Kim, Sungjin



Assistant Professor

B.S./ M.S., Seoul National University (South Korea)

Ph.D., Mt. Sinai Medical Center, City University of New York

Postdoctoral Fellow / Instructor, Washington University

Address:
Department of Microbiology and Molecular Genetics
5198 Biomedical Physical Sciences
Michigan State University
East Lansing, MI 48824
 Phone: (517) 884-5367
 kimsj@msu.edu
 

Research

Research in this lab is focused on natural killer (NK) cells, the third major population of lymphocytes that are important for host defense against virus infections and malignancy. Currently, we are interested in understanding how NK cells mount effective immune responses against viral infections (e.g., herpesviruses, influenza and HIV-1).

We have recently discovered a novel subset of human NK cells that displays very potent anti-viral responses. This novel subset is characterized by a deficiency in the expression of signaling adaptor FcRg, which is associated with the IgG Fc receptor (CD16) in conventional NK cells (cartoon below). These FcRg-deficient NK cells, termed ‘g-NK cells’, express another CD16-associated adaptor CD3z. Importantly, we have found that g-NK cells exhibit greatly enhanced functional and proliferative responses toward target cells infected with a variety of viruses in the presence of virus-specific antibodies (Ab).


Intriguingly, g-NK cells have been found in approximately 40% of healthy donors, and the presence of g-NK cells is associated with prior infection with cytomegalovirus (CMV), a common herpesvirus that infects billions of people worldwide. Our research aims to understand 1) how g-NK cells function better than conventional NK cells, 2) how g-NK cells are generated and maintained, and 3) what role g-NK cells play in immune responses to viral infections.

We are also pursuing a better understanding of NK cell anti-viral responses using an infection model in mice. In particular, we are working to identify molecular and biochemical mechanisms by which NK cells are activated in response to influenza infection.