Lithium salts as a treatment for COVID-19: Pre-clinical outcomes.

INTRODUCTION: Identifying effective drugs for Coronavirus disease 2019 (COVID-19) is urgently needed. An efficient approach is to evaluate whether existing approved drugs have anti-SARS-CoV-2 effects. The antiviral properties of lithium salts have been studied for many years. Their anti-inflammatory and immune-potentiating effects result from the inhibition of glycogen synthase kinase-3. AIMS: To obtain pre-clinical evidence on the safety and therapeutic effects of lithium salts in the treatment of COVID-19. RESULTS: Six different concentrations of lithium, ranging 2-12 mmol/L, were evaluated. Lithium inhibited the replication of SARS-CoV-2 virus in a dose-dependent manner with an IC50 value of 4 mmol/L. Lithium-treated wells showed a significantly higher percentage of monolayer conservation than viral control, particularly at concentrations higher than 6 mmol/L, verified through microscopic observation, the neutral red assay, and the determination of N protein in the supernatants of treated wells. Hamsters treated with lithium showed less intense disease with fewer signs. No lithium-related mortality or overt signs of toxicity were observed during the experiment. A trend of decreasing viral load in nasopharyngeal swabs and lungs was observed in treated hamsters compared to controls. CONCLUSIONS: These results provide pre-clinical evidence of the antiviral and immunotherapeutic effects of lithium against SARS-CoV-2, which supports an advance to clinical trials on COVID-19's patients.

A vaccine against S. pyogenes: design and experimental immune response.

Streptococcus pyogenes causes severe invasive infections: the post-streptococcal sequelae of acute rheumatic fever (RF) and rheumatic heart disease (RHD), acute glomerulonephritis, and uncomplicated pharyngitis and pyoderma. Efforts to produce a vaccine against S. pyogenes began several decades ago, and different models have been proposed. Here, we describe the methodology used in the development of a new vaccine model, consisting of both T and B protective epitopes constructed as synthetic peptides and recombinant proteins. Two adjuvants were tested in an experimental inbred mouse model: a classical Freund's adjuvant and a new adjuvant (AFCo1) that induces mucosal immune responses and is obtained by calcium precipitation of a proteoliposome derived from the outer membrane of Neisseria meningitides B. The StreptInCor vaccine epitope co-administrated with AFCo1 adjuvant induced mucosal (IgA) and systemic (IgG) antibodies as preferential Th1-mediated immune responses. No autoimmune reactions were observed, suggesting that the vaccine epitope is safe.

Antifungal and immunomodulatory activity of a novel cochleate for amphotericin B delivery against Sporothrix schenckii.

INTRODUCTION: Sporotrichosis is an emergent subcutaneous mycoses caused by species of the Sporothrix schenckii complex. Amphotericin B (AmB) remains the main antifungal drug for the treatment of systemic infections, but its use is limited by toxicity reasons. AFCo3 is a novel cochleate containing detoxified LPS, which exhibits drug delivery and immunomodulating properties. Here, AFCo3 was used as the vehicle for AmB to evaluate the immunomodulatory and antifungal efficacy against S. schenckii in vitro and in vivo. METHODS AND RESULTS: The minimum inhibitory concentrations of AFCo3-AmB and AmB were 0.25 and 1µg/mL respectively. The minimum fungicidal concentration was 0.5µg/mL for AFCo3-AmB and 2µg/mL for AmB. AFCo3-AmB was less cytotoxic than AmB for peritoneal macrophages, using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) method and reduced the AmB-induced hemolysis in murine erythrocytes. AFCo3-AmB improved the intracellular killing of phagocytized yeast and it enhanced the in vitro production of IL-1ß, TNF-α and NO in peritoneal macrophages. Moreover, AFCo3-AmB was more effective than AmB in reducing spleen and liver fungal burden after repeated (five days) intraperitoneal administration of 5mg/kg of AmB, in a Balb/c model of systemic infection, associated to a significant induction of Th1/Th17 response. Finally, blood chemistry revealed that AFCo3-AmB did not cause changes suggestive of nephrotoxicity, such as increases in total proteins, albumin, creatinine and blood urea nitrogen that were caused by free AmB. CONCLUSIONS: AFCo3-AmB exhibited a significant immunomodulator action, reduced toxicity and improved antifungal action against S. schenckii, suggesting a potential use as AmB delivery for systemic sporotrichosis treatment.

Nitric oxide participates in the immune response against Neisseria meningitidis serogroup B.

The present report explores the role of nitric oxide into the immune response against Neisseria meningitidis serogroup B. Here we show that NO mediates the alphaTNF increase induced by N. meningitidis derived lipopolysaccharides (LPS), at the same time that participates in the bactericidal activity of resting or gammaIFN activated macrophages and plays a role in the specific DTH and IgG response induced by a commercial anti-meningococcal vaccine. Our findings suggest a positive role for NO at the final effector mechanisms and in the early events driving the immunity against N. meningitidis, suggesting also an insight into its role in endotoxic shock.

Evaluation of the immune response in symptomatic and asymptomatic human giardiasis.

To better understand the common association of Giardia lamblia infection and allergic reactivity, total and specific IgE values were evaluated and different manifestations of symptomatic and asymptomatic infected human hosts were analyzed. The humoral, cellular, and nonspecific immune responses were evaluated in Cuban adults. Increased total serum IgE levels were significantly higher (p < 0.01) in Giardia patients than in negative controls; cure of giardiasis was characterized by a decrease in IgE levels and some patients regained normal IgE values. The skin test was positive in 91% (103/123) of chronic patients and only in 23% (20/123) of negative controls (p < 0.05). A positive test was seen in patients with antecedents of recent giardiasis (< 4 months). Specific IgE was higher in patients than in control sera, and in the former it decreased with sera dilution. During the follow-up period of cured patients, the proportion of IgE decreased and the opposite occurred in noncured patients. The cellular response evaluated by LIF was positive in 92% (11/12) of carriers and significantly higher (p < 0.05) than in symptomatic patients 8% (1/12); the same occurred with IgG and IgA antibody response; titers mainly of IgA were higher in asymptomatic carriers than in patients; all carriers were negative to the skin test. These results indicate the presence of total and specific IgE responses in humans infected with Giardia, but the response in symptomatic cases (patients) is different from that in asymptomatic cases (carriers).(ABSTRACT TRUNCATED AT 250 WORDS)

Human prophylactic vaccine adjuvants and their determinant role in new vaccine formulations.

Adjuvants have been considered for a long time to be an accessory and empirical component of vaccine formulations. However, accumulating evidence of their crucial role in initiating and directing the immune response has increased our awareness of the importance of adjuvant research in the past decade. Nevertheless, the importance of adjuvants still is not fully realized by many researchers working in the vaccine field, who are involved mostly in the search for better target antigens. The choice of a proper adjuvant can be determinant for obtaining the best results for a given vaccine candidate, but it is restricted due to intellectual property and know-how issues. Consequently, in most cases the selected adjuvant continues to be the aluminum salt, which has a record of safety, but predominantly constitutes a delivery system (DS). Ideally, new strategies should combine immune potentiators (IP) and DS by mixing both compounds or by obtaining structures that contain both IP and DS. In addition, the term immune polarizer has been introduced as an essential concept in the vaccine design strategies. Here, we review the theme, with emphasis on the discussion of the few licensed new adjuvants, the need for safe mucosal adjuvants and the adjuvant/immunopotentiating activity of conjugation. A summary of toxicology and regulatory issues will also be discussed, and the Finlay Adjuvant Platform is briefly summarized.

Human prophylactic vaccine adjuvants and their determinant role in new vaccine formulations

Adjuvants have been considered for a long time to be an accessory and empirical component of vaccine formulations. However, accumulating evidence of their crucial role in initiating and directing the immune response has increased our awareness of the importance of adjuvant research in the past decade. Nevertheless, the importance of adjuvants still is not fully realized by many researchers working in the vaccine field, who are involved mostly in the search for better target antigens. The choice of a proper adjuvant can be determinant for obtaining the best results for a given vaccine candidate, but it is restricted due to intellectual property and know-how issues. Consequently, in most cases the selected adjuvant continues to be the aluminum salt, which has a record of safety, but predominantly constitutes a delivery system (DS). Ideally, new strategies should combine immune potentiators (IP) and DS by mixing both compounds or by obtaining structures that contain both IP and DS. In addition, the term immune polarizer has been introduced as an essential concept in the vaccine design strategies. Here, we review the theme, with emphasis on the discussion of the few licensed new adjuvants, the need for safe mucosal adjuvants and the adjuvant/immunopotentiating activity of conjugation. A summary of toxicology and regulatory issues will also be discussed, and the Finlay Adjuvant Platform is briefly summarized.

New vaccines require potent adjuvants like AFPL1 and AFCo1.

Neisseria meningitidis B proteoliposome (AFPL1 when used as adjuvant) and its derivative-Cochleate (AFCo1) contain immunopotentiating and immunomodulating properties and delivery system capacities required for a good adjuvant. Additionally, they contain meningococcal protective antigens and permit packaging of other antigens and pathogen-associated molecular patterns (PAMP). Consequently, we hypothesized that they would function as good vaccine adjuvants for their own antigens and also for non-related antigens. AFPL1 is a detergent-extracted outer membrane vesicle of N. meningitidis B transformed into AFCo1 in calcium environment. Both are produced at Finlay Institute under good manufacture practices (GMP) conditions. We show their exceptional characteristics: combining in the same structure, the potentiator activity, polarizing agents and delivery system capacities; presenting multimeric protein copies; containing multiprotein composition and multi and synergistic PAMP components; acting with incorporated or co-administrated antigens; inducing type I IFN-gamma and IL-12 cytokines suggesting the stimulation of human plasmocytoid precursor and conventional dendritic cells, respectively, inducing a preferential Th1 immune response with TCD4(+), TCD8(+), cross-presentation and cytotoxic T-lymphocyte (CTL) in vivo responses; and functioning by parenteral and mucosal routes. AFPL1-AFCo1 protective protein constitutions permit per se their function as a vaccine. In addition to Phase IV Men BC vaccine, AFPL1 has ended the preclinical stage in an allergy vaccine and is concluding the preclinical stage of a nasal meningococcal vaccine. In conclusion, AFPL1 and AFCo1 induced signal 1, 2 and 3 polarizing to a Th1 (including CTL) response when they acted directly as vaccines or were used as adjuvants with incorporated or co-administered antigens by parenteral or mucosal routes. Both are very promising adjuvants.

[A group of African students parasitized with Mansonella perstans in Cuba (a non-endemic area) from 1979 to 1982]. / Estudio de un grupo de estudiantes Africanos parasitados con Manzonella perstans en Cuba (área no endémica) durante 1979 a 1982.

Sixty cases of Manzonella perstans were studied during a three year period by clinical and blood parasitologic studies. It was observed that 31.2 was negative and that mean microfilaremia decreased from 49.3, at the beginning of the study, to 32.9 at the end of it, in those cases yet positive. According to the persistent microfilaremia, which means a relative longevity of adult parasites, the surveillance of individuals suffering it is recommended at their arrival to a non-endemic area where the vectors of such disease are present.

[Prevalence of HBSAG in blood donors and patients at the central hospital of Maputo, Mozambique, 1985]. / Prevalencia de Ag HBs en donantes de sangre y enfermos del hospital central de Maputo, Mozambique, 1985.

A study is made of 681 donors who came to the Blood Bank of Maputo Central Hospital in Mozambique during the months of November, 1984, to January, 1985. By means of the technique of counterimmunoelectrophoresis it was determined that 18.6% of donors were positive for Ag HBs. Likewise, 90 patients were analyzed; these patients were hospitalized in the Gastroenterology Service of the hospital with different clinical diagnoses: primary liver carcinoma (14), acute hepatitis (24), cirrhosis (10), chronic hepatitis (7), and others (35). 41.6% of the patients hospitalized with hepatitis were type B. There was a significant relationship between Ag HBs carriers and patients with primary liver carcinoma.

[Indirect immunofluorescence in filariasis. I. Standardization of the technique. Cuba, 1983]. / Inmunofluorescencia indirecta en filariasis. I. Normalizacion de la tecnica. Cuba, 1983.

Indirect immunofluorescence was standardized for the diagnosis of human filiariae, using antigens of Dipetalonema viteae. Due to the determined sensibility and specificity, the tier of 1:512 was recommended for aiding clinicians in the individual diagnosis of suspicious patients and that of 1:256 for epidemiologic studies. The titers of cross reactions were less than 1:128.

[Indirect immunofluorescence in filariasis. III. Comparison of microfilaremia and treatment. Cuba, 1983]. / Inmunofluorescencia indirecta en filariasis. III. Comparacion de la microfilaremia y el tratamiento. Cuba, 1983.

Twenty six patients coming from endemic areas, with diagnosis of filariasis caused by Wuchereria bancrofti, Loa loa and Manzonella (Dipetalonema perstans) and 29 patients suspicious of suffering filariasis were studied by means of Knott, membrane filter and indirect immunofluorescence techniques. Results of microfilaremia were compared with antibody titers and it was verified that there was not relationship between these parameters. The suspicious patients presented higher antibody levels than those of the verified patients. In additions, a preliminary study was carried out on the serologic behaviour of some patients treated with diethylcarbamazine (6 mg/kg daily, during 14 days) and increase of antibody titers was observed in most of the cases after three days and a decrease after the first month of treatment.

[Indirect immunofluorescence in filariasis. II. Humoral response in a population living close to a patient with confirmed Wuchereria bancrofti (Nematoda: Filarioidea), Cuba, 1983]. / Inmunofluorescencia indirecta en filariasis. II. Respuesta humoral en una población alrededor de un paciente confirmado con Wuchereria bancrofti (Nematoda: Filarioidea), Cuba, 1983.

This paper deals with the study by Knott technique, membrane filter and indirect immunofluorescence, of 256 individuals living in Pinar del Rio City, neighbors of a patient suffering elephantiasis produced by Wuchereria bancrofti, 111 donors of the blood bank in the same city, and 10 patients coming from endemic areas who were hospitalized at the "Pedro Kouri" Tropical Medicine Institute, with certainty diagnosis of bancroftiasis. Circulating microfilariae were not found in the neighbors of the positive case, however, a high antifilaria antibody titer (1:512) was observed in the neighbors, suggesting it that in any time this population could have been in contact with this parasite.

Angiostrongylus cantonensis: role of eosinophils in the neurotoxic syndrome (Gordon-like phenomenon).

The role of eosinophils in the pathophysiology of Angiostrongylus cantonensis infections was investigated in nonpermissive (guinea pig) and permissive (rat) hosts. Neurological symptoms similar to the Gordon phenomenon (ataxia, tremor, paralysis) together with a loss of Purkinje cells in the cerebellum were observed after intracraneal injection of human eosinophil extracts or after infection with A. cantonensis, only in guinea pigs and not in rats. Blood eosinophilia as well as eosinophil numbers present in the cerebellum and in the cerebrospinal fluid were higher in guinea pigs than in rats, at all times after infection with A. cantonensis. Increased levels of cytotoxicity toward L3 larvae in vitro were obtained in the presence of guinea pig eosinophils and IgE antibodies, rather than with the corresponding rat effector system. The detection of one eosinophil granule component, the eosinophil peroxidase, in the cerebrospinal fluid from infected guinea pigs but not from rats suggested that in nonpermissive hosts, neurological disorders, similar to the previously described Gordon phenomenon, might be due to eosinophil neurotoxins released after interaction of eosinophils with the parasites.

[Epidemic human fascioliasis. Cuba 1983. VI. Clinical study of 40 children in the Hospital Provincial of Sagua la Grande]. / Fascioliasis humana epidémica. Cuba 1983. VI. Estudio clínico de 40 niños del Hospital Provincial de Sagua la Grande.

We studied forty children with "Febrile-eosinophilic-Syndrome". They presented Fasciola Hepatic infection confirmed by: Fever, high eosinophils and abdominal pain. 82% used to eat watercress. All of them had positive biopsies-laparoscopies-intradermo-reaction and also reaction to Fasciola antigen. We present the results of and epidemic in Cuba during 1983.

Brugia malayi microfilariae share epitopes with Aedes aegypti.

Shared antigens between Brugia malayi and Aedes aegypti were studied. The experiments carried out with sera from infected Mastomys natalensis indicated that an immunological response against A. aegypti antigens (Mr 185, 35, 32 kDa) appeared often when animals became microfilaraemic and increased progressively in intensity during the time-course of infection. Sera of animals immunized with B. malayi reacted with the crude extract of mosquitoes and conversely, antibodies from animals immunized with A. aegypti reacted with the surface of B. malayi microfilariae. The implications of these findings of the natural history of B. malayi infection are discussed.

Total and specific IgE in serum and cerebrospinal fluid of rats and guinea pigs infected with Angiostrongylus cantonensis.

The total and specific IgE response to Angiostrongylus cantonensis infection was evaluated according to host permissiveness. Total IgE levels measured by a double antibody radioimmunoassay (RIA) increased slowly in the permissive host (the rat), reaching a maximum between 4 and 8 weeks after infection. This maximum was earlier but significantly lower in the non-permissive host (the guinea pig). IgE antibodies specific for adult worms or L1 or L3 larvae of A. cantonensis were measured by a radioallergosorbent test (RAST). In the case of adult worms and L1 antigens, specific IgE antibody levels showed large variations in relation to the duration of infection in rats. In contrast to total IgE levels, the specific IgE response to L3 larvae was lower in rats than in guinea pigs in both the serum and cerebrospinal fluid (CSF). These results suggest variations in the total vs specific IgE response according to host permissiveness or non-permissiveness to A. cantonensis infection. These results are discussed in the context of the possible participation of IgE antibodies in immune defence.

Immune response induction and new effector mechanisms possibly involved in protection conferred by the Cuban anti-meningococcal BC vaccine.

This report explores the participation of some afferent mechanisms in the immune response induced by the Cuban anti-meningococcal vaccine VA-MENGOC-BC. The induction of delayed-type hypersensitivity in nursing babies and lymphocyte proliferation after immunization is demonstrated. The presence of gamma interferon IFN-gamma and interleukin-2 (IL-2) mRNAs but absence of IL-4, IL-5, and IL-10 mRNAs were observed in peripheral blood mononuclear cells from immunized subjects after in vitro challenge with outer membrane vesicles. In addition, some effector functions were also explored. The presence of opsonic activity was demonstrated in sera from vaccinees. The role of neutrophils as essential effector cells was shown. In conclusion, we have shown that, at least in the Cuban adult population, VA-MENGOC-BC induces mechanisms with a T-helper 1 pattern in the afferent and effector branches of the immune response.

Preliminary assessment of the safety and immunogenicity of a new CTXPhi-negative, hemagglutinin/protease-defective El Tor strain as a cholera vaccine candidate.

Vibrio cholerae 638 (El Tor, Ogawa), a new CTXPhi-negative hemagglutinin/protease-defective strain that is a cholera vaccine candidate, was examined for safety and immunogenicity in healthy adult volunteers. In a double-blind placebo-controlled study, no significant adverse reactions were observed in volunteers ingesting strain 638. Four volunteers of 42 who ingested strain 638 and 1 of 14 who received placebo experienced loose stools. The strain strongly colonized the human small bowel, as evidenced by its isolation from the stools of 37 of 42 volunteers. V. cholerae 638, at doses ranging from 4 x 10(7) to 2 x 10(9) vibrios, elicited significant serum vibriocidal antibody and anti-Ogawa immunoglobulin A antibody secreting cell responses.