ABSTRACT
The cerebral accumulation of beta-amyloid (Abeta) is a pathological hallmark of Alzheimer's disease (AD). Abeta vaccination or anti-Abeta specific antibodies may be a possible therapeutic option for AD. Previously, we demonstrated variation in the humoral response between B6D2F1 and C57BL/6 during short term (14 weeks) Abeta immunization. In the present study, we determined the humoral and cellular immune responses in these same mouse strains to a longer period of Abeta vaccination and further refined the major B cell epitope to Ass1-7. B6D2F1 mice generated a greater humoral and Th1 immune response versus C57BL/6 mice. Immunization with 25 microg Abeta produced a greater T cell response in B6D2F1 mice compared to 50 or 100 microg Abeta but resulted in comparable humoral immunity. Thus, Abeta vaccination is affected by the genetic background and amount of Abeta peptide used as immunogen. These data may help explain some differences observed in Abeta immunization studies in mice of various genetic backgrounds and aid in the design of Abeta vaccines.
Subject(s)
Alzheimer Vaccines/immunology , Amyloid beta-Peptides/immunology , Antibody Formation , Immunity, Cellular , Amyloid beta-Peptides/administration & dosage , Animals , Antibodies/blood , Epitope Mapping , Epitopes/chemistry , Epitopes/immunology , Immunoglobulin G/blood , Interferon-gamma/analysis , Interleukin-2/analysis , Interleukin-4/analysis , Interleukin-5/analysis , Lymphocyte Activation , Mice , Mice, Inbred C57BL , Mice, Inbred DBA , Species Specificity , Time Factors , VaccinationABSTRACT
Amyloid beta (A beta) immunization of amyloid precursor protein (APP)-transgenic (tg) mice with human A beta induces humoral immunity, however, the immune response to endogenous rodent A beta is unknown. Fourteen-month J20 APP-tg mice and non-tg littermates were immunized subcutaneously followed by chronic intranasal boosting with human or rodent A beta peptide and adjuvant LT(R192G). Rodent A beta-immunized APP-tg mice had anti-rodent A beta antibody levels of 257.8 micrograms/ml and those immunized with human A beta had anti-human A beta antibodies of 120.8 micrograms/ml. Non-tg littermates had anti-rodent and anti-human A beta antibody concentrations of 98.8 and 231.1 microgram/ml, respectively. Inter-species cross-reactivity was minimal. Anti-human A beta antibodies were predominately IgG1 and IgG2b, while anti-rodent A beta antibodies were equally IgG1, IgG2a, and IgG2b. Anti-human A beta antibodies recognized an epitope within human A beta1-9. Anti-rodent A beta antibodies did not stain Alzheimer's disease (AD) plaques but bound some plaques in APP-tg mice. Splenocytes proliferated modestly to their respective antigen and secreted low levels of IL-2 and IFN-gamma. Therefore, immunizing APP-tg and non-tg mice with rodent A beta resulted in a species-specific humoral response with modest T cell reactivity.
Subject(s)
Alzheimer Disease/immunology , Amyloid beta-Peptides/immunology , Antibodies/immunology , Antibody Formation/immunology , Immunization , Alzheimer Disease/physiopathology , Animals , Animals, Genetically Modified , Antibodies/blood , Antibody Formation/genetics , Cells, Cultured , Disease Models, Animal , Epitopes/immunology , Female , Humans , Immunoglobulin G/blood , Immunoglobulin G/immunology , Interferon-gamma/immunology , Interleukin-2/immunology , Male , Mice , Plaque, Amyloid/immunology , Species Specificity , T-Lymphocytes/immunologyABSTRACT
Amyloid beta (Abeta) protein immunotherapy lowers cerebral Abeta and improves cognition in mouse models of Alzheimer's disease (AD). Here we show that Caribbean vervet monkeys (Chlorocebus aethiops, SK) develop cerebral Abeta plaques with aging and that these deposits are associated with gliosis and neuritic dystrophy. Five aged vervets were immunized with Abeta peptide over 10 months. Plasma and cerebral spinal fluid (CSF) samples were collected periodically from the immunized vervets and five aged controls; one monkey per group expired during the study. By Day 42, immunized animals generated plasma Abeta antibodies that labeled Abeta plaques in human, AD transgenic mouse and vervet brains; bound Abeta1-7; and recognized monomeric and oligomeric Abeta but not full-length amyloid precursor protein nor its C-terminal fragments. Low anti-Abeta titers were detected in CSF. Abetax-40 levels were elevated approximately 2- to 5-fold in plasma and decreased up to 64% in CSF in immunized vervets. Insoluble Abetax-42 was decreased by 66% in brain homogenates of the four immunized animals compared to archival tissues from 13 age-matched control vervets. Abeta42-immunoreactive plaques were detected in frontal cortex in 11 of the 13 control animals, but not in six brain regions examined in each of the four immunized vervets. No T cell response or inflammation was observed. Our study is the first to demonstrate age-related Abeta deposition in the vervet monkey as well as the lowering of cerebral Abeta by Abeta vaccination in a non-human primate. The findings further support Abeta immunotherapy as a potential prevention and treatment of AD.
Subject(s)
Alzheimer Disease/prevention & control , Alzheimer Vaccines/administration & dosage , Amyloid beta-Peptides/administration & dosage , Central Nervous System/metabolism , Chlorocebus aethiops/metabolism , Peptide Fragments/administration & dosage , Age Factors , Alzheimer Disease/genetics , Alzheimer Disease/pathology , Animals , Blotting, Western , Central Nervous System/pathology , Chlorocebus aethiops/blood , Chlorocebus aethiops/cerebrospinal fluid , Electrophoresis, Polyacrylamide Gel , Enzyme-Linked Immunosorbent Assay , Female , Humans , Image Processing, Computer-Assisted , Immunohistochemistry , Male , Mice , Mice, Transgenic , Neocortex/metabolism , Neocortex/pathology , Plaque, Amyloid/metabolism , Plaque, Amyloid/pathology , Time FactorsABSTRACT
En los últimos años, la participación del sistema inmune innato en el desarrollo de la pre-eclampsia ha sido el objetivo de numerosos estudios. Sin embargo, el rol de las células agresoras naturales (NK) en esta patología no ha sido totalmente aclarado. Las células NK, componentes del sistema inmune innato, poseen actividad citotóxica espontánea, y secretan citoquinas tales como interferón gamma (INF-y ) y Factor de Necrosis Tumoral alfa (TNF-alfa). En el presente estudio hemos analizado la actividad funcional y el inmunofenotipo de células NK obtenidas desde sangre periférica de pacientes con pre-eclampsia, mujeres sanas embarazadas y mujeres sanas no embarazadas. Se cuantificó la actividad cititóxica usando el ensayo de liberación de51cromo. La producción de citoquinas en respuesta a activadores policlonales y el inmunofenotipo (CD3-CD16+CD56+) fueron determinados por citometría de flujo. Estos parámetros no evidenciaron diferencias significativas entre los grupos estudiados; sin embargo, en las pacientes con pre-eclampsia se observa una tendencia hacia una menor citotoxicidad y menor producción de TNF-alfa en células NK estimulada sin vitro, y una proporción aumentada del subtipo celular NK CD56-CD16+ en sangre periférica en relación con los otros dos grupos estudiados.
NK cells functionality during pregnancy. During the last few years, the role of innate immune system in development of pre-eclampsia has been the focus of a number of studies. However, the role of natural killer (NK) cells in pregnancy and pre-eclampsia has not been totally clarified. NK cells, an important component of innate immune system, normally exhibit spontaneus cytolytic activity and secrete cytokines such as interferon gamma (IFN-y) and tumor necrosis factor alpha (TNF-alpha). In current paper, we studied functional activity and immunophenotype of peripheral blood NKcells obtained from patients with pre-eclampsia, healthy pregnant women and non-pregnant healthy women. For this purpose, we quantified cytolytic activity using 51chromium release assay. We determined cytokine production in response to polyclonal activators and cells immunophenotype (CD3-CD16+CD56+) by flow cytometry. We found no significant differences in these parameters among the three groups studied, however, in patients with pre-eclampsia, there is a tendency to a decreased cytotoxic activity and less production of TNF-alpha by NK cells in vitro as well as an increased proportion of the NK subset CD56-CD16+, in peripheral blood.
Subject(s)
Humans , Female , Pregnancy , Pre-Eclampsia/diagnosis , Pre-Eclampsia/bloodABSTRACT
We studied eight affected and four unaffected individuals from a Colombian family with autosomal dominant diffuse high bone density. Affected individuals have normal, proportional height and high serum alkaline phosphatase activity. Radiographically, affected members exhibit generalized, symmetrically diffuse endosteal hyperostosis of the long bones and skull with narrow medullary cavities and loss of the diploë, respectively. There is no periosteal reaction or decreased hematopoiesis. Furthermore, osteosclerosis affects vertebral bodies, ribs, pelvis, mandible, clavicles, and scapulae. Bone mineral density is 2.4-7.3 SD above the mean for age and gender in affected individuals. Affected vs. unaffected individuals' Z-scores were (mean +/- SD) 5.03 +/- 1.77 vs. 0.08 +/- 0.97, respectively, P = 0.0004). Three affected subjects older than 40 yr old lost bone mass in 6 yr. No dysmorphism, abnormal facial features, bone fractures, or cranial nerve involvement was found. The pattern of inheritance, the absence of asymmetries and malformations, the increased serum alkaline phosphatase, the peak bone mass that appears to decrease physiologically with age, and the involvement of cortical and trabecular bone suggest a new variant of hyperostosis/osteosclerosis that affects the entire skeleton.
Subject(s)
Alkaline Phosphatase/blood , Genes, Dominant , Hyperostosis/genetics , Osteosclerosis/genetics , Osteosclerosis/metabolism , Adult , Aged , Bone Density , Bone and Bones/diagnostic imaging , Bone and Bones/metabolism , Female , Humans , Hyperostosis/diagnostic imaging , Hyperostosis/metabolism , Male , Middle Aged , Osteosclerosis/diagnostic imaging , Pedigree , Radiography , Radionuclide ImagingABSTRACT
Alzheimer's disease is the most prevalent form of dementia worldwide. Therapies are desperately needed to prevent and cure the disease. Mouse models of amyloid-beta deposition [APP and PSAPP transgenic (tg) mice] have been useful in determining the role of amyloid-beta (A beta) in both the pathogenesis and cognitive changes in AD. In addition, they have allowed scientists to investigate potential AD therapies in living animals. Active and passive A beta immunizations have been employed successfully in APP and PSAPP tg mice to lower cerebral A beta levels and improve cognition. Optimization of immunization protocols and characterization of immune responses in wildtype mice have been reported. Based on the promising results of A beta immunization studies in mice, a clinical trial was initiated for A beta vaccination in humans with AD. Although no adverse effects were reported in the Phase I safety trials, about 5% of AD patients in the phase II clinical trial developed meningoencephalitis, ending the trial prematurely in March 2002. Studies in AD mouse models and wildtype mice may help elucidate the mechanism for these unwanted side effects and will be useful for testing newer, safer vaccines for future use in human clinical trials.
Subject(s)
Alzheimer Disease/prevention & control , Amyloid beta-Peptides/immunology , Immunization , Animals , Animals, Wild , Humans , Immunization, Passive , Mice , Mice, Transgenic , VaccinationABSTRACT
El feto considerado como un trasplante semialogénico que se desarrolla por nueve meses en el vientre materno, nos hace vislumbrar la idea de que existen mecanismos protectores que impiden que se induzca daño a dicho feto y permitan su sobrevida y su tolerancia. Estos mecanismos afinados muy sutilmente y localizados en un sitio "privilegiado" evitan que el feto sea rechazado, mientras que la madre sigue manteniendo la homeostasis perfecta de su sistema inmunológico. La tolerancia hacia al feto semialogénico por el sistema inmune materno es un mecanismo activo. Mientras que el tejido fetal se previene de ser reconocido como tejido extraño y de ser rechazado por las células del sistema inmune materno, la placenta actúa como barrera inmunológica activa, en el sentido que permite que dos organismos antigénicamente diferentes se toleren el uno al otro. La tolerancia hacia el feto se lleva a cabo por la interacción de las células natural killer con sus respectivos receptores, las moléculas HLA G, HLA C, el balance de las diferentes subpoblaciones de citoquinas Th1 y Th2, mecanismos de apoptosis y la síntesis de factores reguladores como citoquinas y hormonas. Todos estos mecanismos involucrados en la tolerancia maternofetal se correlacionan los unos con los otros, existiendo una verdadera integración de estos elementos, que aun cuando son de origen y modo de acción diferentes, resultan en la existencia de otro ser humano
