Evaluation of Selected Parameters of the Specific Immune Response against Pseudomonas aeruginosa Strains

The immune response to Pseudomonas aeruginosa strains could be influenced by differences in antibiotic resistance and virulence. At the present time, it is unclear which type of immune responses enables uncontrolled invasion of opportunistic pathogens. The conditional pathogenicity of Pseudomonas aeruginosa served as an inspiration to begin a study on this bacterium. The aim of this study was to gain insight into selected parameters describing immune responses with regards to the adaptable agents of this pathogen. For the analysis of the specific immune response, the potential of Pseudomonas aeruginosa to stimulate lymphocytes, including Th17 lymphocytes, dendritic cells and other components of the adaptive immune response, was examined. The highest percentage of CD83+CD1a-HLA-DR++ cells was found after stimulation with lysates of strains isolated from the patients with severe systemic infection. We found statistically significant differences in percentages of HLA-DR+ PBMCs and MFI of HLA-DR between groups of Pseudomonas aeruginosa strains isolated from the patients with different clinical courses of infection. Our results suggest that the clinical course and outcomes of Pseudomonas aeruginosa infections are not associated with impairment of the specific immune response.

Comirnaty-Elicited and Convalescent Sera Recognize Different Spike Epitopes

Many of the approved SARS-CoV-2 vaccines are based on a stabilized variant of the spike protein. This raises the question of whether the immune response against the stabilized spike is identical to the immune response that is elicited by the native spike in the case of a SARS-CoV-2 infection. Using a peptide array-based approach, we analysed the binding of antibodies from Comirnaty-elicited, convalescent, and control sera to the peptides covering the spike protein. A total of 37 linear epitopes were identified. A total of 26 of these epitopes were almost exclusively recognized by the convalescent sera. Mapping these epitopes to the spike structures revealed that most of these 26 epitopes are masked in the pre-fusion structure. In particular, in the conserved central helix, three epitopes that are only exposed in the post-fusion conformation were identified. This indicates a higher spike-specific antibody diversity in convalescent sera. These differences could be relevant for the breadth of spike-specific immune response.

Non-specific immune response of Pacific white shrimp Litopenaeus vannamei by supplementation of sodium alginate of Sargassum collected from Lampung Indonesia

This study aims to determine the effectiveness of supplementation of sodium (Na) alginate Sargassum sp. from Lampung waters to enhance the non-specific immune response and the resistence of Pacific white shrimp (Litopenaeus vannamei) against white spot disease. This study used a completely randomized design with 3 treatments, namely feeding without alginate supplementation (A) or control, dietary Na alginate Sargassum supplementation at a dose of 2.0 (B), and 4.0 g kg−1 feed (C), each with four replications, for 14 days. Hemolymph sampling was performed on days 0, 7 and 14 to observe the parameter of shrimp hematology included total haemocyte count (THC), phagocytocyte activity (PA), phagocytic index (PI), and total plasma protein (TPP). The hepatopancreas histology profile and water quality were observed at the end of treatment. Data were analyzed by Anova at 95% of confidence interval and continued with Duncan test. Result showedthat the supplementation of Na alginat from Sargassum sp. significantly enhance several shrimp immune response namely THC, PA, and TPP. Meanwhile, the histology of the hepatopancreas of both shrimp treatment and control showed not significantly effect on tissue damage. The water quality was still in normal condition during the treatment. The results of this study indicate that the application of Sargassum alginate supplementation at a dose of 2gr/kg of feed is the best treatment to enhance the immune response of Pacific white shrimp.