Toll-like receptor 1 variations influence susceptibility and immune response to Mycobacterium tuberculosis

Background: Tuberculosis (TB), a disease caused by Mycobacterium tuberculosis (MTB) infection, is still a global public health problem. TB susceptibility varies greatly in infected individuals, and mycobacterial recognition by the innate immune system likely affects disease course and outcome. This research describes a single nucleotide polymorphism in the Toll-like receptor (TLR) 1 gene that functionally alters the innate immune response to MTB and is associated with TB susceptibility in India. Methods: 206 TB patients and 239 healthy controls from Hyderabad, India were analyzed for SNPs in the TLR1 and TLR2 genes, which were subsequently correlated to TB susceptibility. To test individual responses to MTB lysates, we stimulated PBMCs from genotyped healthy German individuals, as well as HEK cells transfected with TLR1/2 variants. TNF production and NF-kappa B activation were assessed respectively. Results: Cohort analysis associated the TLR1-248N SNP (RS4833095) with TB protection. TLR1-248N expressing PBMCs from healthy controls exhibited an increased TNF response to MTB lysates. In addition to this, functional studies using HEK cell lines transfected with TLR1-248N and stimulated with MTB showed an increased NF-kappa B activation. Conclusion: SNP TLR1-248N is associated with TB protection in an Indian population and exhibits an increased immune response to MTB lysate in vitro. (C) 2015 Elsevier Ltd. All rights reserved.