Análise de polimorfismos do gene humano da MBL e sua associação com infecções por Chlamydia trachomatis

Abstract

Chlamydiaceae are intracellular bacteria that parasitize eukaryotic cells. Chlamydia trachomatis is a strictly human pathogen and is the main bacterial species transmitted by sexual contact. In women they can cause urethritis, cervicitis, pelvic inflammatory disease, ectopic pregnancy and lymphogranuloma venereum. Mannose binding lectin (MBL), a component of the complement system is a key protein of the innate immune system, acting in the first line of defense against pathogens. MBL has the function of opsonin, by binding to carbohydrate rich in mannose, fucose and glucosamine, found on the cell surface of various microorganisms. MBL attached to the cell surface glycoprotein of C. trachomatis are important in host defense, because they inhibit the binding of bacteria to target cells. MBL gene (mbl2) is located onchromosome 10 and has three functional polymorphisms located in exon 1. These mutation points are known as variant B, C and D, and the variant A corresponds to the wild type. The characterization of the genetic profile of MBL in patients with sexually transmitted diseases may be an alternative of great relevance for the assessment of susceptibility to these infections. The objective of this study was to initiate a study for the detection of polymorphisms in this gene to investigate any correlation between MBL and manifestations of C. trachomatis infection. We usedfive positive and six negative endocervical samples for C. trachomatis infection. The DNA purified from these samples was used for the amplification of a fragment of the mbl2 gene. The kit Wizard SV Genomic DNA proved to be the best alternative for the purification of the PCR product to be used for the sequencing of the gene mbl2. All sequenced 11 samples showed no polymorphism in the mutation regions, showing to be allele A, the wild type. Studies with a larger number of positive and negative samples are needed to establish a correlation between the various manifestations of infections caused by each of the 19 different genotypes of C. trachomatis and polymorphisms in the mbl2 gene, as suggested for other pathogens.