAKs, TRAF6, TAK1, and IKK complex, resulting in induction of pro-inflammatory genes in macrophages and cDCs. TLR: Toll-Like Receptor; TIR: Toll-IL1-Receptor Domain; TIRAP: TIR domain containing adaptor protein; MyD88: Myeloid Differentiation Primary Response Gene 88; IRAK: Interleukin-1 Receptor associated kinase 1; TRAF: TNF Receptor Associated Factor; TAK: TGF-β-Actiated Kinase; IκB: Inhibitor of NF-κB; IKK: IκB kinase.