Synthetic peptides coupled to the lipotripeptide P3CSS induce in vivo B and Thelper cell responses to HIV-1 reverse transcriptase

Theranostic efficiency of biosurfactants against COVID-19 and similar viruses - A review

The world has witnessed an extreme vulnerability of a pandemic during 2020; originated from China. The coronavirus disease 2019 (COVID-19) is infecting and beginning deaths in thousands to millions, creating of the global economic crisis. Biosurfactants (BSs) can carry the prevention, control and management of pandemic out through diverse approaches, such as pharmaceutical, therapeutic, hygienic and environmental. The microbiotas having virulent intrinsic properties towards starting as easily as spreading of diseases (huge morbidity and mortality) could be inhibited via BSs. Such elements could be recognised for their antimicrobial activity, capability to interact with the immune system via micelles formation and in nanoparticulate synthesis. However, they can be used for developing novel and more effective therapeutics, pharmaceuticals, non-toxic formulations, vaccines, and effective cleaning agents. Such approaches can be utilized for product development and implemented for managing and combating the pandemic conditions. This review emphasized on the potentiality of BSs as key components with several ways for protecting against unknown and known pathogens, including COVID-19.

Biosurfactants in the sustainable eradication of SARS COV-2 from the environmental surfaces

The COVID-19 outbreak has brought the world, at least, to one consensus that cleanliness is unavoidable under all circumstances. Hands are the main body part to interact with the environment and thus are prone to receive, initiate and propagate the chain of infection. Hand hygiene has, therefore, been most emphasized by experts to interrupt the spread of infection. Various harsh chemicals like synthetic surfactants and alcoholic preparations have been in practice to eradicate and disinfect the germs. This choice may be unsafe and cause a subsequent chain of adversities. Thereby, biosurfactants have been proposed as sustainable, non-toxic and safe surface cleaners cum disinfectants under a wide range of physiological and environmental conditions. The amphiphilic micellar behavior of biosurfactants makes them promising candidates as hygienic surface cleaners and therapeutic carriers. We overview the possibilities of using biosurfactants in different ways against microbial pathogens, in general, and the SARS COV-2, in specific.

Biosurfactants: A Covid-19 Perspective

The recent outbreak in severe acute respiratory syndrome - coronavirus-2 (SARS-CoV-2) has demonstrated the complete inability of nations across the world to cope with the pressures of a global pandemic, especially one in which the only current feasible treatments are those which deal with the symptoms alone and not the viral cause. As the death toll rises, scientists begin to fall toward new avenues of research, with novelty showing itself to be an incredible and so far, underrated resource. In this case, the use of biosurfactants in dealing with this pandemic justifies extensive study with their potential applications being in the prevention of viral spread; dealing with the symptoms that develop after the incubation period; directly targeting viral infected cells and preventing the spread of the virus throughout the host, all in addition to also acting as potential drug delivery systems and cleaning agents. This extensive avenue of biosurfactants owes to the simplicity in their amphiphilic structure which permits them to interact directly with the lipid membrane of the coronavirus, in a way which wouldn't be of significant threat to the host. Although it could possibly interact and affect the virus, it could also affect human internal organs/cells by interacting with lipid membrane, if (biosurfactant is) ingested, and it still needs further studies in human models. The structure of the coronavirus, in this case SARS-CoV-2, is detrimentally dependent on the integrity of its lipid membrane which encloses its vital proteins and RNA. Biosurfactants possess the innate ability to threaten this membrane, a result of their own hydrophobic domains across their amphiphilic structure. With biosurfactants additionally being both natural and sustainable, while also possessing a remarkably low cytotoxicity, it is of no doubt that they are going to be of increasing significance in dealing with the current pandemic.

Protection of farm goats by combinations of recombinant peptides and formalin inactivated spores from a lethal Bacillus anthracis challenge under field conditions

Background

Bacillus (B.) anthracis, the causal agent of anthrax, is effectively controlled by the Sterne live spore vaccine (34F2) in animals. However, live spore vaccines are not suitable for simultaneous vaccination and antibiotic treatment of animals being at risk of infection in an outbreak situation. Non-living vaccines could close this gap.

Results

In this study a combination of recombinant protective antigen and recombinant Bacillus collagen-like antigen (rBclA) with or without formalin inactivated spores (FIS), targeted at raising an immune response against both the toxins and the spore of B. anthracis, was tested for immunogenicity and protectiveness in goats. Two groups of goats received from local farmers of the Kars region of Turkey were immunized thrice in three weeks intervals and challenged together with non-vaccinated controls with virulent B. anthracis, four weeks after last immunization. In spite of low or none measurable toxin neutralizing antibodies and a surprisingly low immune response to the rBclA, 80% of the goats receiving the complete vaccine were protected against a lethal challenge. Moreover, the course of antibody responses indicates that a two-step vaccination schedule could be sufficient for protection.

Conclusion

The combination of recombinant protein antigens and FIS induces a protective immune response in goats. The non-living nature of this vaccine would allow for a concomitant antibiotic treatment and vaccination procedure. Further studies should clarify how this vaccine candidate performs in a post infection scenario controlled by antibiotics.

Electronic supplementary material

The online version of this article (doi:10.1186/s12917-017-1140-2) contains supplementary material, which is available to authorized users.

Self-adjuvanting C18 lipid vinil sulfone-PP2A vaccine: study of the induced immunomodulation against Trichuris muris infection

Despite the importance of the adjuvant in the immunization process, very few adjuvants merge with the antigens in vaccines. A synthetic self-adjuvant oleic-vinyl sulfone (OVS) linked to the catalytic region of recombinant serine/threonine phosphatase 2A from the nematode Angiostrongylus costaricensis (rPP2A) was used for intranasal immunization in mice previously infected with Trichuris muris. The animal intranasal immunization with rPP2A-OVS showed a reduction of 99.01% in the number of the nematode eggs and 97.90% in adult. The immunohistochemical analysis of the intestinal sections showed that in immunized animals with lipopeptide the mucus was significantly higher than in the other experimental groups. Also, these animals presented significantly different chemokine, CCL20 and CCL11, levels. However, although the number and size of Tuft cells did not vary between groups, the intensity of fluorescence per cell was significant in the group immunized with the rPP2A-OVS. The results of the present study suggest that mice immunized with the lipopeptide are capable of activating a combined Th17/Th9 response. This strategy of immunization may be of great applicability not only in immunotherapy and immunoprophylaxis to control diseases caused by nematodes but also in pathologies necessitating action at the level of the Th9 response in the intestinal mucosa.

Effect of Glycoamphiphiles on the Solubilization and Dendritic Cell Uptake of a Lipopeptide: A Preliminary Study

The selective delivery of antigens to professional antigen-presenting cells represents a promising approach to improve vaccine efficacy. Addition of a glycoamphiphile to a lipopeptide, whose interest for vaccination is now well-established, greatly favors its solubilization in aqueous solutions through the formation of mixed vesicles. Flow cytometry experiments indicate that this formulation does not diminish the uptake of the lipopeptide by the dendritic cells (DCs). These preliminary results suggest a possible straightforward, noncovalent targeting of cocktail-lipopeptide vaccines to the DCs via carbohydrate receptor-mediated endocytosis.

Immunization with Th-CTL fusion peptide and cytosine-phosphate-guanine DNA in transgenic HLA-A2 mice induces recognition of HIV-infected T cells and clears vaccinia virus challenge

We evaluated immunogenicity of a novel Th-CTL fusion peptide composed of the pan DR Th epitope and a CTL epitope derived from HIV-pol in two transgenic HLA-A*0201/K(b) mouse models. The immunogenicity of peptides of this structure is highly dependent on coadministered cytosine-phosphate-guanine DNA. Initial evaluations of peptide-specific immunity are based on results of chromium release assay, intracellular cytokine, and tetramer staining. Significant cytotoxic T cell responses are found upon a single immunization with as low as 0.1 nmol both peptide and cytosine-phosphate-guanine DNA. Splenocytes from immunized mice recognize naturally processed HIV-pol expressed from vaccinia virus (pol-VV). Translation of immunologic criteria into more relevant assays was pursued using systemic challenge of immunized mice with pol-VV. Only mice receiving both peptide and DNA together successfully cleared upward of 6 logs of virus from ovaries, compared with controls. Challenge with pol-VV by intranasal route of intranasal immunized mice showed a significant reduction in the levels of VV in lung compared with naive mice. A convincing demonstration of the relevance of these vaccines is the robust lysis of HIV-infected Jurkat T cells (JA2/R7/Hyg) by immune splenocytes from peptide- and DNA-immunized mice. This surprisingly effective immunization merits consideration for clinical evaluation, because it succeeded in causing immune recognition and lysis of cells infected with its target virus and reduction in titer of highly pathogenic VV.

Lipopeptide vaccines--yesterday, today, and tomorrow

Peptide-based vaccines offer several potential advantages over the conventional whole proteins (or whole gene, in the case of genetic immunisation) in terms of purity and a high specificity in eliciting immune responses. However, concerns about toxic adjuvants, which are critical for immunogenicity of synthetic peptides, still remain. Lipopeptides, a form of peptide vaccine, discovered more then a decade ago, are currently under intensive investigation because they can generate comprehensive immune responses, without the use of adjuvants. In this review, we address the past of lipopeptide vaccines, highlight the progress made toward their optimisation, and stress future challenges and issues related to their synthesis, formulation, and delivery. In particular, the recent development of mucosal application of lipopeptide vaccines may present an ideal strategy against many pathogens that infect mucosal surfaces.

Lipopeptide stimulation of MHC class I-restricted memory cytotoxic T lymphocytes from equine infectious anemia virus-infected horses

The immunogenicity of equine infectious anemia virus (EIAV) Gag and Env equine leukocyte alloantigen (ELA)-A5.1, -A9, and -A1 restricted cytotoxic T lymphocyte (CTL) epitopes synthesized on multiple antigenic peptide (MAP) system coupled to tripalmitoyl-S-glycerylcysteine (P3C) was evaluated in vitro. P3C-MAP-peptide-stimulated peripheral blood mononuclear cells (PBMCs) from horses, chronically infected with EIAV, had memory CTL (CTLm) similar to that of PBMCs stimulated with either the minimal CTL epitopes, longer peptides containing the CTL epitopes, or EIAV. The stimulated CTL lysed EIAV-infected target cells and the percent specific lysis was dependent on the dose of P3C-MAP-peptide used to stimulate PBMCs in vitro and was peptide specific and ELA-A restricted. The results suggest that these P3C-MAP-peptides can be used as immunogens to stimulate primary immune responses in vivo.

Single-chain lipopeptide vaccines for the induction of virus-specific cytotoxic T cell responses in randomly selected populations

Effective vaccine development is now taking advantage of the rapidly accumulating information concerning the molecular basis of a protective immune response. Analysts and medicinal chemists have joined forces with immunologists and taken up the clear challenge of identifying immunologically active structural elements and synthesizing them in pure, reproducible forms. Current literature reveals the growing interest for extremely reductionist approaches aiming at producing totally synthetic vaccines that would be fully defined at the molecular level and particularly safe. The sequential information contained in these formulations tends to be minimized to those epitopes which elicit neutralizing antibodies, or cell-mediated responses. In the following review, we describe some of our results in developing fully synthetic, clinically acceptable lipopeptide vaccines for inducing cytotoxic T lymphocytes (CTL) responses in randomly selected populations.

Generation of antibodies directed against the low-immunogenic peptide-toxins microcystin-LR/RR and nodularin

The preparation of antibodies against the liver toxin microcystin, as described here, is of major importance for its detection and purification in food and water, and for a therapeutic approach to neutralize the toxin by passive immunization. Microcystin-LR (MLR) and microcystin-RR (MRR) were purified from cyanobacterial cell materials by extraction, Sephadex LH-20-, ODS silica gel-, ionic exchange and RP-HPLC-chromatography. In order to reduce the toxicity for parenteral administration, microcystins were coupled by the carbodiimide method to poly-L-lysine (PLL(50.000)). Mice and rabbits were immunized with the conjugates in the presence of two lipopeptide immunoadjuvants (P(3)CSK(4) and P(3)CS-T(h)). High MLR-specific antibody levels were observed after parenteral coadministration of antigen and lipopeptides, whereas no anti-MLR antibodies were obtained with free microcystin or the microcystin-PLL(50.000)-conjugate in the absence of lipopeptide. In oral immunization, coadministration of antigen and adjuvants resulted in an accelerated development of anti MLR-specific antibodies and high antibody levels. Using the antisera, we could detect different microcystins and nodularin down to a concentration range of 10-50 ng/ml by a competitive inhibition ELISA; detection of microcystins in crude cell preparations was also possible. Furthermore, microcystins from different sources could be detected and discriminated from cyclic cyanopeptolines.

Cytotoxic T-cell responses to HIV-1 reverse transcriptase, integrase and protease

OBJECTIVES

To determine immunodominant regions and new epitopes for cytotoxic T cells (CTL) directed against the HIV-1 pol products reverse transcriptase (RT), integrase and protease in a large cohort of patients at different stages of disease.

DESIGN AND METHODS

Cross-sectional analysis of 98 patients from the French IMMUNOCO cohort (CD4 counts: 125-1050 x 10(6) cells/l), monitored for CTL recognition of HIV-1 pol products using recombinant vaccinia virus constructs and synthetic peptides.

RESULTS

Memory CTL responses against HIV-1 pol products were detected in 78% of all patients whatever the stage of disease. RT was more immunogenic (81%, 30 out of 37 patients) than integrase and protease (51% and 24%, respectively). CTL recognition of RT was more frequent against Pol amino acids 310-460 (61%, 11 out of 18 patients) than against the other three portions (Pol 168-310, Pol 450-600, Pol 590-728) in patients with CD4 counts > 400 x 10(6)/l, whereas in patients at advanced stages no prominent differences were observed. Two new clusters of antigenic regions were found in the NH2 segment: three epitopes between amino-acids Pol 200 and 217 and four epitopes between amino-acids Pol 346 and 387, using five different HLA-restricting elements. A new cluster of three conserved epitopes was found in the COOH segment of RT.

CONCLUSIONS

This study shows that memory CTL responses against HIV-1 RT, integrase and protease are detectable in most patients at different stages of disease. The capacity of CTL to recognize simultaneously clusters of epitopes may become important for the immune control to reinforce antiretroviral drug efficiency.

Bacterial cell wall components as immunomodulators--I. Lipopeptides as adjuvants for parenteral and oral immunization

We investigated the immunostimulatory properties of synthetically prepared lipopeptides derived from the cell wall of Gram negative bacteria. These compounds constitute potent macrophage activators and polyclonal B-lymphocyte stimulators. They are also immunoadjuvants in parenteral or oral immunization. By coupling the lipopeptides to haptens or low molecular weight antigens which are not immunogenic per se, highly immunogenic conjugates can be prepared. Lipopeptide antigen conjugates as synthetic vaccines give protection by enhancing the antibody-mediated immune response, and they stimulate the cellular immune response in vivo by priming of cytotoxic T-cells.

Drug specific antibodies: T-cell epitope-lipopeptide conjugates are potent adjuvants for small antigens in vivo and in vitro

To generate conventional or monoclonal antibodies for the serological detection of drugs, antibiotics, toxins and other low molecular mass substances, a suitable and effective adjuvant is needed. Lipopeptides derived from a major component of the bacterial cell wall constitute potent nontoxic and nonpyrogenic immunoadjuvants when mixed with conventional antigens. Here we demonstrate that the synthetic lipopeptide N-palmitoyl-S-[2,3-bis(palmitoyloxy)-(2R,S)-propyl]-(R)-cysteinyl- serine (P3CS) coupled to a Th-cell epitope (P3CS-Th) can efficiently enhance the specific immune response against low molecular weight compounds in different species. In the presence of the synthetic lipopeptide P3CS-Th, the peptides which are per se non-immunogenic stimulated a specific humoral immune response in mice after intraperitoneal application. Mixtures containing adjuvants without the Th sequence showed no significant antibody induction. A marked enhancement of the humoral immune response was obtained with the low molecular mass antigens Iturin AL, Herbicolin A and Microcystin (MLR) coupled to poly-l-lysin (MLR-PLL), in rabbits and in chickens. Lipopeptide-Th cell epitope conjugates also constituted adjuvants for the in vitro immunization of either human mononuclear cells or mouse B-cells with MLR-PLL; after fusion of the immunized cultures with the heteromyeloma cell lines CB-F7 or the mouse myeloma cell line SP 2/0, respectively, we observed a significantly increased yield of antibody secreting hybridomas.