Activity of matrix metalloproteinase 2 and 9 isoforms in sputum samples from individuals infected with M. tuberculosis.

M. tuberculosis stimulates matrix metalloproteinases secretion in the host; however, the patterns of matrix metalloproteinase 9 (MMP-9) and 2 (MMP-2) isoforms are unknown. Therefore, the aim of this study was to evaluate the activities of these isoforms in sputum samples of patients with varying degrees of mycobacterial load. Sputum samples were recovered from individuals with positive and negative diagnosis of tuberculosis. Bacillary load was determined by bacilloscopy, and presence and activity of MMP-2 and MMP-9 isoforms determined by gelatin zymography. Of the recovered samples; 39 were from individuals without tuberculosis and 48 with tuberculosis; 12 had low bacillary and 36 high bacillary load. Participation of MMP-2 isoforms were not observed, but in MMP-9, there was a decrease in the latent, associated with lipocalin and homodimeric isoforms. In contrast, there was a rise in the active isoform, all with statistical significance. In conclusion our results show that MMP-2 isoforms do not seems to be directly involved with tuberculosis evolution of infection. However, variations in MMP-9 isoforms were observed, which coincided with the progression of tuberculosis infection. These results raise questions regarding how MMP-9 isoforms might influence the formation and progression of granuloma, and their use as markers of progression of tuberculosis infection.

Expression, purification, and evaluation of diagnostic potential and immunogenicity of a recombinant NS3 protein from all serotypes of dengue virus.

Dengue is one of the major public health concerns in the world. Since all the four serotypes are actively circulating in Mexico, there is a need to develop an efficient diagnosis system to improve case management of the patients. There exist few studies evaluating the use of the NS3 protein as a protective antigen against dengue virus (DENV). In this paper we show the expression of a recombinant NS3 protein from all serotypes of dengue virus (GST-DVNS3-1-4) and report a reliable "in-house detection system" for the diagnosis of dengue infection which was field-tested in a small village (Tezonapa) in the state of Veracruz, Mexico. The fusion proteins were immunogenic, inducing antibodies to be able to recognize to antigens up to a 1 : 3200 dilution. The purified proteins were used to develop an in-house detection system (ELISA) and were further tested with a panel of 239 serum samples. The in-house results were in excellent agreement with the commercial kits with κ = 0.934 ± 0.064 (95% CI = 0.808-1.061), and κ = 0.872 ± 0.048 (95% CI = 0.779-0.965) for IgM and IgG, respectively. The agreement between the NS1 antigen detection versus the rNS3 ELISA, κ = 0.837 ± 0.066 (95% CI = 0.708-0.966), was very good. Thus, these results demonstrate that recombinant NS3 proteins have potential in early diagnosis of dengue infections.

Characterization of an influenza A virus in Mexican swine that is related to the A/H1N1/2009 pandemic clade.

In the spring of 2009, swine-origin influenza H1N1pdm09 viruses caused the first influenza pandemic of this century. We characterized the influenza viruses that circulated early during the outbreak in Mexico, including one newly sequenced swine H1N1pdm09 virus and three newly sequenced human H1N1pdm09 viruses that circulated in the outbreak of respiratory disease in La Gloria, Veracruz. Phylogenetic analysis revealed that the swine isolate (A/swine/Mexico/4/2009) collected in April 2009 is positioned in a branch that is basal to the rest of the H1N1pdm09 clade in two (NP and PA) of the eight single-gene trees. In addition, the concatenated HA-NA and the complete whole-genome trees also showed a basal position for A/swine/Mexico/4/2009. Furthermore, this swine virus was found to share molecular traits with non-H1N1pdm09 H1N1 viral lineages. These results suggest that this isolate could potentially be the first one detected from a sister lineage closely related to the H1N1pdm09 viruses.