Research Article Specific Binding Peptides from Rv3632: A Strategy for Blocking Mycobacterium tuberculosis Entry to Target Cells? Christian David Sánchez-Barinas, 1,2 Marisol Ocampo , 1,2 Luisa Tabares, 1,2 Maritza Bermúdez, 1,2 Manuel Alfonso Patarroyo , 1,2 and Manuel Elkin Patarroyo 1,3 1 Fundaci´ on Instituto de Inmunolog´ ıa de Colombia (FIDIC), Carrera 50 No. 26–20, 111321 Bogot´ a, Colombia 2 Universidad del Rosario, Carrera 24 No. 63C-69, 111321 Bogot´ a, Colombia 3 Universidad Nacional de Colombia, Carrera 45 No. 26-85, 11001 Bogot´ a, Colombia Correspondence should be addressed to Marisol Ocampo; marisol.ocampo@urosario.edu.co Received 13 November 2018; Revised 13 February 2019; Accepted 3 March 2019; Published 14 April 2019 Academic Editor: Rita Casadio Copyright © 2019 Christian David S´ anchez-Barinas et al. Tis is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Tuberculosis is an infectious disease caused by Mycobacterium tuberculosis (Mtb, i.e., the aetiological agent); the WHO has established this disease as high priority due to its ensuing mortality. Mtb uses a range of mechanisms for preventing its elimination by an infected host; new, viable alternatives for blocking the host-pathogen interaction are thus sought constantly. Tis article updates our laboratory’s systematic search for antigens using bioinformatics tools to clarify the Mtb H37Rv Rv3632 protein’s topology and location. Tis article reports a C-terminal region consisting of peptides 39255 and 39256 ( 81 Tr-Arg 114 ) having high specifc binding regarding two infection-related cell lines (A549 and U937); they inhibited mycobacterial entry to U937 cells in a concentration-dependent manner. Rv3632 forms part of the mycobacterial cell envelope, formed by six linear synthetic peptides. Circular dichroism enabled determining the protein’s secondary structure. It was also found that peptide 39254 ( 61 Gly-Tr 83 ) was a HABP for alveolar epithelial cells and inhibited mycobacteria entry to these cells regardless of concentration. Sera from active or latent tuberculosis patients did not recognise HABPs 39254 and 39256. Tese sequences represent a promising approach aiming at their ongoing modifcation and for including them when designing a multi-epitope, anti-tuberculosis vaccine. 1. Introduction Tuberculosis has had a high incidence regarding the world’s population; it afected more than 10 million people in 2017 and was the second cause of death by an infectious agent [1]. Te appearance of new strains reported as having multi- drug resistance to antibiotics has hampered efective medical treatment [2]. Te Mycobacterium bovis Bacillus Calmette-Gu´ erin (BCG) vaccine is currently endorsed by the WHO as it grants partial protection against Mycobacterium tuberculosis (Mtb), the main cause of tuberculosis [1]. Tis vaccine is only applied as a single dose to neonates to protect them against meningeal and miliary tuberculosis; however, it does not prevent infection in adults or the development of pulmonary tuberculosis [3, 4]. Several vaccination strategies have been advanced and 12 vaccine candidates are currently being tested in clinical phases (only three in phase 3) [5, 6]; these have been unconvincing so far and have proved uncertain when a long-term protective immune response has been assessed. Tey have not surpassed the current vaccine’s performance. A logical and rational alternative has been described by our institute (FIDIC) in its search for candidate antigens for an efective anti-tuberculosis vaccine. Such search has been based on identifying pathogen cell surface protein- derived peptides which are able to specifcally bind infection target cells (i.e., the so-called high activity binding peptides, HABPs); these peptides are then tested to evaluate their ability to inhibit Mtb H37Rv entry in vitro. Tis methodology has led to peptides being proposed for a synthetic anti-tuberculosis vaccine derived from the 34 pertinent proteins analysed to date [7–12]. Te sequences involved in pathogen-host interaction represent candidates Hindawi BioMed Research International Volume 2019, Article ID 8680935, 13 pages https://doi.org/10.1155/2019/8680935