RESUMEN
Given the mucosal transmission of HIV-1, we compared whether a mucosal vaccine could induce mucosal cytotoxic T lymphocytes (CTLs) and protect rhesus macaques against mucosal infection with simian/human immunodeficiency virus (SHIV) more effectively than the same vaccine given subcutaneously. Here we show that mucosal CTLs specific for simian immunodeficiency virus can be induced by intrarectal immunization of macaques with a synthetic-peptide vaccine incorporating the LT(R192G) adjuvant. This response correlated with the level of T-helper response. After intrarectal challenge with pathogenic SHIV-Ku2, viral titers were eliminated more completely (to undetectable levels) both in blood and intestine, a major reservoir for virus replication, in intrarectally immunized animals than in subcutaneously immunized or control macaques. Moreover, CD4+ T cells were better preserved. Thus, induction of CTLs in the intestinal mucosa, a key site of virus replication, with a mucosal AIDS vaccine ameliorates infection by SHIV in non-human primates.
Asunto(s)
Vacunas contra el SIDA/inmunología , Síndrome de Inmunodeficiencia Adquirida/prevención & control , Mucosa Intestinal/inmunología , Mucosa Intestinal/virología , Síndrome de Inmunodeficiencia Adquirida del Simio/prevención & control , Vacunas contra el SIDA/administración & dosificación , Administración Rectal , Secuencia de Aminoácidos , Animales , Epítopos de Linfocito T/inmunología , Productos del Gen gag/inmunología , Productos del Gen pol/inmunología , Antígenos de Histocompatibilidad Clase I/inmunología , Macaca mulatta , Datos de Secuencia Molecular , Recto/virología , Linfocitos T Citotóxicos , Linfocitos T Colaboradores-Inductores , Vacunación , Vacunas Sintéticas/administración & dosificación , Vacunas Sintéticas/uso terapéutico , Carga ViralRESUMEN
Cytotoxic T-lymphocyte (CTL) responses to human immunodeficiency virus arise early after infection, but ultimately fail to prevent progression to AIDS. Human immunodeficiency virus may evade the CTL response by accumulating amino-acid replacements within CTL epitopes. We studied 10 CTL epitopes during the course of simian immunodeficiency virus disease progression in three related macaques. All 10 of these CTL epitopes accumulated amino-acid replacements and showed evidence of positive selection by the time the macaques died. Many of the amino-acid replacements in these epitopes reduced or eliminated major histocompatibility complex class I binding and/or CTL recognition. These findings strongly support the CTL 'escape' hypothesis.
Asunto(s)
Productos del Gen env/inmunología , Productos del Gen nef/inmunología , Virus de la Inmunodeficiencia de los Simios/química , Linfocitos T Citotóxicos/inmunología , Secuencia de Aminoácidos , Animales , Secuencia de Bases , Cartilla de ADN , Mapeo Epitopo , Epítopos/química , Epítopos/inmunología , Productos del Gen env/química , Productos del Gen nef/química , Antígenos de Histocompatibilidad Clase I/inmunología , Macaca mulatta , Datos de Secuencia Molecular , Homología de Secuencia de Aminoácido , Síndrome de Inmunodeficiencia Adquirida del Simio/inmunologíaRESUMEN
CD8+ (suppressor/cytotoxic) lymphocytes block replication of HIV-1 or the simian immunodeficiency virus of macaques (SIVmac) in PBL of infected individuals. We now show that these CD8+ lymphocytes undergo clonal expansion in vivo after AIDS virus infection of the individual, suggesting they may be antigen-specific T cells. These CD8+ cells block replication of virus in autologous but not MHC class I-mismatched PBL. The inhibitory lymphocytes express the integrin family molecule 4B4 and the CTL-associated S6F1 epitope of LFA-1. Finally, physical contact is required for the CD8+ lymphocyte-mediated inhibition of AIDS virus replication, since this inhibitory function is blocked by anti-LFA-1 and anti-CD8 mAbs. These studies suggest that the cell that inhibits AIDS virus replication in PBL of infected individuals is a CTL.
Asunto(s)
VIH/crecimiento & desarrollo , Inmunidad Celular , Virus de la Inmunodeficiencia de los Simios/crecimiento & desarrollo , Linfocitos T Citotóxicos/inmunología , Animales , Antígenos de Diferenciación de Linfocitos T/inmunología , Comunicación Celular , Antígenos de Histocompatibilidad Clase I/inmunología , Humanos , Técnicas In Vitro , Células Asesinas Naturales/inmunología , Macaca mulatta , Factores de Tiempo , Replicación ViralRESUMEN
A tetrameric recombinant major histocompatibility complex (MHC) class I-peptide complex was used as a staining reagent in flow cytometric analyses to quantitate and define the phenotype of Gag-specific cytotoxic T lymphocytes (CTLs) in the peripheral blood of simian immunodeficiency virus macaque (SIVmac)-infected rhesus monkeys. The heavy chain of the rhesus monkey MHC class I molecule Mamu-A*01 and beta2-microglobulin were refolded in the presence of an SIVmac Gag synthetic peptide (p11C, C-M) representing the optimal nine-amino acid peptide of Mamu-A*01-restricted predominant CTL epitope to create a tetrameric Mamu-A*01/p11C, C-M complex. Tetrameric Mamu-A*01/p11C, C-M complex bound to T cells of SIVmac-infected, Mamu-A*01(+), but not uninfected, Mamu-A*01(+), or infected, Mamu-A*01(-) rhesus monkeys. Specific staining of peripheral blood mononuclear cells (PBMC) from SIVmac-infected, Mamu-A*01(+) rhesus monkeys was only found in the cluster of differentiation (CD)8alpha/beta+ T lymphocyte subset and the percentage of CD8alpha/beta+ T cells in the peripheral blood of four SIVmac-infected, Mamu-A*01+ rhesus monkeys staining with this complex ranged from 0.7 to 10.3%. Importantly, functional SIVmac Gag p11C-specific CTL activity was seen in sorted and expanded tetrameric Mamu-A*01/p11C, C-M complex-binding, but not nonbinding, CD8alpha/beta+ T cells. Furthermore, the percentage of CD8alpha/beta+ T cells binding this tetrameric Mamu-A*01/p11C, C-M complex correlated well with p11C-specific cytotoxic activity as measured in both bulk and limiting dilution effector frequency assays. Finally, phenotypic characterization of the cells binding this tetrameric complex indicated that this lymphocyte population is heterogeneous. These studies indicate the power of this approach for examining virus-specific CTLs in in vivo settings.
Asunto(s)
Productos del Gen gag/inmunología , Complejo Mayor de Histocompatibilidad/inmunología , Virus de la Inmunodeficiencia de los Simios/inmunología , Linfocitos T Citotóxicos/inmunología , Animales , Linfocitos T CD8-positivos/inmunología , Pruebas Inmunológicas de Citotoxicidad , Epítopos/química , Citometría de Flujo , Productos del Gen gag/química , Antígenos de Histocompatibilidad Clase I/química , Macaca mulatta , Fenotipo , Conformación Proteica , Proteínas Recombinantes/inmunologíaRESUMEN
A statistical study of DNA sequences of alleles at the highly polymorphic class I MHC loci of humans, HLA-A and HLA-B, showed evidence of both large-scale recombination events (involving recombination of exons 1-2 of one allele with exons 3-8 of another) and small-scale recombination events (involving apparent exchange of short DNA segments). The latter events occurred disproportionately in the region of the gene encoding the antigen recognition site (ARS) of the class I molecule. Furthermore, they involved the ARS codons which are under the strongest selection favoring allelic diversity at the amino acid level. Thus, the frequency of recombinant alleles appears to have been increased by some form of balancing selection (such as overdominant selection) favoring heterozygosity in the ARS. These analyses also revealed a striking difference between the A and B loci. Recombination events appear to have occurred about twice as frequently at the B locus, and recombinants at the B locus were significantly more likely to affect polymorphic sites in the ARS. At the A locus, there are well-defined allelic lineages that have persisted since prior to the human-chimpanzee divergence; but at the B locus, there is no evidence for such long-lasting allelic lineages. Thus, relatively frequent interallelic recombination has apparently been a feature of the long-term evolution of the B locus but not of the A locus.
Asunto(s)
Genes MHC Clase I , Recombinación Genética , Alelos , Animales , Secuencia de Bases , Evolución Biológica , Codón/genética , ADN/genética , Exones , Ligamiento Genético , Antígenos HLA-A/genética , Antígenos HLA-B/genética , Humanos , Datos de Secuencia Molecular , Familia de Multigenes , Pan troglodytes , Filogenia , Selección GenéticaRESUMEN
MHC class I genes evolve by recombination, largely within loci, and selection (presumably pathogen-driven) maintains these new alleles in the population. Although chimpanzees and humans share an A locus allelic lineage, the B locus molecules of the chimpanzee were less similar to human B locus molecules. The A and B locus molecules in rhesus and cynomolgus monkeys were even less similar to their human counterparts, with little conservation of allelic lineages between macaques and humans. In contrast to the instability of MHC class I alleles and allelic lineages, the MHC class I loci themselves are well conserved during the evolution of Great Ape and Old World primates. Homologues of HLA-A, -B, -E, and -F have been found in macaques. The C locus, however, has only been found in gorillas and chimpanzees, whereas in orangutans and rhesus monkeys it is possible that the A and B loci have been duplicated. Classical New World monkey MHC class I genes are all more similar to the nonclassical HLA-G gene and a nonclassical F-like gene is present in the cotton-top tamarin. Duplication and either subsequent deletion or expansion of MHC class I loci, therefore, appear to be the modus operandi of the evolution of these genes in primates.
Asunto(s)
Evolución Molecular , Antígenos HLA/genética , Indígenas Sudamericanos/genética , Complejo Mayor de Histocompatibilidad/genética , Primates/genética , Secuencia de Aminoácidos , Animales , Secuencia de Consenso , Susceptibilidad a Enfermedades/inmunología , Femenino , Frecuencia de los Genes , Predisposición Genética a la Enfermedad , Variación Genética , Antígenos HLA-B/química , Antígenos HLA-B/clasificación , Antígenos HLA-B/genética , Humanos , Indígenas Norteamericanos/genética , Infecciones/genética , Infecciones/inmunología , Masculino , Datos de Secuencia Molecular , Primates/inmunología , Grupos Raciales/genética , Selección Genética , Alineación de Secuencia , Homología de Secuencia de Aminoácido , Especificidad de la Especie , Espondilitis Anquilosante/genética , Espondilitis Anquilosante/inmunologíaRESUMEN
BACKGROUND: Renal allografts were performed in rhesus monkeys using FN18-CRM9, a potent immunotoxin capable of depleting T cells to less than 1% of baseline levels in blood and lymph nodes, as a preparative agent. We have recently reported that animals pretreated with FN18-CRM9 1 week before transplantation without further immunosuppression had prolonged graft survival time compared with control animals, and frequently became tolerant. METHODS: This report examines the alloimmune responses of recipient monkeys to the donor, including cytotoxic T lymphocyte precursor (CTLp) frequency, mixed lymphocyte response, and antidonor IgG response. RESULTS: CTLp frequencies declined significantly (P<0.01) after FN18-CRM9 treatment and renal transplantation. This decline in CTLp was initially nonspecific, as CTLp frequencies against third-party animals also declined (P<0.01). The decrease in CTLp was maintained in five of five animals tested 6 months after transplant. However, unresponsiveness was limited to the CTL arm of the immune response as antidonor IgG was detected in four of four animals tested, and the 5-day mixed lymphocyte response stimulation index and relative response were not significantly different before and after transplant. In long-term survivors (>150 days), an increase in anti-third-party CTLp was detected 1 month after grafting with third-party skin. No change was seen in the antidonor CTLp frequency after donor skin grafting, indicating that a specific defect in the antidonor CTL response had developed. CONCLUSIONS: These data suggest that FN18-CRM9 treatment of rhesus monkeys allows the development of specific down-regulation of antidonor CTL activity in renal allograft recipients.
Asunto(s)
Proteínas Bacterianas/farmacología , Toxina Diftérica/farmacología , Tolerancia Inmunológica/efectos de los fármacos , Inmunotoxinas/farmacología , Trasplante de Riñón/inmunología , Animales , Anticuerpos Monoclonales/farmacología , Linfocitos B/efectos de los fármacos , Linfocitos B/inmunología , Supervivencia de Injerto/efectos de los fármacos , Supervivencia de Injerto/inmunología , Inmunoglobulina G/biosíntesis , Inmunoglobulina G/inmunología , Prueba de Cultivo Mixto de Linfocitos , Subgrupos Linfocitarios/efectos de los fármacos , Subgrupos Linfocitarios/inmunología , Macaca mulatta , Trasplante de Piel/inmunología , Linfocitos T/efectos de los fármacos , Linfocitos T/inmunología , Linfocitos T Citotóxicos/efectos de los fármacos , Linfocitos T Citotóxicos/inmunología , Linfocitos T Colaboradores-Inductores/efectos de los fármacos , Linfocitos T Colaboradores-Inductores/inmunología , Trasplante HomólogoRESUMEN
This article describes a novel approach to HIV vaccine design that is, as yet, unproven and still in preliminary development. In rhesus macaques infected with simian immunodeficiency virus (SIV), we have identified particular cellular immune responses that select for viral variants during primary infection. We speculate that the detection of viral variants with altered amino acids in CTL epitopes implies the successful clearance of cells harboring wild-type virus. Here, we present our rationale suggesting why such potent early CTL responses that exert an antiviral effect may be particularly attractive targets for induction by candidate vaccines. Conventional wisdom suggests that regions of the virus that are structurally and functionally important will generally be well-conserved both among clades and within an infected host. Amino acid replacements within these well-conserved regions should be difficult for the virus to accommodate. Therefore, these regions are traditionally considered ideal targets for vaccine induced immune responses because they are refractory to CTL escape mutations. Many examples of these regions have been identified in both HIV-1 and SIV(mac) (J. Immunol. 162 (1999) 3727; J. Virol. 67 (1993) 438) and have been included in candidate vaccine formulations. Human clinical trials testing these vaccines are currently underway. Our proposed method of vaccination with CTL epitopes that escape explores an alternative hypothesis. Rather than engendering responses to regions of the virus that do not escape, we reason that vaccination needs to accelerate the development of the initial immune responses that effectively select for amino acid variants during acute infection. By examining CTL escape during the acute phase, we will identify CTL responses that the virus cannot tolerate and incorporate these responses into vaccines.
Asunto(s)
Vacunas contra el SIDA/farmacología , Epítopos Inmunodominantes/administración & dosificación , Linfocitos T Citotóxicos/inmunología , Secuencia de Aminoácidos , Animales , Variación Genética , Antígenos VIH/administración & dosificación , Infecciones por VIH/inmunología , Infecciones por VIH/prevención & control , Infecciones por VIH/virología , VIH-1/genética , VIH-1/inmunología , Humanos , Epítopos Inmunodominantes/genética , Macaca mulatta , Vacunas contra el SIDAS/administración & dosificación , Síndrome de Inmunodeficiencia Adquirida del Simio/inmunología , Síndrome de Inmunodeficiencia Adquirida del Simio/prevención & control , Síndrome de Inmunodeficiencia Adquirida del Simio/virología , Virus de la Inmunodeficiencia de los Simios/genética , Virus de la Inmunodeficiencia de los Simios/inmunologíaRESUMEN
Highly polymorphic HLA class I molecules may influence rates of disease progression of HIV-infected individuals. Recent evidence suggests that individuals who mount vigorous CTL responses to multiple HIV-1 epitopes have reduced viral loads, and survive longer than individuals that make a less robust or less diverse CTL response. It has been difficult, however, to define associations between particular HLA class I alleles and rates of disease progression. This may be due, in part, to the uncontrolled variables associated with naturally acquired HIV infections. Studies using MHC-defined, non-human primates infected with well characterized viral stocks should help to clarify this relationship. To explore the possibility that MHC class I polymorphism can influence disease progression, we infected four Mamu-DRB-identical individuals from a family of MHC-defined rhesus macaques intravenously with 40 TCID50SIVmac239. Two of these macaques developed severe wasting and were euthanized within 80 days of infection, while the other two survived for more than 400 days without showing any symptoms of disease. Since all four of these macaques were Mamu-DRB-identical, we were able to exclude the MHC class II DRB loci as determinant of disease progression. Interestingly, both of the slow progressors made CTL responses to the same three SIV CTL epitopes, which were restricted by two molecules (Mamu-B*03 and B*04) encoded by their common maternal haplotype. The two rapid progressors did not share this haplotype with the slow progressors, and we were unable to detect CTL responses in these two siblings. These observations implicate products of the Mamu-B*03 and B*04 alleles in resistance to disease progression in this family of SIV-infected macaques, and provide additional evidence that certain MHC class I-restricted CTL responses may play a significant role in delaying the onset of AIDS.
Asunto(s)
Antígenos de Histocompatibilidad Clase I/inmunología , Síndrome de Inmunodeficiencia Adquirida del Simio/inmunología , Alelos , Secuencia de Aminoácidos , Animales , Línea Celular , Progresión de la Enfermedad , Epítopos de Linfocito T/inmunología , Productos del Gen env/inmunología , Productos del Gen nef/inmunología , Macaca mulatta , Datos de Secuencia Molecular , Linfocitos T Citotóxicos/inmunologíaRESUMEN
In this study, we carried out a phenotypic and functional characterization of lymphocytes isolated from the uterine endometrium of the pregnant rhesus monkey. A majority (80%) of these cells were CD56(bright+), CD3- had typical large granular lymphocyte/uterine natural killer (NK) cell morphology and contained numerous cytoplasmic granules. Flow cytometric evaluation showed that rhesus decidual CD56(bright+) cells shared other phenotypic features of human uterine NK cells, including low levels of CD45RA and CD62L expression. A majority of the rhesus uterine CD56(bright+) cells expressed low levels of CD 16 but were CD2-. In contrast, most rhesus CD16+ peripheral blood cells were CD56-. In addition to the primary population of CD56(bright+) cells, a minor subset of smaller and less granular CD56(intermediate+) decidual lymphocytes was identified, the majority of which were CD16-, CD2(+). Decidual CD56+ cells did not express monocyte/macrophage markers, including CD14, CD64 and CD68. Decidual lymphocytes effectively lysed K562, Raji and particularly 721.221 targets in cytotoxicity assays. Together, these results suggest that as in human pregnancy, rhesus decidual CD56(bright+) cells represent a distinct lymphocyte subset that belongs to the NK cell lineage.
Asunto(s)
Antígeno CD56/biosíntesis , Citotoxicidad Inmunológica , Decidua/inmunología , Decidua/metabolismo , Células Asesinas Naturales/inmunología , Subgrupos Linfocitarios/inmunología , Animales , Decidua/citología , Femenino , Humanos , Inmunofenotipificación , Células K562 , Células Asesinas Naturales/metabolismo , Subgrupos Linfocitarios/metabolismo , Macaca mulatta , Macrófagos/inmunología , Macrófagos/metabolismo , Embarazo , Receptores de IgG/biosíntesis , Subgrupos de Linfocitos T/inmunología , Subgrupos de Linfocitos T/metabolismo , Células Tumorales CultivadasRESUMEN
A juvenile western lowland gorilla (Gorilla gorilla gorilla) experienced recurrent fever, lethargy, diarrhea, and/or arthritis starting at age 6 mo. During an episode at age 15 mo, Shigella sp. was isolated from diarrheic feces. At age 41 mo, reactive arthritis was diagnosed. In addition, the gorilla's growth was retarded. All arthritic attacks were managed symptomatically prior to age 4 yr, at which time a severe episode precipitated the implementation of therapy with sulfasalazine, an arthritis suppressive medication. Examination 27 mo later revealed cessation of progressive joint pathology although the animal exhibited decreased range of motion in most joints. The gorilla has been on sulfasalazine therapy for 4 yr without lameness. Growth has resumed, and there has been no radiographic evidence of progressive joint degeneration. Immunogenetic analysis of whole blood obtained at age 68 mo identified the gorilla major histocompatibility class I allele, Gogo-B*0101, which has limited nucleotide sequence similarity to HLA-B27, an allele associated with postinfection reactive arthritis in humans. Sulfasalazine therapy effectively managed reactive arthritis in this gorilla and should be considered for similarly frequently affected animals. Juvenile gorillas, in populations with a history of clinical shigellosis and/or postdiarrhea arthritis, may benefit from prophylactic sulfasalazine therapy after episodes of bacterial enterocolitis. Sulfasalazine therapy should be considered in all gorillas, juvenile and adult, experiencing confirmed Shigella sp.-associated enterocolitis.
Asunto(s)
Antirreumáticos/uso terapéutico , Artritis Reactiva/veterinaria , Gorilla gorilla , Enfermedades de los Primates/tratamiento farmacológico , Sulfasalazina/uso terapéutico , Animales , Antirreumáticos/administración & dosificación , Artritis Reactiva/tratamiento farmacológico , Artritis Reactiva/etiología , Disentería Bacilar/complicaciones , Disentería Bacilar/veterinaria , Trastornos del Crecimiento/complicaciones , Trastornos del Crecimiento/veterinaria , Antígenos de Histocompatibilidad Clase I/análisis , Inmunogenética , Masculino , Shigella/aislamiento & purificación , Sulfasalazina/administración & dosificaciónAsunto(s)
Infecciones por VIH/inmunología , VIH-1/inmunología , Linfocitos T/inmunología , Animales , Citocinas/biosíntesis , Ensayo de Inmunoadsorción Enzimática/métodos , Infecciones por VIH/virología , VIH-1/genética , Humanos , Macaca mulatta , Síndrome de Inmunodeficiencia Adquirida del Simio/inmunología , Síndrome de Inmunodeficiencia Adquirida del Simio/virología , Virus de la Inmunodeficiencia de los Simios/inmunologíaAsunto(s)
Sondas de ADN , Genes MHC Clase II , Antígenos HLA-DR/genética , Prueba de Histocompatibilidad , Animales , Variación Genética , Prueba de Histocompatibilidad/métodos , Humanos , Macaca fascicularis , Macaca mulatta , Hibridación de Ácido Nucleico , Papio , Polimorfismo de Longitud del Fragmento de Restricción , SaimiriAsunto(s)
Tolerancia Inmunológica/fisiología , Intercambio Materno-Fetal/inmunología , Animales , Decidua/citología , Desarrollo Embrionario y Fetal/fisiología , Femenino , Feto/inmunología , Feto/fisiología , Antígenos de Histocompatibilidad Clase I/análisis , Inmunohistoquímica/métodos , Células Asesinas Naturales/citología , Macaca mulatta , Embarazo , Coloración y EtiquetadoRESUMEN
Non-human primates, in general, and Indian rhesus macaques, specifically, play an important role in the development and testing of vaccines and diagnostics destined for human use. To date, several frequently expressed macaque MHC molecules have been identified and their binding specificities characterized in detail. Here, we report the development of computational algorithms to predict peptide binding and potential T cell epitopes for the common MHC class I alleles Mamu-A*01, -A*02, -A*11, -B*01 and -B*17, which cover approximately two thirds of the captive Indian rhesus macaque populations. We validated this method utilizing an SIV derived data set encompassing 59 antigenic peptides. Of all peptides contained in the SIV proteome, the 2.4% scoring highest in the prediction contained 80% of the antigenic peptides. The method was implemented in a freely accessible and user friendly website at . Thus, we anticipate that our approach can be utilized to rapidly and efficiently identify CD8+ T cell epitopes recognized by rhesus macaques and derived from any pathogen of interest.
Asunto(s)
Bases de Datos Genéticas , Genes MHC Clase I/inmunología , Macaca mulatta/inmunología , Péptidos/inmunología , Algoritmos , Alelos , Animales , Biología Computacional , Ensayo de Inmunoadsorción Enzimática , Epítopos/genética , Frecuencia de los Genes , Interferón gamma/química , Internet , Péptidos/síntesis química , Péptidos/genética , Población , Valor Predictivo de las Pruebas , Unión Proteica , Curva ROC , Vacunas contra el SIDAS/químicaRESUMEN
Adenovirus 5 (Ad5) vectors show promise as human immunodeficiency virus vaccine candidates. Indian rhesus macaques vaccinated with Ad5-gag controlled simian-human immunodeficiency virus SHIV89.6P viral replication in the absence of Env immunogens that might elicit humoral immunity. Here we immunized 15 macaques using either a homologous Ad5-gag/Ad5-gag (Ad5/Ad5) or a heterologous DNA-gag/Ad5-gag (DNA/Ad5) prime-boost regimen and challenged them with a high dose of simian immunodeficiency virus SIVmac239. Macaques vaccinated with the DNA/Ad5 regimen experienced a brief viral load nadir of less than 10,000 viral copies per ml blood plasma that was not seen in Mamu-A*01-negative DNA/Ad5 vaccinees, Mamu-A*01-positive Ad5/Ad5 vaccinees, or vaccine-naive controls. Interestingly, most of these animals were not durably protected from disease progression when challenged with SIVmac239. To investigate the reasons underlying this short-lived vaccine effect, we investigated breadth of the T-cell response, immunogenetic background, and viral escape from CD8+ lymphocytes that recognize immunodominant T-cell epitopes. We show that these animals do not mount unusually broad cellular immune response, nor do they express unusual major histocompatibility complex class I alleles. Viral recrudescence occurred in four of the five Mamu-A*01-positive vaccinated macaques. However, only a single animal in this group demonstrated viral escape in the immunodominant Gag181-189 CM9 response. These results suggest that viral "breakthrough" in vaccinated animals and viral escape are not inextricably linked and underscore the need for additional research into the mechanisms of vaccine failure.
Asunto(s)
Productos del Gen gag/inmunología , Vacunas contra el SIDAS/administración & dosificación , Síndrome de Inmunodeficiencia Adquirida del Simio/prevención & control , Linfocitos T Citotóxicos/metabolismo , Vacunas de ADN/administración & dosificación , Viremia/inmunología , Adenoviridae/genética , Animales , Anticuerpos Antivirales/sangre , Antígenos de Histocompatibilidad Clase I/aislamiento & purificación , Macaca mulatta , Recombinación Genética , Vacunas contra el SIDAS/inmunología , Virus de la Inmunodeficiencia de los Simios/genética , Virus de la Inmunodeficiencia de los Simios/inmunología , Vacunación , Vacunas de ADN/inmunología , Carga Viral , Viremia/patologíaRESUMEN
Extensive polymorphism at the major histo-compatibility complex (MHC) is thought to confer immune protection on populations. A New World primate, the cotton-top tamarin (Saguinus oedipus), has a high prevalence of ulcerative colitis and adenocarcinoma of the colon and dies after infection with several human viruses. Lymphocytes from all animals tested expressed on common MHC class I allelic product. Another MHC class I allelic product was expressed by 39 of 41 tested animals. Four other allelic products were also expressed on the lymphocytes of these animals at a frequency of greater than 50%. MHC class II gene products, however, were polymorphic. Restriction fragment length polymorphism analysis confirmed that there were a limited number of cotton-top tamarin MHC class I alleles, whereas the MHC class II gene loci were polymorphic. This sharing of MHC class I alleles is unprecedented in a higher primate species and may play a role in the susceptibility of this endangered species to pathogens.
Asunto(s)
Callitrichinae/genética , Genes MHC Clase I , Polimorfismo Genético , Saguinus/genética , Alelos , Animales , Electroforesis en Gel de Poliacrilamida , Genes MHC Clase II , Antígenos de Histocompatibilidad Clase I/análisis , Antígenos de Histocompatibilidad Clase I/genética , Antígenos de Histocompatibilidad Clase II/análisis , Antígenos de Histocompatibilidad Clase II/biosíntesis , Antígenos de Histocompatibilidad Clase II/genética , Focalización Isoeléctrica , Polimorfismo de Longitud del Fragmento de Restricción , Pruebas de Precipitina , Saguinus/inmunologíaRESUMEN
The MHC class I genes of the New World primate, the cotton-top tamarin (Saguinus oedipus), are an exception to the high polymorphism and variability displayed by this multigene family. We report the isolation of the first two processed pseudogenes from the MHC region in primates. These two MHC class I-processed pseudogenes (MHC-PS1 and -PS2) were found in several species of New World primates, suggesting a possible explanation for the cotton-top tamarin's limited MHC class I diversity. The pattern of synonymous and nonsynonymous substitutions in PS1 suggests that the gene that gave rise to this processed pseudogene was once subject to selection for variability in the peptide binding region and might, therefore, have been functional. Additionally, PSI is not closely related to the expressed cotton-top tamarin's MHC class I genes, but does show some similarity to So-N1, a tamarin pseudogene from which no transcript has been found. Thus, PS1 may represent a remnant of a once active MHC class I gene that is no longer functional in the cotton-top tamarin. The MHC class I loci in primates, therefore, appear to be evolving by a continual process of duplication and inactivation. This process seems to be exaggerated in New World primates and may in part be responsible for the cotton-top tamarin's limited MHC class I diversity.
Asunto(s)
Genes MHC Clase I/inmunología , Seudogenes/inmunología , Saguinus/genética , Saguinus/inmunología , Animales , Secuencia de Bases , Clonación Molecular , Masculino , Datos de Secuencia Molecular , Familia de Multigenes/inmunología , Polimorfismo Genético/inmunología , Procesamiento Postranscripcional del ARN/inmunologíaRESUMEN
One of the best animal approaches for testing HIV vaccines is the challenge of vaccinated rhesus macaques with SHIV or SIV. Production of rhesus macaques in which all of the MHC class I and II alleles are known represents an opportunity to characterize the entire immune response to SIV and should be an invaluable resource for understanding pathogenesis and vaccine-induced immune responses. Unfortunately, there are few MHC-defined rhesus macaques available for vaccine research. Selective breeding supports the production of limited numbers of macaques that express particular MHC class I alleles. If both parents express the allele of interest, only three quarters of the offspring will express the same allele. However, assisted reproductive technologies, such as in vitro fertilization (IVF) and embryo transfer, can be used for production of MHC-defined macaques, expressing multiple MHC class I and II molecules for which SIV peptides, tetramers and ELISPOT assays exist. Here, we report the birth of MHC-defined rhesus monkeys produced by assisted reproductive technology. Continued improvements in assisted reproductive technologies in rhesus monkeys will enable us to develop a unique prototypic animal production program for the creation of MHC-defined and genetically-identical monkeys for vaccine research.