RESUMEN
Solid organ transplant candidates encountered increased wait times and mortality rates during the coronavirus 2019 (COVID-19) pandemic. Despite improvement in medical management and vaccination efficacy, this patient population remains at increased risk for complications post COVID-19 including organ rejection. We describe the development of antibody mediated rejection with or without cellular rejection in heart transplant (HT) recipients and previous COVID-19 infection or vaccination. Although centers have changed their management of outpatient follow-up for orthotopic heart transplant patients, little is known on surveillance of rejection and management of HT recipients after COVID-19 infection. We recommend frequent surveillance for rejection or allograft dysfunction after COVID-19 infection. We have adopted a transplant surveillance protocol for HT recipients with COVID-19 infection, given our recent experience with transplanted patients affected of COVID-19.
Asunto(s)
COVID-19 , Trasplante de Corazón , Trasplante de Órganos , Humanos , Rechazo de Injerto/diagnóstico , Rechazo de Injerto/etiología , COVID-19/epidemiología , COVID-19/etiología , Trasplante HomólogoRESUMEN
A promising concept for human immunodeficiency virus (HIV) vaccines focuses immunity on the highly conserved transition state structures and epitopes that appear when the HIV glycoprotein gp120 binds to its receptor, CD4. We are developing chimeric antigens (full-length single chain, or FLSC) in which gp120 and CD4 sequences are flexibly linked to allow stable intrachain complex formation between the two moieties (A. DeVico et al., Proc Natl Acad Sci U S A 104:17477-17482, 2007, doi:10.1073/pnas.0707399104; T. R. Fouts et al., J Virol 74:11427-11436, 2000, doi:10.1128/JVI.74.24.11427-11436.2000). Proof of concept studies with nonhuman primates show that FLSC elicited heterologous protection against simian-human immunodeficiency virus (SHIV)/simian immunodeficiency virus (SIV) (T. R. Fouts et al., Proc Natl Acad Sci U S A 112:E992-E999, 2016, doi:10.1073/pnas.1423669112), which correlated with antibodies against transition state gp120 epitopes. Nevertheless, advancement of any vaccine that comprises gp120-CD4 complexes must consider whether the CD4 component breaks tolerance and becomes immunogenic in the autologous host. To address this, we performed an immunotoxicology study with cynomolgus macaques vaccinated with either FLSC or a rhesus variant of FLSC containing macaque CD4 sequences (rhFLSC). Enzyme-linked immunosorbent assay (ELISA) binding titers, primary CD3(+) T cell staining, and temporal trends in T cell subset frequencies served to assess whether anti-CD4 autoantibody responses were elicited by vaccination. We find that immunization with multiple high doses of rhFLSC did not elicit detectable antibody titers despite robust responses to rhFLSC. In accordance with these findings, immunized animals had no changes in circulating CD4(+) T cell counts or evidence of autoantibody reactivity with cell surface CD4 on primary naive macaque T cells. Collectively, these studies show that antigens using CD4 sequences to stabilize transition state gp120 structures are unlikely to elicit autoimmune antibody responses, supporting the advancement of gp120-CD4 complex-based antigens, such as FLSC, into clinical testing.
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Autoanticuerpos/sangre , Antígenos CD4/inmunología , Anticuerpos Anti-VIH/sangre , Proteína gp120 de Envoltorio del VIH/inmunología , Proteínas Recombinantes/inmunología , Animales , Antígenos CD4/genética , Recuento de Linfocito CD4 , Ensayo de Inmunoadsorción Enzimática , Femenino , Proteína gp120 de Envoltorio del VIH/genética , Macaca fascicularis , Masculino , Proteínas Recombinantes/genética , Subgrupos de Linfocitos T/inmunologíaRESUMEN
Bacille Calmette-Guérin (BCG) vaccination of new born babies can protect children against tuberculosis (TB), but fails to protect adults consistently against pulmonary TB underlying the urgent need to develop novel TB vaccines. Majority of first generation TB vaccine candidates have relied on a very limited number of antigens typically belonging to the active phase of infection. We have designed a multi-antigenic and multiphasic vaccine, based on the Modified Vaccinia Ankara virus (MVA). Up to fourteen antigens representative of the three phases of TB infection (active, latent and resuscitation) were inserted into MVA. Using three different strains of mouse (BALB/c, C57BL/6 and C3H/HeN), we show that a single vaccination results in induction of both CD4 and CD8 T cells, displaying capacity to produce multiple cytokines together with cytolytic activity targeting a large array of epitopes. As expected, dominance of responses was linked to the mouse haplotype although for a given haplotype, responses specific of at least one antigen per phase could always be detected. Vaccination of non-human primates with the 14 antigens MVA-TB candidate resulted in broad and potent cellular-based immunogenicity. The remarkable plasticity of MVA opens the road to development of a novel class of highly complex recombinant TB vaccines to be evaluated in both prophylactic and therapeutic settings.
Asunto(s)
Inmunidad Celular , Vacunas contra la Tuberculosis/inmunología , Tuberculosis/inmunología , Vacunas Virales/inmunología , Animales , Antígenos Bacterianos/genética , Antígenos Bacterianos/inmunología , Citocinas/metabolismo , Citotoxicidad Inmunológica , Modelos Animales de Enfermedad , Interferón gamma/biosíntesis , Masculino , Ratones , Mycobacterium bovis/inmunología , Subgrupos de Linfocitos T/inmunología , Subgrupos de Linfocitos T/metabolismo , Linfocitos T Citotóxicos/inmunología , Linfocitos T Citotóxicos/metabolismo , Tuberculosis/prevención & control , Tuberculosis/terapia , Vacunas contra la Tuberculosis/genética , Vacunas de ADN , Vacunas Virales/genéticaRESUMEN
The late assembly domain of many viruses is critical for budding. Within these domains, encoded in viral structural proteins, are the conserved motifs PTAP, PPxY and YPxL. These sequences are the key determinants for association of viral proteins with intracellular molecules such as Tsg101, Nedd4 and AIP1/ALIX. While roles for Tsg101 and AIP1/ALIX in HIV-1 budding have been well established, less is known about the role of Nedd4. Recent studies, however, have identified a function for Nedd4-like protein in HIV-1 release. In this study, we investigated post-transcriptional changes of Nedd4 following SHIVSF162P3 infection of rhesus macaques, its role on HIV-1 p24 and gp120 levels in vitro and its potential as an immune modulator in HIV vaccination of BALB/c mice. Increased Nedd4 protein levels were noted in both CD4+ and CD8+ T cells following SHIVSF162P3-infection of naïve macaques. Transient co-transfection studies in 293 cells with HXB2 and Nedd4 demonstrated a Nedd4-mediated increase in p24 and gp120 levels. This increase was found to be dependent on the Ca2+/calmodulin-regulated phospholipid binding C2 domain and not ubiquitin ligase activity or HIV LTR activity. Co-transfection of Nedd4 with plasmid DNA expressing Gag or Env was further shown to augment both intracellular and extracellular Gag or Env proteins. To assess the potential of Nedd4 as an immune modulator, BALB/c mice were immunized intramuscularly with plasmid DNA encoding HIV gag, env and Nedd4. Nedd4 co-administration was found to increase serum anti-p24 but not anti-gp120 antibodies. Nedd4 co-injection was found to have no affect on Gag- or Env-specific IFNγ but had a trend of increased Gag-specific IL-6, IL-17A and TNFα that was not seen following Env stimulation. Based on our initial findings, Nedd4-mediated changes in HIV protein levels and its potential use in HIV-1 vaccine development warrants further investigation.
Asunto(s)
Complejos de Clasificación Endosomal Requeridos para el Transporte/metabolismo , VIH-1/metabolismo , Inmunidad , Ubiquitina-Proteína Ligasas/metabolismo , Vacunación , Vacunas de ADN/inmunología , Productos del Gen env del Virus de la Inmunodeficiencia Humana/metabolismo , Productos del Gen gag del Virus de la Inmunodeficiencia Humana/metabolismo , Animales , Calcio/metabolismo , Calmodulina/metabolismo , Complejos de Clasificación Endosomal Requeridos para el Transporte/química , Humanos , Inmunidad Celular , Inmunidad Humoral , Macaca mulatta/inmunología , Macaca mulatta/virología , Ratones Endogámicos BALB C , Ubiquitina-Proteína Ligasas Nedd4 , Regiones Promotoras Genéticas/genética , Estructura Terciaria de Proteína , ARN Interferente Pequeño/metabolismo , Síndrome de Inmunodeficiencia Adquirida del Simio/metabolismo , Virus de la Inmunodeficiencia de los Simios/inmunología , Transfección , Ubiquitina-Proteína Ligasas/químicaRESUMEN
BACKGROUND: In humans it has been reported that a major site of the latent reservoir of HIV is within CD4+ T cells expressing the memory marker CD45RO, defined by the mAb UCHL1. There are conflicting reports regarding the expression of this antigen in macaques, the most relevant animal species for studying HIV pathogenesis and testing new therapies. There is now a major effort to eradicate HIV reservoirs and cure the infection. One approach is to eliminate subsets of cells housing the latent reservoir, using UCHL1 to target these cells. So that such studies may be performed in macaques, it is essential to determine expression of CD45RO. METHODS: We have used immunofluorescence and flow cytometry to study cell surface expression of CD45RO on lymphocytes from PBMC, lymphoid, and GI organs of rhesus, pigtailed, and cynomolgus macaques. Both direct and indirect immunofluorescence experiments were performed. FINDINGS: CD45RO is expressed on a subset of CD4+ lymphocytes of all pigtailed, a fraction of rhesus, and neither of the cynomolgus macaques studied. The binding of UCHL1 to macaque cells was of lower avidity than to human cells. This could be overcome by forming UCHL1 multimers. Directly conjugating fluors to UCHL1 can inhibit UCHL1 binding to macaque cells. Patterns of UCHL1 expression differ somewhat in macaques and humans, and from that of other memory markers often used in macaques. CONCLUSIONS: CD45RO, defined with mAb UCHL1, is well expressed on CD4+ cells in pigtailed macaques. Using tissues recovered from latently infected pigtailed macaques we are determining whether UCHL1, or other memory markers, can define the cellular locus of the reservoir. The low avidity of this interaction could limit the utility of UCHL1, in its conventional form, to eliminate cells in vivo and test this approach in macaque models of HIV infection.
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Regulación de la Expresión Génica/inmunología , Antígenos Comunes de Leucocito/metabolismo , Linfocitos T Colaboradores-Inductores/inmunología , Linfocitos T Colaboradores-Inductores/metabolismo , Adulto , Animales , Anticuerpos Monoclonales/inmunología , Biomarcadores/metabolismo , Regulación de la Expresión Génica/efectos de los fármacos , Humanos , Inmunotoxinas/toxicidad , Macaca , Linfocitos T Colaboradores-Inductores/efectos de los fármacosRESUMEN
The Plasmodium falciparum apical membrane antigen 1 (AMA1) is a leading vaccine candidate and was tested for safety and immunogenicity in human Phase I Clinical Trials. PBMC from vaccine recipients were analyzed by flow cytometric methods to determine the nature of T-cell responses and AMA1-reactive memory T cells. Both CD4 and CD8 T cells produced a number of cytokines following AMA1 re-stimulation, with IL-5-producing cells at the highest frequency, consistent with a Th2 bias. The relative frequency of multifunctional cells synthesizing Th1 cytokines IFN-gamma, IL-2 and TNF-alpha changed after each vaccination. Interestingly, median fluorescence intensity measurements revealed that cells producing more than one cytokine contributed greater quantities of each cytokine than cell populations that produced each of the cytokines alone. AMA1 vaccination also elicited the development of memory cell populations, and both central and effector memory T cells were identified concurrently after the AMA1 vaccination. The detailed profile of multifunctional T-cell responses to AMA1 presented here will advance our ability to assess the immunogenicity of human malarial vaccines.
Asunto(s)
Antígenos de Protozoos/inmunología , Linfocitos T CD4-Positivos/inmunología , Memoria Inmunológica , Vacunas contra la Malaria/inmunología , Malaria Falciparum/prevención & control , Proteínas de la Membrana/inmunología , Plasmodium falciparum/inmunología , Proteínas Protozoarias/inmunología , Animales , Anticuerpos Antiprotozoarios/sangre , Linfocitos T CD4-Positivos/metabolismo , Linfocitos T CD8-positivos/inmunología , Linfocitos T CD8-positivos/metabolismo , Humanos , Interferón gamma/inmunología , Interleucina-2/inmunología , Interleucina-5/inmunología , Factor de Necrosis Tumoral alfa/inmunologíaRESUMEN
A number of blood-stage malaria Ags are under development as vaccine candidates, but knowledge of the cellular responses to these vaccines in humans is limited. We evaluated the nature and specificity of cellular responses in healthy American volunteers vaccinated with a portion of the major merozoite surface protein-1 (MSP1) of Plasmodium falciparum, MSP1(42), formulated on Alhydrogel. Volunteers were vaccinated three times with 80 microg of either MSP1(42)-FVO/Alhydrogel or MSP1(42)-3D7/Alhydrogel. Cells collected 2 wk after the third vaccination produced Th1 cytokines, including IFN-gamma and IL-2 following Ag stimulation, and greater levels of the Th2 cytokines IL-5 and IL-13; the anti-inflammatory cytokine IL-10 and the molecule CD25 (IL-2Ralpha) were also detected. The volunteers were evaluated for the MSP1(42)-FVO or MSP1(42)-3D7 specificity of their T cell responses. Comparison of their responses to homologous and heterologous Ags showed ex vivo IFN-gamma and IL-5 levels that were significantly higher to homologous rather than to heterologous Ags. The epitopes involved in this stimulation were shown to be present in the dimorphic MSP1(33) portion of the larger MSP1(42)-3D7 polypeptide, and indirect experiment suggests the same for the MSP1(42)-FVO polypeptide. This contrasts with B cell responses, which were primarily directed to the conserved MSP1(19) portion. Furthermore, we explored the maturation of memory T cells and found that 46% of vaccinees showed specific memory T cells defined as CD4(+)CD45RO(+)CD40L(+) after long-term in vitro culture. The identification of human-specific CD4(+) memory T cells provides the foundation for future studies of these cells both after vaccination and in field studies.
Asunto(s)
Linfocitos T CD4-Positivos/inmunología , Vacunas contra la Malaria/inmunología , Proteína 1 de Superficie de Merozoito/inmunología , Plasmodium falciparum/inmunología , Alelos , Animales , Citocinas/inmunología , Humanos , Inmunidad Celular/genética , Memoria Inmunológica , Interferón gamma/metabolismo , Interleucina-10/metabolismo , Subunidad alfa del Receptor de Interleucina-2/metabolismo , Células TH1/inmunología , Células Th2/inmunología , VacunaciónRESUMEN
The performance of Fas2-ELISA for the diagnosis of Fasciola hepatica infection in children living in areas of high endemicity for fascioliasis in the Peruvian Andes is analyzed. Fas2-ELISA is based on the detection of circulating IgG antibodies elicited in infected individuals against a F. hepatica antigen termed Fas2. The study was conducted in three Andean localities, Huertas-Julcan in Junin, Asillo in Puno, and Cajamarca, with a total population of 634 children in an age range 1 to 16 years old. Child fascioliasis prevalence was 21.1% in Huertas-Julcan, 25.4% in Asillo, and 24% in Cajamarca, estimated by coprological inspection. The seroprevalence of F. hepatica infection, determined by Fas2-ELISA, was 27.8% in Huertas-Julcan, 44.6% in Asillo, and 29.1% in Cajamarca. The overall sensitivity of Fas2-ELISA was 92.4%, the specificity 83.6%, and the negative predictive value 97.2%. No association between OD(450) Fas2-ELISA and infection intensity measured by egg counting was observed. Results show that Fas2-ELISA is a highly sensitive immunodiagnostic test for the detection of F. hepatica infection in children living in human fascioliasis endemic areas.
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Anticuerpos Antihelmínticos/sangre , Antígenos Helmínticos/inmunología , Cisteína Endopeptidasas/inmunología , Ensayo de Inmunoadsorción Enzimática/métodos , Fasciola hepatica/inmunología , Fascioliasis/diagnóstico , Adolescente , Factores de Edad , Animales , Niño , Preescolar , Ensayo de Inmunoadsorción Enzimática/normas , Fascioliasis/epidemiología , Heces/parasitología , Femenino , Helmintiasis/epidemiología , Humanos , Inmunoglobulina G/sangre , Lactante , Intestinos/parasitología , Masculino , Perú/epidemiología , Prevalencia , Infecciones por Protozoos/epidemiología , Factores de Riesgo , Sensibilidad y EspecificidadRESUMEN
The polymorphisms in the Plasmodium falciparum multidrug resistance 1 (pfmdr1) and P. falciparum chloroquine resistance transporter (pfcrt) genes, which are associated with chloroquine resistance, were examined in 48 P. falciparum isolates from uncomplicated malaria patients from the West Lombok District in Indonesia. The point mutation N86Y in pfmdr1 was present in 35.4% of the isolates and mutation K76T in pfcrt was found in all but one of the samples studied. Identified pfcrt haplotypes were mainly identical to the Papua New Guinea type S(agt)VMNT (42 of 48, 87.5%), and a few isolates had the Southeast Asia type CVIET (5 of 48, 10.4%). Moreover, one P. falciparum isolate harbored the K76N mutation, giving rise to the haplotype CVMNN, which was not previously reported in field isolates. Our findings suggest that chloroquine resistance in this area might have the same origin as in Papua New Guinea.
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Cloroquina/farmacología , Resistencia a Medicamentos/genética , Proteínas de la Membrana/genética , Plasmodium falciparum/genética , Animales , ADN Protozoario/química , Haplotipos , Humanos , Indonesia , Proteínas de Transporte de Membrana , Plasmodium falciparum/efectos de los fármacos , Polimorfismo Genético , Proteínas ProtozoariasRESUMEN
In vitro drug sensitivity to chloroquine (CQ), mefloquine (MQ) and quinine was investigated in 60 culture-adapted Plasmodium falciparum isolates from malaria patients in Padrecocha, a village in the Amazonian Department of Loreto, Peru. All isolates showed resistance to CQ, decreased susceptibility to quinine, and sensitivity to MQ. These isolates were examined for mutations in the P. falciparum multidrug resistance 1 (pfmdr1) and chloroquine resistance transporter (pfcrt) genes previously linked to CQ resistance. The mutations N86Y and D1246Y, two of the five mutations commonly observed in the pfmdr1 gene of CQ-resistant clones, were not found. The pfcrt mutation K76T, associated with CQ resistance, was identified in all the isolates tested. Sequence analysis of codons 72-76 in the pfcrt gene showed the haplotypes SVMNT and CVMNT.
Asunto(s)
Antimaláricos/farmacología , Cloroquina/farmacología , Genes MDR , Proteínas de la Membrana/genética , Plasmodium falciparum/efectos de los fármacos , Polimorfismo Genético , Animales , Resistencia a Múltiples Medicamentos , Genotipo , Mefloquina/farmacología , Proteínas de Transporte de Membrana , Mutación , Pruebas de Sensibilidad Parasitaria , Plasmodium falciparum/genética , Proteínas Protozoarias , Quinina/farmacologíaRESUMEN
CD4(+) T cells co-expressing CD25 (CD4(+)CD25(+) T cells) have been identified as immunoregulatory suppressors modulating autoimmune response. Beside that, autoimmune response was supposed to be associated with malaria infection. Based on these data, we hypothesised that CD4(+)CD25(+) T cells may influence protective immunity to malaria parasites, while suppressing autoimmune response arising throughout the course of malarial infection. To test this possibility, we evaluated the kinetics of CD4(+)CD25(+) T cells during malaria infection and investigated the influence of CD25 depletion by anti-mouse CD25 monoclonal antibody (PC61) on the infection, using a mouse model of premunition to Plasmodium berghei NK65 malaria. The results showed that, during exacerbation of P. berghei NK65 infection, the proportion of CD4(+)CD25(+) T cells among CD4(+) T cells decreased, although that of CD4(+) T cells increased. CD25 depletion clearly delayed the growth of parasitaemia during parasite challenge, particularly in immunised mice. These findings demonstrated that CD4(+)CD25(+) T cells are able to influence protective immunity underlying premunition to P. berghei NK65 parasites.
Asunto(s)
Antígenos CD4/inmunología , Linfocitos T CD4-Positivos/inmunología , Malaria/inmunología , Plasmodium berghei/inmunología , Receptores de Interleucina-2/inmunología , Animales , Antígenos de Protozoos/inmunología , Autoinmunidad , Recuento de Linfocito CD4 , Femenino , Inmunización , Malaria/prevención & control , Ratones , Ratones Endogámicos BALB C , Modelos AnimalesRESUMEN
Routine microscopical examination of stool specimens for diagnosis of strongyloidiasis is insensitive and serological methods using Strongyloides stercoralis antigen are at present not available for field studies. We evaluated 2 techniques, enzyme-linked immunosorbent assay (ELISA) and gelatin particle indirect agglutination (GPIA), using an antigen obtained from the rodent parasite, S. venezuelensis. Fifty-four Peruvian patients with different clinical forms of strongyloidiasis were studied: 12 asymptomatic, 31 symptomatic, and 11 hyperinfection cases. Our results demonstrate that both ELISA and GPIA using S. venezuelensis antigen are useful for diagnosis of strongyloidiasis, with sensitivities of 74.1% and 98.2%, respectively and a specificity of 100% for both techniques. We found that GPIA is a highly sensitive test for patients with suspected chronic infection and/or hyperinfection. In the hyperinfection cases, significantly lower concentrations of specific immunoglobulin antibodies and eosinophils (P < 0.001) were found compared with the asymptomatic and symptomatic cases.
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Pruebas de Aglutinación/métodos , Ensayo de Inmunoadsorción Enzimática/métodos , Estrongiloidiasis/diagnóstico , Adolescente , Adulto , Anciano , Pruebas de Aglutinación/normas , Análisis de Varianza , Animales , Antígenos Helmínticos/análisis , Niño , Preescolar , Ensayo de Inmunoadsorción Enzimática/normas , Infecciones por HTLV-I/complicaciones , Humanos , Persona de Mediana Edad , Sensibilidad y Especificidad , Strongyloides/inmunología , Strongyloides/aislamiento & purificaciónRESUMEN
Antimalarial treatments during primary Plasmodium berghei NK65 infection in BALB/c mice influenced the acquisition of protective immunity against reinfection. Among subcurative treatments, lower doses better enable mice to acquire protective immunity than do higher doses. Eradication of parasites from the start of infection did not promote protective immunity.