Molecular mimicry between Larrea divaricata Cav. plant and a reference strain of Pseudomonas aeruginosa.

Currently, the world health sector faces a big problem due to the increase of bacterial strains resistant to antibiotics. In 2017, the World Health Organization reported a list of resistant bacteria, among which Pseudomonas aeruginosa was present. This opportunistic pathogen is associated to nosocomial infections, and no effective vaccines against this bacterium have been found. Larrea divaricata Cav. (jarilla) is a shrub highly distributed in America and widely used in folk medicine. In our laboratory, cross-reactivity of antibodies obtained from the recognition of jarilla proteins against proteins from gram-negative bacteria has been demonstrated. The objective of this study was to study the cross-reactivity of anti-L. divaricata antibodies with P. aeruginosa extracellular proteins in order to find an innocuous prophylactic therapy against this nosocomial pathogen. We observed that antibodies generated by proteins from jarilla crude extract recognized antigenic determinants present in extracellular proteins of P. aeruginosa. However, further studies are needed to investigate the neutralizing capacity of these antibodies on the specific enzymatic proteins involved in the pathogenicity of this bacterium.

Immunization with Larrea divaricata Cav. proteins elicits opsonic antibodies against Pseudomonas aeruginosa and induces phagocytic activity of murine macrophages.

Pseudomonas aeruginosa is an opportunistic pathogen implicated in nosocomial infections for which no vaccines have been approved. Larrea divaricata Cav. (Jarilla) is a widely spread plant in America and it is used in folk medicine to treat several pathologies. It has also been shown that antibodies elicited against Jarilla proteins of crude extract (JPCE) cross-react with proteins from gram-negative bacteria. In this study we aim to assess the contribution of anti-JPCE antibodies in the opsonophagocytosis of P. aeruginosa by murine macrophages. Levels of reactivity of anti-JPCE IgG and IgA antibodies against cell and membrane proteins suggest that these proteins induce a response that could favor opsonic bacterial recognition, which is important for the elimination of bacteria on mucous membranes, useful in the early stages of infection. Opsonophagocytosis assays also show that these antibodies could favor bacteria intake. These results together with previous observations that indicate that anti-JPCE antibodies are able to neutralize P. aeruginosa enzymes point L. divaricata proteins as candidates for vaccine development.