Joshua A. Kramer

Vaccine delivery with microneedle skin patches in nonhuman primates

Peter C. DeMuth1,2, Adrienne V. Li1, Peter Abbink3, Jinyan Liu3, Hualin Li3, Kelly A. Stanley3, Kaitlin M. Smith3, Christy L. Lavine3, Michael S. Seaman3, Joshua A. Kramer4, Andrew D. Miller4, Wuhbet Abraham1,2,5, Heikyung Suh1,2,5, Jamal Elkhader1, Paula T. Hammond2,6,7, Dan H. Barouch3,8, and Darrell J. Irvine1,2,7,8,9 1Department of Biological Engineering, Massachusetts Institute of Technology (MIT), Cambridge, Massachusetts, 02139 USA

Differential contribution of dietary fat and monosaccharide to metabolic syndrome in the common marmoset (Callithrix jacchus).

There is a critical need for animal models to study aspects type 2 diabetes (T2D) pathogenesis and prevention. While the rhesus macaque is such an established model, the common marmoset has added benefits including reduced zoonotic risks, shorter life span, and a predisposition to birth twins demonstrating chimerism. The marmoset as a model organism for the study of metabolic syndrome has not been fully evaluated. Marmosets fed high‐fat or glucose‐enriched diets were followed longitudinally to observe effects on morphometric and metabolic measures. Effects on pancreatic histomorphometry and vascular pathology were examined terminally. The glucose‐enriched diet group developed an obese phenotype and a prolonged hyperglycemic state evidenced by a rapid and persistent increase in mean glycosylated hemoglobin (HgbA1c) observed as early as week 16. In contrast, marmosets fed a high‐fat diet did not maintain an obese phenotype and demonstrated a delayed increase in HgbA1c that did not reach statistical significance until week 40. Consumption of either diet resulted in profound pancreatic islet hyperplasia suggesting a compensation for increased insulin requirements. Although the high‐fat diet group developed atherosclerosis of increased severity, the presence of lesions correlated with glucose intolerance only in the glucose‐enriched diet group. The altered timing of glucose dysregulation, differential contribution to obesity, and variation in vascular pathology suggests mechanisms of effect specific to dietary nutrient content. Feeding nutritionally modified diets to common marmosets recapitulates aspects of metabolic disease and represents a model that may prove instrumental to elucidating the contribution of nutrient excess to disease development.

Small Intestinal Adenocarcinoma in Common Marmosets (Callithrix jacchus)

Small intestinal adenocarcinomas are uncommon neoplasms that are rarely reported in nonhuman primates. These neoplasms are also rare in humans, although they are thought to share a similar pathogenesis with the more common colorectal carcinoma. Herein the authors report the clinical, histologic, immunohistochemical, and molecular characteristics of small intestinal adenocarcinoma in 10 common marmosets (Callithrix jacchus). Retrospective analysis of necropsy records revealed small intestinal carcinoma to be the most common neoplastic cause of morbidity and mortality in aged common marmosets. The average age of affected animals was 6.6 years old, and there was no sex predilection. Nine of 10 (90%) tumors arose within the proximal small intestine near the interface with the duodenum. All cases were characterized by disorganization, loss of polarity, and proliferation of neoplastic epithelial cells along the crypt to midvillous interface. Two of 10 (20%) were defined as carcinoma in situ. Eight of 10 (80%) had some degree of invasion, with lymphatic invasion and lymph node metastasis present in 6 of 10 (60%) animals. Immunohistochemically, 10 of 10 (100%) expressed cytokeratin; 7 of 9 (77%) expressed E-cadherin; and 8 of 9 (88%) expressed β-catenin. The expression of E-cadherin and β-catenin was decreased in the cell membrane and increased in the cytoplasm. No Helicobacter-like bacteria were observed via silver stain, and callitrichine herpesvirus 3 was detected by polymerase chain reaction with equal frequency from neoplastic and nonneoplastic intestinal sections. The tumors described in this population illustrate comparable features to human cases of small intestine carcinoma and may serve as a potential animal model for small intestinal carcinomas.

Acute liver damage associated with innate immune activation in a small nonhuman primate model of Hepacivirus infection.

ABSTRACT Despite its importance in shaping adaptive immune responses, viral clearance, and immune-based inflammation, tissue-specific innate immunity remains poorly characterized for hepatitis C virus (HCV) infection due to the lack of access to acutely infected tissues. In this study, we evaluated the impact of natural killer (NK) cells and myeloid (mDCs) and plasmacytoid (pDCs) dendritic cells on control of virus replication and virus-induced pathology caused by another, more rapidly resolving hepacivirus, GB virus B (GBV-B), in infections of common marmosets. High plasma and liver viral loads and robust hepatitis characterized acute GBV-B infection, and while viremia was generally cleared by 2 to 3 months postinfection, hepatitis and liver fibrosis persisted after clearance. Coinciding with peak viral loads and liver pathology, the levels of NK cells, mDCs, and pDCs in the liver increased up to 3-fold. Although no obvious numerical changes in peripheral innate cells occurred, circulating NK cells exhibited increased perforin and Ki67 expression levels and increased surface expression of CXCR3. These data suggested that increased NK cell arming and proliferation as well as tissue trafficking may be associated with influx into the liver during acute infection. Indeed, NK cell frequencies in the liver positively correlated with plasma (R = 0.698; P = 0.015) and liver (R = 0.567; P = 0.057) viral loads. Finally, soluble factors associated with NK cells and DCs, including gamma interferon (IFN-γ) and RANTES, were increased in acute infection and also were associated with viral loads and hepatitis. Collectively, the findings showed that mobilization of local and circulating innate immune responses was linked to acute virus-induced hepatitis, and potentially to resolution of GBV-B infection, and our results may provide insight into similar mechanisms in HCV infection. IMPORTANCE Hepatitis C virus (HCV) infection has created a global health crisis, and despite new effective antivirals, it is still a leading cause of liver disease and death worldwide. Recent evidence suggests that innate immunity may be a potential therapeutic target for HCV, but it may also be a correlate of increased disease. Due to a lack of access to human tissues with acute HCV infection, in this study we evaluated the role of innate immunity in resolving infection with a hepacivirus, GBV-B, in common marmosets. Collectively, our data suggest that NK cell and DC mobilization in acute hepacivirus infection can dampen virus replication but also regulate acute and chronic liver damage. How these two opposing effects on the host may be modulated in future therapeutic and vaccine approaches warrants further study.

Integumentary System Diseases of Nonhuman Primates

Proper identification of skin lesions is an important aspect of nonhuman primate clinical medicine. While skin disease can be due to an isolated dermatologic condition, many skin conditions are caused by systemic diseases for which part of the clinical spectrum includes skin lesions. In this regard, the skin is a unique window to more generalized health concerns. Furthermore, while sedation is often necessary to examine other major organ systems in nonhuman primates, the skin can be observed in awake animals, adding to its clinical utility. Herein, we describe the basic structure and function of the skin and discuss the concept of the skin as a complex organ system. Examination of the skin and description of lesions is covered in depth and a discussion of specific diseases follows. Clinicians should pay close attention to patterns of lesions present with different types of disease so that a list of differential diagnoses can be formulated from specific dermatologic lesions.

Systemic Spironucleosis in 2 Immunodeficient Rhesus Macaques (Macaca mulatta)

Spironucleus spp are parasites of fish and terrestrial vertebrates, including mice and turkeys, that rarely cause extraintestinal disease. Two rhesus macaques (Macaca mulatta) were experimentally inoculated with simian immunodeficiency virus mac251. Both progressed to simian acquired immune deficiency syndrome within 1 year of inoculation and developed systemic protozoal infections in addition to common opportunistic infections, including rhesus cytomegalovirus, rhesus lymphocryptovirus, and rhesus adenovirus. In the first case, the protozoa were associated with colitis, multifocal abdominal abscessation, and lymphadenitis. In the second case, they were one of a number of organisms associated with extensive pyogranulomatous pneumonia and colitis. Ultrastructural, molecular, and phylogenetic analysis revealed the causative organism to be a species of Spironucleus closely related to Spironucleus meleagridis of turkeys. This report is the first of extraintestinal infection with Spironucleus sp in higher mammals and expands the list of opportunistic infections found in immunocompromised rhesus macaques.

Preventative Medicine in Nonhuman Primates

Establishing a thorough preventive medicine program is crucial to protecting and maintaining the health of captive nonhuman primate colonies. A variety of components contribute to an adequate preventive medicine program and their implementation should be based on a careful risk assessment. These components are discussed in and include an occupational health and safety program to protect and monitor personnel, a comprehensive quarantine program to limit the introduction of new pathogens to an established colony, good animal husbandry to maintain the health and well-being of colony animals, thorough disease surveillance to monitor for unexpected outbreaks of disease, and an animal vaccination program.

Immune‐mediated interface dermatitis in a rhesus macaque

Autoimmune dermatitis, specifically interface dermatitis, is rarely reported in nonhuman primates.

Hypergammaglobulinemia in an SIV-Infected Rhesus Macaque with a B cell neoplasm with plasma cell differentiation

An SIV‐infected rhesus macaque presented with anemia, hypercalcemia, and hyperglobulinemia. Neoplastic round cells with plasma cell morphology infiltrated multiple organs and stained immunohistochemically positive for CD45, MUM1/IRF4, CD138, VS38C, and Kappa light chain and variably positive for CD20 and CD79a, consistent with a B‐cell neoplasm with plasma cell differentiation.