The central importance of the immune system in the natural history of cancer control and progression is now clearly established. It can prevent growth and kill the cancer cells, but also facilitate tumour progression through selection of the most fit cells to survive in an immunocompetent host or through altering the local microenvironment that promotes tumour outgrowth.1 Immunotherapy (IM) has now been clinically validated as an effective treatment for many cancers. The important breakthroughs were led by the impressive impact of blockade of cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4) or programmed cell death protein 1 (PD1) on survival of a proportion of patients with, for example, metastatic melanoma or non-small-cell lung cancer, which were previously relatively refractory to existing treatments.2 However, objective tumour responses are only seen in a fraction of patients across different malignancies; many do not benefit at all and there can be significant toxicities. Numerous strategies are currently being evaluated both preclinically and clinically to better understand and combat the immune-suppressive factors significantly limiting patient response to therapy.3 IM has usually been considered as an alternative to more traditional modalities. Previously the view has been that chemotherapy is inherently immunosuppressive and not suitable for combining with IM. These generalizations are being challenged by a new paradigm whereby immune surveillance is the agent that improves and even cures some patients with cancer, even those treated by conventional radioor chemotherapy.4
The central importance of the immune system in the natural history of cancer control and progression is now clearly established. It can prevent growth and kill the cancer cells, but also facilitate tumour progression through selection of the most fit cells to survive in an immunocompetent host or through altering the local microenvironment that promotes tumour outgrowth.1 Immunotherapy (IM) has now been clinically validated as an effective treatment for many cancers. The important breakthroughs were led by the impressive impact of blockade of cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4) or programmed cell death protein 1 (PD1) on survival of a proportion of patients with, for example, metastatic melanoma or non-small-cell lung cancer, which were previously relatively refractory to existing treatments.2 However, objective tumour responses are only seen in a fraction of patients across different malignancies; many do not benefit at all and there can be significant toxicities. Numerous strategies are currently being evaluated both preclinically and clinically to better understand and combat the immune-suppressive factors significantly limiting patient response to therapy.3 IM has usually been considered as an alternative to more traditional modalities. Previously the view has been that chemotherapy is inherently immunosuppressive and not suitable for combining with IM. These generalizations are being challenged by a new paradigm whereby immune surveillance is the agent that improves and even cures some patients with cancer, even those treated by conventional radioor chemotherapy.4
Objectives: Vaccination against tuberculosis with live-attenuated Bacillus Calmette-Guérin (BCG) is widely used even though its effectiveness is controversial. BCG-lymphadenitis (BCG-LA) is its most common complication. Some studies have proposed that BCG-LA can be associated with primary immunodeficiencies (PIs). This study’s aim is to see whether patients who developed BCG-LA (named as ‘LA’) developed more infections than BCG-vaccinated children without BCG-LA (named as ‘NON-LA’). Methods: From January 2009 to April 2014, 31 LA children were seen at the outpatient clinic of the General Hospital of Tijuana, Mexico. Among them, 22 (70.97%), 5 (16.13%) and 4 (12.9%) had axillary, supraclavicular, or both BCG-LA, respectively. No treatment was given and complications were not seen. Per LA subject, a NON-LA not >1 month of age difference and same gender was paired and followed for 3 years to look for ambulatory infections (AINFs), acute otitis media (AOM) and hospitalizations. Surveillance per patient was performed by phone monthly, and they were seen at the clinic every 4 months. All patients were HIV-negative and had no family history of PI. Statistical analyses used were relative risk (RR) with confidence intervals (CI), t test for independent variables and z test. Results: In total 62 subjects were enrolled: 31 LA paired with 31 NON-LA. Between them, there were no differences in age, day care attendance and breastfeeding. There were no differences in the total number of AINF per patient (LA: 18.61 avg. ± 5.03 SD versus NON-LA: 18.19 avg. ± 4.17 SD, RR = 1.06, 95% CI = 0.33–0.66), AOM total episodes (LA: 30 versus NON-LA: 26, RR = 0.87, 95% CI = 0.31–0.68) and hospitalizations (LA: 5 versus NON-LA: 4, RR = 1, 95% CI = 0.25–0.74). Conclusions: This cohort strongly suggests that BCG-LA in healthy children is not associated with more episodes of AINF and hospitalizations, when paired and compared with children BCG-vaccinated without BCG-LA.
Leishmaniasis is a parasitic disease that ranges in severity from skin lesions to fatality. Since long-lasting protection is induced upon recovery from cutaneous leishmaniasis, development of an effective vaccine is promising. However, there is no vaccine for use in humans yet. It seems limited efficacy in leishmaniasis vaccines is due to lack of an appropriate adjuvant or delivery system. Hence, the use of particulate adjuvants such as liposomes for effective delivery to the antigen presenting cells (APCs) is a valuable strategy to enhance leishmaniasis vaccine efficacy. The extraordinary versatility of liposomes because of their unique amphiphilic and biphasic nature allows for using antigens or immunostimulators within the core, on the surface or within the bilayer, and modulates both the magnitude and the T-helper bias of the immune response. In this review article, we attempt to summarize the role of liposomal adjuvants in the development of Leishmania vaccines and describe the main physicochemical properties of liposomes like phospholipid composition, surface charge, and particle size during formulation design. We also suggest potentially useful formulation strategies in order for future experiments to have a chance to succeed as liposomal vaccines against leishmaniasis.
Meningococcal disease is rare, easily misdiagnosed, and potentially deadly. Diagnosis in the early stages is difficult and the disease often progresses extremely rapidly. In North America, the incidence of invasive meningococcal disease (IMD) is highest in infants and young children, with a secondary peak in adolescents, a population predominantly responsible for the carriage of disease. Neisseria meningitidis serogroup B (MenB) accounts for a large proportion of meningococcal disease in North America, with documented outbreaks in three universities in the United States (US) during 2008–2013. Vaccination is the most effective way to protect against this aggressive disease that has a narrow timeframe for diagnosis and treatment. 4CMenB is a multi-component vaccine against MenB which contains four antigenic components. We describe in detail the immunogenicity and safety profile of 4CMenB based on results from four clinical trials; the use of 4CMenB to control MenB outbreaks involving vaccination at two US colleges during outbreaks in 2013–2014; and the use of 4CMenB in a Canadian mass vaccination campaign to control the spread of MenB disease. We discuss the reasons why adolescents should be vaccinated against MenB, by examining both the peak in disease incidence and carriage. We consider whether herd protection may be attained for MenB, by discussing published models and comparing with meningitis C (MenC) vaccines. In conclusion, MenB vaccines are now available in the US for people aged 10–25 years, representing an important opportunity to reduce the incidence of IMD in the country across the whole population, and more locally to combat MenB outbreaks.
Objectives: Several vaccine adjuvants comprise complex nano- or micro-particle formulations, such as oil-in-water emulsions. In order to characterize interactions and compatibility of oil-in-water emulsion adjuvants with protein antigens in vaccines, effective protein characterization methods that can accommodate potential interference from high concentrations of lipid-based particles are needed. Methods: Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) is a standard protein characterization technique which is affected by the presence of adjuvants such as oil-in-water emulsions. In this article, we investigate variations in SDS-PAGE methods that result in a reduction of adjuvant-induced staining artifacts. We have investigated whether the SDS method or the adjuvant composition were the reason for these artifacts and succeeded in reducing the artifacts with a modified sample preparation and different staining procedures. Results: The best results were obtained by using gold staining or silver staining instead of a Coomassie Blue staining procedure. Moreover, the replacement of the dilution buffer (20% SDS to disrupt emulsion) by alternative detergents such as Tween® 80 and Triton® X-100 removed adjuvant-induced streaking artifacts at the top of the gel. Conclusions: These methods may be useful for improving characterization approaches of antigen–adjuvant mixtures by SDS-PAGE.
Substantial data from experimental and clinical investigation support the role of immune-mediated mechanisms in atherogenesis, with immune systems responding to many endogenous and exogenous antigens that play either proatherogenic or atheroprotective roles. An active immunization strategy against many of these antigens could potentially alter the natural history of atherosclerosis. This review mainly focuses on the important studies on the search for antigens that have been tested in vaccine formulations to reduce atherosclerosis in preclinical models. It will also address the opportunities and challenges associated with potential clinical application of this novel therapeutic paradigm.
Backgound: The introduction of the pneumococcal conjugate and polysaccharide vaccines have been valuable tools for combating invasive pneumococcal infection in children and healthy adults. Despite the available vaccination strategies, pneumococcal pneumonia and associated diseases continue to cause substantial morbidity and mortality, particularly in individuals with chronic disease and ageing populations. Next-generation pneumococcal vaccines will need to be highly immunogenic across patient populations providing both mucosal and systemic protective immunity. Mucosal immunization is an effective strategy for stimulating the immune response at the site of pathogen entry while increasing systemic immunity. In this study we utilized intranasal immunization with pneumococcal surface protein A (PspA), in combination with the mucosal adjuvant cholera toxin B (CTB), to characterize the immune components providing protection against S. pneumoniae challenge. Methods: Mice were immunized intranasally with CTB and PspA individually, and in combination, followed by lethal bacterial challenge with S. pneumoniae, strain A66.1. Animals were monitored for survival and tested for lung bacterial burden, cytokine production as well as S. pneumoniae-specific antibody titer in mouse sera. The primary immunological contributor to the observed protection was confirmed by cytokine neutralization and serum passive transfer. Results: The combination of CTB and PspA provided complete protection against bacterial challenge, which coincided with a significant decrease in lung bacterial burden. Increases in the T-helper (Th) 1 cytokines, interferon (IFN)-γ and interleukin (IL)-2 were observed in the lung 24 h post-challenge while decreases in proinflammatory mediators IL-6 and tumor necrosis factor (TNF)-α were also recorded at the same time point. The adjuvanted PspA immunization induced significant titers of S. pneumoniae-specific antibody in the serum of mice prior to infection. Serum adoptive transfer passively protected animals against subsequent challenge while IFN-γ neutralization had no impact on the outcome of immunization, suggesting a primary role for antibody-mediated protection in the context of this immunization strategy. Conclusion: Mucosal immunization with CTB and PspA induced a local cellular immune response and systemic humoral immunity which resulted in effective reduction of pulmonary bacterial burden and complete protection against S. pneumoniae challenge. While induction of the pleiotropic cytokine IFN-γ likely contributes to control of infection through activation of effector pathways, it was not required for protection. Instead, immunization with PspA and CTB-induced S. pneumoniae-specific antibodies in the serum prior to infection that were sufficient to protect against mucosal challenge.
It is now recognized that the immune system can be a key component of restraint and control during the neoplastic process. Human papillomavirus (HPV)-associated cancers of the anogenital tract and oropharynx represent a significant clinical problem but there is a clear opportunity for immune targeting of the viral oncogene expression that drives cancer development. However, high-risk HPV infection of the target epithelium and the expression of the E6/E7 oncogenes can lead to early compromise of the innate immune system (loss of antigen-presenting cells) facilitating viral persistence and increased risk of cancer. In these circumstances, a succession of interacting and self-reinforcing events mediated through modulation of different immune receptors, chemokine and cytokine responses (CCL20; CCL2; CCR2; IL-6; CCR7; IL-12) further promote the generation of an immune suppressive microenvironment [increased levels of Tregs, Th17, myeloid-derived suppressor cells (MDSCs) and PD-L1]. The overexpression of E6/E7 expression also compromises the ability to repair cellular DNA, leading to genomic instability, with the acquisition of genetic changes providing for the selection of advantaged cancer cells including additional strategies for immune escape. Therapeutic vaccines targeting the HPV oncogenes have shown some encouraging success in some recent early-phase clinical trials tested in patients with HPV-associated high-grade anogenital lesions. A significant hurdle to success in more advanced disease will be the local and systemic immune suppressive factors. Interventions targeting the different immunosuppressive components can provide opportunity to release existing or generate new and effective antitumour immunity. Treatments that alter the protumour inflammatory environment including toll-like receptor stimulation, inhibition of IL-6-related pathways, immune-checkpoint inhibition, direct modulation of MDSCs, Tregs and macrophages could all be useful in combination with therapeutic HPV vaccination. Future progress in delivering successful immunotherapy will depend on the configuration of treatment protocols in an insightful and timely combination.
Objectives: Meningococcal meningitis is reported as a rare condition in Mexico. There are no internationally published studies on bacterial causes of meningitis in the country based on active surveillance. This study focuses on finding the etiology of bacterial meningitis in children from nine Mexican Hospitals. Methods: From January 2010 to February 2013, we conducted a three years of active surveillance for meningitis in nine hospitals throughout Mexico. Active surveillance started at the emergency department for every suspected case, and microbiological studies confirmed/ruled out all potentially bacterial pathogens. We diagnosed based on routine cultures from blood and cerebrospinal fluid (not polymerase chain reaction or other molecular diagnostic tests), and both pneumococcal serotyping and meningococcal serogrouping by using standard methods. Results: Neisseria meningitidis was the leading cause, although 75% of cases occurred in the northwest of the country in Tijuana on the US border. Serogroup C was predominant. Streptococcus pneumoniae followed Neisseria meningitides, but was uniformly distributed throughout the country. Serotype 19A was the most incident but before universal implementation of the 13-valent pneumococcal conjugate vaccine. Other bacteria were much less common, including Enterobacteriaceae and Streptococcus agalactiae (these two affecting mostly young infants). Conclusions: Meningococcal meningitis is endemic in Tijuana, Mexico, and vaccination should be seriously considered in that region. Continuous universal vaccination with the 13-valent pneumococcal conjugate vaccine should be nationally performed, and polymerase chain reaction should be included for bacterial detection in all cultures – negative but presumably bacterial meningitis cases.
Vaccination against influenza was found in geriatric patients to correlate with a reduced risk of death, hospitalization and costs on health system [Nichol et al. 1994]; vaccination against influenza is indeed recognised by the World Health Organization as an efficacious strategy to prevent the health-threatening effects of influenza viruses [World Health Organization, 2012]. As with all drugs, the vaccine against influenza is associated with some adverse drug reactions (ADRs) [Vaxigrip, 2015]; while some neurological and psychiatric ADRs have been reported no evidence of visual and auditory hallucination exists. A case of extended hallucinations is now reported.
OBJECTIVES:The only human Lyme disease vaccine of LYMErix was voluntarily removed from the market in the United States in 2002 for a number of reasons. A new human Lyme disease vaccine is currently being developed. We would like any future approved human Lyme disease vaccine to be of interest and marketable to consumers.METHODS:We surveyed 714 participants to determine variables associated with intentions to receive a Lyme disease vaccine. Predictor variables included demographics, protection motivational theory, Lyme disease knowledge, Lyme disease preventive behaviors, beliefs and perceived health.RESULTS:We found in multivariate linear regression analyses that Asian/Asian American race/ethnicity (p < 0.001), South Asian race/ethnicity (p = 0.01) and coping appraisal variables of response efficacy (p < 0.001) and self-efficacy (p < 0.001) were each significantly associated with increased intentions. The belief that vaccines are typically not safe was significantly associated with decreased intentions (p = 0.03).CONCLUSIONS:Asian/Asian American and South Asian race/ethnicities have a strong interest in receiving a Lyme disease vaccine. Although pharmaceutical companies may benefit by advertising a Lyme disease vaccine to Asian/Asian Americans and South Asians, marketers need to address and use approaches to interest those from other race/ethnicities. Also, marketers need to address the erroneous belief that vaccines are typically not safe in order to interest those with such beliefs to use a Lyme disease vaccine.
Varicella-zoster virus (VZV) infection causes two distinct clinical conditions. Primary varicella infection results in chickenpox, a contagious rash illness typically seen among children. VZV can reactivate years after the initial infection to cause herpes zoster (HZ) and lead to post-herpetic neuralgia, a common complication resulting in persistent pain that may last for years after the zoster rash resolves. A person's risk of having longer lasting and more severe pain associated with HZ increases with age. Since the introduction of VZV vaccines, the rates of infection, hospitalizations, and mortality have declined. In this review, we discuss in detail current VZV vaccines available for the prevention of VZV and HZ infections. Varilrix (GSK Biologicals, UK), Varivax (Merck, USA) and the combined measles, mumps, rubella, and varicella (MMRV) vaccine contain the live attenuated Oka strain of VZV for routine varicella vaccination. While Zostavax is the only HZ vaccine currently approved for use in the United States and the European Union [EMEA, 2011], a subunit vaccine candidate called HZ/su has recently shown improved efficacy for zoster prevention in two clinical trial phase III studies. VariZIG, a post-exposure prophylactic, uses zoster immune globulin to prevent VZV infection in those who have recently been in contact with VZV but lack evidence of varicella immunity and are contraindicated to receive the varicella vaccine. Further, we discuss the skin tropic and neurotropic factor VZV ORF7 gene and its involvement in varicella infection, reactivation and latency in ganglia. Ultimately, these studies can contribute to the development of a neuroattenuated vaccine candidate against varicella or a vector for delivery of other virus antigens.
OBJECTIVES:Previous studies have demonstrated that intranasal administration of inactivated (fixed) Francisella tularensis (iFt) live vaccine strain (LVS) in conjunction with the mucosal adjuvant, cholera toxin B (CTB), provides full protection against subsequent lethal challenge with Ft LVS and partial protection against the more virulent Ft SchuS4 strain. Understanding the mechanisms of CTB-induced immune stimulation that confer protection against Ft will be valuable to the development of an effective vaccine against this highly virulent fatal pathogen. In this study, an in vitro system was utilized to further elucidate the immunologic adjuvant effect of CTB when administered with the fixed bacterial immunogen iFt.METHODS:The murine macrophage cell line (RAW264.7) was treated with combinations of iFt and CTB. The treated RAW264.7 cells and their supernatants were collected and assessed for cell surface marker expression and cytokine secretion. In addition, the ability of RAW264.7 cells to present bacterial antigens (iFt or LVS) to an Ft-specific T-cell hybridoma cell line, following exposure to CTB, was analyzed.RESULTS:We found that RAW264.7 cells responded to treatment with iFt + CTB by an increased secretion of the proinflammatory cytokines interleukin 6 and tumor necrosis factor α and upregulation of the surface expression of toll-like receptor 4 and the costimulatory molecules CD80 and CD86. Furthermore, the experimental vaccine treatment iFt + CTB enhanced the ability of macrophages to present iFt antigens to an FT-specific T-cell hybridoma cell line, although they failed to do so with LVS.CONCLUSION:The adjuvant CTB administered in conjunction with iFt showed evidence of enhancing an antigen-specific proinflammatory response in vitro. These observations allow us to define, in part, the mechanisms of immune activation conferred by mucosal administration of iFt + CTB against lethal F. tularensis challenge.
The ongoing outbreak of Ebola virus disease in West Africa highlighted the lack of a licensed drug or vaccine to combat the disease and has renewed the urgency to develop a pipeline of Ebola vaccines. A number of different vaccine platforms are being developed by assessing preclinical efficacy in animal models and expediting clinical development. Over 15 different vaccines are in preclinical development and 8 vaccines are now in different stages of clinical evaluation. These vaccines include DNA vaccines, virus-like particles and viral vectors such as live replicating vesicular stomatitis virus (rVSV), human and chimpanzee adenovirus, and vaccinia virus. Recently, in preliminary results reported from the first phase III trial of an Ebola vaccine, the rVSV-vectored vaccine showed promising efficacy. This review charts this rapidly advancing area of research focusing on vaccines in clinical development and discusses the future opportunities and challenges faced in the licensure and deployment of Ebola vaccines.
Human papilloma virus (HPV) vaccination has been implemented in several countries for about the past 7 years, mainly in the adolescent female population, with varying coverage results. Although the impact of immunization on cervical and other HPV-related cancers will be evident in the next decades, a marked decrease of prevalent HPV infections, precancerous lesions and genital warts is already dramatic in the vaccinated cohorts, and also in their sexual partners, thus providing clear evidence of the effectiveness of HPV vaccination, including a herd-protection effect. Today, recommendations and implementation of universal HPV vaccination for adolescent girls are a public-health priority in all countries of the world. Countries with limited resources are presently involved in demonstration projects and, in some cases, have launched national programmes with the help of international agencies and alliances. Extension of immunization offer to young women and to adolescent male subjects has become an important additional opportunity for several countries, with a special focus needed on homosexual men with HIV infection who are at particularly increased risk of HPV-related diseases. Public-health authorities are confronted with the need to enlarge HPV-vaccination offer to all target groups, especially pre-adolescent girls, so that they can be saved from dreadful cancers by reaching high immunization coverage.
Haemophilus influenzae type b (Hib) is an important cause of meningitis and pneumonia in children. Despite the availability of Hib conjugate vaccine, many countries are still to implement it in their immunization schedule. Before introducing the vaccine in routine immunization programs, it is important to know not only the cumulative efficacy but also the efficacy of each vaccine dose. The primary objective of this review is to find whether two primary dose schedule of Hib vaccine is equally efficacious as the standard three primary dose schedule. A highly sensitive online search was run using the terms ‘Haemophilus Vaccines’ or ‘ Haemophilus influenzae type b’ and ‘conjugate vaccine’, and Medline (Ovid), PubMed, Embase, CENTRAL and Scopus were explored for prospective randomized controlled studies. Data were extracted in a predesigned proforma and analyzed using RevMan software. Nine randomized studies were included in the analysis. Pooled vaccine efficacy using a fixed effects model against confirmed invasive Hib disease following the 3, 2 and 1 primary dose schedule were 82% [95% confidence interval (CI) 73-87], 79% (95% CI 54–90) and 65% (95% CI 23–84), respectively, and the overall efficacy was 80% (95% CI 72–85). To conclude, we found that Hib conjugate vaccine is highly efficacious and that the two dose regime is as good as the three dose regime. [The protocol was registered with PROSPERO (CRD42013004490)].
Flublok is the first recombinant hemagglutinin (HA) vaccine licensed by the US Food and Drugs Administration for the prevention of influenza in adults aged 18 and older. The HA proteins produced in insect cell culture using the baculovirus expression system technology are exact analogues of wild type circulating influenza virus HAs. The universal HA manufacturing process that has been successfully scaled to the 21,000L contributes to rapid delivery of a substantial number of doses. This review discusses the immunogenicity, efficacy and safety data from five pivotal clinical studies used to support licensure of trivalent Flublok for adults 18 years of age and older in the United States. The trial data demonstrate that the higher antigen content in Flublok results in improved immunogenicity. Data further suggest improved efficacy and a slightly lower local reactogenicity compared with standard inactivated influenza vaccine, despite the presence of more antigen (statistically significant). Flublok influenza vaccine can include HAs designed to mimic ‘drift’ in influenza viruses as the process of predicting antigenic drift advances and, at a minimum, could address late appearing influenza viruses. The implementation of the latter will require support from regulatory authorities.
Group B Streptococcus (GBS) is cause of neonatal invasive diseases as well as of severe infections in the elderly and immune-compromised patients. Despite significant advances in the prevention and treatment of neonatal disease, sepsis and meningitis caused by GBS still represent a significant public health care concern globally and additional prevention and therapeutic strategies against infection are highly desirable. The introduction of national recommended guidelines in several countries to screen pregnant women for GBS carriage and the use of antibiotics during delivery significantly reduced disease occurring within the first hours of life (early-onset disease), but it has had no effect on the late-onset diseases occurring after the first week and is not feasible in most countries. Availability of an effective vaccine against GBS would provide an effective means of controlling GBS disease. This review provides an overview of the burden of invasive disease caused by GBS in infants and adults, and highlights the strategies for the development of an effective vaccine against GBS infections.
