Cross-reactivity of anti-human chemokine receptor and anti-TNF family antibodies with common marmoset (Callithrix jacchus) leukocytes

Marmosets as models of infectious diseases

Animal models of infectious disease often serve a crucial purpose in obtaining licensure of therapeutics and medical countermeasures, particularly in situations where human trials are not feasible, i.e., for those diseases that occur infrequently in the human population. The common marmoset (Callithrix jacchus), a Neotropical new-world (platyrrhines) non-human primate, has gained increasing attention as an animal model for a number of diseases given its small size, availability and evolutionary proximity to humans. This review aims to (i) discuss the pros and cons of the common marmoset as an animal model by providing a brief snapshot of how marmosets are currently utilized in biomedical research, (ii) summarize and evaluate relevant aspects of the marmoset immune system to the study of infectious diseases, (iii) provide a historical backdrop, outlining the significance of infectious diseases and the importance of developing reliable animal models to test novel therapeutics, and (iv) provide a summary of infectious diseases for which a marmoset model exists, followed by an in-depth discussion of the marmoset models of two studied bacterial infectious diseases (tularemia and melioidosis) and one viral infectious disease (viral hepatitis C).

Immunohematological features of free-living Alouatta belzebul (Linnaeus, 1766) red-handed howler monkeys in the Eastern Amazon

The red-handed howler monkey (Alouatta belzebul) is one of the 35 threatened Brazilian primate species found in two highly endangered Brazilian biomes. Their Amazonian native populations have been declining due to exponential deforestation associated with human activities, especially the construction of dams. The studied population (n = 27) was located in the Belo Monte dam Area of Influence. For the first time, we presented hematological parameters and the basic profile of T (CD3) and B (BSAP PAX5) cells by immunocytochemistry. The results supported the hypothesis that the immuno-hematological profile is influenced by sex, age, and season. Eosinophils were significantly higher in females (p = 0.03), monocytes statistically greater in juveniles (p = 0.04), and total plasma protein increased significantly (p > 0.001) during the dry season. Furthermore, adults showed a statistically higher average absolute number of B lymphocytes than young individuals (p = 0.03), in contrast to T lymphocytes. Even without knowing the full history of antigenic exposure, these results not only contribute to elucidating the boundaries between health and disease but may help lay the groundwork for future research into the effects of anthropogenic stress on immune activation.

The Common Marmoset-Biomedical Research Animal Model Applications and Common Spontaneous Diseases

Marmosets are becoming more utilized in biomedical research due to multiple advantages including (1) a nonhuman primate of a smaller size with less cost for housing, (2) physiologic similarities to humans, (3) translatable hepatic metabolism, (4) higher numbers of litters per year, (5) genome is sequenced, molecular reagents are available, (6) immunologically similar to humans, (7) transgenic marmosets with germline transmission have been produced, and (8) are naturally occurring hematopoietic chimeras. With more use of marmosets, disease surveillance over a wide range of ages of marmosets has been performed. This has led to a better understanding of the disease management of spontaneous diseases that can occur in colonies. Knowledge of clinical signs and histologic lesions can assist in maximizing the colony's health, allowing for improved outcomes in translational studies within biomedical research. Here, we describe some basic husbandry, biology, common spontaneous diseases, and animal model applications for the common marmoset in biomedical research.

Hepatic Differentiation of Marmoset Embryonic Stem Cells and Functional Characterization of ESC-Derived Hepatocyte-Like Cells

Background

Primary human hepatocytes (PHHs) are the ideal candidates for studying critical liver functions such as drug metabolism and toxicity. However, as they are isolated from discarded livers that are unsuitable for transplantation, they possess limited expansion ability in vitro and their enzymatic functions deteriorate rapidly because they are often of poor quality. Therefore, there is a compelling reason to find reliable alternative sources of hepatocytes.

Methods

In this study, we report on efficient and robust differentiation of embryonic stem cells (ESC) from the common marmoset Callithrix jacchus into functional hepatocyte-like cells (HLC) using a simple, and reproducible three-step procedure. ESC-derived HLCs were examined by morphological analysis and tested for their expression of hepatocyte-specific markers using a combination of immunohistochemistry, RT-PCR, and biochemical assays. Primary human hepatocytes were used as controls.

Results

ESC-derived HLCs expressed each of the hepatocyte-specific markers tested, including albumin; α-fetoprotein; asialoglycoprotein receptor 1; α-1 antitrypsin; hepatocyte nuclear factors 1α and 4; cytokeratin 18; hepatocyte growth factor receptor; transferrin; tyrosine aminotransferase; alkaline phosphatase; c-reactive protein; cytochrome P450 enzymes CYP1A2, CYP2E1 and CYP3A4; and coagulation factors FVII and FIX. They were functionally competent as demonstrated by biochemical assays in addition to producing urea.

Conclusion

Our data strongly suggest that marmoset HLCs possess characteristics similar to those of PHHs. They could, therefore, be invaluable for studies on drug metabolism and cell transplantation therapy for a variety of liver disorders. Because of the similarities in the anatomical and physiological features of the common marmoset to that of humans, Callithrix jacchus is an appropriate animal model to study human disease conditions and cellular functions.

Detection of Signal Regulatory Protein α in Saimiri sciureus (Squirrel Monkey) by Anti-Human Monoclonal Antibody

Non-human primates (NHP) are suitable models for studying different aspects of the human system, including pathogenesis and protective immunity to many diseases. However, the lack of specific immunological reagents for neo-tropical monkeys, such as Saimiri sciureus, is still a major factor limiting studies in these models. An alternative strategy to circumvent this obstacle has been the selection of immunological reagents directed to humans, which present cross-reactivity with NHP molecules. In this context and considering the key role of inhibitory immunoreceptors—such as the signal regulatory protein α (SIRPα)—in the regulation of immune responses, in the present study, we attempted to evaluate the ability of anti-human SIRPα monoclonal antibodies to recognize SIRPα in antigen-presenting S. sciureus peripheral blood mononuclear cells (PBMC). As shown by flow cytometry analysis, the profile of anti-SIRPα staining as well as the levels of SIRPα-positive cells in PBMC from S. sciureus were similar to those observed in human PBMC. Furthermore, using anti-SIRPα monoclonal antibody, it was possible to detect a decrease of the SIRPα levels on surface of S. sciureus cells after in vitro stimulation with lipopolysaccharides. Finally, using computed-based analysis, we observed a high degree of conservation of SIRPα across six species of primates and the presence of shared epitopes in the extracellular domain between humans and Saimiri genus that could be targeted by antibodies. In conclusion, we have identified a commercially available anti-human monoclonal antibody that is able to detect SIRPα of S. sciureus monkeys and that, therefore, can facilitate the study of the immunomodulatory role of SIRPα when S. sciureus is used as a model.

Comprehensive panel of cross-reacting monoclonal antibodies for analysis of different immune cells and their distribution in the common marmoset (Callithrix jacchus)

BACKGROUND

Common marmosets are extensively used in immunological and pharmacological research, and the usage of methods such as flow cytometry gain increasing importance.

METHODS

Using multicolor flow cytometry cross-reactivity of monoclonal antibodies with cells of common marmosets was analyzed. Furthermore, frequencies of immune cells and immunological parameters were assessed in healthy common marmosets.

RESULTS

A total of 97 clones of monoclonal antibodies raised against CD markers, chemokine receptors, and miscellaneous markers were tested. Additionally, baseline frequencies of different innate and adaptive immune cells as well as certain parameters, such as activation and memory T-cell and B-cell distribution, are provided.

CONCLUSION

Our study gives an extended overview of cross-reactive antibodies for flow cytometric analysis of immune cells as well as baseline values for different immune parameters in healthy common marmosets.

Exploring the innate immunological response of an alternative nonhuman primate model of infectious disease; the common marmoset

The common marmoset (Callithrix jacchus) is increasingly being utilised as a nonhuman primate model for human disease, ranging from autoimmune to infectious disease. In order to fully exploit these models, meaningful comparison to the human host response is necessary. Commercially available reagents, primarily targeted to human cells, were utilised to assess the phenotype and activation status of key immune cell types and cytokines in naive and infected animals. Single cell suspensions of blood, spleen, and lung were examined. Generally, the phenotype of cells was comparable between humans and marmosets, with approximately 63% of all lymphocytes in the blood of marmosets being T cells, 25% B-cells, and 12% NK cells. The percentage of neutrophils in marmoset blood were more similar to human values than mouse values. Comparison of the activation status of cells following experimental systemic or inhalational infection exhibited different trends in different tissues, most obvious in cell types active in the innate immune response. This work significantly enhances the ability to understand the immune response in these animals and fortifies their use as models of infectious disease.

A novel nonhuman primate model for influenza transmission

Studies of influenza transmission are necessary to predict the pandemic potential of emerging influenza viruses. Currently, both ferrets and guinea pigs are used in such studies, but these species are distantly related to humans. Nonhuman primates (NHP) share a close phylogenetic relationship with humans and may provide an enhanced means to model the virological and immunological events in influenza virus transmission. Here, for the first time, it was demonstrated that a human influenza virus isolate can productively infect and be transmitted between common marmosets (Callithrix jacchus), a New World monkey species. We inoculated four marmosets with the 2009 pandemic virus A/California/07/2009 (H1N1pdm) and housed each together with a naïve cage mate. We collected bronchoalveolar lavage and nasal wash samples from all animals at regular intervals for three weeks post-inoculation to track virus replication and sequence evolution. The unadapted 2009 H1N1pdm virus replicated to high titers in all four index animals by 1 day post-infection. Infected animals seroconverted and presented human-like symptoms including sneezing, nasal discharge, labored breathing, and lung damage. Transmission occurred in one cohabitating pair. Deep sequencing detected relatively few genetic changes in H1N1pdm viruses replicating in any infected animal. Together our data suggest that human H1N1pdm viruses require little adaptation to replicate and cause disease in marmosets, and that these viruses can be transmitted between animals. Marmosets may therefore be a viable model for studying influenza virus transmission.

Overview of the marmoset as a model in nonclinical development of pharmaceutical products

Callithrix jacchus (common marmoset) is one of the more primitive non-human primate species and is used widely in fundamental biology, pharmacology and toxicology studies. Marmosets breed well in captivity with good reproductive efficiencies and their sexual maturity is reached within 18 months of age allowing for rapid expansion of colonies and early availability of sexually mature animals permitting an earlier assessment of product candidates in the adult. Their relatively small size allows a reduction in material requirements leading to a reduction in development time and cost. Fewer animals are also required due to their ability to be used in both pharmacology and toxicology (nonclinical) studies. These factors, alongside a better understanding of their optimal nutrient and welfare requirements over recent years, facilitate the generation of a more cohesive and robust dataset. With the growth of biotechnology-derived pharmaceuticals, non-human primate use has, by necessity, also increased; nevertheless, there is also a growing public call for minimizing their use. Utilizing, the more primitive marmoset species may provide the optimal compromise and once the scientific rationale has been carefully considered and their use justified, there are several advantages to using the marmoset as a model in nonclinical development of pharmaceutical products.

Propagation and characterisation of dendritic cells from G-CSF mobilised peripheral blood monocytes and stem cells in common marmoset monkeys

The common marmoset is a small New World Primate that has been used as an immunological model for a number of human diseases. Dendritic cells (DC) have not been extensively characterised in this species and in particular protocols to derive DC from living donors without the need for animal sacrifice are presently lacking. This study establishes new protocols to generate substantial numbers of marmoset DC for use in cell therapy studies. Recombinant human G-CSF was used to mobilise peripheral blood monocytes and CD34(+) stem cells in sufficient numbers for large scale in-vitro DC propagation using cytokine conditioning including IL-4, GM-CSF, FLT3-L, stem cell factor and thrombopoietin. Marmoset DC exhibited morphology similar to human DC, were capable of antigen uptake and presentation and had moderate allo-stimulatory ability. Monocyte-derived DC had a maturation-resistant immature phenotype, whereas haematopoietic precursor-derived DC were semi-mature in phenotype and function. This study confirms the feasibility of the marmoset as a unique small primate model in which to pursue DC-based immunotherapy strategies.

The common marmoset as a novel preclinical transplant model: identification of new MHC class II DRB alleles and prediction ofin vitroalloreactivity

The difficulties with using nonhuman primate species such as rhesus macaques and baboons have led us to investigate the common marmoset (Callithrix jacchus) as an alternative preclinical model for transplantation research. This requires reliable methods of detecting alloreactivity between donor and recipient pairs, particularly if colonies are inbred and share just a few common alleles for leucocyte antigens. We firstly identified marmoset major histocompatibility complex (MHC) Class II DRB genes (Caja-DRB*W1201, Caja-DRB1*03, Caja-DRB*W16) using sequence-based typing techniques. Genomic DNA (n= 49) was extracted from whole blood or spleen tissue. Exon 2 of target genes was amplified by PCR using primers specific for known marmoset alleles, and then sequenced using ABI PRISM((R)) Big Dye Terminator technology and Assign sequence analysis software. DRB*W1201 was universally present. Eight DRB*W16 alleles and five DRB1*03 alleles were identified in this colony. We also identified two previously unreported DRB*W16 alleles, and confirmed inheritance of these alleles within several sibling groups. Subsequently, we investigated whether matching at MHC Class II DRB loci alone could predict alloreactivity, as assessed in vitro by two-way mixed lymphocyte reactions (MLRs). Fully DRB-matched, partially mismatched and fully mismatched animal pairs were prospectively chosen. MLR was performed using mononuclear cells (MNC) isolated from whole blood by density gradient separation. T-cell proliferation after 5-day culture was measured by (3)H-thymidine incorporation. Combined MNC from fully mismatched and partially mismatched animal pairs exhibited significant in vitro T-cell proliferation above single cell controls (P < 0.01). MNC from fully DRB-matched (but unrelated) animal pairs exhibited no proliferation compared with controls (P= 0.3). Using DRB genotyping, suitably alloreactive donor-recipient pairs may therefore be rapidly and accurately identified for use in further studies of cellular and solid organ transplantation.

MHC Class II DRB genotyping is highly predictive of in-vitro alloreactivity in the common marmoset

The common marmoset (Callithrix jacchus) is emerging as a promising alternative pre-clinical model for transplantation and immunological research. It is therefore important to establish a rapid and reliable method of confirming alloreactivity between donor-recipient pairs. In this study of a large marmoset colony (n=49), we firstly characterised MHC Class II genes (Caja-DRB*W1201, Caja-DRB1*03, Caja-DRB*W16) using, for the first time in this species, sequence-based allelic typing techniques. Exon 2 was amplified using M13-tailed PCR primers specific for known marmoset alleles, and sequenced using universal M13 sequencing primers and dye terminator cycle sequencing. Twenty-six genotypes involving monomorphic Caja-DRB*W1201, 8 Caja-DRB*W16 and 5 Caja-DRB1*03 alleles were observed. Two new DRB*W16 alleles were identified. Subsequently we investigated whether matching at MHC-DRB loci alone could accurately predict in-vitro alloreactivity as assessed by mixed lymphocyte reactions. Peripheral blood mononuclear cells (PBMC) isolated from fully and partially DRB-matched and fully mismatched animal pairs were mixed and co-cultured for T-cell proliferation. PBMC co-cultured from fully or partially mismatched pairs exhibited significant T cell proliferation above single cell controls (p<0.01). Mixed PBMC from fully DRB-matched pairs exhibited no proliferation over controls (p=0.3). Thus using Caja-DRB genotyping, suitably alloreactive donor-recipient pairs can be rapidly and accurately identified for use in further studies of cellular and solid organ transplantation.