Parastrongylus cantonensis in a nonhuman primate, Florida

Parastrongylus (= Angiostrongylus) cantonensis is a parasitic nematode of Norway rats throughout tropical regions. This parasite is neurotropic and causes disease and death in humans and other mammals. We report the first identification of P. cantonensis as the cause of a debilitating neurologic disease in a captive primate in Florida.     

Rhesus offspring produced by intracytoplasmic injection of testicular sperm and elongated spermatids

OBJECTIVE: To establish pregnancies in rhesus monkeys using testicular sperm and elongated spermatids injected into oocytes. DESIGN: Comparative animal study. SETTING: Regional Primate Research Center. ANIMAL(S): Prime, fertile rhesus monkeys. INTERVENTION(S): Oocytes collected by laparoscopy from gonadotropin-stimulated female rhesus monkeys were injected with testicular sperm or elongated spermatids obtained from the testis of males. Cleavage stage embryos were transferred to surrogate females. MAIN OUTCOME MEASURE(S): Fertilization, embryo cleavage, and the establishment of pregnancies. Fertilization failures were fixed and processed for the detection of microtubules and chromatin configurations. RESULT(S): Fertilization, assessed by the presence of two pronuclei within 15 hours after injection, was 60% for intracytoplasmic sperm injection with testicular sperm and 47% for elongated spermatid injection. Fertilized zygotes co-cultured in Connaughts Medical Research Labs (CMRL) medium on a Buffalo Rat Liver cell monolayer resulted in hatched blastocysts after testicular sperm extraction-intracytoplasmic sperm injection and elongated spermatids. Embryos transferred at the 4- to 8-cell stage gave rise to three pregnancies: 2/3 from testicular sperm and 1/1 from an elongated spermatid. Three healthy infants were delivered by cesarean. Oocytes that failed to fertilize typically remained arrested in metaphase of meiosis. CONCLUSION(S): Testicular sperm and elongated spermatids can be used for fertilization in the rhesus monkey resulting in live births.     

The nucleotide sequences of the parathyroid gene in primates (suborder Anthropoidea)

Nucleotide sequences of the parathyroid (PTH) gene of 12 species of primates belonging to suborder Anthropoidea were examined. The PTH gene contains one intron that separates two exons that code the sequence of prepro and PTH, respectively. The intron of the PTH gene in Cebus apella, Callithrix jacchus, and Saguinus oedipus was 102 bp long, whereas a 103-bp intron was observed in the remaining species. Phylogenetic analysis using the nucleotide sequences of PTH revealed that these 12 species of primates of suborder Anthropoidea could be divided into two groups of the infraorder Platyrrhini (C. apella, C. jacchus, and S. oedipus) and the infraorder Catarrhini (Macaca fascicularis, Macaca fuscata, Cercopithecus aethiops, Papio hamadryas, Presbytes obscura, Hylobates lar, Pongo pygmaeus, Pan troglodytes, and Pan paniscus). The latter infraorder could be further subdivided into two subgroups belonging to the superfamily Cercopithecoidea (M. fascicularis, M. fuscata, C. aethiops, P. hamadryas, and P. obscura) and the superfamily Hominoidea (H. lar, P. pygmaeus, P. troglodytes, and P. paniscus). The deduced amino acid sequences of PTH gene between 12 species of nonhuman primates and human revealed no amino acid substitution in mature PTH among orangutans, chimpanzees, and humans. The results indicated that the PTH gene is very conserved among primates, especially between great apes and humans. The apes are the most suitable animals to be used for studying the bone metabolism and applying the knowledge to clinical use in humans.     

Immune Responses Against the Myelin/Oligodendrocyte Glycoprotein in Experimental Autoimmune Demyelination

Myelin/oligodendrocyte glycoprotein (MOG) is a surface-exposed antigen of myelin and an important target for autoimmune responses which mediate inflammatory demyelination in the central nervous system. Experimentally, MOG induces strong pathogenic T cell responses in many strains of laboratory animals. Immunological studies in humans also identify MOG as a surprisingly prevalent antigenic molecule among the myelin proteins. In addition, the encephalitogenic properties of MOG are linked to the induction of antibody responses which have been demonstrated to directly promote central nervous system demyelination, a hallmark neuropathological feature in disorders such as human multiple sclerosis. Factors responsible for autoimmunity to MOG likely include genetic influences as well as other mechanisms, which are the subject of intense investigation. This article reviews experimental data currently available on specificity and pathogenic roles of T cell and antibody responses against MOG, which have implications relevant to multiple sclerosis and related disorders.     

Graphical analysis of 2-[18F]FA binding to nicotinic acetylcholine receptors in rhesus monkey brain

External imaging of nicotinic acetylcholine receptors (nAChRs) using techniques such as PET would help to clarify the roles of these receptors in the physiology and pathology of brain function. Here we report the results of quantitative PET studies of cerebral nAChRs with 2-[(18)F]fluoro-A-85380 (2-[(18)F]FA) in rhesus monkeys. Data from dynamic PET scans were analyzed using graphical methods. Binding potential (BP) values of 2.0, 0.4, 0.3, and 0.03 observed in the thalamus (Th), cortex (Cx), striatum (Str), and cerebellum (Cb), respectively, were consistent with the pattern of alpha(4)beta(2) nAChR distribution in monkey brain. The high value of 2-[(18)F]FA-specific binding in the rhesus monkey Th and low level of that in Cb compared with nonspecific accumulation of radioactivity in these structures allowed use of Cb as a reference region for calculation of BP and volume of distribution of specific binding (VDsb) in Th by graphical methods, both with and without the plasma input function. In contrast, estimation of 2-[(18)F]FA specific binding in low-receptor-density regions such as Cx and Str required assessment of nondisplaceable volume of distribution (VDnd) in a separate study and measurement of nonmetabolized radioligand concentrations in the plasma. For accurate quantitation of 2-[(18)F]FA-specific binding by graphical analysis, PET studies should last up to 7 h due to the slow kinetics of 2-[(18)F]FA brain distribution. Further, to avoid substantial underestimation in measured BP values the doses of administered 2-[(18)F]FA should not exceed 0.1 nmol/kg body weight. The findings suggest that 2-[(18)F]FA is a promising ligand for quantitation of nAChRs in human brain.     

Effects of specific anti-B and/or anti-plasma cell immunotherapy on antibody production in baboons: depletion of CD20- and CD22-positive B cells does not result in significantly decreased production of anti-alphaGal antibody

Anti-Galalpha1-3Gal antibodies (antialphaGal Ab) are a major barrier to clinical xenotransplantation as they are believed to initiate both hyperacute and acute humoral rejection. Extracorporeal immunoadsorption (EIA) with alphaGal oligosaccharide columns temporarily depletes antialphaGal Ab, but their return is ultimately associated with graft destruction. We therefore assessed the ability of two immunotoxins (IT) and two monoclonal antibodies (mAb) to deplete B and/or plasma cells both in vitro and in vivo in baboons, and to observe the rate of return of antialphaGal Ab following EIA. The effects of the mouse anti-human IT anti-CD22-ricin A (proportional to CD22-IT, directed against a B cell determinant) and anti-CD38-ricin A (proportional to CD38-IT, B and plasma cell determinant) and the mouse anti-human anti-CD38 mAb (proportional to CD38 mAb) and mouse/human chimeric anti-human anti-CD20 mAb (proportional to CD20 mAb, Rituximab, B cell determinant) on B and plasma cell depletion and antialphaGal Ab production were assessed both in vitro and in vivo in baboons (n = 9) that had previously undergone splenectomy. For comparison, two baboons received nonmyeloablative whole body irradiation (WBI) (300 cGy), and one received myeloablative WBI (900 cGy). Depletion of B cells was monitored by flow cytometry of blood, bone marrow (BM) and lymph nodes (LN), staining with anti-CD20 and/or anti-CD22 mAbs, and by histology of LN. EIA was carried out after the therapy and antialphaGal Ab levels were measured daily. In vitro proportional to CD22-IT inhibited protein synthesis in the human Daudi B cell line more effectively than proportional to CD38-IT. Upon differentiation of B cells into plasma cells, however, less inhibition of protein synthesis after proportional to CD22-IT treatment was observed. Depleting CD20-positive cells in vitro from a baboon spleen cell population already depleted of granulocytes, monocytes, and T cells led to a relative enrichment of CD20-negative cells, that is plasma cells, and consequently resulted in a significant increase in antialphaGal Ab production by the remaining cells, whereas depleting CD38-positive cells resulted in a significant decrease in antialphaGal Ab production. In vivo, WBI (300 or 900 cGy) resulted in 100% B cell depletion in blood and BM, > 80% depletion in LN, with substantial recovery of B cells after 21 days and only transient reduction in antialphaGal Ab after EIA. Proportional to CD22-IT depleted B cells by > 97% in blood and BM, and by 60% in LN, but a rebound of B cells was observed after 14 and 62 days in LN and blood, respectively. At 7 days, serum antialphaGal IgG and IgM Ab levels were reduced by a maximum of 40-45% followed by a rebound to levels up to 12-fold that of baseline antialphaGal Ab by day 83 in one baboon. The results obtained with proportional to CD38-IT were inconclusive. This may have been, in part, due to inadequate conjugation of the toxin. Cell coating was 100% with proportional to CD38 mAb, but no changes in antialphaGal Ab production were observed. Proportional to CD20 mAb resulted in 100% depletion of B cells in blood and BM, and 80% in LN, with recovery of B cells starting at day 42. Adding 150cGy WBI at this time led to 100% depletion of B cells in the BM and LN. Although B cell depletion in blood and BM persisted for > 3 months, the reduction of serum antialphaGal IgG or IgM Ab levels was not sustained beyond 2 days. Proportional to CD20 mAb + WBI totally and efficiently depleted CD20- and CD22-positive B cells in blood, BM, and LN for > 3 months in vivo, but there was no sustained clinically significant reduction in serum antialphaGal Ab. The majority of antibody secretors are CD38-positive cells, but targeting these cells in vitro or in vivo with proportional to CD38-IT was not very effective. These observations suggest that CD20-and CD22-positive B cells are not the major source of antialphaGal Ab production. Future efforts will be directed towards suppression of plasma cell function.     

Rapid Action of Oestrogen in Luteinising Hormone-Releasing Hormone Neurones: The Role of GPR30

Previously, we have shown that 17β-oestradiol (E₂) induces an increase in firing activity and modifies the pattern of intracellular calcium ([Ca²⁺]_i) oscillations with a latency < 1 min in primate luteinising hormone-releasing hormone (LHRH) neurones. A recent study also indicates that E₂, the nuclear membrane impermeable oestrogen, oestrogen-dendrimer conjugate, and the plasma membrane impermeable oestrogen, E₂-BSA conjugate, all similarly stimulated LHRH release within 10 min of exposure in primate LHRH neurones, indicating that the rapid action of E₂ is caused by membrane signalling. The results from a series of studies further suggest that the rapid action of E₂ in primate LHRH neurones appears to be mediated by GPR30. Although the oestrogen receptor antagonist, ICI 182, 780, neither blocked the E₂-induced LHRH release nor the E₂-induced changes in [Ca²⁺]_i oscillations, E₂ application to cells treated with pertussis toxin failed to result in these changes in primate LHRH neurones. Moreover, knockdown of GPR30 in primate LHRH neurones by transfection with human small interference RNA for GPR30 completely abrogated the E₂-induced changes in [Ca²⁺]_i oscillations, whereas transfection with control siRNA did not. Finally, the GPR30 agonist, G1, resulted in changes in [Ca²⁺]_i oscillations similar to those observed with E₂. In this review, we discuss the possible role of G-protein coupled receptors in the rapid action of oestrogen in neuronal cells.     

Cortical connections of the caudal subdivision of the dorsolateral area (V4) in monkeys.

Evidence suggests that all primates have rostral and caudal subdivisions in the region of visual cortex identified as the dorsolateral area (DL) or V4. However, the connections of DL/V4 have not been examined in terms of these subdivisions. To determine the cortical connections of the caudal subdivision of DL (DLC) in squirrel monkeys, injections of the neuroanatomical tracers wheat germ agglutinin conjugated to horseradish peroxidase, Diamidino Yellow, and Fluoro-Gold were made in cortex rostral to V II. To aid in delineating the borders of DLC, cortex was also evaluated architectonically. Based on similar patterns of connections, DLC extends from dorsolateral to ventrolateral cortex. DLC receives strong, feedforward input from V II and projects in a feedforward fashion to the rostral subdivision of DL (DLR) and caudal inferior temporal (IT) cortex, including a separate location in the inferior temporal sulcus. DLC has weaker connections with V I, the middle temporal area (MT), cortex rostral to MT in the location of the fundal superior temporal area (FST), cortex dorsal to DLC, ventral cortex rostral to V II, and cortex in the frontal lobe, lateral to the inferior arcuate sulcus. Only lateral DLC has connections with V I, and only dorsolateral DLC has connections with cortex dorsal to DLC. The topographic organization of DLC was inferred from its connections with V II. Thus, dorsolateral DLC represents the lower field, lateral DLC represents central vision, and ventrolateral DLC represents the upper field. Limited observations were made on DLR. Confirming earlier observations (Cusick and Kaas: Visual Neurosci. 1:211, 1988), DLR is paler than DLC myeloarchitectonically. DLR receives only sparse feedforward input from V II, but stronger input from DLC. DLR has strong connections with cortex just rostral to dorsal V II, ventral posterior parietal cortex in the sylvian fissure, MT, the medial superior temporal area, FST, and the inferior temporal sulcus. DLR also shares connections with IT cortex. Thus, while both DLC and DLR are involved in the pathway relaying visual information to IT cortex, an area specialized for object vision, DLR also projects densely to areas such as MT involved in the pathway relaying to posterior parietal cortex, a region specialized for spatial localization and motion perception.     

Xenotransplantation: back to the future?

The field of xenotransplantation has fluctuated between great optimism and doubts over the last 50 years. The initial clinical attempts were extremely ambitious but faced technical and ethical issues that prompted the research community to go back to preclinical studies. Important players left the field due to perceived xenozoonotic risks and the lack of progress in pig‐to‐nonhuman‐primate transplant models. Initial apparently unsurmountable issues appear now to be possible to overcome due to progress of genetic engineering, allowing the generation of multiple‐xenoantigen knockout pigs that express human transgenes and the genomewide inactivation of porcine endogenous retroviruses. These important steps forward were made possible by new genome editing technologies, such as CRISPR/Cas9, allowing researchers to precisely remove or insert genes anywhere in the genome. An additional emerging perspective is the possibility of growing humanized organs in pigs using blastocyst complementation. This article summarizes the current advances in xenotransplantation research in nonhuman primates, and it describes the newly developed genome editing technology tools and interspecific organ generation.     

Durable immunogenicity,adaptation to emerging variants,and low-dose efficacy of an AAV-based COVID-19 vaccine platform in macaques

1. Download : Download high-res image (97KB)
2. Download : Download full-size image