Dr. Metcalf Pate’s research focuses on the role of platelets in the innate immune response to viral infection, and how modulating the response of platelets to infection alters the course of disease. Platelets are tiny anuclear cells that outnumber leukocytes in the peripheral blood more than one hundred to one. Platelets are known to participate in innate immunity through cytokine signaling and direct interactions with other cells, and the platelet has the potential to significantly influence disease outcomes. However, platelet immunology is still a relatively new discipline, and the downstream effects of platelet interactions with other immune cells have yet to be determined in the context of viral infection.
The well-characterized and consistent SIV-infected pigtailed macaque model of HIV infection provides an ideal animal model in which to explore the consequences of platelet-leukocyte aggregates during acute infection. Dr. Metcalf Pate has demonstrated that 80% of CD16+ monocytes are bound to platelets during acute SIV infection, while only 6% of this population are bound in mock-inoculated controls. CD16+ monocytes are known to play important roles in the pathogenesis of SIV infection as they are infected more frequently than CD16- monocytes and transmigrate through endothelium early in infection to establish inflammatory foci in organs such as the brain and lungs. Current research aims include further characterization of the platelet-monocyte interaction during acute viral infection with the goal of establishing methods of pharmacologically manipulating this association, and establishing how platelet binding to a monocyte influences the monocyte’s susceptibility to lentiviral infection and the monocyte’s interactions with endothelium.
Dr. Metcalf Pate is additionally interested in the effect of physiologic stress on platelet function, specifically on the platelet’s future immune response to infection, and in the development and optimization of novel in vitro systems that better model in vivo conditions. She welcomes collaborative inquiries from local undergraduates, veterinary students, and researchers with complementary interests.
Current Funded Projects
- "Detecting latent viral reservoirs in blood and organs with the murine viral outgrowth assay", Johns Hopkins University Catalyst Grant
- “The Role of Platelet-Monocyte Interactions in SIV Infection”, NIH OD K01 OD018244, in collaboration with Dr. Chris Zink, Dr. Janice Clements, Dr. Lucio Gama and Dr. Wilbur Lam
- Alyssa Chalmin, Undergraduate Researcher, Johns Hopkins University
- Shefali Vijay, Undergraduate Researcher, former Summer High School Researcher 2016, Johns Hopkins University
- Alicia Braxton, DVM, Veterinarian Postdoctoral Fellow, Molecular and Comparative Patholobiology Research Training Program
- Casey Kissel, DVM, Veterinarian Postdoctoral Fellow, Molecular and Comparative Patholobiology Laboratory Animal Medicine Training Program
Current Research Staff
- Selena Guerrero-Martin, Research Technologist
Former Postdoctoral Students
- Meghan Vermillion, DVM, DACLAM, Veterinarian Postdoctoral Fellow 2013 - 2017, Johns Hopkins University School of Medicine Molecular and Comparative Patholobiology Research Training Program, currently a graduate student in the Cellular and Molecular Medicine Graduate Program
- Jessica Izzi, DVM, MS, DACLAM, Veterinarian Postdoctoral Fellow 2013 - 2015, Molecular and Comparative Patholobiology Laboratory Animal Medicine Training Program, currently a veterinarian at the NIH
- Zachary Freeman, DVM, PhD, DACLAM, Veterinarian Postdoctoral Fellow 2011 - 2015, Molecular and Comparative Patholobiology Research Training Program, currently an Assistant Professor at University of Michigan School of Medicine
- Victoria Baxter, DVM, PhD, DACLAM, eterinarian Postdoctoral Fellow 2010 - 2013, Molecular and Comparative Patholobiology Research Training Program, currently an Assistant Professor at University of North Carolina Chapel Hill
Former Predoctoral Students and Staff
- Wilfred Ikejiofor, Summer Undergraduate Researcher 2017, University of Maryland
- Paul Moon, Summer High School Researcher 2017, Center for Talented Youth
- Karl Johnson, Undergraduate Researcher 2015 - 2017, Johns Hopkins University
- Liz Engle, Master's Thesis Student 2015 - 2016, Johns Hopkins University Biotechnology Masters Program, currently a Lab Manager at Johns Hopkins School of Medicine Tumor Microenvironment Core
- Kevin Najarro, Research Technologist 2014 - 2016, currently a Lab Manager at University of Colorado
- Benjamin Aledejebi, Summer High School Researcher 2015, Center for Talented Youth, currently an undergraduate at Bucknell University
- Jacqueline Brockhurst, Summer Merial Veterinary Research Scholar 2015, currently a veterinary student at University of Pennsylvania School of Veterinary Medicine
- Hayley Weidenbenner, Undergraduate Researcher, Johns Hopkins University School of Medicine
- Claire Lyons, Undergraduate Researcher 2012 – 2013, Research Technologist 2013 - 2014, currently a veterinary student at Tufts University Cummings School of Veterinary Medicine.
- Catherine Cryer, Summer Veterinary Student Researcher 2014, University of Pennsylvania School of Veterinary Medicine, currently a veterinarian.
- Hannah Schneider, Summer Undergraduate Researcher 2013, currently an undergraduate at Colorado State University
View all on Pubmed
Metcalf Pate KA, Lyons CE, Dorsey JL, Shirk EN, Queen SE, Adams RJ, Gama L, Morrell CN, Mankowski JL. Platelet activation and platelet-monocyte aggregate formation contribute to platelet decline during acute SIV infection in pigtailed macaques. J Infect Dis. 2013; 208(6):874-883. PMCID 23852120
Baxter VK, Shaw GC, Sotuyo NP, Carlson CS, Olson EJ, Zink MC, Mankowski JL, Adams RJ, Hutchinson EK, Metcalf Pate KA. Serum Albumin and Body Weight as Biomarkers for the Antemortem Identification of Bone and Gastrointestinal Disease in the Common Marmoset. PLoS One. 2013; 8(12): e82747. PMCID 24324827
Metcalf Pate KA, Lyons CE, Dorsey JL, Queen SE, Adams RJ, Morrell CN, Mankowski JL. Thrombopoietin downregulation and elevated plasma TGFβ are associated with platelet decline in asymptomatic SIV infection. JAIDS. 2014; 65(5): 510-6. PMCID 24220290
Metcalf Pate KA, Pohlmeyer CW, Walker-Sperling VE, Foote JB, Najarro KM, Cryer CG, Salgado M, Engle EL, Shirk EN, Queen SE, Chioma S, Vermillion ME, Bullock B, Li M, Lyons CE, Adams RJ, Gama L, Zink MC, Clements JE, Mankowski JL, Blankson JN. A murine viral outgrowth assay to detect residual HIV-1 infection. J Infect Dis. 2015; 212(9): 1387-96. PMCID: 25883388
Vermillion MS, Lyons CE, Najarro KM, Adams RJ, Metcalf Pate KA. Platelets are immune activated in response to serial phlebotomy in pigtailed macaques (Macaca nemestrina). Comp Med. 2017; 67(4): 360-367