Effects of anti‐human T lymphocyte immune globulins in patients: new or old

Multiple studies demonstrated that anti‐human T lymphocyte immune globulins (ATG) can decrease the incidence of acute and chronic graft rejection in cell or organ transplants. However, further in‐depth study indicates that different subgroups may benefit from either different regimes or alteration of them. Studies among renal transplant patients indicate that low immunological risk patients may not gain the same amount of benefit and thus tilt the risk versus benefit consideration. This may hold true for low immunological risk patients receiving other organ transplants and would be worth further investigation. The recovery time of T cells and natural killer (NK) cells also bears consideration and the impact that it has on the severity and incidence of opportunistic infections closely correlated with the dosage of ATG. The use of lower doses of ATG in combination with other induction medications may offer a solution. The finding that ATG may lose efficacy in cases of multiple transplants or re‐transplants in the case of heart transplants may hold true for other transplantations. This may lead to reconsideration of which induction therapies would be most beneficial in the clinical setting. These studies on ATG done on different patient groups will naturally not be applicable to all, but the evidence accrued from them as a whole may offer us new and different perspectives on how to approach and potentially solve the clinical question of how to best reduce the mortality associated with chronic host‐versus‐graft disease.     

Human CD8+ T cells transduced with an additional receptor bispecific for both Mycobacterium tuberculosis and HIV‐1 recognize both epitopes

Tuberculosis (TB) and human immunodeficiency virus type 1 (HIV‐1) infection are closely intertwined, with one‐quarter of TB/HIV coinfected deaths among people died of TB. Effector CD8⁺ T cells play a crucial role in the control of Mycobacterium tuberculosis (MTB) and HIV‐1 infection in coinfected patients. Adoptive transfer of a multitude of effector CD8⁺ T cells is an appealing strategy to impose improved anti‐MTB/HIV‐1 activity onto coinfected individuals. Due to extensive existence of heterologous immunity, that is, T cells cross‐reactive with peptides encoded by related or even very dissimilar pathogens, it is reasonable to find a single T cell receptor (TCR) recognizing both MTB and HIV‐1 antigenic peptides. In this study, a single TCR specific for both MTB Ag85B_199‐207 peptide and HIV‐1 Env_120‐128 peptide was screened out from peripheral blood mononuclear cells of a HLA‐A*0201⁺ healthy individual using complementarity determining region 3 spectratype analysis and transferred to primary CD8⁺ T cells using a recombinant retroviral vector. The bispecificity of the TCR gene‐modified CD8⁺ T cells was demonstrated by elevated secretion of interferon‐γ, tumour necrosis factor‐α, granzyme B and specific cytolytic activity after antigen presentation of either Ag85B_199‐207 or Env_120‐128 by autologous dendritic cells. To the best of our knowledge, this study is the first report proposing to produce responses against two dissimilar antigenic peptides of MTB and HIV‐1 simultaneously by transfecting CD8⁺ T cells with a single TCR. Taken together, T cells transduced with the additional bispecific TCR might be a useful strategy in immunotherapy for MTB/HIV‐1 coinfected individuals.     

Characterization and anti-biofilm activity of extracellular polymeric substances produced by the marine biofilm-forming bacterium Pseudoalteromonas ulvae strain TC14

This study investigated soluble (Sol-EPS), loosely bound (LB-EPS), and tightly bound extracellular polymeric substances (TB-EPS) harvested from biofilm and planktonic cultures of the marine bacterium Pseudoalteromonas ulvae TC14. The aim of the characterization (colorimetric methods, FTIR, GC-MS, NMR, HPGPC, and AFM analyses) was to identify new anti-biofilm compounds; activity was assessed using the BioFilm Ring Test®. A step-wise separation of EPS was designed, based on differences in water-solubility and acidity. An acidic fraction was isolated from TB-EPS, which strongly inhibited biofilm formation by marine bacterial strains in a concentration-dependent manner. The main constituents of this fraction were characterized as two glucan-like polysaccharides. An active poly(glutamyl-glutamate) fraction was also recovered from TB-EPS. The distribution of these key EPS components in Sol-EPS, LB-EPS, and TB-EPS was distinct and differed quantitatively in biofilm vs planktonic cultures. The anti-biofilm potential of the fractions emphasizes the putative antifouling role of EPS in the environment.     

Surface metabolites of the brown alga Taonia atomaria have the ability to regulate epibiosis

This study aimed to improve understanding of the strategies developed by the Mediterranean seaweed Taonia atomaria to chemically control bacterial epibiosis. An experimental protocol was optimized to specifically extract algal surface-associated metabolites by a technique involving dipping in organic solvents whilst the integrity of algal cell membranes was assessed by fluorescent microscopy. This methodology was validated using mass spectrometry-based profiles of algal extracts and analysis of their principal components, which led to the selection of methanol as the extraction solvent with a maximum exposure time of 15 s. Six compounds (A–F) were identified in the resulting surface extracts. Two of these surface-associated compounds (B and C) showed selective anti-adhesion properties against reference bacterial strains isolated from artificial surfaces while remaining inactive against epibiotic bacteria of T. atomaria. Such specificity was not observed for commercial antifouling biocides and other molecules identified in the surface or whole-cell extracts of T. atomaria.