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University of Maryland School of Medicine Division of Infectious Diseases

 
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Nicholas Milton Stamatos, MD
Assistant Professor of Medicine

PhD: University of Rochester, 1987
MD: George Washington University, 1991

Phone: 410-706-2645
Fax: 410-706-4619
E-mail: stamatos@umbi.umd.edu
Address:
Institute of Human Virology   N558
University of Maryland
725 West Lombard St.
Baltimore, MD  21201

RESEARCH INTERESTS

Role of cellular and viral surface glycoconjugates and of cellular sialidase(s) in the pathogenesis of HIV-1.

The biological activity of glycoproteins distributed throughout nature is influenced by modulation of their sialic acid content.  Neuraminidase (referred to as sialidase in mammalian cells) removes terminal sialyl residues from glycoconjugates and is one of several carbohydrate-modifying enzymes which alter the sialic acid composition of glycoproteins. Growth of HIV-1 is enhanced in vitro in lectin-activated peripheral blood mononuclear cells (PBMCs), which express increased sialidase activity and display cell surface glycoproteins with modified sialylation patterns.  We have shown that the infectivity of HIV-1 in PBMCs in the absence of lectin stimulation is also promoted in vitro by desialylation of glycoconjugates on the cellular and viral surfaces using exogenous bacterial neuraminidase (NANase).  HIV-1 does not encode a NANase, as do some other viruses whose life-cycle depends on the action of NANase.  Therefore, if removal of sialic acid from glycomoieties on the surface of either the host cell or virus is necessary for infection by HIV-1, the host cell sialidase(s) may have a vital role in viral pathogenesis.  The objective of my research is (i) to refine and extend an understanding of the association between desialylation of specific cellular and/or viral glycoproteins and infection of PBMCs by HIV-1 and (ii) to determine the mechanism(s) by which desialylation of cellular and viral glycoproteins leads to enhanced infection.

RECENT PUBLICATIONS

Stamatos, N. M., P. J. Gomatos, J. Cox, A. Fowler, N. Dow, J. A. Wohlhieter, and A. S. Cross. Desialylation of peripheral blood mononuclear cells promotes growth of HIV-1. Virology 228: 123-131, 1997.

Stamatos, N. M., Mascola, J., Kalyanaraman, V., Louder, M., Birx, D. and T. VanCott.  1998.  Neutralizing antibodies from the sera of human immunodeficiency virus type 1-infected individuals bind to monomeric gp120 and oligomeric gp140.  J. Virol. 72: 9656-9667

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To contact us:

Phone: 410-706-7560
Fax: 410-706-4619
E-mail: kvardjan@ihv.umaryland.edu

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