Early pneumococcal clearance in mice induced by systemic immunization with recombinant BCG PspA-PdT prime and protein boost correlates with cellular and humoral immune response in bronchoalveolar fluids (BALF)

© 2019 The Author(s) An effective immunological response in the lungs during a pneumococcal infection is a key factor to the bacteria clearance and prevention of sepsis. In order to develop broad-range pneumococcal vaccines several pneumococcal proteins and strong adjuvants have been investigated. Previously, we constructed a recombinant BCG (rBCG) strain expressing a fragment of PspA (Pneumococcal surface protein A) fused to PdT (detoxified form of pneumolysin). Immunization of mice with a priming dose of rBCG PspA-PdT followed by a booster dose of rPspA-PdT fused protein induced a high antibody response in the serum and protected mice against lethal challenge. Here, we investigated the humoral and cellular immune response in the Bronchoalveolar lavage fluid (BALF). Immunization of mice with rBCG PspA-PdT / rPspA-PdT induced rapid clearance of bacteria after challenge, an early control of the cellular influx and reduced inflammatory cytokine levels in the BALF. In addition, rBCG PspA-PdT / rPspA-PdT induced higher lymphocyte recruitment to the lungs at 48 h, showing an increased percentage of CD4+ T cells. Furthermore, BALF samples from mice immunized with rBCG PspA-PdT / PspA-PdT showed high binding of IgG2c and enhanced complement deposition on the pneumococcal surface; antibody binding was specific to PspA as no binding was observed to a PspA-knockout strain. Taken together, our results show that the immunization with rBCG PspA-PdT / rPspA-PdT induces humoral and cellular immune responses in the lungs, promotes an early clearance of pneumococci and protects against the systemic dissemination of pneumococci

Designing antibiotic cycling strategies by determining and understanding local adaptive landscapes

The evolution of antibiotic resistance among bacteria threatens our continued ability to treat infectious diseases. The need for sustainable strategies to cure bacterial infections has never been greater. So far, all attempts to restore susceptibility after resistance has arisen have been unsuccessful, including restrictions on prescribing [1] and antibiotic cycling [2,3]. Part of the problem may be that those efforts have implemented different classes of unrelated antibiotics, and relied on removal of resistance by random loss of resistance genes from bacterial populations (drift). Here, we show that alternating structurally similar antibiotics can restore susceptibility to antibiotics after resistance has evolved. We found that the resistance phenotypes conferred by variant alleles of the resistance gene encoding the TEM {\beta}-lactamase (blaTEM) varied greatly among 15 different {\beta}-lactam antibiotics. We captured those differences by characterizing complete adaptive landscapes for the resistance alleles blaTEM-50 and blaTEM-85, each of which differs from its ancestor blaTEM-1 by four mutations. We identified pathways through those landscapes where selection for increased resistance moved in a repeating cycle among a limited set of alleles as antibiotics were alternated. Our results showed that susceptibility to antibiotics can be sustainably renewed by cycling structurally similar antibiotics. We anticipate that these results may provide a conceptual framework for managing antibiotic resistance. This approach may also guide sustainable cycling of the drugs used to treat malaria and HIV

Diagnóstico molecular para o nematóide Rotylenchulus reniformis.

bitstream/CPAC-2010/30255/1/bolpd-214.pd

Identificação molecular de Heterodera glycines, o nematóide de cistos da soja.

bitstream/CPAC-2010/30252/1/bolpd-211.pd

Identificação molecular do nematóide Pratylenchus brachyurus.

bitstream/CPAC-2010/30251/1/bolpd-210.pd