Kathrine Phillippi-Falkenstein

Persistence of Borrelia burgdorferi in Rhesus Macaques following Antibiotic Treatment of Disseminated Infection

The persistence of symptoms in Lyme disease patients following antibiotic therapy, and their causes, continue to be a matter of intense controversy. The studies presented here explore antibiotic efficacy using nonhuman primates. Rhesus macaques were infected with B. burgdorferi and a portion received aggressive antibiotic therapy 4–6 months later. Multiple methods were utilized for detection of residual organisms, including the feeding of lab-reared ticks on monkeys (xenodiagnosis), culture, immunofluorescence and PCR. Antibody responses to the B. burgdorferi-specific C6 diagnostic peptide were measured longitudinally and declined in all treated animals. B. burgdorferi antigen, DNA and RNA were detected in the tissues of treated animals. Finally, small numbers of intact spirochetes were recovered by xenodiagnosis from treated monkeys. These results demonstrate that B. burgdorferi can withstand antibiotic treatment, administered post-dissemination, in a primate host. Though B. burgdorferi is not known to possess resistance mechanisms and is susceptible to the standard antibiotics (doxycycline, ceftriaxone) in vitro, it appears to become tolerant post-dissemination in the primate host. This finding raises important questions about the pathogenicity of antibiotic-tolerant persisters and whether or not they can contribute to symptoms post-treatment.

A Non-Human Primate Model for Gluten Sensitivity

Background and Aims Gluten sensitivity is widespread among humans. For example, in celiac disease patients, an inflammatory response to dietary gluten leads to enteropathy, malabsorption, circulating antibodies against gluten and transglutaminase 2, and clinical symptoms such as diarrhea. There is a growing need in fundamental and translational research for animal models that exhibit aspects of human gluten sensitivity. Methods Using ELISA-based antibody assays, we screened a population of captive rhesus macaques with chronic diarrhea of non-infectious origin to estimate the incidence of gluten sensitivity. A selected animal with elevated anti-gliadin antibodies and a matched control were extensively studied through alternating periods of gluten-free diet and gluten challenge. Blinded clinical and histological evaluations were conducted to seek evidence for gluten sensitivity. Results When fed with a gluten-containing diet, gluten-sensitive macaques showed signs and symptoms of celiac disease including chronic diarrhea, malabsorptive steatorrhea, intestinal lesions and anti-gliadin antibodies. A gluten-free diet reversed these clinical, histological and serological features, while reintroduction of dietary gluten caused rapid relapse. Conclusions Gluten-sensitive rhesus macaques may be an attractive resource for investigating both the pathogenesis and the treatment of celiac disease.

Use of a Recombinant Envelope Protein Subunit Antigen for Specific Serological Diagnosis of West Nile Virus Infection

ABSTRACT Serological diagnosis of West Nile virus (WNV) infection is complicated by extensive antigenic cross-reactivity with other closely related flaviviruses, such as St. Louis encephalitis virus. Here we describe a recombinant, bacterially expressed antigen equivalent to structural domain III of the WNV envelope protein that has allowed clear discrimination of antibody responses to WNV from those against other related flaviviruses in indirect enzyme-linked immunosorbent assays using standardized control antisera and field-collected samples.

Clinical and immunopathologic alterations in rhesus macaques affected with globoid cell leukodystrophy.

Globoid cell leukodystrophy, or Krabbes disease, is a severe disorder of the central and peripheral nervous system caused by the absence of galactocerebrosidase (GALC) activity. Herein, we describe the clinical, neuropathological, histochemical, and immunohistological features observed in rhesus macaques affected with Krabbes disease. Clinical signs included pronounced muscle tremors of head and limbs, difficulty ambulating, ataxia, hypermetria, proprioceptive deficits, and respiratory abnormalities. Histopathologically, all animals presented with evidence of demyelination in the peripheral and central nervous systems and accumulation of mononuclear and multinuclear globoid cells in the cerebral and cerebellar white matter associated with severe gliosis. Using immunohistochemistry and multi-label confocal microscopy, it was determined that globoid cells were CD68+, HAM56+, LN5+, CD163+, IBA-1+, and Glut-5+, suggesting that both peripheral blood-derived monocytes/macrophages and resident parenchymal microglia gave rise to globoid cells. Interestingly, many of the globoid cells and parenchymal microglia with a more ameboid morphology expressed HLA-DR, indicating immune activation. Increased expression of iNOS, TNF-alpha, and IL-1 beta were observed in the affected white matter, colocalizing with globoid cells, activated microglia, and astrocytes. Cytokine mRNA levels revealed markedly increased gene expression of CCL2 in the brain of affected macaques. CCL2-expressing cells were detected throughout the affected white matter, colocalizing with GFAP+ cells and astrocytes. Collectively, these data suggest that dysregulation of monocyte/macrophage/microglia and up-regulation of certain cytokines may contribute to the pathogenesis of Krabbes disease.

Age as a determinant of reproductive success among captive female rhesus macaques (Macaca mulatta).

A retrospective analysis was performed on fertility outcomes among a colony of captive Indian rhesus monkeys. The analysis covered over 30 years and was based on 1443 females with a total of 11,453 pregnancies. Various determinants of fertility were assessed including birth rates, pregnancy loss, infant survival, interbirth intervals, and interval from last birth to death. Binary variables were analyzed with generalized linear models with random intercepts, while linear mixed models were used for analysis of continuous variables. Age of the dam was a significant factor in determining whether a pregnancy resulted in a birth and whether an infant survived the first 30 days with primiparous or older mothers being less likely to produce an infant surviving to that age. In contrast, sex proved to be the only significant factor in determining whether an infant lived to 1 year, with females being more likely to survive. The interval between births proved to be affected primarily by dam age, while the late death of an infant depressed the likelihood of an extended time interval between her last birth and her death. Overall, these results demonstrate that maternal age contributes significantly to a decline in fertility and older females can live relatively long periods following birth of their last infant.

Serial electrophysiologic studies in rhesus monkeys with Krabbe disease.

Krabbe disease is a progressive leukodystrophy that results in demyelination in the central and peripheral nervous systems in humans. It has been described in a number of mammalian species including the rhesus monkey. We performed serial nerve conduction studies beginning within the first 2 months of life in four homozygous, two heterozygous, and two normal rhesus monkeys (Macaca mulatta) to characterize the peripheral neuropathy. Mean conduction velocities of the median, ulnar, and tibial nerves were significantly slower in the affected than unaffected monkeys at all ages (P < 0.0001). The conduction velocity differences became more apparent between the affected and unaffected as the monkeys aged. When compared to the unaffected monkeys, the serial conduction velocities suggested occurrence of dysmyelination followed by demyelination in the affected monkeys. These observations provide further insight into the disease process and suggest an early window of opportunity for treating Krabbe disease. Muscle Nerve, 2005

Comparison of efficacy of moxidectin and ivermectin in the treatment of Strongyloides fulleborni infection in rhesus macaques

Background  Strongyloides infection may result in clinical disease or confound experimental protocols that utilize non‐human primates. There is presently a Strongyloides fulleborni infection rate of approximately 27% in the Tulane National Primate Research Centers breeding colonies despite the routine therapeutic and prophylactic use of ivermectin.

A RHESUS MACAQUE MODEL OF STREPTOCOCCUS PNEUMONIAE CARRIAGE

Background  Nasopharyngeal colonization by Streptococcus pneumoniae precedes pneumococcal disease. Elucidation of procedures to prevent or eradicate nasopharyngeal carriage in a model akin to the human would help to diminish the incidence of both pneumonia and invasive pneumococcal disease.

SNP-based genetic characterization of the Tulane National Primate Research Center's conventional and specific pathogen-free rhesus macaque (Macaca mulatta) populations

The rhesus macaque is an important biomedical model organism, and the Tulane National Primate Research Center (TNPRC) has one of the largest rhesus macaque breeding colonies in the United States.