Top PDF Immunogenicity and protective efficacy of a live attenuated H5N1 vaccine in nonhuman primates.

Immunogenicity and protective efficacy of a live attenuated H5N1 vaccine in nonhuman primates.

Immunogenicity and protective efficacy of a live attenuated H5N1 vaccine in nonhuman primates.

Although the precise responses that must be induced to protect against H5N1 infection in humans are unknown, animal studies indicate a central role for the cellular immune response [12]. Thus, in the face of a pandemic, a vaccine that elicits cellular immunity could be valuable in reducing the severity of disease and mortality, if not in providing complete protection from infection [25]. Moreover, a vaccine that induces a cellular immune response Figure 5. Vaccine efficacy in nonhuman primates assessed on the basis of lung lesions. Eight macaques were euthanized on day 3 postchallenge with AH/05 virus (A–D) or BHG/05 virus (E–H). Vaccinated animals (A,B,E,F) had less extensive bronchopneumonia (i.e., smaller foci of consolidation) than did unvaccinated animals (C,D,G,H). The vaccinated animals also showed prominent peribronchial lymph follicles (a, e; arrows), and their consolidated lung areas lacked viral antigen-positive cells (B,F). By contrast, the unvaccinated animals had lung lesions of moderate size with a wide consolidated area (C,G; outlined by yellow dashes), smaller and less abundant peribronchial lymph follicles (C,G; arrows), and pneumonic lesions containing many antigen-positive cells (D,H; brown pigment). (I) Schematic diagrams indicating distribution of pathologic lesions in the lungs of animals vaccinated and challenged with AH/05 (V1 and V2); nonvaccinated and challenged with AH/05 (C1 and C2); vaccinated and challenged with BHG/05 (V3 and V4); and nonvaccinated and challenged with BHG/05 (C3 and C4). In vaccinated animals, scant-to-moderate bronchopneumonia was present in each lobe, but viral antigens were not detected in the lesions (V1, V2, V3, and V4; purple). By contrast, more severe bronchopneumonia was observed in nonvaccinated macaque lungs (C1, C2, C3, and C4). Moreover, viral antigens were prominent in the pneumonic lesions in the most affected lung lobes (C1, C2, C3, and C4; red). One lung lobe was entirely affected by pneumonia after infection with the BHG/05 virus (C3). Purple, bronchopneumonia without viral antigen; red, bronchopneumonia with viral antigen.
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A novel live-attenuated vaccine candidate for mayaro Fever.

A novel live-attenuated vaccine candidate for mayaro Fever.

protein, DNA and virus-like particles (VLP) as well as traditionally attenuated and chimeric vaccines [40,41]. All of these approaches emphasize safety but have significant drawbacks including a multiple dose requirement for efficacy, short-lived immunogenicity necessitating boosters, challenging delivery (DNA via electropora- tion) and complex, expensive manufacture (VLPs) and the risk of residual live virus after inactivation, which was shown to result in the death of an eastern equine encephalitis-vaccinated horse in California [42]. Our MAYV/IRES candidate overcomes all of these shortcomings to generate rapid immunity following a single dose, and should have greatly reduced reactogenicity due to its robust, highly stable attenuation design. Although further testing should be done to evaluate the duration of protective immunity, other IRES-based alphavirus vaccines have generated completely protective immunity in macaques for over one year (C. Roy, S.C.W., unpublished). MAYV/IRES therefore should be ideal for inducing rapid, long-lived immunity after a single dose for use in developing countries where MAYV is endemic, as well as for a traveler’s vaccine for persons visiting South America.
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Generation and Characterization of Live Attenuated Influenza A(H7N9) Candidate Vaccine Virus Based on Russian Donor of Attenuation.

Generation and Characterization of Live Attenuated Influenza A(H7N9) Candidate Vaccine Virus Based on Russian Donor of Attenuation.

vaccine [15, 19, 20], recombinant virus-like particles [15, 21], cell-based whole virus vaccine [22, 23]. In all studies either several doses of administration or various adjuvants were required for complete protection. LAIV A/Anhui/1/2013 (H7N9) seed virus developed on A/AnnAr- bor/6/60 backbone [24] however, demonstrated the complete protection of ferrets from homol- ogous wild-type (wt) A/Anhui/1/2013 (H7N9) virus after a single dose, another study showed protective efficacy of similar LAIV virus in a mouse model [25]. The clinical studies of A (H7N9) vaccine suggest that to achieve protective immunity against subtype A(H7N9) viruses multiple vaccinations might be required [26–28]. A recent study found that the quantity, epi- tope diversity, and affinity of H7 head-specific antibodies increased rapidly after the vaccina- tion with inactivated vaccine in LAIV-primed subjects only, emphasizing the value of LAIVs as a tool for pre-pandemic vaccination [29]. The development of LAIV which could be used in countries with pandemic potential is of high importance. The preferable method approved by WHO for LAIV preparation is reassortment in eggs, in the case of newly emergent, potentially pandemic viruses, a reverse genetics approach is also accepted [30, 31]. However, due to intel- lectual property issues currently present for reverse genetics generated LAIV vaccines, the pro- duction of such vaccines could be costly, which is a concern for developing countries
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Side-by-side comparison of gene-based smallpox vaccine with MVA in nonhuman primates.

Side-by-side comparison of gene-based smallpox vaccine with MVA in nonhuman primates.

We, and others, have previously tested molecular smallpox vaccines in the NHP MPXV intravenous challenge model [29,30,31,32,33,45]. Most studies involved a prime followed by multiple booster vaccinations, including a recent DNA vaccine study that delivered the 4pox immunogens plus four others by both skin and muscle electroporation [33]. Only two studies involved a single boost. In one study, the 4pox targets were formulated into an alphavirus replicon system and the challenge dose was 5610 6 pfu of MPXV [31]. In a second study, the 4pox targets were delivered as purified proteins combined with adjuvant and the challenge dose was 2610 7 [30]. In both of those studies there was 100% protection against lethal disease and none of the vaccinated animals developed .100 lesions (i.e., no severe disease). Here, we report the first study where a smallpox DNA vaccine delivered as a single boost has been tested in the NHP MPXV intravenous challenge model. Moreover, it is the first side- by-side comparison of any molecular smallpox vaccine against MVA. Our reason for directly comparing the 4pox vaccine with MVA was to determine if a DNA vaccine could elicit protective immunity comparable to an attenuated virus vaccine already in advanced development. Advantages and disadvantages of an effective DNA vaccine versus a protein subunit, viral-vectored, or attenuated live-virus vaccine have been discussed elsewhere [46]. Before performing the direct comparison study in NHP, we sought to maximize the potency of the 4pox vaccine. The L1R, A27L, A33R, and B5R plasmids used in this study all contained open reading frames that were optimized for mammalian expression and mRNA stability (46). In addition, the L1R open reading frame was modified by the addition of an endoplasmic reticulum (ER) retention signal. This modification targeted the L1 protein to the ER resulting in correct disulphide bond formation and protein folding [36]. These improvements resulted in higher levels of neutralizing antibodies after fewer boosts, and overcame previ- ously observed interference when vaccinations involved the co- delivery of combinations of the L1R and A33R plasmids [27].
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Developing an HIV vaccine: the role of efficacy studies in nonhuman primates.

Developing an HIV vaccine: the role of efficacy studies in nonhuman primates.

Since only a limited number of HIV/AIDS vaccines can be tested for effi cacy in phase-III studies, evidence-based criteria for selection of candidate HIV/AIDS vaccines for these trials have to be defi ned. If an immune correlate of protection were available, small-scale immunogenicity studies in humans would provide required parameters. However, the specifi c immune responses needed for a successful HIV/AIDS vaccine remain unknown. The Global HIV/AIDS Vaccine Enterprise prioritizes research on vaccines eliciting neutralizing antibodies and T cell responses [1]. Standardization of laboratory assays measuring these parameters is proposed to allow comparison of different vaccines.
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An Overview on Avian Influenza

An Overview on Avian Influenza

Inactivated AI vaccines should be given by injection, as demonstrated for conventional inactivated homologous or heterologous HA virus, both with heterologous NA, in order to enable the differentiation from the circulating virus through the DIVA strategy (differentiating infected from vaccinated animals), and were successfully used in Italy (Capua & Marangon, 2006), although in Mexico they were questioned for the possible induction of selective pressure (Lee et al., 2004; Webster et al., 2006). After fatal infections by HPAIV H5N1 in Falconiformes, ten hawks were vaccinated with an inactivated H5N2, which was considered protective and reduced transmission (Lierz et al., 2007). A Vero cell culture of the H5N1 virus was highly immunogenic in animal models after inactivation, allowing rapid high yield of a candidate pandemic virus in cell culture (Kistner et al., 2007). Current H5N1 strain vaccine responses may provide the necessary priming in humans to cope with variant HPAIV emerging strains, as determined by a Vero cell grown H5N1 given to mice (Sabartha et al., 2010). Mice were studied as an alternative to eggs to produce influenza human vaccines, considering a possible egg shortage during pandemics (Hoelscher et al., 2006). Several inactivated recombinant vaccines expressing genes encoding protection-inducing proteins were evaluated. Mice given an incompetent adenovirus recombinant vector expressing H5 (Had-H5NA) were resistant to homologous and heterologous H5N1 challenge (Hoelscher et al., 2006). However, virus shedding was reported (Sasaki et al., 2009). Employing reverse genetics, one AIV subtype H5 was constructed for the expression of the ecto-domain of Newcastle disease virus (NDV) HN, instead of N1 (Park et al., 2006). The intranasal administration of gamma-irradiated, but not formalin- or UV-inactivated A/PR/8/Puerto Rico/8/34 (H1N1), protected mice against mortality after challenge with a HPAIV A/Vietnam/1203/2004 [H5N1] and other heterologous strains (Furuya et al., 2010).
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Establishment of a colony of nonhuman primates (Aotus lemurinus griseimembra) in Colombia

Establishment of a colony of nonhuman primates (Aotus lemurinus griseimembra) in Colombia

Colombia’s National Institute of Health (Insri- tuto National de Salud-INS) began malaria immunology studies using Aotus specimens in 1979 as a means of evaluating diff[r]

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Antibodies with higher bactericidal activity induced by a Neisseria gonorrhoeae Rmp deletion mutant strain.

Antibodies with higher bactericidal activity induced by a Neisseria gonorrhoeae Rmp deletion mutant strain.

complement, has been commonly used as the index for the in vitro evaluation on the protectiveness of gonococcal vaccines [15,18,20,23]. The antisera of wild-type and mutant strains were mixed with wild-type N. gonorrhoeae WHO-A strain and incubated for 15 min, respectively, into which was added fresh human serum as the source of complement, followed by another 45 min of incubation. Then the number of survival colonies in the mixture was detected by plate counting. Significant bactericidal effect of inhibiting .50% gonococcal survival was discerned when the 1/ titer of the Rmp deletion mutant strain antiserum was $0.008. The bacteria survival rate of the mutant strain antiserum group was significantly lower than that of the wild-type one at each dilution of sera 1/titer $0.008 (P , 0.05) (Fig. 7A), suggesting that the Rmp deletion mutant strain induced effective antibody immunity without Rmp immune repression [32]. To further reveal the immunity-blocking effect of Rmp antibodies, we used the mixture of rrRmp and rrPorB immune sera for complement- Figure 5. Growth curve of N. gonorrhoeae Rmp deletion mutant and wild-type strains. Same amounts of Rmp deletion mutant and wild- type strains were inoculated to FB liquid culture medium, from which 10 ml was sampled to measure the OD 600 value every one hour.
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Effect of environmental mycobacteria (Mycobacterium avium) on immunity induced by a DNA vaccine (DNAhsp65) against tuberculosis

Effect of environmental mycobacteria (Mycobacterium avium) on immunity induced by a DNA vaccine (DNAhsp65) against tuberculosis

ABSTRACT: The efficacy of BCG vaccine (attenuated Mycobacterium bovis) against pulmonary tuberculosis varies enormously among different populations. The prevailing hypothesis attributes this variation to interactions between the vaccine and mycobacteria common in the environment. Studies have revealed that most protective antigens expressed by the antituberculous vaccine are conserved in M. avium, supporting the hypothesis that exposure to environmental mycobacteria generates a cross-reactive immune response that interferes with BCG efficacy. In this study we investigated the effect of a prior exposure to heat-killed M. avium on the immune response and the protective efficacy induced by a genetic vaccine pVAXhsp65 (hsp65 gene from M. leprae inserted in pVAX vector) against experimental tuberculosis. To evaluate the effect on the immune response, female BALB/c mice were initially injected with distinct doses (0.08x10 6 , 4x10 6 , and 200x10 6 ) of heat-killed M. avium by subcutaneous route. Three weeks later, the animals were immunized with 3 doses of DNAhsp65 by intramuscular route (100μg/15 days apart). Control groups received only M. avium, vaccine (pVAXhsp65), vector (pVAX) or saline solution. Cytokine production and antibody levels were determined by ELISA. To evaluate the effect on the protective efficacy, animals were initially sensitized with 200x10 6 heat-killed CFU of M. avium by subcutaneous route and then immunized with 3 doses of pVAXhsp65 (100μg/15 days apart) by intramuscular route. Control groups were injected with saline, pVAX (4 doses), pVAXhsp65 (4 doses), M. avium or M. avium plus pVAX (3 doses). Fifteen days after last DNA dose, the animals were infected with 1x10 4 viable CFU of H37Rv M. tuberculosis by intratracheal route. Thirty days after challenge, the animals were sacrificed and the bacterial burden was determined by counting the number of CFU in the lungs. Lung histological sections were also analyzed. Splenic cells from primed animals produced more IL-5 but less IFN-gamma than non-primed ones. Also, prior contact with M. avium determined higher production of IgG1 and IgG2a anti-hsp65 antibodies in comparison to control groups. However, this higher immune response did not decrease the bacterial burden in the lungs. In addition, prior sensitization with M. avium decreased the parenchyma preservation observed in the group immunized only with pVaxhsp65. These results indicate that environmental mycobacteria can interfere with immunity and protective efficacy induced by DNAhsp65.
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Immunogenicity and tolerability of hepatitis a vaccine in HIV-infected children

Immunogenicity and tolerability of hepatitis a vaccine in HIV-infected children

All of the HIV-infected children were exposed by vertical transmission. To be enrolled in the study, the children in both groups had to be HAV-seronegative (HAV antibody titer, ! 20 mIU/mL) before vaccination, have no history of any previous viral hepatitis, not be a chronic carrier of hepatitis B or C, not have recent contact with patients with viral hepatitis, present with normal aspartate aminotransferase and alanine amino- transferase serum levels, and not have any acute disease at study entry. To assess the probability of a decline in CD4 +
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Immunogenicity of a combined DTPa-HB vaccine co-administered with Haemophilus influenzae type B conjugate vaccine (PRP-T) for primary and booster vaccinations

Immunogenicity of a combined DTPa-HB vaccine co-administered with Haemophilus influenzae type B conjugate vaccine (PRP-T) for primary and booster vaccinations

and simultaneous application of inactivated polio vaccine (IPV) and PRP-T vaccines, also reported similar results, with GMT of 1.2 IU/mL for anti-diphtheria antibodies and 2.3 IU/mL for anti-tetanus antibodies, and all of the vaccinated patients attained a protective seropositivity rate after completing the basic immunization scheme, as we also found in our study [16]. There was a decline in anti-diphtheria and anti- tetanus antibody titers before the booster dose. The values obtained (GMT of 0.08 IU/mL and seropositivity rate of 33.7% for diphtheria, and GMT of 0.47 IU/mL and seropositivity rate of 93.9% for tetanus) were similar to those obtained in another study [16], which found a GMT of 0.1 IU/mL and a seropositivity rate of 64.4% for diphtheria, and a GMT of 0.5 IU/mL and a seropositivity rate of 100% for tetanus; these authors utilized the same serological test (ELISA). To determine the negative anti-diphtheria antibody titers, by ELISA, the authors [16] utilized the Vero cell neutralization test; when these two tests (ELISA and Vero cell neutralization) were used, the seropositivity rate rose from 64.4% to 90.3%. This suggests that the large fall in anti-diphtheria antibodies observed immediately prior to the booster dose was mainly due to the serological method utilized, since the neutralization test has greater sensitivity for detecting the immunological response for diphtheria when the antibody titer is less than 0.1 IU/ mL and therefore ELISA underestimates the seroprotection rate for this group [17]. The large increase in concentrations of these two antibodies that occurred after the booster dose, in relation to the concentrations found immediately before this dose, was also found in an American study [16]. However, in that study, the GMT findings for both the anti-diphtheria antibodies (5.01 IU/mL vs. 2.0 IU/mL) and the anti- tetanus antibodies (14.18 IU/mL vs. 6.1 IU/mL) were about twice the level that we found. However, in both studies the seropositivity rates became 100% for both antibodies, and the GMT values after the booster dose exceeded the pre-booster values by a factor of at least 12.
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Comparison of five parasitological techniques for laboratory diagnosis of Balantidium coli cysts

Comparison of five parasitological techniques for laboratory diagnosis of Balantidium coli cysts

The Faust and modified Sheather techniques showed low recovery of B. coli cysts from fecal samples of both pigs and nonhuman primates. These results are contrary to those of Machado et al. (1969) who reported that the Faust technique showed the highest diagnostic efficiency for B. coli cysts (0.74%), followed by direct examination (0.57%), spontaneous sedimentation (0.49%) and Willis (0.49%), in 1214 human stool samples. They noted that flotation techniques are used primarily to recover cysts and oocysts of protozoa, through processing with solutions of different densities, which facilitates floatation of light parasite structures (DRYDEN et al., 2005). High sensitivity of cyst and oocyst recovery has been demonstrated by several authors. Machado et al. (2001) reported that the technique of Faust showed higher positivity of G. duodenalis in the feces of children than did iron hematoxylin, direct examination using Lugol’s solution or enzyme immunoassay. Likewise, Huber  et  al. (2003) showed higher frequency of Cryptosporidium spp. oocysts and G. duodenalis cysts in the feces of calves by using the modified Sheather technique than by using sedimentation with formaldehyde-ether.
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Correction: Rabies in nonhuman primates and potential for transmission to humans: a literature review and examination of selected French national data.

Correction: Rabies in nonhuman primates and potential for transmission to humans: a literature review and examination of selected French national data.

There are several errors throughout the text of this article. The country, India, appears several times instead of the correct country, Thailand. In Table 1, the second county under the heading “Asia” should be Thailand. In the Results section under the subsection “Asia and the Middle East (Appendix S1, Tables 1 and 2)”, India in sentence three should be changed to Thailand. In the fifth sentence of the same subsection, the first mention of India, “. . .reported in local popu- lations in India. . .”, should be changed to Thailand. In the last sentence of the first paragraph of the Discussion section, the first mention of India, “. . .in India [20]. . .”, should be changed to Thailand.
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Experimental Gastric Carcinogenesis in Cebus apella Nonhuman Primates

Experimental Gastric Carcinogenesis in Cebus apella Nonhuman Primates

The evolution of gastric carcinogenesis remains largely unknown. We established two gastric carcinogenesis models in New- World nonhuman primates. In the first model, ACP03 gastric cancer cell line was inoculated in 18 animals. In the second model, we treated 6 animals with N-methyl-nitrosourea (MNU). Animals with gastric cancer were also treated with Canova immunomodulator. Clinical, hematologic, and biochemical, including C-reactive protein, folic acid, and homocysteine, analyses were performed in this study. MYC expression and copy number was also evaluated. We observed that all animals inoculated with ACP03 developed gastric cancer on the 9 th day though on the 14 th day presented total tumor remission. In the second model, all animals developed pre-neoplastic lesions and five died of drug intoxication before the development of cancer. The last surviving MNU-treated animal developed intestinal-type gastric adenocarcinoma observed by endoscopy on the 940 th day. The level of C-reactive protein level and homocysteine concentration increased while the level of folic acid decreased with the presence of tumors in ACP03-inoculated animals and MNU treatment. ACP03 inoculation also led to anemia and leukocytosis. The hematologic and biochemical results corroborate those observed in patients with gastric cancer, supporting that our in vivo models are potentially useful to study this neoplasia. In cell line inoculated animals, we detected MYC immunoreactivity, mRNA overexpression, and amplification, as previously observed in vitro. In MNU-treated animals, mRNA expression and MYC copy number increased during the sequential steps of intestinal-type gastric carcinogenesis and immunoreactivity was only observed in intestinal metaplasia and gastric cancer. Thus, MYC deregulation supports the gastric carcinogenesis process. Canova immunomodulator restored several hematologic measurements and therefore, can be applied during/after chemotherapy to increase the tolerability and duration of anticancer treatments.
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EVALUATION OF OIL BASED AVIAN INFLUENZA VACCINE (H5NI) PREPARED WITH DIFFERENT CONCENTRATIONS OF ADJUVANT

EVALUATION OF OIL BASED AVIAN INFLUENZA VACCINE (H5NI) PREPARED WITH DIFFERENT CONCENTRATIONS OF ADJUVANT

effectively controlled the disease in the vaccinated flock but due to quick absorption, immunity produced was of shorter duration and frequent booster doses are needed. Keeping in view the duration of immunity and to avoid stress to the birds by repeating aqueous vaccine, an economical and quality oil based avian influenza vaccine from local strain of avian influenza virus subtype H 5 N 1 (A/chicken/Pakistan/ NARC-

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SOCIAL ECONOMY – A FORM OF INCLUSION AND OF ''REACTIVATING'' OF LABOR IN THE CONTEXT OF THE CURRENT CRISIS

SOCIAL ECONOMY – A FORM OF INCLUSION AND OF ''REACTIVATING'' OF LABOR IN THE CONTEXT OF THE CURRENT CRISIS

The cultivating, through different social policies, especially through the ideologization of the values , of the contempt for the real, productive work represents a major problem. Only one country in the world set the objective – within the constitution – to not spend more

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Absence of intestinal colonization by vancomycin-resistant enterococci in nonhuman primates

Absence of intestinal colonization by vancomycin-resistant enterococci in nonhuman primates

Few surveillance studies in wild animals have tested antimicrobial resistance to the clinically important antibiotics teicoplanin, ampicillin, gentamicin, and streptomycin. A previous study that analyzed 140 enterococci isolated from wild animals in Portugal revealed susceptibility to teicoplanin and ampicillin; resistance to gentamicin and, streptomycin occurred in only two isolates from an owl (Poeta et al. 2005). Low resistance rates to kanamycin, streptomycin, and ampicillin (9.0%, 6.7%, 3.7%), and susceptibility to gentamycin was found in samples from Sus scrofa (Poeta et al. 2007). In our study, E. faecalis strains isolated from the nonhuman primates Cebus apella and Callithrix penicillata were all susceptible to teicoplanin, ampicillin, gentamicin, and streptomycin. The low prevalence of antimicrobial resistance in enterococci isolated from wild animal species contrasts with those data concerned to food animals. This fact corroborates the selective pressure theory, in which the volume of antibiotic use would affect the rate of resistance development (Aarestrup et al. 2001).
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VF Amaral, A Teva, R Porrozzi, AJ Silva, MS Pereira, MP Oliveira-Neto, G Grimaldi Jr

VF Amaral, A Teva, R Porrozzi, AJ Silva, MS Pereira, MP Oliveira-Neto, G Grimaldi Jr

Current research employing mouse models is also providing the foundation for studies designed to identify leishmanial protective immunogens and the immune mechanisms responsible for immunity in vaccinated mice (Reed & Scott 1993). However, small experimental animals may not be good pre- dictors of human responses. Simian species most closely related to humans should be more attrac- tive as animal models to evaluate the safety and immunogenicity of vaccines. The hominoid pri- mates (chimpanzees, orangutans, gorillas, and gib- bons), which diverged from humans over 5 mil- lion years ago, are the most likely to mimic accuratly the disease state and the immunological response to infection (Kennedy et al. 1997a). How- ever, cost considerations and other factors (great apes are endangered species) for using hominoid primate species in biomedical studies represent serious limitations. Next in evolutionary distance are Old World monkeys (macaques, baboons, man- drills, and mangageys), which diverged from the human line between 15 and 20 million years ago. Most distantly related to humans (over 30 million years apart) are the New World monkeys (aotus, owl, cebus monkeys, and marmosets) (Kennedy et al. 1997b). Genetic studies have shown that class I and class II major histocompatibility complex (MHC) products in great apes and nonhominoid Old World monkeys much resemble their human counterparts; in contrast, New World monkeys have a condensed or smaller MHC as compared to humans (reviewed in Kennedy et al. 1997a). There- fore, vaccine trials in Old World primates will prob- ably not be hindered due to divergence of MHC molecules (Prilliman et al. 1996).
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Correction: Antigenicity, Immunogenicity and Protective Efficacy of Three Proteins Expressed in the Promastigote and Amastigote Stages of Leishmania infantum against Visceral Leishmaniasis.

Correction: Antigenicity, Immunogenicity and Protective Efficacy of Three Proteins Expressed in the Promastigote and Amastigote Stages of Leishmania infantum against Visceral Leishmaniasis.

1. Martins VT, Chávez-Fumagalli MA, Lage DP, Duarte MC, Garde E, Costa LE, et al. (2015) Antigenicity, Immunogenicity and Protective Efficacy of Three Proteins Expressed in the Promastigote and Amastigote Stages of Leishmania infantum against Visceral Leishmaniasis. PLoS ONE 10(9): e0137683. doi:10.1371/journal.pone.0137683 PMID: 26367128

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Transient Loss of Protection Afforded by a Live Attenuated Non-typhoidal Salmonella Vaccine in Mice Co-infected with Malaria.

Transient Loss of Protection Afforded by a Live Attenuated Non-typhoidal Salmonella Vaccine in Mice Co-infected with Malaria.

production was observed with in vivo antigen challenge as well as ex vivo stimulation with PMA/iono (Fig 3B–3E). With increased surface expression of PD1 on memory CD4 T cells (Fig 5A), the phenotypic traits of Salmonella vaccine-induced memory T cells during malaria share characteristics of exhausted CD4 T cells identified during chronic viral infection [46]. This finding is consistent with previous reports of CD4 T cell dysfunction during malaria [38,47], which has been shown to have the beneficial effect of preventing immunopathology during acute infection [48,49]. Blockade of PDL-1, CTLA4 and LAG3 restored the ability of antigen-specific CD4 T cells to produce IFN-γ, suggesting that in addition to its previously described effect on control of acute malaria [38], upregulation of inhibitory ligands contributes to dysfunction of memory CD4 T cells generated by vaccination. However, this effect alone is insufficient to explain loss of vaccine-induced immunity (Fig 5D). Since IL-10 blockade par- tially restored protection against NTS in the context of concurrent P. yoelii infection (Fig 4C), it is likely that the suppressive effect of IL-10 on macrophage bactericidal function is a contrib- uting factor to loss of immunity, similar to what we have reported previously in the context of primary S. Typhimurium infection [35]. It is interesting to note in this context that both IL-10 blockade and blockade of PDL-1, CTLA4 and LAG3 reduced the level of circulating malaria parasites, however only IL-10 blockade restored vaccine-mediated protection. Thus, while reduction of parasitemia may have contributed to the improved control of S. Typhimurium after IL-10 blockade, it may not be sufficient on its own to restore immune responses during the acute phase of infection.
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